The new science of aging is shedding light on the coveted fountain of youth. Our midlife represents both risk and opportunity. As we creep into our middle years we often begin to experience disruptive symptoms and face increased risk of chronic diseases such as diabetes, heart disease and cancer. This is the critical time where we have the most important opportunity to take charge of our aging.
At midlife, we begin to face accelerated loss of vital factors: our hormones, our nutrients, our sleep and our telomeres, which are protective caps on the ends of our chromosomes that shorten as we age and place a finite limit on our lifespan. Rapid aging ensues: From the age of 40 to 50 years women age twice as fast as any other decade. While men's aging speeds up too, by about 60 per cent, they do not face the same cliff in the aging process.
The rapid loss of the ovarian hormones estrogen and progesterone during a woman's menopause produces this cliff effect. By 50 years of age, many other critical hormones have dwindled, including melatonin (which sets our sleep-wake cycle), the adrenal hormone DHEA (which has been linked with vitality and libido in women) and other hormones regulating our metabolism.
It is not only our hormonal rhythms that begin to fail, but so too our nutritional status. Even if we take in the required nutrients in our diet, our guts become less able to absorb them. Acquired deficiencies in essential minerals and vitamins may arise interrupting key pathways and functions.
Just a few years ago, Nobel-Prize winning research unlocked the code to our biological aging. The discovery of telomeres and an enzyme called telomerase has shed light on cellular aging. Telomerase is a housekeeping enzyme that functions to preserve telomeres. With defects in the enzyme and shortening of our telomeres, cells face programmed cell death. More recently, it has been shown that telomere length can be improved with comprehensive lifestyle changes including diet, exercise, stress management and social support.
While hormones and telomeres are important – so too are nutritional factors. Dietary factors may determine approximately 30 per cent of our lifespan and add as much as a decade to our life. Animal models have shown caloric restrictions have anti-aging effects. Mice fed low-calorie diets remain more youthful; both on the inside and out. They have longer life expectancies and are also less likely to have cancer, diabetes and heart disease. Clearly, it is not just how much you eat but what you eat that matters.
So is there a longevity diet? It is instructive to look at populations that boast the highest proportion of centenarians and longest life expectancy. With an average lifespan of 81 years, Okinawa islanders of Japan are considered the oldest demographic in the world. The Okinawa diet is plant-based with little red meat. Compared with other Japanese diets, theirs is lower in calories, carbs and salt and higher in nutrients such as calcium, iron and vitamins.
American gerontologist Dr. Craig Willcox's book, The Okinawa Program, describes his findings from a 25-year study of Okinawan longevity and recommends that we "eat as low down the food chain as possible"
Other studies have confirmed that very low meat intake may contribute to longevity. Vegetarians in three continents have been shown to live longer than people on the Standard American Diet high in refined sugars, trans fats and meat products.
Life stress doesn't help either, especially when it is chronic and extreme. Stress works like the common denominator when it comes to aging; shortening telomeres, and depleting our hormones. It is estimated that chronic stress may shave more than seven years off the lifespan due in part to the shortening of telomeres. Proven stress-management techniques such as yoga, meditation and tai chi may favourably affect cellular aging by reversing the deleterious effects of stress.
The science of aging is complex and evolving rapidly. Achieving a lifestyle optimal for your genes and body type is the cornerstone to maintaining health and vitality through the ages.
Dr. Jennifer Pearlman is a physician focused on women's health and wellness, a staff physician at the Menopause Clinic at Mount Sinai Hospital in Toronto and medical director of PearlMDRejuvenation, a Women's health and wellness facility.