Saturday, May 16, 2009

The Coronary Heart Disease Epidemic: Possible Culprits Part I

In the last post, I reviewed two studies that suggested heart attacks were rare in the U.K. until the 1920s -1930s. In this post, I'll be discussing some of the diet and lifestyle factors that preceded and associated with the coronary heart disease epidemic in the U.K and U.S. I've cherry picked factors that I believe could have played a causal role. Many things changed during that time period, and I don't want to give the impression that I have "the answer". I'm simply presenting ideas for thought and discussion.

First on the list: sugar. Here's a graph of refined sugar consumption in the U.K. from 1815 to 1955, from the book The Saccharine Disease, by Dr. T. L. Cleave. Sugar consumption increased dramatically in the U.K. over this time period, reaching near-modern levels by the turn of the century, and continuing to increase after that except during the wars: Here's a graph of total sweetener consumption in the U.S. from 1909 to 2005 (source: USDA food supply database). Between 1909 and 1922, sweetener consumption increased by 40%:

If we assume a 10 to 20 year lag period, sugar is well placed to play a role in the CHD epidemic. Sugar is easy to pick on. Diets high in refined sugar tend to promote obesity due to overeating.  An excess causes a number of detrimental changes in animal models and human subjects that are partially dependent on the development of obesity, including fatty liver, the metabolic syndrome, and small, oxidized low-density lipoprotein particles (LDL). Small and oxidized LDL associate strongly with cardiovascular disease risk and may be involved in causing it. These effects seem to be partly attributable to the fructose portion of sugar, which is 50% of table sugar (sucrose), about 50% of most naturally sweet foods, and 55% of the most common form of high-fructose corn syrup. That explains why starches, which break down into glucose (another type of sugar), don't have the same negative effects as table sugar and HFCS.

Hydrogenated fat is the next suspect. I don't have any graphs to present, because no one has systematically tracked hydrogenated fat consumption in the U.S. or U.K. to my knowledge. However, it was first marketed in the U.S. by Procter & Gamble under the brand name Crisco in 1911. Crisco stands for "crystallized cottonseed oil", and involves taking an industrial waste oil (from cotton seeds) and chemically treating it using high temperature, a nickel catalyst and hydrogen gas (see this post for more information). Hydrogenated fats for human consumption hit markets in the U.K. around 1920. Here's what Dr. Robert Finlayson had to say about margarine in his paper "Ischaemic Heart Disease, Aortic Aneurysms, and Atherosclerosis in the City of London, 1868-1982":
...between 1909-13 and 1924-28, margarine consumption showed the highest percentage increase, whilst that of eggs only increased slightly and that of butter remained unchanged. Between 1928 and 1934, margarine consumption fell by one-third, while butter consumption increased by 57 percent: and increase that coincided with a fall of 48 percent in its price. Subsequently, margarine sales have burgeoned, and if one is correct in stating that the coronary heart disease epidemic started in the second decade of this century, then the concept of hydrogenated margarines as an important aetiological factor, so strongly advocated by Martin, may merit more consideration than hitherto.
Partially hydrogenated oils contain trans fat, which is truly new to the human diet, with the exception of small amounts found in ruminant fats including butter. But for the most part, natural trans fats are not the same as industrial trans fats, and in fact some of them, such as conjugated linoleic acid (CLA), may be beneficial. To my knowledge, no one has discovered health benefits of industrial trans fats. To the contrary, compared to butter, they shrink LDL size. They also inhibit enzymes that the body uses to make a diverse class of signaling compounds known as eicosanoids. Trans fat consumption associates very strongly with the risk of heart attack in observational studies. Which is ironic, because hydrogenated fats were originally marketed as a healthier alternative to animal fats. The Center for Science in the Public Interest shamed McDonald's into switching the beef tallow in their deep friers for hydrogenated vegetable fats in the 1990s. In 2009, even the staunchest opponents of animal fats have to admit that they're healthier than hydrogenated fat.
The rise of cigarettes was a major change that probably contributed massively to the CHD epidemic. They were introduced just after the turn of the century in the U.S. and U.K., and rapidly became fashionable (source):
If you look at the second to last graph from the previous post, you can see that there's a striking correspondence between cigarette consumption and CHD deaths in the U.K. In fact, if you moved the line representing cigarette consumption to the right by about 20 years, it would overlap almost perfectly with CHD deaths. The risk of heart attack is so strongly associated with smoking in observational studies that even I believe it probably represents a causal relationship. There's no doubt in my mind that smoking cigarettes contributes to the risk of heart attack and various other health problems.

Smoking is a powerful factor, but it doesn't explain everything. How is it that the Kitavans of Papua New Guinea, more than 3/4 of whom smoke cigarettes, have an undetectable incidence of heart attack and stroke? Why do the French and the Japanese, who smoke like chimneys (at least until recently), have the two lowest heart attack death rates of all the affluent nations? There's clearly another factor involved that trumps cigarette smoke. 

23 comments:

Don said...

Other possible contributors in this time frame include:

1. Dramatic rise in unhydrogenated vegetable oil consumption altering the omega-6 to omega-3 ratio of typical diets. This is the reverse of the Lyon Diet Trial effect. As discussed by Peter at Hyperlipid, the only marked difference between the Lyon intervention and the "prudent diet" was the omega-6 to omega-3 ratio, and this resulted in a 30-70% reduced recurrence of heart attack in 5 years. This suggests that moving from a diet with a low n-6:n-3 ratio to one with a high n-6:n-3 ratio, by increased intake of vegetable oils, could cause a 30-70% increased incidence of heart attacks within 5 years.

2. War distress (WWI and WWII) or other social distress. Looking at WHO's 2002 CVD mortality data, some of the highest rates occurred in war-torn and recently war-torn nations, like Somalia, Afghanistan, or nations with high levels of unemployment and social distress, such as the Russian federation. In that year, the CVD rate in Japan was 106 per 100K, in France it was 118, in Somalia 580, in Russian Federation 688, and in Afghanistan 706.


3. Displacement distress (European refugees relocating from their Continental homelands to Britain or the U.S. due to war).

BTW, in 2002, Kazakhstanis consumed only 0.77 g of animal fat per day per capita, but had a CVD mortality rate of 713. Doesn't make a low fat diet look very protective, when you consider that the French ate 6.62 g of animal fat daily, 8 times as much as the Kazakhstanis with less than one-sixth the CVD mortality rate.

Also, in 2002, Belgians had a CVD mortality rate of 162 while consuming a whopping 26 g of animal fat daily. U.S. citizens had an average intake of 3.69 g animal fat daily, with a CVD mortality rate of 188. As we know, all this data blows the 7 Countries Study out of the water. If you think like Ancel Keys (I don't) and you compare Belgians to Kazakhstanis, you can conclude that if Kazakhstanis increased their animal fat consumption from about 1 g per day to 26 g per day they would cut their CVD mortality incidence by 77%!

Stephan said...

Don,

You stole my thunder, haha.

Melissa said...

What about increased consumption of rancid/oxidized fats? Frying, packaged products, and the rise of easily oxidized vegetable oils (lard and coconut oil are pretty resistant to oxidization).

Robert Andrew Brown said...

Another great post Stephan that has taken a great deal of wide ranging reading and research.

Don.

1 - The Omega 3 6 ratio is undoubtedly a factor, and arguably one of the most fundamental. I suspect that Stephan may head in that direction as part of his exploration.

2 - From discussion with those who were around, UK health in terms of western conditions on general terms improved in WW2.

The Russians use a lot of sunflower which is high in Omega 6.

I guess from news shots of food aid deliveries showing plastic containers of food oil, and on cooking habits economics and the value of fats in the diet, that poor countries may have a very poor Omega 3 6 balance because seed/legume based vegetable oils are cheap and available. Due to severe dietary constraints they probably also may have a very low Omega 3 intake, and likely a lack of other essential nutrients.

It is likely access to other fats and saturated fats would be limited, so increasing the prominence and effect of the intake of high Omega 6 oils.

The Omega 3:6 effect happens at any intake level if there is serious imbalance.


Author

Omega Six The Devils Fat

www.Omegasixthedevilsfat.com

Robert Andrew Brown said...

Trans Fats

There are hints that some 'artificial' trans fats are less efficiently oxidised in the mitochondria, leaving oxidised fat remnants, and possibly contributing to mitochondrial swelling.

It is reported the heart obtains a significant proportion of its energy from fats. Long term reduction in mitochondrial functional efficiency is a factor in cardiac conditions.

Jay said...

I attended a very interesting lecture here in Cambridge UK given by David Bernhard of the university of Innsbruck, Austria. He said that:
Cigarette smoke contains Cadmium.
That Cadmium is absorbed by the smoker.
Cadmium causes artery and heart disease.
Zinc is an antidote to Cadmium.
Perhaps those heavy smoking, low CHD people have a high intake of Zinc.
Jay

Dave in Ohio said...

@Don

Can you give a source for your animal fat consumption figures?

The numbers quoted seem extraordinarily low to me. For example, just one ounce of swiss cheese has 9 g. of animal fat. A 4 oz. hamburger has 16 g. One large egg 3.5 g. (per USDA database).

With a 2000 kcal diet, if just 10% is animal fat that's still 22 g.

Thanks,
Dave

Vin said...

Great article Stephen! It's about time people start realizing that saturated fat and dietary cholesterol are not the causes of heart disease.

Another interesting theory on sugar and heart disease is that high blood sugar causes artery damage which is also why diabetics have a higher risk.

What's scary about the numbers on sugar consumption is that they don't included the refined grains such as wheat flour that are such a large part of the modern diet and cause all kinds of blood sugar problems.

If you haven't already read them, two interesting books on this subject are:

"The Cholesterol Myths" by Uffe Ravnskov

"$29 Billion Reasons to Lie About Cholesterol" by Justin Smith

I also wrote an article on this topic called Busting the Cholesterol Myths which is largely based on these two books.

theoddbod said...

good on ya for the CLA comment. very informative post. covered a lot of good information in a very understandable way.

Stephan said...

Vin,

I agree that poor glucose control (and glycosylation from excess fructose) is probably one of the best ways to give yourself heart disease. Interestingly though, white flour consumption was very high at the turn of the century in the U.S., higher than today.

Don said...

@Stephan,

Sorry...I know you will come up with a great post anyway.

@Dave in Ohio

I know the numbers seem really low. I got them directly from the WHO/FAO database. I can think of only a few explanations for their really low numbers:

1) they are per capita, including children

2) They are only counting the grams of saturated fat in the animal fats

3) they got all the data wrong (not surprising for WHO/FAO--what do they have to lose by their mistakes, since they live on handouts, not productivity)

@Robert Andrew Brown

If you look at the graph from Finlayson in Stephan's first post on this topic, the prevalence of IHD deaths started climbing about 1880, climbed rapidly from 1880 to about 1920, and climbed precipitously between 1930 and 1970. It sure doesn't support an idea that deaths from IHD decreased during WWII. Perhaps other Western diseases did decline during that time, but Finlayson's data clearly shows an increase of deaths from IHD through both world wars, then also in the after years. During those post-war years, the U.S. took in many refugees and I believe the U.K. did as well. Social dislocation that breaks up families ranks as one of the most difficult stresses known.

My Grandfather was a post-war, refugee from Hungary to the U.S. He came to the U.S. first without his family (wife and 10 children) to establish a home for them. They were separated something like 5-10 years. When he finally got enough money and a home together so that he could pay for their emigration, when his family arrived, infidelity had occurred and that broke his heart. He died of IHD at his prime (in his 50s), in the early 1960's (I was just a child).

Malcolm discusses how this type of stress promotes IHD in his Cholesterol Myths book.

Don

Jenny Light said...

Stephan:

Interestingly though, white flour consumption was very high at the turn of the century in the U.S., higher than today.Wheat has undergone thousands of forced hybridizations in the last half-century. With that said, I question if wheat much resembles what was grown and consumed in the early 1900's and prior.

An interesting article about this can be found on the WAPF website here:

http://www.westonaprice.org/
moderndiseases/gluten-intolerance.html

Don said...

Another probable factor: decline in long-term breast feeding.

http://www.breastfeeding.com/all_about/all_about_heart.html

Don

Stephan said...

Don,

That's interesting, thanks for bringing it up.

TedHutchinson said...

@ decline in long-term breast feeding.
Fat and Energy Contents of Expressed Human Breast Milk in Prolonged Lactation shows fat content of human breast milk increases over time.
Human milk fat content: within-feed variation.and even during feeding.

Robert Andrew Brown said...

Don

Thanks for your post.

I do not dispute that overall nutrition is key to health or that stress can impact on health.

Thank you for the touching tale of your grandfather.

Here is a link to a post with two graphs that suggest rates may have fallen during WW2.

Your comment is logical, but I would like to see the data, as I wonder how much emphasis was placed on autopsies etc in a war time environment.

Robert Andrew Brown said...

Ooops. My apology I forgot the link

http://www.second-opinions.co.uk/cholesterol_myth_2.html

Dave said...

Is wheat germ agglutinin going to appear in Part II? :-)

Stephan said...

Dave,

Nope, sorry!

Alex said...

How are the Kitavan cancer statistics? Are they relatively free of smoking-induced cancer as well as heart disease?

Stephan said...

Alex,

No one has done an in-depth study of cancer in the Kitavans, but Lindeberg did report that they were free of obvious cancers when he and the rest of the medical team examined them. Except one person who had a carcinoma of the palate from chewing betel.

I'd be willing to bet they're a low-cancer population, but I can't back that up with anything solid at this point.

Ken said...

"When the industrial revolution became widespread in the late 19th century, people moved into crowded, polluted cities and vitamin D deficiency became rampant. Rickets was a scourge that affected more than half of children in some places. Dr. Edward Mellanby discovered that it's caused by severe vitamin D deficiency, milk was fortified with vitamin D2, and rickets was all but eliminated"

What caused the rickets epidemic?.

pat said...

A1c seems to be a far more accurate predictor for CAD. Reference the Asian-Indian studies and the high incidence of CAD in vegan Asian-Indians.