Fishy Origins

 In Preventive Medicine Column

 

Our Fishy Origins

I am just back from a sequence of speaking engagements at scientific conferences in and around Cape Town, South Africa- and, as fate would have it, a quick and illuminating trip to the Stone Age.

That unexpected detour came courtesy of Professor Frits Muskiet of the University of Groningen, The Netherlands. Prof. Muskiet, a clinical chemist extensively published in the area of fatty acid metabolism, was among the plenary speakers at the ISSFAL (International Society for the Study of Fatty Acids and Lipids) 2016 Congress, as, indeed, I was honored to be. He took advantage of the occasion to deliver a talk in equal measure erudite and entertaining in the area of evolutionary medicine, and human adaptations to particularly patterns of dietary fat intake.

The question with which Prof. Muskiet especially wrestled was this: why should humans, with alleged origins in the savannas of Africa, have adapted a need for omega-3 fats? If the question sounds at all odd to you, it should not. Creatures adapt to need what their environment provides, or they make a hasty retreat from living at all. It is not happenstance, for example, that all of the vitamins and minerals we discover to be essential in some way to human metabolism are found on this planet. The same may be said of the gases we breathe.

Stated differently, if we have evolved a dependence on omega-3 fatty acids in our diets- a fact indicated by the categorization of these among others as “essential” fatty acids- then omega-3 fats must have been part of the nutritional habitat in which humans evolved. Where, then, were these fats now routinely called “fish oil” coming from on African savannas?

My answer has long been from the flesh of wild game that is to the flesh of grain-fed, domestic cattle as Saber-Tooth is to tabby. This is by no means an argument of my own devising. Rather, just this is suggested by the seminal, peer-reviewed papers on Paleolithic nutrition, now spanning several decades.

Among others, Prof. Boyd Eaton, whose work and insights I have gratefully acknowledged before, and colleagues have suggested stark differences between the meat that prevails in modern societies, and the meat consumed by our hunter-gatherer forebears. In brief, well over 30% of the calories in modern beef come routinely from fat, much of it saturated, and effectively none of it omega-3. In contrast, the flesh of antelope, thought roughly approximate to that of favored Stone Age game, derives as little as 7% of total calories from fat, little if any of it saturated, and a meaningful portion of it omega-3.

The simple conclusion is that what we now call fish oil- the long-chain omega-3 fatty acids, EPA and DHA- has been domesticated out of terrestrial animals by adulterating the composition of their diets. We are at risk of doing the same to fish by altering their diets in aquaculture.

Prof. Muskiet allowed for this when I asked him about it, but he made a compelling, parallel case. Citing the work of various paleoanthropologists and archaeologists, and tracing findings through the stages of human ancestry, his argument was that humanity has long favored life at a land/water interface. Much of this involved lakes and rivers, and sourcing shellfish from tidal flats. Quite ancient archeological sites indicate human, and even pre-human, consumption of mussels and other mollusks. Fishing hooks many thousands of years old suggest that even fish from the sea figured in the human diet long before the dawn of agriculture.

There are two important implications of our omega-3 requirement. The first is that popular expressions of the Paleo fantasy that emphasize the fatty meats of land animals are woefully misguided. Seldom does one see ardent proponents of Stone Age dietary patterns emphasize fish, let alone mussels – to say nothing of the arduous daily exertions and estimated 100 grams of daily fiber that were also thought to figure in it. Rather, the Paleo “brand” has been corrupted into pop-culture nonsense, and an invitation to eat more bacon.

We have three options for getting the omega-3 our bodies need: eating plant sources, such as flax, walnuts, and seaweed, which provide ALA, but generally not EPA and DHA; eating fish and seafood routinely; and taking supplements. For the latter two, attention to sustainability is key, and information is available on-line. These options are, of course, not mutually exclusive; I rely personally on all three.

Prevailing pop-culture expressions of Paleo devotion are much about salesmanship, and not at all about scholarship. Mussels and mammoth are Paleo; bacon, baloney and lard- are not. Whatever the temptations of telling people what they want to hear, you simply can’t make a polyester purse from a wooly mammoth’s ear.

-fin Dr. David L. Katz;www.davidkatzmd.com; author, Disease Proof; founder, True Health Initiative

Dr. David L. Katz
DAVID L. KATZ MD, MPH, FACPM, FACP, FACLM, is the founding director (1998) of Yale University's Yale-Griffin Prevention Research Center, and current President of the American College of Lifestyle Medicine. He earned his BA degree from Dartmouth College (1984); his MD from the Albert Einstein College of Medicine (1988); and his MPH from the Yale University School of Public Health (1993). He completed sequential residency training in Internal Medicine, and Preventive Medicine/Public Health. He is a two-time diplomate of the American Board of Internal Medicine, and a board-certified specialist in Preventive Medicine/Public Health. He has received two Honorary Doctorates. Dr. Katz has published roughly 200 scientific articles and textbook chapters, and 15 books to date, including multiple editions of leading textbooks in both Preventive Medicine, and nutrition. Recognized globally for expertise in nutrition, weight management and the prevention of chronic disease, he has a social media following of well over half a million. In 2015, Dr. Katz established the True Health Initiative to help convert what we know about lifestyle as medicine into what we do about it, in the service of adding years to lives and life to years around the globe.
Recent Posts