Lectins are proteins found in many plants, particularly whole grains and legumes (beans, chick peas and lentils). In 2017 Steven Gundry, M.D., a former cardiac surgeon, wrote a book called “The Plant Paradox,” which claimed that lectins cause inflammatory diseases, obesity, cancer, arthritis and GI problems. Other books followed, including a lectin-avoidance cookbook, and before long Dr. Gundry was marketing expensive supplements such as “Lectin Shield,” anti-aging creams and supplements containing the nutrients you’d miss by following his diet.
The January issue of the University of California, Berkeley, Wellness Letter has a front-page article with the title “Lectins: the new gluten?” Based on this article, and Dr. Greger’s nutritionfacts.org, here are the proven facts about lectins:
• Lectins in raw beans, especially kidney beans, can cause health (such as GI) problems, but who eats raw beans? Cooking, fermenting and processing legumes for canning eliminates the danger.
• Inflammation: Certain lectins have been shown to cause inflammation in lab animals, but in humans lectins reduce markers of inflammation, such as C-reactive protein. Lectins also reduce the incidence of inflammatory diseases such as rheumatoid arthritis — and of diseases where inflammation plays a role, such as coronary artery disease..
• Obesity: Diets high in whole grains and beans result in lower body weight and body fat — not obesity.
• Cancer: Lectins inhibit cancer cell growth in the lab, and in human studies people who eat lectin-rich foods have a lower rate of several cancers.
• High legume intake stands out as the most important common thread explaining why people in the 5 Blue Zones live such long, disease-free lives.
• Dr. Greger’s evidence-based book (132 pages of well-researched references) notes that “people who eat more whole grains tend to live significantly longer lives” and that whole grains “appear to reduce the risk of heart disease, type 2 diabetes, obesity, and stroke.”
The Berkeley Wellness Letter summarizes the Gundry hoax like this: “If there’s one thing evidence-based health and nutrition experts agree on, it’s that people should eat a largely plant-based diet. For those looking for an excuse not to do so, Dr. Gundry offers a contrarian, pseudoscientific voice. But he is wrong — and self-serving.”
Here are the take-home messages from this column:
• Don’t eat raw or undercooked beans.
• Don’t trust health care providers who are selling supplements and other products (how can they be unbiased?).
• There are lots of people on the internet pushing unscientific medical and nutritional theories, and selling snake oil — unfortunately some of them are M.D.s (who don’t get educated about nutrition in medical school). Others, besides Dr. Gundry, are Dr. Sonatra and Dr. Mercola.
Next week’s column will be about where you can find medical information you can trust.
Dr. Feinsinger, who retired from Glenwood Medical Associates after 42 years as a family physician, has a nonprofit Center For Prevention and Treatment of Disease Through Nutrition. He is available for free consultations about heart attack prevention and other medical issues. Call 970-379-5718 for an appointment. For questions about his columns, email him at gfeinsinger@comcast.net.