In the last few years, a number of "experts" have become quite vocal with the notion that saturated fat isn't bad for you. They drive me a little nuts, to be honest, because they all fall back on the same three, flawed arguments.
- Ancient, indigenous peoples who ate a bunch of saturated fat and were still super healthy.
- It's refined carbs, not saturated fats, that are responsible for our obesity epidemic, as well as skyrocketing diabetes and heart disease numbers.
- The science behind the link between saturated fat and heart disease is wrong.
I want to focus on the third one today, but let's blow through those first two quickly. Regarding those indigenous people, they lived in toxin-free environments, ate entirely natural diets and exercised huge amounts. Could it be that they were healthy in spite of the saturated fats? Furthermore, the amount of saturated fats they actually ate is up for some degree of speculation. Even when they nail down numbers of these "high saturated fat" diets, it's not that much fat. From Whole Health Source:
First, there's the whole coconut saturated fat versus animal saturated fat issue, which I'm going to save for another blog. Them there's the fact that 21% fat is bordering on a low-fat diet, so lipid advocates should probably tread softly when mentioning the Kitavans. Third, the rest of their moderately low-calorie diet was "root vegetables (yam, sweet potato, taro, tapioca), fruit (banana, papaya, pineapple, mango, guava, watermelon, pumpkin), vegetables (and) fish." Sorry, fellas, but there are just too many confounding variables in there to elevate saturated fat to "must eat" status.
Next, the whole refined carb thing. I'm just going to say this: Has it ever occurred to you that both bad carbs and bad fat could be the problem? What is it with nutrition "experts" and their mutually exclusive villains?
Now, let's move on to #3, the heart disease thing. Some of the research in the past might not have been spot-on - and that's compelling, but here's the deal: Heart disease isn't the only illness that saturated fat might play a part in. All these pro-sat-fat sites are happy to warble on about heart disease, but they all seem to side step the increasing body of evidence linking saturated fat to cancer, including...
And why stop at cancer? Researchers at UC San Diego have a found a link between saturated fat and type 2 diabetes.
This is hard science. It's not some bare-chested beef-o-phile trying to pitch his blueprint book. It's not some conspiracy theory "foundation" looking to Eskimos for advice on modern living. (The fact that it never occurred to them to drop down a few latitudes when it got chilly kind of discredits them for me personally.) These are serious scientists breaking down our relationship with food on a cellular level. They should be listened to.
Don't get me wrong. I'm all for ancient wisdom and traditional cures. I'm in the middle of getting a masters in holistic nutrition, for Pete's sake! But in the same way I think the anti-bad-carb and anti-bad-fat crews need to work together, I think that the fringe needs to check in with the mainstream sometimes to make sure that they're not spouting lunacy.
http://nutsci.org/2011/08/12/latest-cochrane-review-on-dietary-fats-and-cardiovascular-disease/
ReplyDelete"Based on multiple, large meta-analyses from different study designs, saturated fat is still in a bit of hot water. But with all of this research we now know it is much less of a threat than originally thought."
Awesome. My weekend read! :) I wonder if this meta-study considers this diabetes research?
ReplyDeletehttp://www.ajcn.org/content/early/2010/01/13/ajcn.2009.27725.abstract
ReplyDeleteThis put together data from 21 different studies that included nearly 350,000 people, about 11,000 of whom developed cardiovascular disease, tracked for an average of 14 years, and concluded that there is no relationship between the intake of saturated fat and the incidence of heart disease or stroke.
That's great, Jeff, but did you even bother to read the blog post before posting that?
ReplyDeleteYeah, I see that he talks about cancer and ignores heart disease. I have some comments about the findings in the cancer links but I'll respond when I have more time. I posted the link I did due to the dismissive nature of sat fat/heart disease relationships and the 'fringe' crow that advocates consuming sat fat.
ReplyDeleteWell, the "he" you refer to is me and I look forward to your comments, but if you really want to make an impact, perhaps you can directly comment on the diabetes findings.
ReplyDeleteAh, I didn't know you were the author, I will be happy to
ReplyDeleteLooks like your biases show:
ReplyDelete2 randomized trials showing PUFAs --> Cancer:
1. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2871%2991086-5/abstract
2. http://archinte.ama-assn.org/cgi/content/full/158/11/1181
One of numerous epidemiological studies showing PUFAs --> Cancer:
http://onlinelibrary.wiley.com/doi/10.1111/j.1349-7006.2005.00084.x/full
For further reading, note that dairy fat is usually associated with less cancer. Funny given that dairy fat is highly saturated. Take a look at the EPIC study. Could be the vit K... But even if so, the palmitic acid doesn't seem to be so bad then.
Try to be a little more objective in the future.
The Karin et al. study seems to be based on in vitro cultured cells and on mice. A controlled study with humans would be a lot more persuasive. Since we know of human cultures that eat diets high in saturated fat but are remarkably free of diabetes, I think the burden of proof required to establish a link between saturated fat intake and diabetes is unmet by in vitro or rodent studies — which isn't to say that such studies are worthless.
ReplyDeleteYou may have already seen this, but in case you haven't, here is Denise Minger's review of another study linking fat intake with diabetes in mice:
http://www.marksdailyapple.com/does-a-high-fat-diet-cause-type-2-diabetes/
My biases? Have you read my blog much? I doubt it, or you would be familiar with the times I've defended sat fat.
ReplyDeleteAs for your studies, the first one is from 1971 whereas all my studies are from the last ten years. The vast amount we've learned about cancer in the last 40 years dates this study instantly.
Your second study lumps sat fat and polyunsaturated fat in the same group. It doesn't differentiate, so the researchers wouldn't know which, if either, was the problem fat - and even if PUFAs were the problem, where have you ever read me espousing the benefits of a high-vegetable fat diet? On the other hand, I've committed a lot of words to the benefits of omega-3 fatty acids - which the study you've pointed to seems to think are the reason behind the lack of cancer.
Finally, that last study admits that the reason the PUFAs caused an issue was because of the decrease in omega fatty acids. Where have I EVER recommended that?
And I don't see you addressing the diabetes issue.
You're totally trying to twist my words for your own agenda and in so doing, totally proving my point. If you want to engage me and prove me wrong, I would love that, but don't do it by lobbing studies at me that I can knock back. To be honest, I was waaaaaaaaaaay more interested in the diabetes research than the cancer stuff, so I didn't scrutinize the studies I linked as much as I should. HAVE A LOOK AT THEM. TEAR THEM APART - then I'll respect your stance.
maurile -
ReplyDeleteI like your comment and your point is valid. Thank you. I'm not a fan of the Daily Apple. He frequently distorts research, but I will look at it nonetheless.
I'm just a little steamed up right now, so I'm taking a break.
The diabetes article doesn't implicate dietary saturated fat, it's about the type of fat in cell membranes. Eating a 100% carb diet you will still end up with palmitoleic acid in your cell membranes, inter alia, because that's what our body stores calories as. Everything get stored as animal fat calories. Take a natural, healthy, all grass-eating cow (or animal) and their fat will be roughly half saturated half mono-unsaturated. Fwiw, if you feed them more grains, or more calories generally then they'll more saturated fat.
ReplyDeleteTo pre-empt objection, I see that they also tested the mice after feeding them a fattening 60% fat diet and found, to their shock I'm sure, that they were unhealthy. I can't read the paper from here, but I'm willing to bet that this is another examples of mice being fed an inappropriate high artificial fat (possibly trans fat), high sucrose, zero food diet and getting sick. It's also not a fair comparison to contrast saturated fat versus EPA. We know that added n3 oils can reduce diabetes, that doesn't suggest that plain SFA worsens diabetes compared to unsaturated fats. We also know that eating a high EPA, or at least high n3 diet, is naturally impossible and extremely ill-advised.
Others have already pointed out that you are basically just cherry-picking epidemiological evidence when not all studies support your conclusions, and no correlative data could actually support a conclusion anyway because of confounding factors, which you seem to be aware of. Perhaps confounding factors are only relevant when they support your beliefs.
ReplyDeleteBut the diabetes study is different. There is basically no evidence that dietary saturated fat causes insulin resistance in humans, and there have been randomized controlled trials that falsified the notion http://wholehealthsource.blogspot.com/2010/02/saturated-fat-and-insulin-sensitivity.html.
Even just reading your source it is hard to say that the phenomenon described implicates saturated fat, as they noted that EPA was preventative of the JNK downregulation. It should not be interpreted as 'saturated fat bad, EPA good" but as "EPA is necessary for the proper regulation of palmitic acid's role in regulating insulin sensitivity". Indeed, most of the studies in rats that claim to show that saturated fat in the diet is bad do so in the context of an omega-3 deficiency, if you add some fish oil there is no damage done http://www.ncbi.nlm.nih.gov/pubmed/3303333
It strikes me as nonsensical that the body would be designed to harm itself on exposure to saturated fat, natural selection doesn't create organisms that induce pathology upon encountering a nutrient just for the heck of it. The reason why palmitic acid has a role in downregulating JNK is not because natural selection wants us to die, but because palmitic acid in the cell is often a sign of a glucose shortage. When glucose is short, we do not want our skeletal muscles to take up glucose, because we need it more for the brain. The muscles can run on fats, but certain parts of the brain can't. So palmitic acid induces a reduction in insulin signaling to prevent the muscles from leeching glucose from the blood stream. It is adaptive, and not pathological, because in healthy people you will only ever get this insulin resistance in the context of low serum glucose, and so there will be no hyperglycemia associated with insulin resistance and once glucose is more abundant in the body insulin sensitivity will be restored http://high-fat-nutrition.blogspot.com/2009/09/physiological-insulin-resistance-and.html
Stabby -
ReplyDeleteI like all of what you have to say, save that first paragraph, which is just kind of weird considering I said this earlier, "I was waaaaaaaaaaay more interested in the diabetes research than the cancer stuff, so I didn't scrutinize the studies I linked as much as I should. HAVE A LOOK AT THEM. TEAR THEM APART - then I'll respect your stance."
Before judging me, you should take some time to read this blog - as in, more than this entry. My "beliefs" are that all things should be taken in moderation and that sacred cows need to be questioned. That's about it.
Regarding all the stuff you and David said about diabetes, I find it absolutely fascinating. A great perspective. In fact, I now have a ton of questions, so next week I'm going to try to get hold of the scientists who did this diabetes study and ask them. If you have anything you'd like to ask, please let me know. Please keep your questions objective and polite.
Denis - Nice post. Simple question: Are you saying that you agree with point number 3?
ReplyDeleteThanks.
No I'm not. I should have been more clear, perhaps. I think the science is extremely gray. I think people who pick a side in the debate - either side - are ignoring a lot of science. I think it's cool to have an opinion, but I think it's a mistake to get dogmatic about it.
ReplyDeleteI also think that 99% of the literature out that's pro-sat-fat is deeply flawed, for reasons listed above. Both Mark Sisson and Sally Fallon drive me nuts. They totally twist stuff.
I'm really impressed with some of the responses here today. I'm thankful to meet intelligent people on the pro-sat-fat side because I have been having a hard time finding them. I used to read Hyperlipid but stopped because I didn't have the knowledge I have now and it went over my head. I think I'll resume.
D Faye,
ReplyDeleteI definitely don't drink the "paleo" kool aid and disagree with a lot of the wisdom preached as part of that way of eating. I also agree with you on Sally Fallon and sort of on Mark Sisson (I try to keep up with his blog and I think he honestly tries, sometimes he misses but more from misunderstanding than twisting things, as far as I read into it, and he gets a lot right).
The fact is that the actual studies out there are not completely convincing one way or another. But one thing you have to be very careful about (aside from the usual epidemiological caveats) with the fat-leads-to-bad-outcomes studies is that you would be hard pressed to find studies where high-quality fats are used. Many surveys on human consumption consider consumed fat very loosely. You simply won't find any study that differentiates between high quality whole food fat intake (i.e. steak vs. a processed hamburger with a bun; eggs cooked in butter vs. a bacon-egg-and-cheese sandwich from the corner store) and still finds any meaningfully bad outcome. Those studies simply dont exist, and part of the reason is that it is not a standard Western diet or a diet that can be easily controlled for in a lab. Standardized high-fat chows are simply nothing like a whole food or "paleo" diet would be in a human. The couple studies that you pointed to, in my opinion, are not meaningful. Some of the comments are spot on.
And where I also agree with the paleo people is that there is no biological reason/mechanism that consumption of saturated fat in itself should be bad for the body. Without that sort of foundation, these studies can be interesting but I would look at them much more critically than you looked at these few here. Would be nice to have a compelling RCT, for instance.
The sat. fat question is a big one because it's so ingrained in official recommendations. However, I don't see how the kind of saturated fat that you'd get in grass-fed beef, for instance, could possibly exert a negative effect on the body in and of itself. Also, when you get saturated fat from whole food animal sources you are also getting a very high concentration of amino acids and micronutrients, which is a pretty compelling reason to eat anything.
"No I'm not. I should have been more clear, perhaps. I think the science is extremely gray. I think people who pick a side in the debate - either side - are ignoring a lot of science. I think it's cool to have an opinion, but I think it's a mistake to get dogmatic about it."
ReplyDeleteWell I'm glad to hear this. Despite all the bad science and lacking any type of reasonable hypothesis and physical mechanism, the anti-staturated fat crowd has used up all the dogma for a few generations to come. The concept that saturated fat is bad for us is so engrained is our thinking that most people take it as a given without even questioning its validity. Many doctors don't even question it, and will tell you to stop eating fat and write a statin prescription before you can get a word in edgewise.
Two wrongs don't make a right.
ReplyDeleteI agree, and I'm not picking a side.
ReplyDeleteIn my mind, the real damage is that a large fraction of doctors and research funding agencies have gone along with the dietary saturated fat/heart disease link thinking that it was/is the real cause and that they had the correct cures in the form of low fat diets and statins. When in fact they don't, and if this was realized earlier an actual cure could be pursued and we'd have less heart disease.
Again, nice post.
I have been looking at the Paleo way of thinking, and I see good and possibly bad points. One thing it has done is bring new foods (and ways to prepare them) into my line of vision. I am a medical technologist and a fitness junkie, so the high fat (of any kind) that are in some of these foods bothers me....I work in a medical lab, and every day I see people whose blood looks like milk from all the fat. It makes me cringe. While I will incorporate some Paleo practices, I will still eat grains and dairy occasionally....I just like them, and it gives me some variety. Common sense should be the key word here; a bag of chips is not healthy- eat an apple! My Grams used to say all things are good in moderation. She was a smart woman.
ReplyDelete"I'm not a fan of the Daily Apple. He frequently distorts research, but I will look at it nonetheless." - Dfaye
ReplyDeleteI find this interesting since he helped develop the original P90X. As you know, he appears at the end of some of the videos shilling the P90X supps.
Care to comment on how you differentiate your diet philosophy with that of the wacky, outdated 'phases' of the the p90x diet?
Sure. Just because someone has done contract work for the same company I work for doesn't mean I have to toe their line. Unlike many, I base my opinions on my own research and analysis.
ReplyDeleteAs for the P90x plan. I fail to see what's outdated about a plan that offers three varied macronutrient profiles and can be adapted to almost any style of eating that comes along - including vegan and paleo, both of which we've provided variations for in the newsletters BTW.
And by the way, I've taken on Mark's notions many times, and I always sign my name to it. He's never received criticism from me assigned "Anonymous."
Bad fat and bad carbs are the problem. But saturated fat isn't included in the "bad fat" category.
ReplyDeleteYour argument doesn't even begin to address the actual argument against saturated fat. In fact, it's exactly the type of argument that I believe has been effectively repudiated. Saturated fat is correlated with poor health because saturated fat is eaten by people who don't care about their health, so they do everything else wrong, too. In addition, most saturated fat is eaten in the form of things like fast food hamburgers and fried foods. Perhaps it's everything eaten alongside the fat (trans fats, wheat, sugar, etc.) that is causing the problems.
Here's a video that you might enjoy: http://www.youtube.com/watch?v=exi7O1li_wA