Time to Rethink Omega-3s?

[Notable New Media]

by Kenneth W. Krause.

Kenneth W. Krause is a contributing editor and “Science Watch” columnist for the Skeptical Inquirer.  Formerly a contributing editor and books columnist for the Humanist, Kenneth contributes regularly to Skeptic as well.  He may be contacted at krausekc@msn.com.

Nutrition researchers have long touted the heart-health benefits of Omega-3 polyunsaturated fatty acids, typically found in wild oily fish and flaxseed, for example.  General recommendations to consume foods rich in Omega-3s and even to supplement with fish oil derived in part from evidence showing that the cold-climate Inuit, for example, have persisted quite healthfully–that is, with a low incidence of cardiovascular disease–on traditional marine diets rich in fat, especially Omega-3s.  The inference was that the Omega-3 fatty acids were protective against heart disease, perhaps because they lowered LDL and raised HDL cholesterol levels in the blood.

But do such benefits accrue to all human populations more or less equally?  Perhaps not.  In a study recently published in Science, researchers scanned the genomes of 191 Greenland Inuit (formerly known as Eskimos, whose ancestors had lived in the Arctic for thousands of years) and compared them to the genomes of 60 Europeans and 44 Han Chinese.  What did they find?  The native Greenlanders had developed special mutations to genes involved in fat metabolism (fatty acid desaturases) that likely evolved through natural selection to help counteract the effects of a diet high in fat, mostly from seals and whales that consume oily fish.

According to these researchers, that 100 percent of the Inuit, but only 2 percent of the Europeans and 15 percent of the Chinese, possessed these adaptations implies that, on average, members of each population might synthesize Omega-3s very differently from members of the other populations.  In other words, one group’s unique evolutionary adaptations–in this case, to cold weather and a traditional, high-fat diet–might render them an inappropriate population upon which to base nutrition advice to the general public.

But those who take personal health seriously already knew better than to receive generalized nutrition advice as gospel.  First, as I’ve argued more than once before, nutrition science is inherently volatile.  Myriad confounding factors, difficult to isolate and measure, often make it nearly impossible for researchers in this field to offer concrete advice.  Second, for many reasons, every individual requires a personalized diet and exercise plan that also evolves as the individual grows older and as continuing and disciplined personal experimentation (that is, science) reveals his or her special health and performance needs.

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One thought on “Time to Rethink Omega-3s?

  1. Emett

    Cool. The same alleles apparently affected Inuit size as well. Interesting how only one or a few genes can have so many varied effects.

    Like

    Reply

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