One reader asks: Where's the proof that vegetarians live longer? Where's the proof that vegans live longer?
The literature is mixed on this subject of longevity. Some studies say that vegetarians and vegans live longer, and others show no difference. While vegetarians and vegans will be more healthy and youthful in their younger years, the difference shrinks as people get into their eighth and ninth decades of life.
Keep in mind, though, that the standard American diet is a major cause of many illnesses, including but not limited to coronary artery disease, diabetes, hypertension, obesity, or cancer. It is known that vegetarians and vegans are much less likely to suffer from these diseases.
These illnesses, which can be avoided by diet, can be debilitating. Take the example of one man, with hypertension and diabetes. He has a heart attack at age 50. He has a stent put in. Then, as his diabetes progresses, his vision becomes worse. He develops disease in the arteries of his legs. He has bypass surgery on his legs, but this does not work and eventually he requires an amputation, confining him to a wheelchair. Then, his kidneys fail as a result of years of diabetes and hypertension, and he requires three hours of dialysis each day in order to survive. At age 70, he dies of another heart attack.
While this person lived a relatively normal life span, his quality of life was clearly impacted by his burden of disease. It is very plausible that he could have lived a much healthier life had his diet been different. He could have had better control of his diabetes. In fact, Dr. Neal Barnard's most recent work shows that a vegan diet has a powerful impact in reversing diabetes (Diabetes Care. 29(8):1777-83, 2006 Aug).
There is some evidence that people who follow a plant-based diet live longer. But, the bottom line is that a plant-based diet reduces the risk of many illnesses, and leads to a far better quality of health throughout most of life.