The World Health Organization (WHO) reports that over sixteen million deaths occur worldwide each year due to cardiovascular disease, and more than half of those deaths occur in developing countries where plant-based diets high in legumes and starches are eaten by the vast majority of the people.
Yet “everyone knows” plant-based diets prevent heart disease. Indeed this myth is repeated so often that massive numbers of educated, health-conscious individuals in first world countries are consciously adopting third world style diets in the hope of preventing disease, optimizing health and maximizing longevity. But if the WHO statistics are correct, plant-based diets might not be protective at all. And today’s fashionable experiment in veganism could end very badly indeed.
HOMOCYSTEINE AND HEART DISEASE
A study published in the August 26, 2001 issue of the journal Nutrition makes a strong case against plant-based diets for prevention of heart disease. The title alone, “Vegetarianism produces subclinical malnutrition, hyperhomocysteinemia and atherogenesis,” sounds a significant warning. The article establishes why subjects who eat mostly vegetarian diets develop morbidity and mortality from cardiovascular disease unrelated to vitamin B status and Framingham criteria.
Co-author Kilmer S. McCully, MD, “Father of the Homocysteine Theory of Heart Disease,” is familiar to WAPF members as a winner of the Linus Pauling Award, WAPF’s Integrity in Science Award, and author of numerous articles published in peer-reviewed journals as well as the popular books The Homocysteine Revolution and The Heart Revolution. In 2009 Dr. McCully was one of the signers of the Weston A. Price Foundation’s petition to the FDA in which we asked the agency to retract its unwarranted 1999 soy/heart disease health claim. (See www.westonaprice.org/soy-alert/soy-heart-health-claim.)
Dr. McCully teamed up with Yves Ingenbleek, MD, of Université Louis Pasteur in Strasbourg, France, which funded the research. Dr. Ingenbleek is well known for his work on malnutrition, the essential role sulfur plays along with nitrogen in metabolism, and sulfur deficiency as a cause of hyperhomocysteinemia.
The study took place in Chad, and involved twenty-four rural male subjects ages eighteen to thirty, and fifteen urban male controls, ages eighteen to twenty-nine. (Women in this region of Chad could not be studied because of their animistic beliefs and proscriptions against collecting their urine.)
The rural men were apparently healthy, physically active farmers with good lipid profiles. Their staple foods included cassava, sweet potatoes, beans, millet and ground nuts. Cassava leaves, cabbages and carrots provided good levels of carotenes, folates and pyridoxine (B6). The rural Chadian diet is plant-based because of a shortage of grazing lands and livestock, but subjects occasionally consume some B12-containing foods, mostly poultry and eggs, though very little dairy or meat. Their diet could be described as high carb, high fiber, low in both protein and fat, and low in the sulfur-containing amino acids. In brief, this diet is the very one recommended by many of today’s nutritional “experts” for overall good health and heart disease prevention.
The urban controls were likewise healthy and ate a similar diet, but with beef, smoked fish and canned or powdered milk regularly on the menus. Their diet was thus higher in protein, fat and the sulfur-containing amino acids, though roughly equivalent in calories.
Dr. McCully’s research over the past forty years on the pathogenesis of atherosclerosis has shown the role of homocysteine in free radical damage and the protective effect of vitamins B6, B12 and folate. Indeed, many doctors today recommend taking this trio of B vitamins as an inexpensive heart disease “insurance policy.”
In Chad, both groups showed adequate levels of B6 and folate. The B12 levels of the vegetarian group were lower, but the difference was only of “borderline significance.” However, as the researchers point out, “A previous study undertaken in the same Chadian area in a larger group of sixty rural participants did demonstrate a weak inverse correlation between B12 and homocysteine concentrations in the twenty subjects most severely protein depleted . . . It is therefore likely that the hyperhomocysteinemia status of some of our rural subjects in the present survey might have resulted from combined B12 and protein deficiencies. The correlation of B12 deficiency with hyperhomocysteinemia could well reach statistical significance if a larger group of subjects were studied.”
ANIMAL PROTEIN AND SULFUR
Clearly it’s wise for people on plant-based diets to supplement their diets with B12, but protein malnutrition must also be addressed. And the issue is not just getting enough protein to eat, but the right kind. The bottom line is we must eat protein rich in bioavailable, sulfur-containing amino acids—and that means animal products. Vegans at this point will surely claim the issue is insufficient protein and trot out soy as the solution. Soy is indeed a complete plant-based protein, but notoriously low in methionine. It does contain decent levels of cysteine, but the cysteine is bound up in protease inhibitors, making it largely biounavailable. (For more information, read my book The Whole Soy Story: The Dark Side of America’s Favorite Health Food, endorsed by Dr. McCully, as well as our petition to the FDA noted above.)
So what did Drs. Ingenbleek and McCully find among the study group of protein-deficient people? Higher levels of homocysteine, of course. Also significant alterations in body composition, lean body mass, body mass index and plasma transthyretin levels. In plain English, the near-vegetarian subjects were thinner, with poorer muscle tone, and showed subclinical signs of protein malnutrition. (So much for popular ideas of extreme thinness being healthy.)
The plant-based diet of the study group was low in all of the sulfur-containing amino acids. As would be expected, labwork on these men showed lower plasma cysteine and glutathione levels compared to the controls. Methionine levels, however, tested comparably. The explanation for this is “adaptive response.” In brief, mammals trying to function with insufficient sulfur-containing amino acids will do whatever is necessary to survive. Given the essential role of methionine in metabolic processes, that means deregulating the transsulfuration pathway, increasing homocysteine levels, and methylating homocysteine to make methionine.
Ultimately, it all boils down to our need for sulfur. As Stephanie Seneff, PhD, and many others have written in Wise Traditions and on the WAPF website, sulfur is vital for disease prevention and maintenance of good health. In terms of heart disease, Drs. Ingenbleek and McCully have shown sulfur deficiency not only leads to high homocysteine levels, but is the likeliest reason some clinical trials using B6, B12 and folate interventions have proved ineffective for the prevention of cardiovascular and cerebrovascular diseases. Over the past few years, headlines from such studies have led to widespread dismissal of Dr. McCully’s “Homocysteine Theory of Heart Disease” and renewed media focus on cholesterol, C-reactive protein and other possible culprits that can be treated by statins and other profitable drugs. In contrast, the research of Drs. McCully and Ingenbleek suggests we can better prevent heart disease with three inexpensive B vitamins and traditional diets rich in the sulfur-containing amino acids found in animal foods.
In the blaze of publicity surrounding the video Forks Over Knives and other blasts of vegan propaganda, few people are likely to hear about this study. That’s sad, for it provides an important missing piece in our knowledge of heart disease development, a strong argument against the plant-based dietary fad, and a bright new chapter in what the New York Times has called “The Fall and Rise of Kilmer McCully.”
This article appeared in Wise Traditions in Food, Farming and the Healing Arts, the quarterly journal of the Weston A. Price Foundation, Winter 2011.