Doctor’s Tip: The science behind plant-based nutrition |

Doctor’s Tip: The science behind plant-based nutrition

Dr. Greg Feinsinger

Dr. Greg Feinsinger
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Last week’s column was a summary of what we should and shouldn’t eat if we want to achieve optimal health, by eating the healthiest diet on the planet: plant-based, whole (unprocessed) food, no-added-oil diet with avoidance of salt and sugar. Today’s column describes some of the science that supports this diet.


In his book “How Not to Die,” and on his website, Michael Greger, M.D. makes the case that the human genome developed over some 25 million years, as humans gradually evolved from tree-dwelling, ape-like plant-eaters. (The Paleo diet supporters make claims based on only the last two million years, when many humans were hunter-gatherers, but most of our genome had already developed by this time).

The jaw and GI structures of humans are those of herbivores, not carnivores.


These are studies of large populations of people, see what they eat, what diseases they get and what they die from.

When missionaries went to Africa over 100 years ago, they found that the Africans who ate a traditional plant-based diet had none of the following: obesity; hypertension; high cholesterol; diabetes; cardiovascular disease (heart attacks and strokes); dementia; inflammatory diseases; autoimmune diseases; dementia; osteoporosis; and very little of the cancers Westerners suffer from, especially colon, breast and prostate. Genetics was not a factor, because Afro-Americans have the same health issues the rest of us on the S.A.D. (standard American diet) have.

T. Colon Campbell found the same thing when he was the lead scientist of the largest epidemiologic study of all time: The China Study (he wrote a book by the same name).

The Norwegians eat a high meat and dairy diet, and as a result have a high rate of heart disease. During World War II, the occupying Nazis kept these foods for their own soldiers, and the heart disease rate in the Norwegians plummeted. After the war the Norwegians started eating meat and dairy again, and their heart disease incidence went right back up.

During the Korean and Vietnam wars, autopsies were done on young soldiers killed in battle. Essentially all the American kids had atherosclerosis (hardening of the arteries), the cause of heart attacks and strokes. Again, this was related to diet, not genetics.

Today, there are still a few societies that remain unaffected by the Western diet. The Seventh Day Adventist women in Los Angeles have been well-studied, because for religious reasons they are at least vegetarians if not vegans. They do not get the chronic diseases that afflict many Americans, and are some of the longest-lived people in the world.


Scientists have done studies involving dripping the blood of animal-eaters on various types of cancer cells in petri dishes in the lab, and the cells grow faster. Blood from plant-based people kills the cancer cells.

We know that if we want healthy arteries, we need to eat food that makes the endothelial lining produce nitric oxide, which causes arteries to dilate. Scientists hook people up to monitors in the lab, feed them steak or oil and their arteries constrict; feed them kale for example and their arteries dilate.


Decades ago Walter Kempner, M.D. showed that severe hypertension could be reversed with plant-based nutrition.

In the 1970s Nathan Pritikin, who was not an M.D., showed that heart disease could be reversed with plant-based nutrition.

Later, Dean Ornish, M.D. and more recently Caldwell Esselstyn, M.D. proved using coronary arteriograms (x-ray pictures of heart arteries) that heart disease can be reversed.

More recently, Dr. Ornish has shown that biopsy-proven prostate cancer can be reversed with this diet.

Other diets, including the Mediterranean and Paleo diets, while healthier than the S.A.D., are not backed by this kind of evidence. Kim Williams, who was recently the president of the American College of Cardiology and who is still on its board, went plant-based several years ago. When asked why, he replied “I don’t mind dying so much, but I don’t want it to be my fault.”

Next week’s column will address the two questions that are occasionally asked: Is a plant-based diet “radical” or restrictive? (Spoiler alert: The answer is no to both questions, and I will explain why.)

Dr. Feinsinger, who retired from Glenwood Medical Associates after 42 years as a family physician, now has a nonprofit Center For Prevention and Treatment of Disease Through Nutrition. He is available for free consultations about heart attack prevention and any other medical concerns. Call 970-379-5718 for an appointment. For questions about his columns, email him at

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