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 heart disease, diabetes and cancer. It is at this critical time that we have the most important opportunity to take charge of our aging. Forget aging gracefully, our generation can choose to age proactively and design the second half of our lives.
But to age well requires that we first understand why we are aging. As we approach midlife, we begin to face accelerated loss of vital factors; our hormones, our nutrients, our sleep and our telomeres. As a result of these losses, rapid aging ensues. Indeed, 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 percent, they do not face the same cliff in the aging process.
The rapid loss of ovarian hormones, estrogen and progesterone, during the years saddling a woman’s menopause contributes to this accelerated aging. 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 telomerase, has shed light on cellular aging. Telomeres are protective caps on the ends of our chromosomes that shorten as we age and place a finite limit on our lifespan. Telomerase is a housekeeping enzyme that functions to preserve telomeres. With defects in the enzyme and shortening of our telomeres, cells face programmed senescence. 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. Food-gene interactions play an important role in shaping our health, risks of disease and aging. Indeed, our diet provides energy, micronutrients to support our body processes and shapes microbiome (the collection of bacteria housed primarily in the colon). Our diet can also predict our aging. Dietary factors are thought to determine approximately 30 percent of how long we live and can add as much as a decade to our life.
In fact, one of the most robust models of longevity is based on caloric restriction in mice. 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. They look younger too, with richer fur, fewer wrinkles and less body fat.
In mice and other animal models, caloric restriction has been shown to promote longevity through the activation of sirtuins, proteins known to regulate the lifespan and contribute to genomic stability. A lot of attention has been given recently to the role of sirtuins in aging, because they play an essential role in the cellular response to environmental, physiological and psychological stress.
For sirtuins to work, they depend on a co-enzyme called NAD+. Nicotinamide Riboside (NR), a form of vitamin B3 , is a precursor to NAD+ and plays the vital role in replenishing the supply of NAD + in the cell. Nicotinamide Riboside, as found in the health supplement Tru Niagen, when taken in a single oral dose has been shown to increase human blood levels of NAD+ by 2.7-fold. So it may be possible to mitigate age related decline in NAD+ levels and accentuate the benefits of caloric restriction through the use of NR supplementation to ramp up NAD+ production.
Despite the potential benefits of caloric restriction, it is not a lifestyle intervention that most would be able to follow successfully. To mimic the benefits of starvation, several caloric restriction mimetic diets have been developed. The most popular is the intermittent fasting (IF) diet and the ketogenic diet (KD). Intermittent Fasting (IF) combines moderate caloric restriction with time restricted eating. At least 3 days per week, a prolonged fast of 12-15 hours sometimes coupled with high intensity exercise (HIIT), is used to activate the sirtuin pathway and other metabolic modifications that occur during fasting. The Ketogenic Diet (KD) shifts the macronutrient make up of the diet, to restrict both carbohydrates and often calories. The ketogenic diet drives a switch in the body’s primary fuel from glucose to ketosis, a state where a more energy efficient form of fuel is used, ketone bodies which are derived from stored body fat as well as dietary fat or dietary ketone supplements. The low carbohydrate ketogenic diet is the best studied low carb diet for weight loss, energy, brain health and longevity. IF and KD are complimentary dietary interventions involving sirtuin activation and NAD+. Supplementation with the dietary ketone, betahydroxybutryrate (BHB), and NR may potentiate the benefits of both IF and KD.
Clearly it is not just calorie counting and timed fasting, but rather qualitative factors that can contribute to a longer lifespan.
So, is there a longevity diet? To design one, it is instructive to look at populations who 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. Compared with other Japanese diets, theirs is lower in calories, carbs and salt and higher in nutrients such as calcium, iron and vitamins.
The Okinawa diet is plant-based with little red meat. American gerontologist, Dr. Craig Willcox authored a book “the Okinawa Program” describing his findings of a 25-year study of Okinawan longevity and recommends that we “eat as low down the food chain as possible.” According to the JAMA network, 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 (SAD), high in refined sugars, trans-fats and meat products.
Life stress, especially when it is chronic and extreme, works like the common denominator when it comes to aging. Stress shortens telomeres, depletes NAD+ as well as the pool of precursors needed for healthy hormone balance, impedes nutrient absorption in the gut and leads to inflammation. 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 mindfulness, meditation, deep breathing and visualization as well as tai chi may favorably affect cellular aging by reversing the deleterious effects of stress. New mindfulness based apps and digital tools and technology are making some of these practices more accessible to a larger population who may not access more conventional psychological resources.
The emerging field of “epigenetics” is revealing how our lifestyle, our stress and environmental exposures can affect the expression of our genes. Our DNA is not our destiny but rather a roadmap that is shaped by our lifestyle and life choices. The understanding of how these gene-environment interactions shape our health is the new frontier of Personalized Medicine.
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. We can now choose to take charge of our aging and live longer better.