In Search of Traditional Asian Diets

It's been difficult for me to find good information on Asian diets prior to modernization. Traditional Chinese, Taiwanese and Japanese diets are sometimes portrayed as consisting mostly of white rice, with vegetables and a bit of meat and soy, but I find that implausible. Rice doesn't grow everywhere, and removing all the bran was prohibitively labor-intensive before the introduction of modern machine milling. One hundred years ago, bran was partially removed by beating or grinding in a mortar and pestle, as it still is in parts of rural Asia today. Only the wealthy could afford true white rice.

Given the difficulty of growing rice in most places, and hand milling it, the modern widespread consumption of white rice in Asia must be a 20th century phenomenon, originating in the last 20-100 years depending on location. Therefore, white rice consumption does not predate the emergence of the "diseases of civilization" in Asia.

In the book Western Diseases: Their Emergence and Prevention, there are several accounts of traditional Asian diets I find interesting.

Taiwan in 1980

The staple constituent of the diet is polished white rice. Formerly in the poorer areas along the sea coast the staple diet was sweet potato, with small amounts of white rice added. Formerly in the mountains sweet potato, millet and taro were the staple foods. During the last 15 years, with the general economic development of the whole island, white polished rice has largely replaced other foods. There is almost universal disinclination to eat brown (unpolished) rice, because white rice is more palatable, it bears kudos, cooking is easier and quicker, and it can be stored for a much longer period.

Traditionally, coronary heart disease and high blood pressure were rare, but the prevalence is now increasing rapidly. Stroke is common. Diabetes was rare but is increasing gradually.

Mainland China

China is a diverse country, and the food culture varies by region.

Snapper (1965)… quoted an analysis by Guy and Yeh of Peiping (Peking) diets in 1938. There was a whole cereal/legume/vegetable diet for poorer people and a milled-cereal/meat/vegetable diet for the richer people.

Symptoms of vitamin A, C and D deficiency were common in the poor, although coronary heart disease and high blood pressure were rare. Diabetes occurred at a higher rate than in most traditionally-living populations.

Japan

On the Japanese island of Okinawa, the traditional staple is the sweet potato, with a smaller amount of rice eaten as well. Seafood, vegetables, pork and soy are also on the menu. In Akira Kurosawa’s movie Seven Samurai, set in 16th century mainland Japan, peasants ate home-processed millet and barley, while the wealthy ate white rice. Although a movie may not be the best source of information, I suspect it has some historical basis.

White Rice: a Traditional Asian Staple?

It depends on your perspective. How far back do you have to go before you can call a food traditional? Many peoples' grandparents ate white rice, but I doubt their great great grandparents ate it frequently. White rice may have been a staple for the wealthy for hundreds of years in some places. But for most of Asia, in the last few thousand years, it was probably a rare treat. The diet most likely resembled that of many non-industrial African cultures: an assortment of traditionally prepared grains, root vegetables, legumes, vegetables and a little meat.

Please add any additional information you may have about traditional Asian diets to the comments section.

Fermented Grain Recipes from Around the World

In my last two posts on grains, I described how traditional food processing methods make grains more nutritious and digestible (1, 2). I promised to briefly describe a few recipes from around the world, then got distracted by other things. Here they are.

Africa: Ogi

Grain fermentation is widespread in Africa and is probably nearly as old as agriculture on the continent. The nutritional importance of fermentation is suggested by the amount of time and effort that many African cultures put into it, when they could save themselves a lot of trouble by simply soaking and cooking their grains.

Ogi is a common West African porridge that's eaten as a staple food by people of all ages. It's even used as a weaning food. It's made in essentially the same manner from corn, sorghum or millet.

Whole grain is soaked in water for one to three days. It's then wet milled, mixed with water and sieved to remove a portion of the bran. Extra bran is fed to animals, while the white, starchy sediment is fermented for two to three days. This is then cooked into a thin or thick porridge and eaten.

South America: Pozol

At first glance, some people may think I left the 'e' off the word 'pozole', a traditional Mexican stew. However, pozol is an entirely different beast, an ancient food almost totally unknown in the US, but which fueled the Mayan empire and remains a staple food in Southeastern Mexico.

To make pozol, first the corn must be 'nixtamalized': whole kernels are boiled in a large volume of water with calcium hydroxide (10% w/v). This is a processing step in most traditional South American corn recipes, as it allows a person to avoid pellagra (niacin deficiency)! The loosened bran is removed from the kernels by hand.

The kernels are then ground into dough, formed into balls and placed into banana leaves to ferment for one to 14 days. Following fermentation, pozol is diluted in water and consumed raw.

Europe: Sourdough Bread

Sourdough bread is Europe's quintessential fermented grain food. Before purified yeast strains came into widespread use in the 20th century, all bread would have been some form of sourdough.

Although in my opinion wheat is problematic for many people, sourdough fermentation renders it more nutritious and better tolerated by those with gluten/wheat sensitivity. In an interesting series of studies, Dr. Marco Gobbetti's group, among others, has shown that fermentation partially degrades gluten, explaining the ability of fermentation to decrease the adverse effects of gluten in those who are sensitive to it (3). They even showed that people with celiac disease can safely eat wheat bread that has been long-fermented with selected bacteria and yeasts under laboratory conditions (4). Rye contains about half the gluten of bread wheat, and is generally nutritionally superior to wheat, so sourdough rye is a better choice in my opinion.

To make sourdough bread, first the dry grains are ground into flour. Next, the flour is sifted through a screen to remove a portion of the bran. The earliest bread eaters probably didn't do this, although there is evidence of the wealthy eating sifted flour in societies as old as ancient Egypt and ancient Rome. I don't know what the optimum amount of bran to include in flour is, but it's not zero. I would be inclined to keep at least half of it, recognizing that the bran is disproportionately rich in nutrients.

Next, a portion of flour is mixed with water and a "sourdough starter", until it has a runny consistency. The starter is a diverse culture of bacteria and yeast that is carefully maintained by the bread maker. This culture acidifies the batter and produces carbon dioxide gas. The mixture is allowed to ferment for 8-12 hours. Finally, flour and salt are added to the batter and formed into dough balls. These are allowed to ferment and rise for a few hours, then baked.

My Experience

I've tried making ogi (millet) and pozol, and I have to admit that neither attempt was successful. Pozol in particular may depend on local populations of bacteria and yeast, as the grains' microorganisms are killed during processing. However, I do eat fermented grains regularly in the form of homemade brown rice 'uthappam' and sourdough buckwheat 'crepes'. The buckwheat crepes are tasty and easy to make. I'll post a recipe at some point.

The first two recipes are from the FAO publication Fermented Cereals: a Global Perspective (5).

Sweet Potatoes

We can debate the nutritional qualities of a food until we're blue in the face, but in the end, we still may not have a very accurate prediction of the health effects of that food. The question we need to answer is this one: has this food sustained healthy traditional cultures?

I'm currently reading a great book edited by Drs. Hugh Trowell and Denis Burkitt, titled Western Diseases: Their Emergence and Prevention. It's a compilation of chapters describing the diet and health of traditional populations around the world as they modernize.

The book contains a chapter on Papua New Guinea highlanders. Here's a description of their diet:

A diet survey was undertaken involving 90 subjects, in which all food consumed by each individual was weighed over a period of seven consecutive days. Sweet potato supplied over 90 percent of their total food intake, while non-tuberous vegetables accounted for less than 5 percent of the food consumed and the intake of meat was negligible... Extensive herds of pigs are maintained and, during exchange ceremonies, large amounts of pork are consumed.

They ate no salt. Their calories were almost entirely supplied by sweet potatoes, with occasional feasts on pork.

How was their health? Like many non-industrial societies, they had a high infant/child mortality rate, such that 43 percent of children died before growing old enough to marry. Surprisingly, protein deficiency was rare. No obvious malnutrition was observed in this population, although iodine-deficiency cretinism occurs in some highlands populations:

Young adults were well built and physically fit and had normal levels of haemoglobin and serum albumin. Further, adult females showed no evidence of malnutrition in spite of the demands by repeated cycles of pregnancy and lactation. On the basis of American standards (Society of Actuaries, 1959), both sexes were close to 100 percent standard weight in their twenties.

The Harvard Pack Test carried out on 152 consecutive subjects demonstrated a high level of physical fitness which was maintained well into middle-age. Use of a bicycle ergometer gave an estimated maximum oxygen uptake of 45.2 ml per kilogram per minute and thus confirmed the high level of cardiopulmonary fitness in this group.

Body weight decreased with age, which is typical of many non-industrial cultures and reflects declining muscle mass but continued leanness.

There was no evidence of coronary heart disease or diabetes. Average blood pressure was on the high side, but did not increase with age. Investigators administered 100 gram glucose tolerance tests and only 3.8 percent of the population had glucose readings above 160 mg/dL, compared to 21 percent of Americans. A study of 7,512 Papuans from several regions with minimal European contact indicated a diabetes prevalence of 0.1 percent, a strikingly low rate. For comparison, in 2007, 10.7 percent of American adults had diabetes (1).

I'm not claiming it's optimal to eat nothing but sweet potatoes. But this is the strongest evidence we're going to come by that sweet potatoes can be eaten in quantity as part of a healthy diet. However, I wish I knew more about the varieties this group ate. Sweet potatoes aren't necessarily sweet. Caribbean 'boniato' sweet potatoes are dry, starchy and off-white. In the US, I prefer the yellow sweet potatoes to the orange variety of sweet potato labeled 'yams', because the former are starchier and less sweet. If I could get my hands on locally grown boniatos here, I'd eat those, but boniatos are decidedly tropical.

Instead, I eat potatoes, but I'm reluctant to recommend them whole-heartedly because I don't know enough about the traditional cultures that consumed them. I believe there are some low-CHD, low-obesity African populations that eat potatoes as part of a starch-based diet, but I haven't looked into it closely enough to make any broad statements. Potatoes have some nutritional advantages over sweet potatoes (higher protein content, better amino acid profile), but also some disadvantages (lower fiber, lower in most micronutrients, toxic glycoalkaloids).

Traditional Preparation Methods Improve Grains' Nutritive Value

Soaking or Germinating Grains

The most basic method of preparing grains is prolonged soaking in water, followed by cooking. This combination reduces the level of water-soluble and heat-sensitive toxins and anti-nutrients such as tannins, saponins, digestive enzyme inhibitors and lectins, as well as flatulence factors. It also partially degrades phytic acid, which is a potent inhibitor of mineral absorption, an inhibitor of the digestive enzyme trypsin and an enemy of dental health (1). This improves the digestibility and nutritional value of grains as well as legumes.

I prefer to soak all grains and legumes for at least 12 hours in a warm location, preferably 24. This includes foods that most people don't soak, such as lentils. Soaking does not reduce phytic acid at all in grains that have been heat-treated, such as oats and kasha (technically not a grain), because they no longer contain the phytic acid-degrading enzyme phytase. Cooking without soaking first also does not have much effect on phytic acid.

The next level of grain preparation is germination. After soaking, rinse the grains twice per day for an additional day or two. This activates the grains' sprouting program and further increases their digestibility and vitamin content. When combined with cooking, it reduces phytic acid, although modestly. Therefore, most of the minerals in sprouted whole grains will continue to be inaccessible. Many raw sprouted grains and legumes are edible, but I wouldn't use them as a staple food because they retain most of their phytic acid as well as some heat-sensitive anti-nutrients (2).

Grinding and Fermenting Grains

Many cultures around the world have independently discovered fermentation as a way to greatly improve the digestibility and nutritive value of grains (3). Typically, grains are soaked, ground, and allowed to sour ferment for times ranging from 12 hours to several days. In some cases, a portion of the bran is removed before or after grinding.

In addition to the reduction in toxins and anti-nutrients afforded by soaking and cooking, grinding and fermentation goes much further. Grinding greatly increases the surface area of the grains and breaks up their cellular structure, releasing enzymes which are important for the transformation to come. Under the right conditions, which are easy to achieve, lactic acid bacteria rapidly acidify the batter. These bacteria are naturally present on grains, but adding a starter makes the process more efficient and reliable.

Due to some quirk of nature, grain phytase is maximally active at a pH of between 4.5 and 5.5, which is mildly acidic. This is why the Weston Price foundation recommends soaking grains in an acidic medium before cooking. The combination of grinding and sour fermentation causes grains to efficiently degrade their own phytic acid (as long as they haven't been heat treated first), making minerals much more available for absorption (4, 5, 6, 7). This transforms whole grains from a poor source of minerals into a good source.

The degree of phytic acid degradation depends on the starting amount of phytase in the grain. Corn, rice, oats and millet don't contain much phytase activity, so they require either a longer fermentation time, or the addition of high-phytase grains to the batter (8). Whole raw buckwheat, wheat, and particularly rye contain a large amount of phytase (9), although I feel wheat is problematic for other reasons.

As fermentation proceeds, bacteria secrete enzymes that begin digesting the protein, starch and other substances in the batter. Fermentation reduces lectin levels substantially, which are reduced further by cooking (10). Lectins are toxins that can interfere with digestion and may be involved in autoimmune disease, an idea championed by Dr. Loren Cordain. Grain lectins are generally heat-sensitive, but one notable exception is the nasty lectin wheat germ agglutinin (WGA). As its name suggests, WGA is found in wheat germ, and thus is mostly absent in white flour. WGA may have been another reason why DART participants who increased their wheat fiber intake had significantly more heart attacks than those who didn't. I don't know if fermentation degrades WGA.

One of the problems with grains is their poor protein quality. Besides containing a fairly low concentration of protein to begin with, they also don't contain a good balance of essential amino acids. This prevents their efficient use by the body, unless a separate source of certain amino acids is eaten along with them. The main limiting amino acid in grains is lysine. Legumes are rich in lysine, which is why cultures around the world pair them with grains. Bacterial fermentation produces lysine, often increasing its concentration by many fold and making grains nearly a "complete protein", i.e. one that contains the ideal balance of essential amino acids as do animal proteins (11, scroll down to see graph). Not very many plant foods can make that claim. Fermentation also increases the concentration of the amino acid methionine and certain vitamins.

Another problem with grain protein is it's poorly digested relative to animal protein. This means that a portion of it escapes digestion, leading to a lower nutritive value and a higher risk of allergy due to undigested protein hanging around in the digestive tract. Fermentation followed by cooking increases the digestibility of grain protein, bringing it nearly to the same level as meat (12, 13, 14, 15). This may relate to the destruction of protease inhibitors (trypsin inhibitors, phytic acid) and the partial pre-digestion of grain proteins by bacteria.

Once you delve into the research on traditional grain preparation methods, you begin to see why grain-eating cultures throughout the world have favored certain techniques. Proper grain processing transforms them from toxic to nutritious, from health-degrading to health-giving. Modern industrial grain processing has largely eschewed these time-honored techniques, replacing them with low-extraction milling, extrusion and quick-rise yeast strains.

Many people will not be willing to go through the trouble of grinding and fermentation to prepare grains. I can sympathize, although if you have the right tools, once you establish a routine it really isn't that much work. It just requires a bit of organization. In fact, it can even be downright convenient. I often keep a bowl of fermented dosa or buckwheat batter in the fridge, ready to make a tasty "pancake" at a moment's notice. In the next post, I'll describe a few recipes from different parts of the world.

Further reading:

How to Eat Grains
A Few Thoughts on Minerals, Milling, Grains and Tubers
Dietary Fiber and Mineral Availability
A New Way to Soak Brown Rice

Lindeberg on Obesity

I'm currently reading Dr. Staffan Lindeberg's magnum opus Food and Western Disease, recently published in English for the first time. Dr. Lindeberg is one of the world's leading experts on the health and diet of non-industrial cultures, particularly in Papua New Guinea. The book contains 2,034 references. It's also full of quotable statements. Here's what he has to say about obesity:

Middle-age spread is a normal phenomenon - assuming you live in the West. Few people are able to maintain their [youthful] waistline after age 50. The usual explanation - too little exercise and too much food - does not fully take into account the situation among traditional populations. Such people are usually not as physically active as you may think, and they usually eat large quantities of food.

Overweight has been extremely rare among hunter-gatherers and other traditional cultures [18 references]. This simple fact has been quickly apparent to all foreign visitors...

The Kitava study measured height, weight, waist circumference, subcutaneous fat thickness at the back of the upper arm (triceps skinfold) and upper arm circumference on 272 persons ages 4-86 years. Overweight and obesity were absent and average [body mass index] was low across all age groups. ...no one was larger around their waist than around their hips.

...The circumference of the upper arm [mostly indicating muscle mass] was only negligibly smaller on Kitava [compared with Sweden], which indicates that there was no malnutrition. It is obvious from our investigations that lack of food is an unknown concept, and that the surplus of fruits and vegetables regularly rots or is eaten by dogs.

The Population of Kitava occupies a unique position in the world in terms of the negligible effect that the Western lifestyle has had on the island.

The only obese Kitavans Dr. Lindeberg observed were two people who had spent several years off the island living a modern, urban lifestyle, and were back on Kitava for a visit.

I'd recommend this book to anyone who has a scholarly interest in health and nutrition, and somewhat of a background in science and medicine. It's extremely well referenced, which makes it much more valuable.

What's the Ideal Fasting Insulin Level?

[2013 update.  I'm leaving this post up for informational purposes, but I think it's difficult to determine the "ideal" insulin level because it depends on a variety of factors including diet composition.  Also, insulin assays are not always comparable to one another, particularly the older assays, so it's difficult to compare between studies]

Insulin is an important hormone. Its canonical function is to signal cells to absorb glucose from the bloodstream, but it has many other effects. Chronically elevated insulin is a marker of metabolic dysfunction, and typically accompanies high fat mass, poor glucose tolerance (prediabetes) and blood lipid abnormalities. Measuring insulin first thing in the morning, before eating a meal, reflects fasting insulin. High fasting insulin is a marker of metabolic problems and may contribute to some of them as well.

Elevated fasting insulin is a hallmark of the metabolic syndrome, the quintessential modern metabolic disorder that affects 24% of Americans (NHANES III). The average insulin level in the U.S., according to the NHANES III survey, is 8.8 uIU/mL for men and 8.4 for women (2). Given the degree of metabolic dysfunction in this country, I think it's safe to say that the ideal level of fasting insulin is probably below 8.4 uIU/mL.

Let's dig deeper. What we really need is a healthy, non-industrial "negative control" group. Fortunately, Dr. Staffan Lindeberg and his team made detailed measurements of fasting insulin while they were visiting the isolated Melanesian island of Kitava (3). He compared his measurements to age-matched Swedish volunteers. In male and female Swedes, the average fasting insulin ranges from 4-11 uIU/mL, and increases with age. From age 60-74, the average insulin level is 7.3 uIU/mL.

In contrast, the range on Kitava is 3-6 uIU/mL, which does not increase with age. In the 60-74 age group, in both men and women, the average fasting insulin on Kitava is 3.5 uIU/mL. That's less than half the average level in Sweden and the U.S. Keep in mind that the Kitavans are lean and have an undetectable rate of heart attack and stroke.

Another example from the literature are the Shuar hunter-gatherers of the Amazon rainforest. Women in this group have an average fasting insulin concentration of 5.1 uIU/mL (4; no data was given for men).

I found a couple of studies from the early 1970s as well, indicating that African pygmies and San bushmen have rather high fasting insulin. Glucose tolerance was excellent in the pygmies and poor in the bushmen (5, 6, free full text). This may reflect differences in carbohydrate intake. San bushmen consume very little carbohydrate during certain seasons, and thus would likely have glucose intolerance during that period. There are three facts that make me doubt the insulin measurements in these older studies:

1. It's hard to be sure that they didn't eat anything prior to the blood draw.
2. From what I understand, insulin assays were variable and not standardized back then.
3. In the San study, their fasting insulin was 1/3 lower than the Caucasian control group (10 vs. 15 uIU/mL). I doubt these active Caucasian researchers really had an average fasting insulin level of 15 uIU/mL. Both sets of measurements are probably too high.

Now you know the conflicting evidence, so you're free to be skeptical if you'd like.

We also have data from a controlled trial in healthy urban people eating a "paleolithic"-type diet. On a paleolithic diet designed to maintain body weight (calorie intake had to be increased substantially to prevent fat loss during the diet), fasting insulin dropped from an average of 7.2 to 2.9 uIU/mL in just 10 days. This is despite a substantial intake of carbohydrate, including fruit and vegetable sugars.  The variation in insulin level between individuals decreased 9-fold, and by the end, all participants were close to the average value of 2.9 uIU/mL. This shows that high fasting insulin is correctable in people who haven't yet been permanently damaged by the industrial diet and lifestyle. The study included men and women of European, African and Asian descent (7).

One final data point. My own fasting insulin, earlier this year, was 2.3 uIU/mL. I believe it reflects a good diet, regular exercise, sufficient sleep, and a relatively healthy diet growing up. It does not reflect: carbohydrate restriction, fat restriction, or saturated fat restriction.

So what's the ideal fasting insulin level? My current feeling is that we can consider anything between 2 and 6 uIU/mL within our evolutionary template.

Malocclusion: Disease of Civilization, Part VIII

Three Case Studies in Occlusion

In this post, I'll review three cultures with different degrees of malocclusion over time, and try to explain how the factors I've discussed may have played a role.

The Xavante of Simoes Lopes

In 1966, Dr. Jerry D. Niswander published a paper titled "The Oral Status of the Xavantes of Simoes Lopes", describing the dental health and occlusion of 166 Brazilian hunter-gatherers from the Xavante tribe (free full text). This tribe was living predominantly according to tradition, although they had begun trading with the post at Simoes Lopes for some foods. They made little effort to clean their teeth. They were mostly but not entirely free of dental cavities:

Approximately 33% of the Xavantes at Simoes Lopes were caries free. Neel et al. (1964) noted almost complete absence of dental caries in the Xavante village at Sao Domingos. The difference in the two villages may at least in part be accounted for by the fact that, for some five years, the Simoes Lopes Xavante have had access to sugar cane, whereas none was grown at Sao Domingos. It would appear that, although these Xavantes still enjoy relative freedom from dental caries, this advantage is disappearing after only six years of permanent contact with a post of the Indian Protective Service.

The most striking thing about these data is the occlusion of the Xavante. 95 percent had ideal occlusion. The remaining 5 percent had nothing more than a mild crowding of the incisors (front teeth). Niswander didn't observe a single case of underbite or overbite. This would have been truly exceptional in an industrial population. Niswander continues:

Characteristically, the Xavante adults exhibited broad dental arches, almost perfectly aligned teeth, end-to-end bite, and extensive dental attrition. At 18-20 years of age, the teeth were so worn as to almost totally obliterate the cusp patterns, leaving flat chewing surfaces.

The Xavante were clearly hard on their teeth, and their predominantly hunter-gatherer lifestyle demanded it. They practiced a bit of "rudimentary agriculture" of corn, beans and squash, which would sustain them for a short period of the year devoted to ceremonies. Dr. James V. Neel describes their diet (free full text):

Despite a rudimentary agriculture, the Xavante depend very heavily on the wild products which they gather. They eat numerous varieties of roots in large quantities, which provide a nourishing, if starchy, diet. These roots are available all year but are particularly important in the Xavante diet from April to June in the first half of the dry season when there are no more fruits. The maize harvest does not last long and is usually saved for a period of ceremonies. Until the second harvest of beans and pumpkins, the Xavante subsist largely on roots and palmito (Chamacrops sp.), their year-round staples.

From late August until mid-February, there are also plenty of nuts and fruits available. The earliest and most important in their diet is the carob or ceretona (Ceretona sp.), sometimes known as St. John's bread. Later come the fruits of the buriti palm (Mauritia sp.) and the piqui (Caryocar sp.). These are the basis of the food supply throughout the rainy season. Other fruits, such as mangoes, genipapo (Genipa americana), and a number of still unidentified varieties are also available.

The casual observer could easily be misled into thinking that the Xavante "live on meat." Certainly they talk a great deal about meat, which is the most highly esteemed food among them, in some respects the only commodity which they really consider "food" at all... They do not eat meat every day and may go without meat for several days at a stretch, but the gathered products of the region are always available for consumption in the community.

Recently, the Xavante have begun to eat large quantities of fish.

The Xavante are an example of humans living an ancestral lifestyle, and their occlusion shows it. They have the best occlusion of any living population I've encountered so far. Here's why I think that's the case:

• A nutrient-rich, whole foods diet, presumably including organs.
  
• On-demand breast feeding for two or more years.
• No bottle-feeding or modern pacifiers.
• Tough foods on a regular basis.
  

I don't have any information on how the Xavante have changed over time, but Niswander did present data on another nearby (and genetically similar) tribe called the Bakairi that had been using a substantial amount of modern foods for some time. The Bakairi, living right next to the Xavante but eating modern foods from the trading post, had 9 times more malocclusion and nearly 10 times more cavities than the Xavante. Here's what Niswander had to say:

Severe abrasion was not apparent among the Bakairi, and the dental arches did not appear as broad and massive as in the Xavantes. Dental caries and malocclusion were strikingly more prevalent; and, although not recorded systematically, the Bakairi also showed considerably more periodontal disease. If it can be assumed that the Bakairi once enjoyed a freedom from dental disease and malocclusion equal to that now exhibited by the Xavantes, the available data suggest that the changes in occlusal patterns as well as caries and periodontal disease have been too rapid to be accounted for by an hypothesis involving relaxed [genetic] selection.

The Masai of Kenya

The Masai are traditionally a pastoral people who live almost exclusively from their cattle. In 1945, and again in 1952, Dr. J. Schwartz examined the teeth of 408 and 273 Masai, respectively (#1 free full text; #2 ref). In the first study, he found that 8 percent of Masai showed some form of malocclusion, while in the second study, only 0.4 percent of Masai were maloccluded. Although we don't know what his precise criteria were for diagnosing malocclusion, these are still very low numbers.

In both studies, 4 percent of Masai had cavities. Between the two studies, Schwartz found 67 cavities in 21,792 teeth, or 0.3 percent of teeth affected. This is almost exactly what Dr. Weston Price found when he visited them in 1935. From Nutrition and Physical Degeneration, page 138:

In the Masai tribe, a study of 2,516 teeth in eighty-eight individuals distributed through several widely separated manyatas showed only four individuals with caries. These had a total of ten carious teeth, or only 0.4 per cent of the teeth attacked by tooth decay.

Dr. Schwartz describes their diet:

The principal food of the Masai is milk, meat and blood, the latter obtained by bleeding their cattle... The Masai have ample means with which to get maize meal and fresh vegetables but these foodstuffs are known only to those who work in town. It is impossible to induce a Masai to plant their own maize or vegetables near their huts.

This is essentially the same description Price gave during his visit. The Masai were not hunter-gatherers, but their traditional lifestyle was close enough to allow good occlusion. Here's why I think the Masai had good occlusion:

• A nutrient-dense diet rich in protein and fat-soluble vitamins from pastured dairy.
• On-demand breast feeding for two or more years.
• No bottle feeding or modern pacifiers.
  

The one factor they lack is tough food. Their diet, composed mainly of milk and blood, is predominantly liquid. Although I think food toughness is a factor, this shows that good occlusion is not entirely dependent on tough food.

Sadly, the lifestyle and occlusion of the Masai has changed in the intervening decades. A paper from 1992 described their modern diet:

The main articles of diet were white maize, [presumably heavily sweetened] tea, milk, [white] rice, and beans. Traditional items were rarely eaten... Milk... was not mentioned by 30% of mothers.

A paper from 1993 described the occlusion of 235 young Masai attending rural and peri-urban schools. Nearly all showed some degree of malocclusion, with open bite alone affecting 18 percent.

Rural Caucasians in Kentucky

It's always difficult to find examples of Caucasian populations living traditional lifestyles, because most Caucasian populations adopted the industrial lifestyle long ago. That's why I was grateful to find a study by Dr. Robert S. Corruccini, published in 1981, titled "Occlusal Variation in a Rural Kentucky Community" (ref).

This study examined a group of isolated Caucasians living in the Mammoth Cave region of Kentucky, USA. Corruccini arrived during a time of transition between traditional and modern foodways. He describes the traditional lifestyle as follows:

Much of the traditional way of life of these people (all white) has been maintained, but two major changes have been the movement of industry and mechanized farming into the area in the last 25 years. Traditionally, tobacco (the only cash crop), gardens, and orchards were grown by each family. Apples, pears, cherries, plums, peaches, potatoes, corn, green beans, peas, squash, peppers, cucumbers, and onions were grown for consumption, and fruits and nuts, grapes, and teas were gathered by individuals. In the diet of these people, dried pork and fried [presumably in lard], thick-crust cornbread (which were important winter staples) provided consistently stressful chewing. Hunting is still very common in the area.

Although it isn't mentioned in the paper, this group, like nearly all traditionally-living populations, probably did not waste the organs or bones of the animals it ate. Altogether, it appears to be an excellent and varied diet, based on whole foods, and containing all the elements necessary for good occlusion and overall health.

The older generation of this population has the best occlusion of any Caucasian population I've ever seen, rivaling some hunter-gatherer groups. This shows that Caucasians are not genetically doomed to malocclusion. The younger generation, living on more modern foods, shows very poor occlusion, among the worst I've seen. They also show narrowed arches, a characteristic feature of deteriorating occlusion. One generation is all it takes. Corruccini found that a higher malocclusion score was associated with softer, more industrial foods.

Here are the reasons I believe this group of Caucasians in Kentucky had good occlusion:

• A nutrient-rich, whole foods diet, presumably including organs.
  
• Prolonged breast feeding.
• No bottle-feeding or modern pacifiers.
• Tough foods on a regular basis.
  

Common Ground

I hope you can see that populations with excellent teeth do certain things in common, and that straying from those principles puts the next generation at a high risk of malocclusion. Malocclusion is a serious problem that has major implications for health, well-being and finances. In the next post, I'll give a simplified summary of everything I've covered in this series. Then it's back to our regularly scheduled programming.

Impressions of Hawai'i

I recently went to Hawai'i for the American Society of Human Genetics meeting in Waikiki, followed by a one-week vacation on Kaua'i with friends. It was my first time in Hawai'i and I really enjoyed it. The Hawai'ians I encountered were kind and generous people.

Early European explorers remarked on the beauty, strength, good nature and exellent physical development of the native Hawai'ians. The traditional Hawai'ian diet consisted mostly of taro root, sweet potatoes, yams, breadfruit, coconut, fish, occasional pork, fowl including chicken, taro leaves, seaweed and a few sweet fruits. It would have been very low (but adequate) in omega-6, because there simply isn't much of it available in this environment. Root crops and most fruit are virtually devoid of fat; seafood and coconut contain very little omega-6; and even the pork and chicken would have been low in omega-6 due to their diets. Omega-3 would have been plentiful from marine foods, and saturated fats would have come from coconut. All foods were fresh and unrefined. Abundant exercise and sunlight would have completed their salubrious lifestyle.

The traditional Hawai'ian diet was rich in easily digested starch, mainly in the form of poi, which is fermented mashed taro. I ate poi a number of times while I was on Kaua'i, and really liked it. It's mild, similar to mashed potatoes, but with a slightly sticky consistency and a purple color (due to the particular variety of taro that's traditionally used to make it).

I had the opportunity to try a number of traditional Polynesian foods while I was on Kaua'i. One plant that particularly impressed me is breadfruit. It's a big tree that makes cantaloupe-sized starchy green fruit. Breadfruit is incredibly versatile, because it can be used at different stages of ripeness for different purposes. Very young, it's like a vegetable, at full size, it's a bland starch, and fully ripe it's starchy and sweet like a sweet potato. It can be baked, boiled, fried and even dried for later use. It has a mild flavor and a texture similar to soft white bread. It's satisfying and fairly rich in micronutrients. On the right are breadfruit, coconut and sugarcane, three traditional Hawai'ian foods.

I find perennial staple crops such as breadfruit very interesting, because they're much less destructive to soil quality than annual crops, and they're a breeze to maintain. I could walk into the backyard of the apartment I was renting and pick a breadfruit, soak it, throw it in the oven and I had something nutritious to eat in just over an hour. It's like picking a bag of potatoes right off a tree. Insects and birds didn't seem to like it at all, possibly because the raw fruit exudes a bitter, rubbery sap when damaged. Unfortunatley, breadfruit is a tropical plant. Temperate starchy staples that were exploited by native North Americans include the majestic American chestnut in the Appalachians, and acorns in the West. These are both more work than breadfruit to prepare, particularly acorns which must be extensively soaked to remove bitter tannins.

One of the foods Polynesian settlers brought to Hawai'i was sugar cane. I had the opportunity to try fresh sugar cane for the first time while I was on Kaua'i. You cut off the outer skin, then cut it into strips and chew to get the sweet juice. It was mild but tasty. I don't know if it was a coincidence or not, but I ended up feeling unwell after eating several pieces. It may simply have been too much sugar for me.

Modern Hawai'i is a hunter-gatherer's dream. There are fruit trees everywhere, including papayas, wild and cultivated guavas, mangoes, avocados, passion fruit, breadfruit, bananas, citrus fruits and many others. Many of those fruits did not predate European contact however. Even pineapples were introduced to Hawai'i after European contact. Coconuts are everywhere, and we could pick one up for a drink and snack on almost any beach. The forests are full of wild chickens (such as the one at left) and pigs, both having resulted from the escape and subsequent mixing of Polynesian and European breeds. Kaua'ians frequently hunt the pigs, which are environmentally damaging due to their habit of rooting through topsoil for food. Large areas of forest on Kaua'i look like they've been ploughed due to the pigs' rooting. Humans are their only predators and their food is abundant.

While I was on Kaua'i, I ate mostly seafood (including delicious raw tuna poke), poi, breadfruit, coconut and sweet fruits-- a real Polynesian style hunter-gatherer diet! I swam every day, hiked in the lovely interior, and kayaked. It was a great trip, and I hope to return someday.

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Ischemic Heart Attacks: Disease of Civilization

Or, more precisely, disease of industrial civilization.

The scientific literature contains examples of cultures that don't suffer from the chronic non-communicable diseases that are so common in modern societies. Much of what I've read indicates that heart attacks are practically unique to cultures that have adopted industrial foodways and a modern lifestyle, being infrequent or entirely absent in those that have not.

I recently came across an incredible paper from 1964 in the American Journal of Cardiology, titled "Geographic Pathology of Myocardial Infarction", by lead author Dr. Kyu Taik Lee (Am. J. Cardiol. 13:30. 1964). This was published during a period of intense research into the cardiovascular health of non-industrial cultures, including Dr. George V. Mann's famous study of the Masai.

The first thing Lee and his colleagues did was collect autopsy statistics from San Francisco and Los Angeles hospitals. They analyzed the data by race, including categories for Caucasian-Americans (white), Japanese-Americans, Chinese-Americans, and Filipino-Americans. All races had a similar incidence of autopsy-proven myocardial infarction (MI = heart attack), including both silent (healed) and fatal MI. For comparison, they included a table with autopsy data from hospitals in Tokyo, South Japan and North Japan. I'm including the data from Tokyo in the graph because it's also an urban environment, but the finding was the same in all three regions. Here's what they found, by age group: The Japanese had a very low rate of MI compared to both Caucasian-Americans and Japanese-Americans. The rate of MI in Caucasian-Americans and Japanese-Americans did not differ significantly. Thus, location but not race determined the susceptibility to MI.

Next, the investigators collected autopsy data from hospitals in New Orleans, again divided by race. This time they exained Caucasian-Americans and African-Americans. Both groups had a very high rate of MI, as expected, although the African-Americans had a lower rate than Caucasian-Americans. They also collected data from autopsies in Nigeria and Uganda for comparison. Here are the data for men: And for women: Again, location but not race largely determined the incidence of MI. MI was extremely rare in the African autopsies. Here's what they had to say:

There was only 1 case of healed myocardial infarction among over 4,000 adult autopsies in the Uganda series, and only 2 cases of healed myocardial infarction among over 500 adult autopsies in the Nigerian series. In the New Orleans Negro series the occurrence rate was far greater in every sex and age group than in either one of the Negro series in East and West Africa.

Over 4,500 autopsies and not a single fatal MI. If this isn't worth studying, what is? These data should be part of first-year training in medicine and health programs.

To satisfy the skeptics, Lee and colleagues imported hundreds of hearts from consecutive autopsies in Albany (USA), Africa, Korea and Japan. They had an American pathologist analyze them side-by side to eliminate any diagnostic bias. Here's what they found:

In the African Negro series no infarct was found in any age group [out of 244 hearts, 39 over 60 years old]. In the Korean series there were only 2 cases of myocardial infarction [out of 106 hearts] and they were both women... In the Japanese series there were 8 cases of myocardial infarction in 259 hearts. All were men...

In the American sample, nearly 40% of the hearts of men and women over 60 showed signs of MI. The findings of the American pathologist confirmed the international autopsy data, showing that diagnostic bias did not contribute to the results significantly. They also took measurements of the thickness of the coronary artery wall, an index of atherosclerosis. They found that the Americans had the most atherosclerosis, but all cultures had some degree of it and there was overlap in the amount of atherosclerosis between samples. This led the investigators to state:

Myocardial infarction and coronary thrombosis are almost nonexistent in Uganda and Nigeria, and the amount of coronary arteriosclerosis is significantly less in Africans than in whites. However, in the two groups there was some overlapping in the degree of arteriosclerosis. No Africans had infarcts, but some had the same or a greater degree of coronary arteriosclerosis as a few whites who had myocardial infarctions. One explanation for this may be that some difference in clotting or clot-lysis mechanisms is present in the two groups. In a previous study, we showed that the incidence of thromboembolic phenomena in the pulmonary circulation [blood clots in the lungs] was low in East Africans as compared with Americans.

Now, the authors' conclusions:

These data strongly suggest that among the Orientals the environmental factor is playing a major role in the etiology of myocardial infarction and coronary thrombosis. If the genetic factor is an important one, those Orientals who moved to this country many years ago or who were born in this country should still maintain their low occurrence rate of myocardial infarction at least to some extent, and one would not expect to see similar occurrence rates of myocardial infarction in Orientals and whites as old as 50 to 59 years... As with the Orientals, this suggests that for Negroes in the United States environmental factors are more important than genetic factors in the etiology of myocardial infarction.

Africans in Africa and Japanese in Japan = low incidence of MI. Africans, Japanese and Caucasians in the US = high and similar incidence of MI. Genes only influence a person's susceptibility to MI when they live in an environment that promotes MI. Otherwise, genes are basically irrelevant.

What do the traditional diets and lifestyles of Japan and Africa have in common? Not much. Even within Nigeria, the diet varies from heavily starch-based (root vegetables, soaked/fermented non-gluten grains, beans, plantains) to mostly reliant on high-fat dairy and meat, though the former is much more common and I'm not sure how much the latter is represented in the data. In fact, I believe it's the wrong question to ask. A better question is "what do we eat/do in the US that traditional Japanese, Koreans, Chinese, Polynesians, Melanesians and Africans don't"? For starters, none of them rely on industrially processed foods. Their food is generally prepared at home using wholesome ingredients and traditional methods.

There are a number of lifestyle factors that probably play a role here.  They probably get more exercise than Americans, even if it's only walking in Tokyo or domestic tasks for women in parts of Africa. Traditional Africans surely get more sunlight and thus more vitamin D. I can't imagine life is less stressful in Tokyo than in San Francisco or Los Angeles.  Cigarettes are probably much less prevalent in parts of Africa than in the modern US.

I really like this study, and I think these graphs should be disseminated as much as possible. I've prepared high-resolution versions in JPEG, Powerpoint and PDF formats. E-mail me (click on my profile for the link) if you would like a copy. Let me know which format(s) you want.

More Thoughts on the Glycemic Index

In the last post, I reviewed the controlled trials on the effect of the glycemic index (GI) of carbohydrate foods on health. I concluded that there is not much evidence that a low GI diet is better for health than a high GI diet.

It is true that for the "average" individual the GI of carbohydrate foods can affect the glucose and insulin response somewhat, even in the context of an actual meal. If you compare two meals of very different GI, the low GI meal will cause less insulin secretion and cause less total blood glucose in the plasma over the course of the day (although the differences in blood glucose may not be large in all individuals).

But is that biologically significant? In other words, do those differences matter when it comes to health? I would argue probably not, and here's why: there's a difference between post-meal glucose and insulin surges within the normal range, and those that occur in pathological conditions such as diabetes and insulin resistance. Chronically elevated insulin is a marker of metabolic dysfunction, while post-meal insulin surges are not (although glucose surges in excess of 140 mg/dL indicate glucose intolerance). Despite what you may hear from some sectors of the low-carbohydrate community, insulin surges do not necessarily lead to insulin resistance. Just ask a Kitavan. They get 69% of their 2,200 calories per day from high-glycemic starchy tubers and fruit (380 g carbohydrate), with not much fat to slow down digestion. Yet they have low fasting insulin, very little body fat and an undetectable incidence of diabetes, heart attack and stroke. That's despite a significant elderly population on the island.

Furthermore, in the 4-month GI intervention trial I mentioned last time, they measured something called glycated hemoglobin (HbA1c). HbA1c is a measure of the amount of blood glucose that has "stuck to" hemoglobin molecules in red blood cells. It's used to determine a person's average blood glucose concentration over the course of the past few weeks. The higher your HbA1c, the poorer your blood glucose control, the higher your likelihood of having diabetes, and the higher your cardiovascular risk. The low GI group had a statistically significant drop in their HbA1c value compared to the high GI group. But the difference was only 0.06%, a change that is biologically meaningless.

OK, let's take a step back. The goal of thinking about all this is to understand what's healthy, right? Let's take a look at how carbohydrate foods are consumed by cultures that rarely suffer from obesity or metabolic disease. Cultures that rely heavily on carbohydrate generally fall into three categories: they eat cooked starchy tubers, they grind and cook their grains, or they rely on grains that become very soft when cooked. In the first category, we have Africans, South Americans, Polynesians and Melanesians (including the Kitavans). In the second, we have various Africans, Europeans (including the villagers of the Loetschental valley), Middle Easterners and South Americans. In the third category, we have Asians, Europeans (the oat-eating residents of the outer Hebrides) and South Americans (quinoa-eating Peruvians).

The pattern here is one of maximizing GI, not minimizing it. That's not because high GI foods are inherently superior, but because traditional processing techniques that maximize the digestibility of carbohydrate foods also tend to increase their GI. I believe healthy cultures around the world didn't care about the glycemic index of foods, they cared about digestibility and nutritional value.

The reason we grind grains is simple. Ground grains are digested more easily and completely (hence the higher GI).  Furthermore, ground grains are more effective than intact grains at breaking down their own phytic acid when soaked, particularly if they're allowed to ferment. This further increases their nutritional value.

The human digestive system is delicate. Cows can eat whole grass seeds and digest them using their giant four-compartment stomach that acts as a fermentation tank. Humans that eat intact grains end up donating them to the waste treatment plant. We just don't have the hardware to efficiently extract the nutrients from cooked whole rye berries, unless you're willing to chew each bite 47 times. Oats, quinoa, rice, beans and certain other starchy seeds are exceptions because they're softened sufficiently by cooking.

Grain consumption and grinding implements appear simultaneously in the archaeological record. Grinding has always been used to increase the digestibility of tough grains, even before the invention of agriculture when hunter-gatherers were gathering wild grains in the fertile crescent. Some archaeologists consider grinding implements one of the diagnostic features of a grain-based culture. Carbohydrate-based cultures have always prioritized digestibility and nutritional value over GI.

Finally, I'd like to emphasize that some people don't have a good relationship with carbohydrate. Diabetics and others with glucose intolerance should be very cautious with carbohydrate foods. The best way to know how you deal with carbohydrate is to get a blood glucose meter and use it after meals. For $70 or less, you can get a cheap meter and 50 test strips that will give you a very good idea of your glucose response to typical meals (as opposed to a glucose bomb at the doctor's office). Jenny Ruhl has a tutorial that explains the process. It's also useful to pay attention to how you feel and look with different amounts of carbohydrate in your diet.

Paleopathology at the Origins of Agriculture

In April of 1982, archaeologists from around the globe converged on Plattsburgh, New York for a research symposium. Their goal:

...[to use] data from human skeletal analysis and paleopathology [the study of ancient diseases] to measure the impact on human health of the Neolithic Revolution and antecedent changes in prehistoric hunter-gatherer food economies. The symposium developed out of our perception that many widely debated theories about the origins of agriculture had testable but untested implications concerning human health and nutrition and our belief that recent advances in techniques of skeletal analysis, and the recent explosive increase in data available in this field, permitted valid tests of many of these propositions.

In other words, they got together to see what happened to human health as populations adopted agriculture. They were kind enough to publish the data presented at the symposium in the book Paleopathology at the Origins of Agriculture, edited by the erudite Drs. Mark Nathan Cohen and George J. Armelagos. It appears to be out of print, but luckily I have access to an excellent university library.

There are some major limitations to studying human health by looking at bones. The most obvious is that any soft tissue pathology will have been erased by time. Nevertheless, you can learn a lot from a skeleton. Here are the main health indicators discussed in the book:

• Mortality. Archaeologists are able to judge a person's approximate age at death, and if the number of skeletons is large enough, they can paint a rough picture of the life expectancy and infant mortality of a population.
• General growth. Total height, bone thickness, dental crowding, and pelvic and skull shape are all indicators of relative nutrition and health. This is particularly true in a genetically stable population. Pelvic depth is sensitive to nutrition and determines the size of the birth canal in women.
• Episodic stress. Bones and teeth carry markers of temporary "stress", most often due to starvation or malnutrition. Enamel hypoplasia, horizontal bands of thinned enamel on the teeth, is probably the most reliable marker. Harris lines, bands of increased density in long bones that may be caused by temporary growth arrest, are another type.
• Porotic hyperostosis and cribra orbitalia. These are both skull deformities that are caused by iron deficiency anemia, and are rather creepy to look at. They're typically caused by malnutrition, but can also result from parasites.
• Periosteal reactions. These are bone lesions resulting from infections.
• Physical trauma, such as fractures.
• Degenerative bone conditions, such as arthritis.
• Isotopes and trace elements. These can sometimes yield information about the nutritional status, diet composition and diet quality of populations.
• Dental pathology. My favorite! This category includes cavities, periodontal disease, missing teeth, abscesses, tooth wear, and excessive dental plaque.

The book presents data from 19 regions of the globe, representing Africa, Asia, the Middle East, Europe, South America, with a particular focus on North America. I'll kick things off with a fairly representative description of health in the upper Paleolithic in the Eastern Mediterranean. The term "Paleolithic" refers to the period from the invention of stone tools by hominids 2.5 million years ago, to the invention of agriculture roughly 10,000 years ago. The upper Paleolithic lasted from about 40,000 to 10,000 years ago. From page 59:

In Upper Paleolithic times nutritional health was excellent. The evidence consists of extremely tall stature from plentiful calories and protein (and some microevolutionary selection?); maximum skull base height from plentiful protein, vitamin D, and sunlight in early childhood; and very good teeth and large pelvic depth from adequate protein and vitamins in later childhood and adolescence...
Adult longevity, at 35 years for males and 30 years for females, implies fair to good general health...
There is no clear evidence for any endemic disease.

The level of skeletal (including cranial and pelvic) development Paleolithic groups exhibited has remained unmatched throughout the history of agriculture. There may be exceptions but the trend is clear. Cranial capacity was 11% higher in the upper Paleolithic. You can see the pelvic data in this table taken from Paleopathology at the Origins of Agriculture.

There's so much information in this book, the best I can do is quote pieces of the editor's summary and add a few remarks of my own. One of the most interesting things I learned from the book is that the diet of many hunter-gatherer groups changed at the end of the upper Paleolithic, foreshadowing the shift to agriculture. From pages 566-568:

During the upper Paleolithic stage, subsistence seems focused on relatively easily available foods of high nutritional value, such as large herd animals and migratory fish. Some plant foods seem to have been eaten, but they appear not to have been quantitatively important in the diet. Storage of foods appears early in many sequences, even during the Paleolithic, apparently to save seasonal surpluses for consumption during seasons of low productivity.

As hunting and gathering economies evolve during the Mesolithic [period of transition between hunting/gathering and agriculture], subsistence is expanded by exploitation of increasing numbers of species and by increasingly heavy exploitation of the more abundant and productive plant species. The inclusion of significant amounts of plant food in prehistoric diets seems to correlate with increased use of food processing tools, apparently to improve their taste and digestibility. As [Dr. Mark Nathan] Cohen suggests, there is an increasing focus through time on a few starchy plants of high productivity and storability. This process of subsistence intensification occurs even in regions where native agriculture never developed. In California, for example, as hunting-gathering populations grew, subsistence changed from an early pattern of reliance on game and varied plant resources to to one with increasing emphasis on collection of a few species of starchy seeds and nuts.

...As [Dr. Cohen] predicts, evolutionary change in prehistoric subsistence has moved in the direction of higher carrying capacity foods, not toward foods of higher-quality nutrition or greater reliability. Early nonagricultural diets appear to have been high in minerals, protein, vitamins, and trace nutrients, but relatively low in starch. In the development toward agriculture there is a growing emphasis on starchy, highly caloric food of high productivity and storability, changes that are not favorable to nutritional quality but that would have acted to increase carrying capacity, as Cohen's theory suggests.

Very interesting.

One of the interesting things I learned from the book is that Mesolithic populations, groups that were halfway between farming and hunting-gathering, were generally as healthy as hunter-gatherers:

...it seems clear that seasonal and periodic physiological stress regularly affected most prehistoric hunting-gathering populations, as evidenced by the presence of enamel hypoplasias and Harris lines. What also seems clear is that severe and chronic stress, with high frequency of hypoplasias, infectious disease lesions, pathologies related to iron-deficiency anemia, and high mortality rates, is not characteristic of these early populations. There is no evidence of frequent, severe malnutrition, so the diet must have been adequate in calories and other nutrients most of the time. During the Mesolithic, the proportion of starch in the diet rose, to judge from the increased occurrence of certain dental diseases [with exceptions to be noted later], but not enough to create an impoverished diet... There is a possible slight tendency for Paleolithic people to be healthier and taller than Mesolithic people, but there is no apparent trend toward increasing physiological stress during the mesolithic.

Cultures that adopted intensive agriculture typically showed a marked decline in health indicators. This is particularly true of dental health, which usually became quite poor.

Stress, however, does not seem to have become common and widespread until after the development of high degrees of sedentism, population density, and reliance on intensive agriculture. At this stage in all regions the incidence of physiological stress increases greatly, and average mortality rates increase appreciably. Most of these agricultural populations have high frequencies of porotic hyperostosis and cribra orbitalia, and there is a substantial increase in the number and severity of enamel hypoplasias and pathologies associated with infectious disease. Stature in many populations appears to have been considerably lower than would be expected if genetically-determined maxima had been reached, which suggests that the growth arrests documented by pathologies were causing stunting... Incidence of carbohydrate-related tooth disease increases, apparently because subsistence by this time is characterized by a heavy emphasis on a few starchy food crops.

Infectious disease increased upon agricultural intensification:

Most [studies] conclude that infection was a more common and more serious problem for farmers than for their hunting and gathering forebears; and most suggest that this resulted from some combination of increasing sedentism, larger population aggregates, and the well-established synergism between infection and malnutrition.

There are some apparent exceptions to the trend of declining health with the adoption of intensive agriculture. In my observation, they fall into two general categories. In the first, health improves upon the transition to agriculture because the hunter-gatherer population was unhealthy to begin with. This is due to living in a marginal environment or eating a diet with a high proportion of wild plant seeds. In the second category, the culture adopted rice. Rice is associated with less of a decline in health, and in some cases an increase in overall health, than other grains such as wheat and corn. In chapter 21 of the book Ancient Health: Bioarchaeological Interpretations of the Human Past, Drs. Michelle T Douglas and Michael Pietrusewsky state that "rice appears to be less cariogenic [cavity-promoting] than other grains such as maize [corn]."

One pathology that seems to have decreased with the adoption of agriculture is arthritis. The authors speculate that it may have more to do with strenuous activity than other aspects of the lifestyle such as diet. Another interpretation is that the hunter-gatherers appeared to have a higher arthritis rate because of their longer lifespans:

The arthritis data are also complicated by the fact that the hunter-gatherers discussed commonly displayed higher average ages at death than did the farming populations from the same region. The hunter-gatherers would therefore be expected to display more arthritis as a function of age even if their workloads were comparable [to farmers].

In any case, it appears arthritis is normal for human beings and not a modern degenerative disease.

And the final word:

Taken as a whole, these indicators fairly clearly suggest an overall decline in the quality-- and probably in the length-- of human life associated with the adoption of agriculture.

How to Eat Grains

Our story begins in East Africa in 1935, with two Bantu tribes called the Kikuyu and the Wakamba. Their traditional diets were mostly vegetarian and consisted of sweet potatoes, corn, beans, plantains, millet, sorghum, wild mushrooms and small amounts of dairy, small animals and insects. Their food was agricultural, high in carbohydrate and low in fat.

Dr. Weston Price found them in good health, with well-formed faces and dental arches, and a dental cavity rate of roughly 6% of teeth. Although not as robust or as resistant to tooth decay as their more carnivorous neighbors, the "diseases of civilization" such as cardiovascular disease and obesity were nevertheless rare among them. South African Bantu eating a similar diet have a low prevalence of atherosclerosis, and a measurable but low incidence of death from coronary heart disease, even in old age.

How do we reconcile this with the archaeological data showing a general decline in human health upon the adoption of agriculture? Humans did not evolve to tolerate the toxins, anti-nutrients and large amounts of fiber in grains and legumes. Our digestive system is designed to handle a high-quality omnivorous diet. By high-quality, I mean one that has a high ratio of calories to indigestible material (fiber). Our species is very good at skimming off the highest quality food in nearly any ecological niche. Animals that are accustomed to high-fiber diets, such as cows and gorillas, have much larger, more robust and more fermentative digestive systems.

One factor that reconciles the Bantu data with the archaeological data is that much of the Kikuyu and Wakamba diet came from non-grain sources. Sweet potatoes and plantains are similar to the starchy wild plants our ancestors have been eating for nearly two million years, since the invention of fire (the time frame is debated but I think everyone agrees it's been a long time). Root vegetables and starchy fruit ted to have a higher nutrient bioavailibility than grains and legumes due to their lower content of anti-nutrients.

The second factor that's often overlooked is food preparation techniques. These tribes did not eat their grains and legumes haphazardly! This is a factor that was overlooked by Dr. Price himself, but has been emphasized by Sally Fallon. Healthy grain-based African cultures often soaked, ground and fermented their grains before cooking, creating a porridge that's nutritionally superior to unfermented grains. The bran was removed from corn and millet during processing, if possible. Legumes were always soaked prior to cooking.

These traditional food processing techniques have a very important effect on grains and legumes that brings them closer in line with the "paleolithic" foods our bodies are designed to digest. They reduce or eliminate toxins such as lectins and tannins, greatly reduce anti-nutrients such as phytic acid and protease inhibitors, and improve vitamin content and amino acid profile. Fermentation is particularly effective in this regard. One has to wonder how long it took the first agriculturalists to discover fermentation, and whether poor food preparation techniques or the exclusion of animal foods could account for their poor health.

I recently discovered a paper that illustrates these principles: "Influence of Germination and Fermentation on Bioaccessibility of Zinc and Iron from Food Grains". It's published by Indian researchers who wanted to study the nutritional qualities of traditional fermented foods. One of the foods they studied was idli, a South Indian steamed "muffin" made from rice and beans. 

The amount of minerals your digestive system can extract from a food depends in part on the food's phytic acid content. Phytic acid is a molecule that traps certain minerals (iron, zinc, magnesium, calcium), preventing their absorption. Raw grains and legumes contain a lot of it, meaning you can only absorb a fraction of the minerals present in them.

In this study, soaking had a modest effect on the phytic acid content of the grains and legumes examined. Fermentation, on the other hand, completely broke down the phytic acid in the idli batter, resulting in 71% more bioavailable zinc and 277% more bioavailable iron. It's safe to assume that fermentation also increased the bioavailability of magnesium, calcium and other phytic acid-bound minerals.

Fermenting the idli batter also completely eliminated its tannin content. Tannins are a class of molecules found in many plants that are sometimes toxins and anti-nutrients. In sufficient quantity, they reduce feed efficiency and growth rate in a variety of species.

Lectins are another toxin that's frequently mentioned in the paleolithic diet community. They are blamed for everything from digestive problems to autoimmune disease. One of the things people like to overlook in this community is that traditional processing techniques such as soaking, sprouting, fermentation and cooking, greatly reduce or eliminate lectins from grains and legumes. One notable exception is gluten, which survives all but the longest fermentation and is not broken down by cooking.

Soaking, sprouting, fermenting, grinding and cooking are the techniques by which traditional cultures have been making the most of grain and legume-based diets for thousands of years. We ignore these time-honored traditions at our own peril.

The Tokelau Island Migrant Study: The Final Word

Over the course of the last month, I've outlined some of the major findings of the Tokelau Island Migrant study. It's one of the most comprehensive studies I've found of a traditional culture transitioning to a modern diet and lifestyle. It traces the health of the inhabitants of the Pacific island Tokelau over time, as well as the health of Tokelauan migrants to New Zealand.

Unfortunately, the study began after the introduction of modern foods. We will never know for sure what Tokelauan health was like when their diet was completely traditional. To get some idea, we have to look at other traditional Pacific islanders such as the Kitavans.

What we can say is that an increase in the consumption of modern foods on Tokelau, chiefly white wheat flour and refined sugar, correlated with an increase in several non-communicable disorders, including overweight, diabetes and severe tooth decay. Further modernization as Tokelauans migrated to New Zealand corresponded with an increase in nearly every disorder measured, including heart disease, weight gain, diabetes, asthma and gout. These are all "diseases of civilization", which are not observed in hunter-gatherers and certain non-industrial populations throughout the world.

One of the most interesting things about Tokelauans is their extreme saturated fat intake, 40- 50% of calories. That's more than any other population I'm aware of. Yet Tokelauans appear to have a low incidence of heart attacks, lower than their New Zealand- dwelling relatives who eat half as much saturated fat. This should not be buried in the scientific literature; it should be common knowledge.

Overall, I believe the Tokelau Island Migrant study (among others) shows us that partially replacing nourishing traditional foods with modern foods such as processed wheat and sugar, is enough to cause a broad range of disorders not seen in hunter-gatherers but typical of modern societies. Changes in lifestyle between Tokelau and New Zealand may have also played a role.
The Tokelau Island Migrant Study: Background and Overview
The Tokelau Island Migrant Study: Dental Health
The Tokelau Island Migrant Study: Cholesterol and Cardiovascular Health
The Tokelau Island Migrant Study: Weight Gain
The Tokelau Island Migrant Study: Diabetes
The Tokelau Island Migrant Study: Asthma
The Tokelau Island Migrant Study: Gout

The Tokelau Island Migrant Study: Weight Gain

Between 1968 and 1982, Tokelauans in nearly all age groups gained weight, roughly 5 kilograms (11 pounds) on average. They also became slightly taller, but not enough to offset the gain in weight. By 1980-82, migrants to New Zealand had become especially heavy, with all age groups weighing more than non-migrants by about 5 kg (11 lb) on average, and 10 kg (22 lb) more than Tokelauans did in 1968.

The body mass index (BMI) is a rough estimate of fat mass (although it can be confounded by muscle mass), and is the weight in kilograms divided by the square of the height in meters [BMI = weight / (height^2)]. A BMI of 25 to 30 is considered overweight; 30 and over is considered obese.

The graphs I'm about to present require some explanation. The data in each graph were collected from the same individuals over time (15-69 years old). That means some weight gain is expected, as this population normally gains weight into middle age (then loses weight). What's interesting to note is the difference in the rate of weight change between migrants and non-migrants. The first two data points in 1968 are baseline, and compare non-migrants with "pre-migrants" still living on Tokelau. The second two data points in 1981-82 compare the same individual migrants in New Zealand with the same non-migrants.
Unless they all decided to become body builders, migrants to New Zealand gained more fat mass than Tokelauans between 1968 and 1982. The rate of weight gain in New Zealand was more than twice as fast for men and more than 50% faster for women than on Tokelau.

Why did Tokelauans and especially migrants to New Zealand gain weight?  Probably because they had greater access to a wide variety of calorie-dense, palatable foods of modern commerce.  The introduction of wheat and sugar, at the expense of coconut and traditional carbohydrate sources, was the main change to the Tokelauan diet during this time period. See this post for a graph.

Finally, there's the question of exercise. Did a change in energy expenditure contribute to weight gain? The study didn't collect data on exercise during the time period in question, so all we have are anecdotes. During this time, men living on Tokelau progressively adopted outboard motors for their fishing boats, replacing the traditional sails and oars. Their energy expenditure probably decreased.

But what about women? Tokelauan women traditionally perform household tasks such as weaving mats and preparing food. Their energy expenditure probably didn't change much over the same time period. Since both men and women on Tokelau gained weight, it would be hard to argue that exercise was a dominant factor.

How about migrants to New Zealand? Here's a quote from Migration and Health in a Small Society: the Case of Tokelau:

Overall it is our belief that most of the migrants expend greater energy in their work than is currently the case in Tokelau.

Exercise doesn't appear to have been the main factor, although the data don't allow us to be totally confident about this.

The Tokelau Island Migrant Study: Cholesterol and Cardiovascular Health

Let's get right to the meat of this study. It's relevant to the hypothesis that saturated fat is a cause of cardiovascular disease.  Tokelauans traditionally obtained 40-50% of their calories from saturated fat, in the form of coconut meat. That's more than any other group I'm aware of.

So are the Tokelauans dropping like flies of cardiovascular disease?  I don't have access to the best data of all: actual heart attack incidence data. But we do have some telltale markers. In 1971-1982, researchers collected data from Tokelau and Tokelauan migrants to New Zealand on cholesterol levels, blood pressure and electrocardiogram (ECG) readings.

The Tokelauan diet, as I've described in detail in previous posts, is traditionally based on coconut, fish, starchy tubers and fruit. By 1982, their diet also contained a significant amount of imported flour and sugar. Migrants to New Zealand had a much more varied diet that was also more typically Western: more carbohydrate, coming chiefly from wheat, sugar and potatoes; more processed sweet foods and drinks; more red meat; more vegetables; more dairy and eggs. Sugar intake was 13 percent of calories, compared to 8 percent on Tokelau. Saturated fat intake in NZ was half of what it was on Tokelau, while total fat intake was similar. Polyunsaturated fat intake was higher in NZ, 4% as opposed to 2% in Tokelau. I don't have data to back this up, but I think it's likely that the n-6:n-3 ratio increased upon migration.

Blood pressure did not change significantly over time in Tokelau from 1971 to 1982, if anything it actually declined slightly. It was consistently higher in NZ than in Tokelau at all timepoints. Men were roughly three times more likely to be hypertensive in NZ than on Tokelau at all timepoints (4.0% vs. 12.0% in the early 1970s). Women were about twice as likely to be hypertensive (8.1% vs. 15.0%).

On to cholesterol. Total cholesterol in male Tokelauans was a bit lower on average than in New Zealand, but neither was particularly elevated (182 vs. 199 mg/dL). LDL was also a bit higher in NZ males (119 vs. 132 mg/dL). Triglycerides were lower in Tokelauan men than in NZ (80 vs. 114 mg/dL). There were no differences in total cholesterol, LDL cholesterol or triglycerides between Tokelauan and NZ women.  It's interesting that serum lipids don't correspond at all to saturated fat intake.

But does it cause heart attacks? The best data I have from this study are ECG readings. These use electrodes to monitor the electrical activity of the heart. There are certain ECG patterns that suggest that a person has had a heart attack (Minnesota codes 1-1 and 1-2). The data I am going to present here are all age-standardized, meaning they are comparing between groups of the same age. On Tokelau in 1982, 0.0% of men 40-69 years old showed ECG readings that indicated a probable past heart attack. In NZ in 1980-81, 1.0% of men 40-69 years old showed the same ECG readings. In Tecumseh U.S.A. in 1965, 3.5% of men 40-69 years old showed the same ECG pattern. I don't have data for women.

These data don't prove that no one ever has a heart attack on Tokelau. Tokelauans do have heart attacks sometimes, and they also have strokes (at least in modern times). But they do allow us to compare in quantitative terms between genetically similar people living in two different environments.

This is consistent with what has been observed on Kitava and other traditional Pacific island cultures: a vanishingly small incidence of cardiovascular disease while they retain their traditional diet and lifestyle (and sometimes even when some processed Western food has been introduced). When diets and lifestyles become modern, there is invariably a rise in the incidence of chronic disease.

These data raise serious questions about the role of saturated fat in cardiovascular disease. Tokelau underlines the fact that a non-industrial diet and lifestyle may be a more significant protective factor than the quality of ingested fat.

Unless otherwise noted, the data in this post are from the book Migration and Health in a Small Society: the Case of Tokelau.