Monday, December 20, 2010

Dairy Fat and Diabetes

Introduction

Having access to embargoed news from the Annals of Internal Medicine is really fun. I get to report on important studies at the same time as the news media. But this week, I got my hands on a study that I'm not sure will be widely reported (Mozaffarian et al. Trans-palmitoleic Acid, Metabolic Risk Factors, and New-Onset Diabetes in US Adults. Ann Internal Med. 2010). Why? Because it suggests that dairy fat may protect against diabetes.

The lead author is Dr. Dariush Mozaffarian, whose meta-analysis of diet-heart controlled trials I recently criticized (1). I think this is a good opportunity for me to acknowledge that Dr. Mozaffarian and his colleagues have published some brave papers in the past that challenged conventional wisdom. For example, in a 2005 study, they found that postmenopausal women who ate the most saturated fat had the slowest rate of narrowing of their coronary arteries over time (2). It wasn't a popular finding but he has defended it. His colleague Dr. Walter Willett thinks dietary fat is fine (although he favors corn oil), whole eggs can be part of a healthy diet, and there are worse things than eating coconut from time to time. Dr. Willett is also a strong advocate of unrefined foods and home cooking, which I believe are two of the main pillars of healthy eating.

Let's hit the data


Investigators collected two measures of dairy fat intake in 3,736 Americans:
  1. 24 hour dietary recall questionnaires, six times. This records volunteers' food intake at the beginning of the study.
  2. Blood (plasma phospholipid) content of trans-palmitoleate. Dairy fat and red meat fat are virtually the only sources of this fatty acid, so it reflects the intake of these foods. Most of the trans-palmitoleate came from dairy in this study, although red meat was also a significant source.
After adjustment for confounding factors, trans-palmitoleate levels were associated with a smaller waist circumference, higher HDL cholesterol, lower serum triglycerides, lower C-reactive protein, lower fasting insulin and lower calculated insulin resistance. Furthermore, people with the highest trans-palmitoleate levels had 1/3 the risk of developing diabetes over the three years volunteers were followed. Keep in mind, however, that this is an observational study and does not prove that dairy fat prevents diabetes.

Even though certain blood fatty acids partially represent food intake, they can also represent metabolic conditions. For example, people on their way to type II diabetes tend to have more saturated blood lipids, independent of diet (3, 4)*. So it's reassuring to see that dietary trans-palmitoleate intake was closely related to the serum level. The investigators also noted that "greater whole-fat dairy consumption was associated with lower risk for diabetes," which increases my confidence that serum trans-palmitoleate is actually measuring dairy fat intake to some degree. However, in the end, I think the striking association they observed was partially due to dairy fat intake, but mostly due to metabolic factors that had nothing to do with dairy fat**.

Here's a nice quote:
Our findings support potential metabolic benefits of dairy consumption and suggest that trans-palmitoleate may mediate these effects***. They also suggest that efforts to promote exclusive consumption of low-fat and nonfat dairy products, which would lower population exposure to trans-palmitoleate, may be premature until the mediators of the health effects of dairy consumption are better established.
Never thought I'd see the day! Not bad, but I can do better:
Our findings support eating as much butter as possible****. Don't waste your money on low-fat cream, either (half-n-half). We're sorry that public health authorities have spent 30 years telling you to eat low-fat dairy when most studies are actually more consistent with the idea that dairy fat reduces the risk obesity and chronic disease.
What are these studies suggesting that dairy fat may be protective, you ask? That will be the topic of another post, my friends.


*Probably due to uncontrolled de novo lipogenesis because of insulin resistance. Many studies find that serum saturated fatty acids are higher in those with metabolic dysfunction, independent of diet. They sometimes interpret that as showing that people are lying about their diet, rather than that serum saturated fatty acids don't reflect diet very well. For example, in one study I cited, investigators found no relationship between dietary saturated fat and diabetes risk, but they did find a relationship between serum saturated fatty acids and diabetes risk (5). They then proceeded to refer to the serum measurements as "objective measurements" that can tease apart "important associations with diabetes incidence that may be missed when assessed by [food questionnaires]." They go on to say that serum fatty acids are "useful as biomarkers for fatty acid intake," which is true for some fatty acids but not remotely for most of the saturated ones, according to their own study. Basically, they try to insinuate that dietary saturated fat is the culprit, and the only reason they couldn't measure that association directly is that people who went on to develop diabetes inaccurately reported their diets! A more likely explanation is that elevated serum saturated fatty acids are simply a marker of insulin resistance (and thus uncontrolled de novo lipogenesis), and had nothing to do with diet.

**Why do I say that? Because mathematically adjusting for dairy and meat fat intake did not substantially weaken the association between phospholipid trans-palmitoleate and reduced diabetes risk (Table 4). In other words, if you believe their math, dairy/meat fat intake only accounted for a small part of the protective association. That implies that healthy people maintain a higher serum phospholipid trans-palmitoleate level than unhealthy people, even if both groups eat the same amount of trans-palmitoleate. If they hadn't mentioned that full-fat dairy fat intake was directly associated with a lower risk of diabetes, I would not find the study very interesting because I'd have my doubts that it was relevant to diet.

***I find it highly doubtful that trans-palmitoleate entirely mediates the positive health outcomes associated with dairy fat intake. I think it's more likely to simply be a marker of milk fat, which contains a number of potentially protective substances such as CLA, vitamin K2, butyric acid, and the natural trans fats including trans-palmitoleate. In addition, dairy fat is low in omega-6 polyunsaturated fat. I find it unlikely that their fancy math was able to tease those factors apart, because those substances all travel together in dairy fat. trans-palmitoleate pills are not going to replace butter.

****That's a joke. I think butter can be part of healthy diet, but that doesn't mean gorging on it is a good idea. This study does not prove that dairy fat prevents diabetes, it simply suggests that it may.

50 comments:

Anna said...

"If you are afraid of butter, use cream. - Julia Childs"

LeonRover said...

Well, Stephan, Ah love KerryGold and Peter Hyperlipid chugs cream!

I grew up that way and never saw a reason to change.

Tuck said...

Stephen, it's tough to express a gleeful smile through prose, but you manage it well in this post.

bee said...

butter is good, but clarified butter (ghee) is better.

Might-o'chondri-AL said...
This comment has been removed by the author.
KB said...

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Matt Stone said...

Guess I don't have to 2nd guess the 7 gallons of high-fat Jersey milk I've consumed over the past 2 weeks. Thanks for the inside "scoop."

ben said...

wow, two more excellent posts that just show why so many of us come back to your blog time and time again. Fantastic reporting.

mike250 said...

how much should the saturated fat consumption of a diet be ?

I currently consume 20g of saturated fat from the following sources: butter, cream and full fat yoghurt

julianne said...

Hi Stephan - on the subject of high fat and diabetes - have you seen this from New Zealand
http://www.3news.co.nz/Randells-revolution/tabid/371/articleID/164713/Default.aspx

Stan (Heretic) said...

You wrote: ****That's a joke. I think butter can be part of healthy diet, but that doesn't mean gorging on it is a good idea. ...

I think it is a very good idea!

I gorge on butter! I have done that for the last 11 years (I am 54). For example, a simple and useful snack: a slice of Swiss cheese with a finger-thick layer of butter spread over it. (More cooking tips, "vegetarian": stir-fry vegetables in a frying pan filled with liquid butter half-way up to the top).

Stan (Heretic)

john said...

Might-o,

If you don't mind answering, how did they die, as it would seem that's quite a [disease] preventative diet?

Ned Kock said...

I am with you on it likely being a marker of health-promoting substances like CLA, vitamin K2, and butyric acid.

Might-o'chondri-AL said...
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sagehill said...

Funny, I started buttering my Swiss cheese too.

I use Swiss mostly for cooking and only rarely eat it out of hand as it's too dry and solid for me. Last week I cut a slice for a snack but after one bite, I added a thick layer of butter to help the rest of the slice go down. The buttered Swiss was so delicious that I've been eating it that way since.

That said, Brie is my favorite cheese, so no wonder the Swiss needs butter. lol

Elizabeth Walling said...

Interesting stuff, and such a shame it isn't more widely reported (guess it's up to us?). This may explain my personal love affair with whole raw milk, as well as my fondness for cream, cheese, and basically all things dairy. I so need to get my own Jersey.

Jenny said...

My guess is that people who eat a lot of dairy fat are protected because they are eating less carbs than the people who eat low fat diets and compensate with starch.

The one concern I have with butter of late is the very troubling finding of high Bisphenol-A levels in supermarket butters, possibly from the wrappers. I'm buying store brand butter with waxed paper rather than the brand names wrapped in slick stuff, but it is possible that the Bisphenol-A is getting into cow fat from feeds and other environmental exposures too, since fat stores hormone mimics.

P.S. Did you catch the study (misreported everywhere) that found that higher levels of HDL but ALSO of LDL and Total Cholesterol correlate with decreased late onset Alzheimers? Even the researchers tried to back away from the finding that all cholesterol in older people is protective.

Willow said...

Thank you for this article, Stephan.

Do you have any information about cis-palmitoleic acid and what, if anything, affects its production in the body?

D.M. said...

True to form the BBC report this news, while carefully managing to avoid all but one, disguised reference to the fact that trans-palmitoleic acid is a fat and prominently quoting an adviser to Diabetes UK saying "dairy foods can be high in fat, which if eaten in excess can contribute to weight gain. So it's advisable to choose lower-fat dairy foods instead."

Alina said...

A lot seems to come down to "be a healthy person", doesn't it?

I am looking forward to reading more about these dairy studies. I don't limit my butter, but I think it would be practically difficult to gorge on it, even if you do add it into a lot of dishes.

Might-o'chondri-AL said...
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R. K. said...

Tim Ferriss, in his most recent book, recommends avoiding milk products when attempting his diet. The reasoning is that milk products have a high "insulinemic index (InIn)". I've never heard of this measure before, nor have I been able to find a list of other high-value foods. Do you have any opinions about the insulinemic index?

Anna said...

Jenny,

Do you have any data on BPA in Kerrygold butter? Kerrygold Irish butter is wrapped in foil (8oz bars that are easy to cut into 4 oz sticks if desired).

Trader Joe's in California carries Kerrygold at the best price I've seen anywhere so it's my everyday butter. Kerrygold's website says their products are sold in 10 store chains in your state. In my hometown area in Upstate NY, the supermarkets usually stock Kerrygold butter and cheese with the imported cheeses near the deli, not with the butter on the dairy aisle.

The Kerrygold website says their herds are pastured/grassfed. Probably doesn't guarantee that the cows don't get some grain (apparently a bit of grain is a like a candy bribe to a cow at milking time), but Ireland does have a *lot* of grass and pasture.

Kerrygold butter is visibly more yellow than just about all supermarket butters I've seen. The yellow hue fluctuates throughout the year, which probably reflects the betacarotene content as the pasture adjusts with the seasons. The homestead butter I sometimes buy at the farmer's market also exhibits quite a bit of seasonal variety in the depth of the yellow color.

Jack said...

Organic Valley's pasture butter is one of the best I've seen. Organic Pastures has raw grass fed butter too here in SoCal, but it's for rich people apparantly. The also have raw cream, but it too is for the rich so I don't use it too often. Best reasonably priced cream option I've found is Clover Farms. No other weirdo ingredients like carrageenan or preservatives. I pour a few tablespoons of it right overtop a small handful of fresh blueberries or sprouted almonds/pecans.

And I am laughed at almost daily about the amount of butter I eat. To me it's not big deal to spread 2tbsp on a slice of sprouted bread or to melt a big dallop of it right on top on a steak, but other people think I'm gonna have a heart attack right there in the lunch room.

Organic butter and cream... a staple in my diet.

EL 66K said...

Stephan, you said: "I think butter can be part of healthy diet, but that doesn't mean gorging on it is a good idea." Do you believe there may be problems with high intakes of diary fat or that other fats are superior?

David said...

so potato starch and dairy fat help prevent diabetes, so what causes it? and please don't say vegetable oils unless you have good cites to back it up...

Peter said...

What happened to LDL in the study? I'm curious because since I've been eating more fat and less carbs my LDL has shot up while the other markers are improved (HDL, TG, FG, HgA1c, CRP). My docter thinks I should take a statin, but I'm not sure. There must be some dietary experiment that would allow me keep the gains without the LDL skyrocketing.

john said...

Peter,

Chris Masterjohn recently posted on that, "Why Is My Cholesterol So High On This Diet? You May Be Curing Yourself of Fatty Liver."

zach said...

I frequently sit down with a half gallon of whole raw milk and potatoes swimming in butter. I love it so!! Always refreshing to be reminded I'm not killing myself, that meal being anathema to both the establishment and so many in the paleo community.

Might-o'chondri-AL said...
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Jack said...

What about whey protein powder? I make a grass fed raw milk whey protein concentrate drink for a post workout gulp. I have read many very positive things about this, never that it spikes insulin.

debbiedoesraw aka grass fed momma said...

For this post alone you have my undying love.
Not enough health writers talk about us lonely, fat deprived post meno ladies.
With love and butter,
Deb

Might-o'chondri-AL said...
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cpsdcarroll said...

Looks like the mainstream media picked up on this:
http://www.latimes.com/health/boostershots/la-heb-dairy-diabetes-122010,0,6787178.story

PJNOIR said...

Fear the Bread NOT the Butter

PJNOIR said...

Jack, the problem I have with any Organic Valley product is that they are strong arming their farmers not to sell Raw Milk and have acted quite like mobsters. I am so happy that I can legally buy raw milk though I can't buy raw cream or butter. I told OV to take a hike. Naturally by Nature has great products and Kerry Gold butter is tops.

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Helen said...

David,

What's causing all this diabetes? From my perspective, as someone who's always done almost everything "right" health-wise (though what seems right changes, frustratingly), and who has diabetes, I'd have to say genes have a lot to do with it. It's kind of like gluten sensitivity. All people will be affected by gluten to some degree, but only those with the right genes will get celiac disease or other serious gluten-related disorders. But there are lots of people with those genes, not a few, as with diabetes.

Diabetes is more complicated than gluten sensitivity, though, because it can arise from a variety of flaws in the metabolic (and immune, in Type I) system, which is why it can't be construed as one disease, or even two or three.

I think one modern culprit tripping the switches for those with vulnerable genes is inflammation - caused by an inflammatory diet, disruptions to gut flora, an overly clean environment, various industrial chemicals and pharmaceuticals, and a lot of other features of our modern age.

All of these factors are also at play in the rise in obesity and insulin resistance. With weight gain and insulin resistance, some people's glucose-sensing/insulin-making capacities are more easily overwhelmed than other people's, leading to Type II diabetes and other forms. Other people can gain substantial weight and develop metabolic syndrome and never get diabetes. They aren't particularly healthy, but they don't have diabetes. On the other hand, I have a BMI of 22 and sort of the opposite of metabolic syndrome and insulin resistance, and I have diabetes (but not Type I).

Jack said...

PJNOIR,

That's weird because OV sells raw milk cheese. I don't know much about their corporate politics. Maybe soon enough I will be able to drop $10 a tub for the raw stuff from Organic Pastures. I buy their raw milk and it's fantastic. Anyway thanks for th info.

-Jack K

Nutripolice said...

Stephan,
Nutritional epidemiology at its best?
Mean plasma trans-palmitoleate was 0.18% of total fatty acids, with about 95% of values between 0.08 and 0.28%. Trans-palmitoleate must therefore be an extremely potent fatty acid, to exert such powerful effects at such tiny amounts, right? Yet there is no actual mechanism to support this.
How many associations do you think were tested? (-without correcting for multiple comparisons). Some consider this type of research 'fishing expedition', although it is clearly not presented as such in the paper.
Stephan,
What odds do you give of this being a causal association?

willw2 said...

I keep trying to find the MCG levels for K2 in commercial butter oil but no one seems to publish that. Your blog has so many postings about k2 that I've been reading and so thoroughly appreciate.

Anyway, let me know if you know of a butter oil that publishes that type of data.

-Will

Stephan said...

Hi Nutripolice,

I think you're right to be skeptical. First of all, the inverse association between trans-palmitoleate and diabetes may not even reflect cause-and-effect in the first place. But assuming for a moment that it does, I find it highly unlikely that trans-palmitoleate is "the active ingredient" rather than simply a marker of dairy fat intake (and also in part a marker of metabolic health that's mostly independent of diet).

My prediction is that if they do a controlled trial with trans-palmitoleate pills, they will find no significant metabolic effects.

Hi willw2,

That information is not publicly available to my knowledge. I suspect it would not be in the manufacturers' best interest to release it. Otherwise they already would have.

robrob said...

I love butter I add it to brown rice to lower its gi. I use alot of cocounut oil, I use extra virgin, I eat organic bacon several times a week (didn't used to eat like this most of my life by the way)I love whole milk now I used to wonder why i craved it even tho I didn't drink it due to high sat fats for years. I would only use skim which I hated so didn't last long then 2 percent then none at all because of all the bad press about dairy.

I did the low fat high carb diets I did low cal diets low carb like atkins I did so many I lost count. never got lean and stayed there. my triglycerides are always high my cholesterol, my bp is a real mess and has been for over 30 years. I worked at keeping my sat fat low. didn't help my parmeters at all. I have done the supplementation, exercise programs nothing helped my hypoglycemia events in the middle of the night the nervousness. the cravings for constant eating especially so called junk carbs like cheetos.

but by mixing up my diet with only whole carbs and whole dairy and lower gi foods like bacon and cheese and meats etc, I have seen a reduction in my nightime hypo events, too early to tell but so far so good.

a good article to read is called the obesity epidemic, is the metabolic syndrome a nutritional deficiency. she has other articles there about fructose and glucose. or you could google stephanie seneff. get to her home page.

I enjoy her articles immensly. I encourage anyone who is struggling with metabolic syndrome and not knowing what is the best diet to view these. they have helped me alot.

Willow said...

@robrob

Can't connect to the articles you recommend by stephanie seneff. I get:

"The server at people.csail.mit.edu is taking too long to respond."

Peter H in AK said...

Stephan - fascinating! Do you have any thoughts on how goat milk would differ from cow milk? I've heard that goat meat is the most commonly consumed meat in the world, so I'd guess that goat milk is the most commonly consumed non-breast milk in the world...

Might-o'chondri-AL said...
This comment has been removed by the author.
ramon25 said...

I know its late but the company with BPA in its butter was lando lakes.....

PJNOIR said...

As a diabetic, don't confuse something that may PREVENT diabetes with having it be good for you WITH diabetes. I do use grass fed butters for most cooking and enjoy a bit of raw milk now and then. But overall Milk causes havoic with my numbers.

v/vmary said...

my mother has metabolic syndrome, diverticulosis, bone cancer, heart disease, type 2 diabetes, fatty liver, high blood pressure. she is 75 and still hanging on with the cancer medicines tykerb and xeloda.

she was a holocaust child. she experienced starvation and consequently her leg bones did not grow to proper length. her trunk length is out of proportion to her legs.

her gall bladder was removed when she was in her 40s.

she has always consumed full fat dairy (even now), sour cream, cream cheese. she eats a lot of processed food as well. she used to always drink tea with sugar.

she has never smoked or taken a drop of alcohol.

my father also has type 2 diabetes. he never smoked or drank alcohol. he grew up eating no processed food, but started to eat a little more after he got married. he was on the chubby side when he was young, but excelled as a safety in football. he used to chug cans of evaporated milk. growing up we always had full fat dairy- i don't know what kind of milk my father drinks now. he has always done heavy physical labor having grown up on a farm and having become a full time farmer in his 40s.

both parents were diagnosed with diabetes in their 50s. but before that they both probably had metabolic syndrome as reflected in their big guts.

morten_g said...

I think you neglected to reiterate in your post that being overweight is still the greatest hazard factor for diabetes (along with genetics).

Just curious - are there any studies comparing homogenized milk with non-homogenized?