Genes help centenarians, healthy diet helps you to live longer

Editor's note: The majority of centenarians have longevity genes, according to a new study. But if you don't those genetic variants, you can still do something to help yourselves to live longer. One thing to do is follow a healthy lifestyle, which may add years to your life-span. It is not easy to become a centenarian even if you have the genes, but it should not be as hard to live a few years longer. Let us know if you have something to share with others.

Genetic patterns found in centenarians

A new study of more than 1000 centenarians led by Tom Perls at Boston Medical Center and colleagues suggests that a set of 150 genes may largely determine a person's longevity or how long a person can live.

The researchers pubulished in Thursday's online edition of the journal Science saying that a math model based on gene variants identified in The New England Centenarian Study may be enlisted to predict whether a person can live over 100 years and the accuracy can be up to 77 percent.

The 150 newly identified genetic markers may be used soon in genetic testing kits, some expert said.

Genetics may be the foundation of longevity. But Winifred Rossi, of the National Institute on Aging's Division of Geriatrics and Clinical Gerontology, which funded the study, said that the genetic influence is complex and a person's life span is also determined by environmental factors.

Those who do not carry the longevity genes may still benefit from following a healthy lifestyle even though they may be able to live long enough to be a centenarian.

Caloric restriction

Researchers have been studying since 1930s how caloric restriction (CR) affects the life-spans of animals and humans and found that eating less calories generally makes animals live longer.  It is speculated that with low intake of calories, the body shuts down many physiological functions and turns into a conservative maintenance mode, preventing the body from suffering many adverse effects such as inflammation induced when the energy is abundant and delaying the aging process.

Fontana L. from Washington University School of Medicine in St. Louis MO and colleagues reported in the April 2010 issue of Science that in rodents, both CR can help prevent age-related loss of function and diseases, including tumors and neurodegeneration, increases life span, protects against diabetes, cancer, and cardiovascular disease in rhesus monkeys, and prevents age-related diseases in humans. 

Fontana and colleagues also reported in the March 2010 issue of Age that individuals aged 28 who followed a calorie-restricted diet and engaged in endurance exercise for an average 7 years were leaner and had higher insulin sensitivity compared to those using Western diet.

According to the researchers, 40 percent of those who followed the CR diet had elevated hyperglycemic response to a glucose load and this impaired glucose tolerance is correlated with lower circulating levels of IGF-1, total testosterone, and triiodothyronine (a thyroid hormone called T3), which actually retard the aging process.

T3 affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate, according to previous studies.

A recent trial led by Edward Weiss at Saint Louis University and colleagues found in those following a CR diet reduced levels of  T3 even though their body mass indexes were similar to those of inviduals on a regular diet, suggesting that CR has a direct or indirect impact on the production of T3 in the aging-retarding process.

The one-year trial involved one group of sedentary, non-smoking and post-menopausal women aged 50 to 60 using a diet with its total energy cut by 300 to 500 calories and another group using a regular diet.

The researchers published their findings in the June 2008 issue of Rejuvenation Research.

CR has been known to retard the aging process at genetic levels.

Leonard Guarente of Massachusetts Institute of Technology reported in the Sept 2005 issue of Mechanisms of  Ageing and Development that SIR2 genes regulate CR in low species like yeast and Drosophila and the mammalian Sirt1 may be responsible for physiological changes during CR.

Mediterranean diet

Pérez-López FR and colleagues of Universidad de Zaragoza in Spain found people who followed Mediterranean diet or a similar diet tended to have a longer lifespan and they were 10 to 20 percent less likely to die of heart disease, cancer or any other cause.

The authors reviewed clinical and laboratory studies cited in the PubMed database and found the Mediterranean diet helps bone metabolism, rheumatoid arthritis, and neurodegenerative age-related diseases (cognitive deficit, Alzheimer's disease, Parkinson's disease).

Their findings were published in the Oct 2009 issue of Maturitas.

Tyrovolas S. and colleagues from Harokopio University in Athens, Greece also published a report in the Nov 30 2009 issue of Eur. J. Public Health saying that Mediterranean diet was associated with the longevity people enjoy in Mediterranean islands.

Okinawa diet

Willcox D.C. and colleagues from Okinawa International University in Japan reported in the Aug 2009 issue of J. Am Coll Nutr. that a diet used by people including many centenarians in Okinawa, the southernmost prefecture of Japan may play a role in the longevity enjoyed by the people in this area.

The so called-Okinawa diet is similar to Mediterranean diet and DASH diet in that it includes high amounts of vegetables and fruit and reduced amounts of meat, refined grains, saturated fat, sugar, salt, and full fat dairy products.

Okinawa diet uses the lowest amounts of fat, particularly saturated fat and highest amounts of carbohydrate,  antioxidant-rich orange-yellow root vegetables such as sweet potatoes and green leafy vegetables.

These three diets share some features like all using low levels of saturated fat, high antioxidant intake and low glycemic load, which help protect against cardiovascular disease, some cancers, and other chronic diseases through multiple mechanisms, including reduced oxidative stress.

Miscellaneous foods/nutrients

Dr. Joe Mercola, owner of mercola.com, says in one of his newsletter articles that 7 foods may help you live a longer life.  They are whey protein - a source of glutathione; raw organic eggs - a good source of essential amino acids, lutein and other nutrients (cholesterol as well); leafy greens like spinach, kale, turnip greens, collard greens - good sources of cancer-fighting antioxidants like beta carotene, vitamin C, and sulforaphane; broccoli; blueberries; chlorella; and garlic.

Rockenfeller P, and Madeo F. from the University of Graz in Australia reported in the April 2010 issue of Biochim Biophys Acta that epidemiological studies suggest that human lifespan can be extended by physical exercise, caloric restriction and consuming certain nutrients or foods such as resveratrol, selenium, flavonoids, zinc, omega 3 unsaturated fatty acids, vitamins E and C, Ginkgobiloba extracts, aspirin, green tea catechins, and antioxidants.

A recent China study  published in Feb 2010 in Zhonghua Yu Fan YiXue Zaxhi finds that the concentrations of serum selenium, manganese, iron, copper and zinc were higher in centenarians.   The study led by Xu J.W. from the Chinese Center for Disease Control and Prevention in Beijing involved 446 elderly people including 208 centenarians.

By David Liu