How Plant-Based Diets May Extend Our Lives


July 10, 2014 by Michael Greger M.D. in News with 5 Comments

How a Plant Based Diet May Help you Live Longer

A recent review suggested that plant-based diets may prove to be a useful nutritional strategy for lifespan extension in part because they tend to be naturally low in the amino acid methionine (see my video Starving Cancer with Methionine Restriction). Apparently, the less methionine there is in body tissues, the longer different animals tend to live. But what are the possible implications for humans? See my video Methionine Restriction as a Life Extension Strategy.

I’ve talked before about the free radical theory of aging, the concept that aging can be thought of as the oxidation of our bodies just like rust is the oxidation of metal (seeMitochondrial Theory of Aging). Methionine is thought to have a pro-oxidant effect. The thinking is that lowering methionine intake leads to less free radical production, thereby slowing aging. Fewer free radicals would decrease the rate of DNA damage, which would curtail the rate of DNA mutation, slowing the rate of aging and disease and potentially increasing our lifespan.

There are three ways to lower methionine intake: The first is caloric restriction. By decreasing our overall intake of food, we would reduce our intake of methionine. Or, because methionine is found protein, we could practice protein restriction, eating a relatively protein deficient diet. The third option is eat enough food, eat enough protein, but just stick to proteins that are relatively low in methionine, which tends to mean plant proteins.

Caloric restriction is hard, because we walk around starving all the time. Something like every-other-day eating is described as “never likely to gain much popularity as a pro-longevity strategy for humans, so it may be more feasible to achieve moderate methionine restriction by eating a plant-based diet.” On a population-wide level, folks could benefit from just lowering their protein intake, period. Researchers noted that “the mean intake of proteins [and thus methionine] of Western human populations is much higher than needed. Therefore, decreasing such levels has a great potential to lower tissue oxidative stress and to increase healthy life span in humans while avoiding the possible undesirable effects of caloric restriction.”

We’re eating around double the protein we need, so the first thing doctors can recommend is to decrease the intake of protein, but we can also get our methionine even lower by eating a plant-based diet.

The fact that beans have comparably low methionine has been classically considered a disadvantage. But, given the capacity of methionine restriction to decrease the rate of free radical generation in internal organs, to lower markers of chronic disease, and to increase maximum longevity, this “disadvantage” may actually be a strong advantage. This fits well with the important role of beans in healthy diets like the traditional Mediterranean diet. Interestingly, soy protein is also especially poor in methionine, which may help explain the healthy effects iof soyfoods. Watch my video Increased Lifespan from Beans.

The reason why plant-based diets are so protective is not known. Yes, vegetables contain thousands of phytochemicals, but separately investigating their possible protective roles would be an impossible task. The idea that the protective effect is not due to any of the individual plant food components, but to a synergic “combined effect” is gaining acceptance. However, based on the relationship of excess dietary methionine to vital organ toxicity, as well as its likely mechanism of action through increases in free radical generation, the possibility exists that the protective effects of plant-based diets can be due, at least in part, to their lower methionine content. As one paper concluded, “The low-methionine content of vegan diets may make methionine restriction feasible as a life extension strategy.”

Plant-based diets can also mimic other benefits of caloric restriction, such as improving levels of the “fountain of youth” hormone DHEA. See The Benefits of Caloric Restriction Without the Actual Restricting.

Americans are living longer but sicker lives. That’s why we need a diet and lifestyle that supports health and longevity. I have a whole presentation on the role diet can play in preventing, arresting, and even reversing many of our top 15 killers: Uprooting the Leading Causes of Death.

I’ve touched previously on the irony that animal protein may be detrimental for the same reasons it’s touted as superior in Higher Quality May Mean Higher Risk.

-Michael Greger, M.D.


Rice Diet Founder Dr. Walter Kempner

In 1934 as a doctor at Duke Hospital, Dr. Walter Kempner starting treating patients with malignant hypertension (very high blood pressure) and kidney disease with what he called “The Rice Diet” when there was no other treatment available anywhere. He gave it the name as patients usually ate a bowl of white rice at every meal. It became obvious to Dr. Kempner that the prevention and treatment of these diseases would be best treated with a no salt added diet. Dr. Kempner found out very early that the low fat content of the diet also enhanced weight loss. When Dr. Kempner tried to have patients maintain their weight by increasing portion size and adding sugars to foods, patients still lost weight. They just couldn’t eat enough calories with so little fat in the diet. The program has continued over the years with the same philosophy of a low-sodium, low-fat diet.

In the 1930′s and 40′s, people that were diagnosed with illnesses such as high blood pressure and kidney disease were offered no hope for long-term survival. These diseases were considered lethal. Dr. Kempner experimented with animal tissue for many years and began to treat human patients in 1939. He began to see unprecedented results starting with a woman who reversed her kidney disease in a few months time and another who was comatose with malignant hypertension who regained alertness. There were no other drugs or treatments available other than this diet.
Dr. Kempner went on to research and publish revolutionary results on the Rice Diet’s dramatic beneficial effect not only on kidney disease and hypertension, but on cholesterol, cardiovascular disease, congestive heart failure and diabetes. He retired in 1992 in his 90th year (as Dr. Kempner would say) and he passed away in 1997. The Rice Diet has continued to produce these significant improvements and outstanding medical results for these diseases along with other disorders of lifestyle origin such as sleep apnea, psoriasis, pulmonary hypertension, edema and joint stiffness associated with arthritis.
Here are some of Dr. Kempner’s articles from his bulletins and other journals:
• Treatment of Heart and Kidney Disease and of Hypertensive and Arteriosclerotic Vascular Disease with The Rice Diet (1949)
• Kempner’s Research on Diseases of Blood Vessels, Kidneys, and Heart (1950)
• Treatment of Heart Disease and Kidney Disease with the Rice Diet (April 1951)
• Clinical Notes and The Patient’s Viewpoint (April 1953)
• Progress Report (August 1954)
• Family History (August 1954)
• Analysis of 177 Cases of Hypertensive Vascular Disease (1955)
• The Changing Attitude Toward Vascular Disease (June 1955)
• Who Wants Salt? (June 1955)
• “A Girl with a New Lease on Life” (June 1955)
• Why Rice? (1956)
• How to Be Happy with Rice (August 1956)
• Effect of Rice Diet on Diabetes Mellitus Associated with Vascular Disease (1958)
• Nephritis. Nephrosis. (1958)
• Coronary Artery Disease (1960)
• Diabetes (1962)
• Proofs for Optimism (June 1972)
• Metabolic Diseases: Research, Diagnosis, Treatment (June 1972)
• The Deadly Role of Salt in Kidney Disease (June 1972)
• Obesity (June 1972)
• Sodium-Restricted Diet (June 1972)
• Walter Kempner: A Biographical Note (1974)
• The Rice Diet: Forty Years of Progress (October 1982)
• The Importance of Oxygen Concentration (October 1982)
• The Rice Diet and Arthritis (October 1982)
• “Out of A Clear Blue Sky…” (October 1982)
• Notes of Interest: Cirrhosis of the Liver (October 1982)
• Disappearance of Psoriatic Lesions on the Rice Diet (1986)
• The Sodium/Diabetes Connection (June 1993)
• What the Fireflies Taught Us More Than 50 Years Ago (June 1993)
>> Publications by Dr. Kempner: Additional Listings