Saturated Fat Paradigm: Time to Update our Thinking?

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Saturated Fat Paradigm: Time to Update our Thinking?

12, June 2014 2:57 PM


For years, the accepted dietary approach to reducing heart disease risk was to minimize intake of saturated fats, which were thought to lead to increased cholesterol levels, atherosclerosis and heart disease. As research has evolved and our knowledge of these associations has improved, this conventional advice is now regarded as overly simplistic. A recent meta-analysis in the Annals of Internal Medicine, which consolidated results from 72 observational and clinical studies, escalated the dialog, showing that saturated fat is not as closely linked to heart disease as once believed.

The change in thinking is difficult for many to embrace given the decades of advice to avoid fat. It was ingrained into anyone educated in the 1980s and 90s that dietary fat is bad, and saturated fat is worse, for a multitude of reasons. As scientists, health professionals and researchers, however, it is our duty to look at the whole body of evidence, put aside outdated paradigms and be open to understanding and explaining new concepts as warranted by the evidence.

Why the complete 180-degree turn in research?

I like to call nutrition, like any science, a ‘living, breathing field’ that evolves over time. It is not that science is or was “wrong” -- rather, good science continuously adds to our knowledge base with new research so that we can better understand the nuances of the effect(s) being examined. Below are some ways our thinking has evolved on this topic:

  • The early studies done on the association between saturated fat and heart disease lumped all saturated fats together. Just as we now know that there are multiple types of carbohydrates -- with differing effects on health -- we also know that there are various types of saturated fat. Some, such as margaric acid, a saturated fat in dairy foods, is associated with lower heart disease risk. Others, such as stearic acid, may have a neutral effect on heart disease. Conversely, the past 5-10 years of research have shown that omega-3s from fish and fish oil -- once deemed the heart’s “supernutrient” -- are less beneficial than once thought. 

  • There are also different types of low-density lipoproteins (LDLs) -- the “bad” cholesterol in our blood—with some types (the small, dense particles) being “more bad” and other types (the large, fluffy particles) being “less bad.” Early research that looked at the effect of saturated fats on LDL was unable to tease out the type of LDL, lumping the results together.

  • The early studies also failed to look at the effect saturated fat has on HDL, the “good” cholesterol. The new meta-analysis found that saturated fat was associated with an increased HDL.

  • Finally, over the past 30-40 years that we have been studying dietary fat and heart disease risk, methods of examining dietary intake have improved, statistical methods have become more robust, confounding factors are better identified, and more clinical studies -- the “gold standard” of nutrition research -- have become available to contribute to the body of research.

So, while it is not time to “throw the baby out with the bathwater,” it is time to relook at the data … time to let go of the dogma that we have been raised on… time to back up and examine whole diets and lifestyle patterns, rather than isolated nutrients, in our quest for disease prevention and optimal health. 

What does this mean for dietary recommendations?

Public health recommendations typically lag behind research. This is both good and bad -- good that recommendations are conservative and don’t jump on the newest bandwagon, but bad in that perhaps individuals and/or groups of people may not benefit from the latest scientific research. For example, people may unnecessarily follow low saturated-fat diets or replace saturated fats with simple carbohydrates which may, in fact, worsen their health. 

While traditional recommendations regarding dietary fat and saturated fat consumption have not yet changed, as health professionals, stakeholders and policy makers adopt this new research the recommendations will undoubtedly be modified in the future to reflect the latest science.

In the meantime, health professionals can help their clients prioritize their health issues and develop individualized plans that best meet their needs, goals and health issues. Public health recommendations such as the Dietary Guidelines for Americans are just that -- for the public -- and, at best, represent a starting point for the individual. Genetic disposition, age, gender, activity level, body weight, disease risk, environment, culture, dietary preferences and lifestyle choices all need to be considered when developing recommendations unique to the individual. In addition, it’s important to remember that a diet for prevention of chronic disease may be different than one for treatment or mitigation of symptoms. 

Lori Hoolihan, Ph.D., R.D.N.

Want more information on the saturated fat – heart disease link? 

Here are some related links:

Blog in the New York Times: http://well.blogs.nytimes.com/2014/03/17/study-questions-fat-and-heart-disease-link/?_php=true&_type=blogs&_php=true&_type=blogs&smid=tw-nytimeshealth&seid=auto&_r=1&

CBS Newsarticle: http://www.cbsnews.com/news/saturated-fats-wont-raise-heart-disease-risk-omega-3s-wont-reduce-it-study/

Reuters article: http://www.reuters.com/article/2014/03/17/us-hear-disease-review-idUSBREA2G1ON20140317

NPR’s The Salt story and audio interview with a co-author of the meta-analysis: http://www.npr.org/blogs/thesalt/2014/03/31/295719579/rethinking-fat-the-case-for-adding-some-into-your-diet?ft=1&f=295719579






Tags: Healthy eating Lori Hoolihan nutrition saturated fat

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