Acai berries, green tea, soy, olive oil and sweet potatoes have all been hyped for their life-prolonging potential. Diets rich in vegetables, fruits and grains, and low on meat may help prevent chronic disease. But so far there's only one dietary approach shown to lengthen life span: eating less. Of course, a dearth of firm data hasn't stopped doctors, scientists and nutritional dilettantes from penning anti-aging diet books. Here are a few of them.
The Longevity Factor
How Resveratrol and Red Wine Activate Genes for a Longer and Healthier Life
Dr. Maroon, professor of neurological surgery at the University of Pittsburgh and neurosurgeon to the Pittsburgh Steelers, says the key to living longer (or one such key) is resveratrol, a potent antioxidant in red wine.
Resveratrol is one of a class of compounds that Maroon refers to as xeno factors, chemicals that plants produce under stressful conditions, such as drought or harsh sun. In plants, xeno factors trigger survival genes that help fight infections and other hazards. Studies show that when lab animals consume plant xeno factors, the chemicals activate the animals' own survival genes and enable them to live up to 50% longer than animals on normal diets. Scientists studying this hypothesis speculate that xeno factors may activate genes that delay aging in any life form.
Maroon cites many studies supporting the life-extending capabilities of the xeno factor resveratrol: fish fed resveratrol live 60% longer; worms and flies 30% longer; mice, 25% longer. Other lab studies suggest how resveratrol may do this: In rats and mice the chemical appears to help regulate blood sugar, prevent platelets from aggregating in blood vessels, slow the growth of cancer cells, reduce brain damage and decrease the death rate following heart attack. In many ways, the chemical's effects mirror that of calorie restriction.
Maroon does not recommend that people ingest resveratrol any way they can to lengthen life span. Instead, he advises eating foods and drinks with high levels of xeno factors -- red wine, green tea, grape juice, dark chocolate and apples -- as part of a heavily plant-based diet, rich in whole grains, low in saturated fats.
Maroon also strongly advocates resveratrol supplements and "resveratrol-like" prescription drugs (none of the latter is on the market yet). But his confident and enthusiastic endorsement of resveratrol is based on research conducted mostly on animals and in test tubes. Relatively little human research has been performed to date. Though existing research suggests the chemical may improve cardiovascular health, none has yet shown it helps prolong life in people.
The Younger (Thinner) You Diet
How Understanding Your Brain Chemistry Can Help You Lose Weight, Reverse Aging, and Fight Disease
The "Younger (Thinner) You Diet" is based on the premise that body weight and aging are tightly bound. "Your excess weight is your aging brain's cry for help," writes Dr. Braverman, who runs a private practice (the Place for Achieving Total Health, or PATH) in New York and is clinical professor of integrative medicine at Weill Cornell Medical College. The aging brain he describes is characterized by low levels of the key nerve cell-signaling chemicals dopamine, acetylcholine, GABA and serotonin, deficiencies he asserts can be remedied with the right foods.
The book is packed with meal plans, shopping lists and recipes for boosting blood chemicals: acetylcholine-boosting frittata, dopamine-boosting scrambled eggs, GABA-boosting salad, serotonin-boosting tofu and total-brain-chemical-boosting lamb tagine. The dishes don't include the chemicals themselves but the building blocks needed to make them, such as the amino acids phenylalanine and tyrosine, precursors to dopamine; and choline, the B vitamin from which acetylcholine is made.
Braverman also provides advice on how to reverse what he refers to as the "pauses," the physiological changes associated with the aging of the body's organs. To make an aging heart younger, he recommends low-sodium, high-fiber foods, complex carbohydrates and foods that provide omega-3 fats. For osteopause he advises foods rich in calcium; for menopause, foods high in vitamin D.
Overall, Braverman recommends a high-protein, high-fiber, low-fat diet packed with foods rich in vitamins, minerals and antioxidants. He prescribes tea, spices with every meal, yogurt and whole grains.
This is all fairly sound dietary advice, but the justifications are sometimes slim: He promotes nutmeg as an antidepressant, for example, although the only evidence for the claim comes from a single study in mice.