The Adventist Health Studies offer some of the best science on the impacts of plant-based diets on health and longevity. Based in California, they include both the longest running study of vegetarians in history as well as the largest contingent of vegans. While most of the attention on the benefits of plant-based eating have focused on reduced rates of many of the top killers, such as heart disease, cancer, strokes, diabetes, obesity, and high blood pressure, the Adventist Health Study--started back in 1974--offered insight into how broadly the potential health benefits may extend.
My NutritionFacts.org video-of-the-day Preventing Allergies in Adulthood (a follow-up to Preventing Childhood Allergies), presents findings from the Adventist Health Study showing that women eating plant-based diets were found to have a 30% lower chance of reporting chemical allergies, 24% less asthma, 17% less drug and bee-sting allergies, and 15% less hay fever, though men eating plant-based appeared to have lower risk only of chemical and drug allergies. This was cross-sectional data, meaning it was just a slice in time, so we don't necessarily know which came first. Still, after adjusting for other factors such as smoking, the findings do suggest a favorable effect of a plant-based diet on the prevalence of allergies.
In Say No To Drugs By Saying Yes To More Plants, I present more findings from the Adventist Health Study. The lower rates of disease found in those eating plant-based diets appear to translate into fewer surgeries (from hysterectomies to varicose veins) and fewer medications. Compared to meat-eating controls, those eating vegetarian had only about half the odds of being on aspirin, sleeping pills, tranquilizers, antacids, pain-killers, blood pressure medications, laxatives, and insulin. So if you're like most people and don't like being dependent on drugs, don't like paying for drugs, and don't like all the side effects, you may be able to cut your odds of needing medications in half by choosing to eat a more plant-based diet.
-Michael Greger, M.D.