Another Dollop of (about, Actually) Butter
David L. Katz, MD, MPH
CMO, Tangelo. Founder: Diet ID; True Health Initiative. Founding Director, Yale-Griffin PRC (1998-2019). Health Journalist. COVID Curmudgeon
In the aftermath of his commentary about butter in the New York Times, and my commentary about his commentary in my LinkedIN and Huffington Post blogs, Mark Bittman and I- along with several others, including Dr. Dariush Mozzafarian from Harvard, one of the authors of the study that set this all in motion- were invited to discuss the health effects of butter on the NPR program, On Point, this morning. Frankly, Mr. Bittman’s on-air comments were very moderate, and very reasonable, far more so than his column, and in particular, the headline. Mr. Bittman let me know via email that the headline was not of his choosing, but that doesn’t matter much, since the headline merely repeats ver batim his own words from the second line of his piece.
In any event, I would like the world to know that if Mr. Bittman’s column had sounded just like his comments on NPR today, I would merely have appended: amen. But it did not. In fact, rather gratifyingly, his comments today sounded rather more like my column than his, at least to my ears. So amen to the on-air comments today, but not to the New York Times column which will doubtless reach many more people, and do some real damage as a result.
Here, in a dollop, is what I have to append to my prior commentary about the nature of that damage.
1) Regarding the study: the new study was very questionable in its significance and implications for many reasons, most salient of which is the complete failure to consider food substitutions. People eating less of A invariably eat more of B in its place. This study did not consider, address, or even mention B. We can, however, make a well-informed guess* about what ‘B’ is in our culture, and I’ll return to that shortly.
2) Regarding Mr. Bittman, and with all due respect: all evidence suggests he opined on the study, in the New York Times no less, never having read it. If he had read it, by his own admission to me on a prior occasion, he lacks qualifications to interpret epidemiologic research as anything other than a guy with a decidedly non-expert opinion, and in this case a pretty clear bias into the bargain.
3) Regarding butter: the study was not about butter. It was about variation in fatty acids, both in dietary intake and in the bloodstream. So the ONLY legitimate way to apply the findings to butter would be to compare the fatty acid profile of butter to the study findings. I think it can go without saying that Mr. Bittman did not do that. I did- as, I presume, did most of my professional colleagues in nutrition. Here are the results of that comparison:
- The most abundant fatty acid in butter is palmitic acid, a 16-carbon saturated fat.
- Of 17 fatty acids included in the analysis, palmitic acid was associated with the 3 greatest INCREASE in rates of heart disease; the greatest increase of all was associated with stearic acid, a 18-carbon saturated fat ALSO abundant in butter.
- Therefore, while it’s a leap of faith to apply this study to butter at all, if that is done- the only conclusion possible is that butter, is indeed, a hazard to the heart, and on that basis best minimized or avoided- not added back.
- As for the effects of butter on recipes, or taste buds, I defer to Mr. Bittman. But he should apply his opinions very cautiously to the public’s coronary arteries before someone gets seriously hurt.
4) *Finally, that informed guess: Abundant evidence indicates clearly what we eat instead when we cut our saturated fat intake. Americans, alas, have not swapped out their salami for spinach, nor their Swiss cheese for Swiss chard. We have swapped out sources of saturated fat for sources of refined starch and added sugar, like Snackwell cookies.
- On the one hand, this readily explains why lower intake of saturated fat is NOT associated with lower rates of heart disease: we simply moved from one way of eating badly to another.
- But more interesting in the context of Mr. Bittman’s argument that starch and sugar are the ‘real’ culprits in our diets: If that were so, the lowest intake of saturated fat should be associated with the HIGHEST rates of heart disease, because less saturated fat means more sugar and starch. But that association was NOT seen; there was almost no variation in heart disease rates with variation in saturated fat intake. So this study ALSO shows that the nutrients replacing saturated fat- namely, sugar and starch- are EQUALLY UNASSOCIATED with variation in heart disease rates. This is a classic case of: what’s good for the goose is good for the gander. There is NO evidence here to support the assertion that something other than saturated fat is the ‘real’ culprit.
- The reason for that, other than the important limitations of the study, is that there is no single ‘culprit’- that effort to find a scapegoat is misguided and harmful. Rather, the overall pattern of the diet exerts an enormous influence on heart health- both because of what the diet includes and what it excludes. The evidence is clear that overall variation in diet quality can dramatically influence heart health, and heart disease risk. And with suitable attention to foods and the pattern of the diet, the nutrients sort themselves out quite handily.
We can all benefit- hedonistically, at least- from Mr. Bittman’s aptitudes in the kitchen. And when the dust clears, he and I agree- in Michael Pollan's good company- about a diet of minimally processed foods, mostly plants. But when it comes to epidemiology, he needs to be a lot more careful about impersonating an expert (whatever the associated headlines). He is otherwise at risk of being one cook too many, and doing nothing more productive for public health than spoiling the stew.
-fin
Dr. David L. Katz has authored three editions of a nutrition textbook for health care professionals. He is editor-in-chief of the peer-reviewed journal, Childhood Obesity, and President of the American College of Lifestyle Medicine. He was commissioned by Annual Review in Public Health to write the review article, Can We Say What Diet is Best for Health? He is the author, most recently, of Disease Proof.
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Director of Clinical Services
9 年burn
Founder / Educational Director at Reading & Spelling Solutions LLC
10 年Good article, and that's why I eat very little butter -even though I am a dairy farmer's daughter.
Regional Director of Operations at Renal Research Institute / Fresenius Medical Care
10 年First, thank you Dr. Katz for your insights. I love reading your articles/blogs. One of the things that I always find amazing when it comes to discussion of foods is that regardless what one article said, there is always another to say just the opposite - the moral of the story is consumption with an open mind not open gullet. Comming from Europe and having grown up on a farm, we had very simple food choices. All natural, all homemade and NO artificial anythings added. My family has a strong history of longevity, despite working bonebreaking labor most of their lives. They are slender and heart healthy. Back home, we worked off what we ate each and every day. I guess my grandmother (the cook) was very smart because she avoided fats from most sources - we cooked with sunflower oil if fat was needed, we drank skim milk, and we never used butter. We were also careful with salt or sugar. We used a lot of home grown herbs and spices for flavor. Farm fare here does look a lot more unhealthy than what we ate. Grandma lived to 87 and my mother is now 81 and in excellent health and her brother is 80 in same good health. It is the whole lifestyle here that is unhealthy and no single study will find the magic bullett to fix it.
Erica Ilton Nutrition
10 年My understanding was that stearic acid is considered neutral regarding its effect on LDL cholesterol, yet you write that this study found it to be associated with the greatest increase in rates of heart disease. I know correlation does not imply causation (and cholesterol's role in heart disease is...complicated) but my first thought on reading this was, "Bummer...do I have to reevaluate my chocolate consumption habits?!"
Nutrition Consulting, Writer, Blogger, Speaker
10 年The intensity of this debate would be more compelling if we weren't talking about epidemiological studies which are limited to establishing correlation, not cause and effect. Our food supply is adulterated and most animals have not been fed their natural diet since the 1950's. Today the USDA even allows CAFOs to feed animals stale bakery products (with all their associated trans fat). In addition, many pollutants are fat soluble and bio-accumulate in the food chain. I often wonder if we are assessing the impact of a contaminated planet as opposed to problems with saturated (animal) fat. Today every large population study is significantly biased, mostly because the public has been admonished to avoid saturated fat and cholesterol for almost forty years. In many of these studies, people who ignore nutritional recommendations also smoke more, don't exercise, don't eat enough fruits and vegetables, don't get enough sleep and engage in all manner of unhealthful behaviors. While researchers try to isolate the variables, I'm fairly skeptical of the statistical gymnastics taking place trying to account for them. And then there is the critical question of how we gather the dietary data in the first place. I continue to wonder why we put so much credibility into 24 hour recalls and food frequency questionnaires. Most of my clients struggle to remember what they ate yesterday, and they have no idea how to measure the amount. Lastly, population studies simply can't address the range of metabolic variability in individuals. Randomized trials inadvertently perpetuate the myth that we are all the same. Genetic and epigenetic factors influence nutrient partitioning, and a diet that works for one individual is not effective for another. People eat food, not nutrients, and the whole of the diet is only one of many factors that influence health. We need to stop pretending that there is one single right way to eat.