The Nation's Health + Nutrition

Are humans meant to be omnivores?

Are humans meant to be omnivores?

Does the ideal human diet include animal products like meat, fish, cheese, eggs, and dairy products?

Or should the ideal diet be devoid of all animal products⎯a vegetarian diet?

Though the argument is distorted by modern food processing methods (e.g., factory farming, long-term administration of antibiotics), convenience foods, and pseudo-foods crafted by food manufacturers, there are, obviously, proponents of both extremes.

The Atkins’ diet, for instance, advocates unrestricted intake of animal products, regardless of production methods or curing (sausage and bacon). At the opposite extreme are diets like Ornish (Dr. Dean Ornish’s Program for Reversal of Heart Disease) and the experiences of Dr. Colin Campbell, articulated in his studies and book, The China Study, in which he lambasts animal products, including dairy, as triggers for cancer and heart disease.

So which end of the spectrum is correct? Or ideal?

For the sake of argument, let's put aside philosophical questions (like not wanting eat animal products because of aversion to killing any living being) or ethical concerns (inhumane treatment of farm animals, cruel slaughtering practices, etc.). Does the inclusion of animal products provide advantage? Disadvantage?

The traditional argument against animal products has been saturated fat. If we accept that we’ve demoted the saturated fat question to a place far down the list of importance (though this is yet another argument to discuss another time), several questions emerge:

• If humans were meant to be vegetarian, why do omega-3 fatty acids (mostly from wild game and fish) yield such substantial health benefits, including dramatic reduction in sudden death from heart disease?

• Why would vitamin K2 (from meats and milk, as well as fermented foods like natto and cheese), obtainable in only the tiniest amounts on a vegetarian diet, provide such significant benefits on bone and cardiovascular health?

• Why would vitamin B12 (from meats) be necessary to maintain a normal blood count, prevent anemia, keep homocysteine at bay, and lead to profound neurologic dysfunction when deficient?

Omega-3 fatty acids and vitamins K2 and B12 cannot be obtained in satisfactory quantities from a pure vegetarian diet. The consequences of deficiency are not measured in decades, but in a few years. The conclusion is unavoidable: Evolutionarily, humans are meant to consume at least some foods from animal sources.

That's not to say that we should gorge ourselves on animal products. Gout (excessive uric acid) and kidney stones are among the unhealthy consequences of excessive quantities of meats in our diets.

It pains me to say this, since I’ve always favored a vegetarian lifestyle, mostly because of philosophical concerns, as well as worries about the safety of our factory farm-raised livestock and rampant inhumane practices.

But, stepping back and objectively examining what nutritional approach appears to stack the odds in favor of optimal health, I believe that only one conclusion is possible: Humans are meant to be omnivorous, meant to consume some quantity of animal products in addition to vegetables, fruits, nuts, and other non-animal products.

The question is how much?

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