Oysters, the Savior of Mankind?

After World War II a new fear swept the country and the world.  FAT was the evil we now were told we must avoid if we were to survive.  To punctuate it, the hero of the war and now the President of the country, Dwight David Eisenhower, had a heart attack, presumably due to the poison, Cholesterol, plugging up his coronary arteries.  A Harvard professor named Dr. Ancel Keys, popularized the idea that we had to give up fat. “People should know the facts,” he said, “then if they want to eat themselves to death, let them!” Dr. Keys made the cover of Time Magazine. He did the “Seven Country Study” to prove his conjecture. Like many scientists who have ulterior motives to prove their theory, he manipulated the data by cherry-picking and leaving out the countries that had the highest fat consumption, but not having the higher coronary deaths that he predicted. Nevertheless, the world bought it, and Dr. Keys got the government contract to develop survival food for the military which he self-aggrandizingly called “K” rations.

Our diet changed. Carbohydrates were substituted for the decrease in fat. The “Food Pyramid” told us what and how much we should eat. Various grains were given higher priority than protein and fat. Butter was vilified and replaced by,  “I can’t believe it’s not butter.” The more solid versions later turned out to be as bad as the real thing. Eggs were de-cholesterolized, and lard became an obscenity. With this change came new devils that can clearly be linked to an increase in obesity and a rise in Type II Diabetes. Whether we can blame the 19% increase in mental illness on the decrease in fat consumption remains an intriguing theory but still debatable.

With time we realized that it is more complicated. Fats are not all that bad. In fact, some fats are essential. Besides, a marbled steak is a lot more satisfying than a bowl of pasta. 60% of our brain consists of fat.  A particular family of fats is especially important; the omega-three fats. And one of them is the most important:  it is DHA (docosahexaenoic acid).  600 million years ago, animal life was evolving in the oceans, and DHA, a product of photosynthesis from algae, was the primary fat that contributed to the development of the brain.

The last Ice Age, the Quaternary, has been in progress since two and a half million years ago and is still evolving since 33% of the earth’s landmass is seasonally covered by snow and ice, but shrinks to only 12% that remains permanently during summer. We are still in the Holocene Interglacial Period that started 12,000 years ago. In the prior four Ice Ages, ice completely melted. There were no glaciers and no ice caps at the poles. I am thinking that some of those early hominids must have had SUVs!

Earth has been completely ice-free 80% of its time in existence, and the North and South Poles were covered with vast forests where wildlife frolicked, all of which have since turned into vast oil fields under the ice that is touted to be the next instrument of our extinction.  One hundred ninety thousand years ago, a glaciation known as Marine Isotope Stage 6 (MIS6) brought cooling and drying of the planet. Great ice sheets covered northern Europe, the Alps, North America, and the Antarctic. When the Laurentide glaciers retreated, it created the Great Lakes on the North American plate. It was connected to the still existing ice sheet covering Greenland.

Ironically this time, global cooling brought us to near extinction, with only a few hundred Homo sapiens still surviving.  We know this because the genetic variation in mitochondrial DNA contracted markedly, which could only occur because of the sharp decline of the breeding population known as a bottleneck.  Mitochondrial DNA is passed on only from females almost always, and our present mitochondrial  DNA does not have the variation it ought to have, which confirmed that only a small gene pool existed then. It gives rise to the “Eve Theory,” which says that the current human race stems from a single female. This is a bit Biblical and not entirely true; nevertheless, it suggests that just a few females were left to carry on our species.

Arizona State University archeologist, Curtis Marean, has been excavating a site on the South African coast called Pinnacle Point for over twenty years that he believes could be one of the sites where the few remaining Homo sapiens found adequate food for survival.  Thousands of years ago and still today, the shallow waters off Africa’s southern tip are packed with mollusks. It required us to rely on a seafood diet. Shellfish are particularly easy to harvest. No hunting is necessary.  The tides expose them just for the taking. Tests have shown that foraging shellfish under optimal tidal conditions can yield up to 3500 calories per hour.

“He was a bold man that first ate an oyster.” So said Jonathan Swift, author of Gulliver’s Travels.  To crack open an oyster and scoop out the salty, slimy grey muck and put it in your mouth must have taken a bit of courage, a strong stomach, and a weak gag reflex. It turns out, however, that seafood has a lot of DHA, a major contributor of fat for the brain.

It is a tantalizing idea, and not inconsistent with recent nutritional research, that if you eat what your brain is made of, you could improve its function. Omega-3’s are now thought to slow the senescence of neurons.  Could it be that eating oysters in the past not only saved us from going extinct, but made us smarter, and presently is helping to prevent dreaded Alzheimer’s disease and other forms of dementia?

Some of the ideas in this essay are taken from the book, A History of the Human Brain by Bret S. Stetka, MD