A review just published in the Annals of Internal Medicine concluded that current evidence does not support limiting saturated fat or increasing polyunsaturated fat for preventing heart disease.
The New York Times report on this study is accompanied by a large color picture of a juicy cheeseburger.
But the important message in the study, which I reveal below, gets lost in the oversimplified headline and cheesy photo.
It feels like the movie, Sleeper, in which all the dietary advice of the 1970s was found to be wrong by the 22nd century.
In fact, most medical dogma of today will be obsolete well before then. The lifespan of a medical "truth" is actually about 30 years. Not because the facts are necessarily wrong, but because a deeper or more comprehensive understanding changes their interpretation.
So what does this new study actually say?
It's a review of 76 previous studies involving about 650,000 people that looked at future risk of heart attack or related cardiovascular events as influenced by dietary fat intake, supplementation or blood levels of specific fats. It pooled data from similar studies (this is called a meta-analysis) and applied a new statistical analysis to determine whether any associations were truly significant and not likely to be due to chance.
Trans Fats Cause Heart Disease
The review found a well-known culprit: trans fats, which were the only dietary fats associated with an increase in cardiovascular events. Trans fats are mostly found in hydrogenated vegetable oils. I warned against their use in my first book, Superimmunity for Kids.
At the time, vegetable oils were considered good for preventing heart disease and warnings about trans fats weren't taken seriously by the medical profession. Since then, all the evidence has shown that hydrogenated vegetable oils are toxic. It took about 30 years for the notion that margarine is good for your heart to be abandoned.
The review also found that margaric acid, which reflects dairy fat consumption, was associated with a significantly reduced risk of heart disease. A protective effect of dairy products has been demonstrated before, many times. Because a protective effect of milk fat doesn't fit into the cholesterol theory of heart disease, which has by now outlived its 30 years as a "truth," this evidence has been largely ignored. That's likely to change.
(More, "Frankenfats: How the Food Industry Created a Monster Fats Should Be Viewed Wholistically.")
The review also found that having high blood levels of two omega-3 fats, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) and an omega-6 fat (arachidonic acid, AA) significantly reduced the risk of future cardiovascular events, although it didn't indicate where these fats came from.
To a large extent, the levels of DHA, EPA and AA in your blood reflect your body's ability to create them from dietary precursors, so these levels may actually reflect the health of your metabolism, which depends upon your consumption of several nutrients in addition to fat, including vitamins B3 and B6 and zinc.
Overall Quality of Nutrition and Reducing Inflammation are Key
The message hidden in this report is that the overall quality of your diet determines your risk of heart disease more than the intake of any particular individual fat. That's the kind of truth that will outlive 30 years.
Present evidence indicates that the ability of your diet to provoke inflammation may be the most important factor in the relationship between diet and health. I've discussed anti-inflammatory foods in many previous blogs on Huffington Post, see "Olive Oil: A Natural Painkiller?"
No single nutrient defines or determines an anti-inflammatory diet. It's the whole dietary pattern, the nature of the food, not just the individual nutrients. A wholistic systems approach is the future of nutrition science. That's the real meaning buried in the Annals review.
Now I'd like to hear from you:
Are you concerned about dietary fats and oils?
How does this new study change your view?
What do you think of the media coverage on this study?
Let me know your thoughts by posting a comment below.
Leo Galland, M.D.
Leo Galland, M.D., is a board-certified internist, author and internationally recognized leader in integrated medicine. Dr. Galland is the founder of Pill Advised, a web application for learning about medications, supplements and food. Sign up for FREE to discover how your medications and vitamins interact. Watch his videos on YouTube and join the Pill Advised Facebook page.
References and Further Reading
Chowdhury R. Warnakula S, Kunutsor S, et al. "Association of Dietary, Circulating, and Supplement Fatty Acids with Coronary Risk." Annals of Internal Medicine 2014: 160: 398-406.
Huth PJ, Park KM. "Influence of dairy product and milk fat consumption on cardiovascular disease risk: a review of the evidence." Adv Nutr. 2012 May 1;3(3):266-85.
Yerlikaya O, Acu M, Kinik O. "Importance of dairy products in cardiovascular diseases and type 2 diabetes." Crit Rev Food Sci Nutr. 2013;53(9):902-8.
Galland L. Diet and inflammation. Nutr Clin Pract. 2010 Dec;25(6):634-40.
Superimmunity for Kids : What to Feed Your Children to Keep Them Healthy Now, and Prevent Disease in Their Future, Leo Galland with Dian Dincin Buchman, Dell
This information is provided for general educational purposes only and is not intended to constitute (i) medical advice or counseling, (ii) the practice of medicine or the provision of health care diagnosis or treatment, (iii) or the creation of a physician--patient relationship. If you have or suspect that you have a medical problem, contact your doctor promptly.