How often have you pondered your dad’s diabetes or the heart disease that runs in the family and thought, “Am I going to get that? Is it inevitable?”
With all we’ve learned about genetics, it seems reasonable to think that some of our health outcomes will be determined by those invisible forces buried deep in our DNA. But a new study has shown that how long we live has more to do with our behaviour than with our genes, implying that our choices may have a much more profound impact on our longevity than we may have thought.
The authors of the study, published in the Human Kinetics Journal, sought to analyse the relationship between physical activity and sedentary behaviour, and their associations with mortality based on a score that evaluated genetic risk factors. The study involved 5,446 post-menopausal women 63 years of age or older. The women were put into three groups based on their genetic risk factors. These risk factors were measured by a “small selection of single-nucleotide polymorphisms” that are well-known to affect longevity.
Single-nucleotide polymorphisms (SNPs) are variations in a genetic sequence that affects one of the sequence’s basic building blocks—adenine, thymine, cytosine, or guanine. SNPs help predict an individual’s response to certain drugs, his or her susceptibility to environmental factors such as toxins, pesticides, or industrial waste, and his or her risk of developing certain diseases.
The study authors conclusively found that, regardless of their genetic risk factors, participants who had a higher rate of physical activity showed a lower risk of mortality, and those who had a higher level of sedentary behaviour increased their chances of dying during an average follow-up period of more than six years.
Ultimately, the findings support the importance of more physical activity and less sedentary behaviour for reducing mortality risk in older women, regardless of their genetic predisposition for longevity.
Genes & Longevity
An article titled “Human Longevity: Genetics or Lifestyle? It Takes Two to Tango,” published in Immunity and Aging in 2016, found that a combination of genetic and non-genetic factors determines healthy aging and longevity in humans. It says that family studies found that about 25% of the variation in human longevity is due to genetic factors. Interestingly, the article also states that studies have indicated that caloric restriction, as well as epigenetic factors, genetics, and lifestyle, play a role in healthy aging.
Epigenetics is the study of how our behaviours and environment can change the way our genes function. Unlike genetic changes, these epigenetic changes are reversible because they don’t affect our DNA.
In contrast, a study published in 2018 in the journal Genetics analysed a staggering 54.43 million family trees by collecting birth and death records for 406 million people born from the 19th century to the mid-20th century from the databases of Ancestry.com. The study found that a mere 7% of people’s lifespan can be attributed to genetics or heritability.
Heritability measures how the differences in human genes account for the differences in individuals’ particular characteristics or traits. These include eye colour, height, hair colour, intelligence, and disorders such as schizophrenia and autism.
Lifestyle & Longevity
Longevity, or the biology of aging, is an exciting field of study that is making important discoveries about the factors that affect how long we live.
Until very recently, life expectancy for humans was between 19 and 35 years, but over the past 150 years, significant improvements in sanitation and living conditions, agricultural practices, access to clean food and water, and medical treatment have dramatically increased lifespans. The average lifespan now is about 76 years of age (it has declined significantly in the United States since 2020 due to COVID-19). If we look at it this way, managing how we age is a relatively new concern.
With aging comes a whole host of age-related diseases, such as heart disease, high blood pressure, kidney disease, diabetes, arthritis, cancer, dementia and Alzheimer’s disease, to name a few. And, as we get older, we are not only more likely to develop these conditions, but also to have several of them at the same time.
Scientists have been studying people who live to be over 100 years old (called centenarians) and those who live to be over 110 (called supercentenarians) in order to understand which factors contribute to their long lives. Scientists have discovered that these individuals have little in common with each other in regard to their education, profession, or income, but they tend to share similar lifestyles: They don’t smoke; they are not obese or overweight; and they cope well with stress. Also, most centenarians and supercentenarians are women.
In our elder years, eating a healthy diet, avoiding tobacco, limiting alcohol, and staying physically active can keep many of us healthy into old age. But in later life—at age 80 and beyond—genetics plays a prominent role in keeping people healthy and avoiding age-related diseases. Research suggests that many centenarians are able to live independently and avoid age-related diseases until the very last years of their lives.
Dr. Nir Barzilai, director of the Institute for Aging Research at the Albert Einstein College of Medicine, studies the biology and genetics of aging. Barzilai says that there are two hypotheses that he and his team have about why centenarians are so long-lived and why they seem to stay healthier longer. The first is that they are doing all the right things regarding their environment, such as eating well and exercising, he says, noting that they have a “blue zone” kind of lifestyle. The blue zones are the six places on earth where people live the longest and are the healthiest.
The second hypothesis, Barzalai says, is that they may have the “perfect genome.” For example, they may not have the genetic risk of SNPs, or variations commonly associated with age-related diseases like Alzheimer’s disease, cardiovascular disease, and cancer.
In Barzilai’s work with centenarians, he also found that their personality and outlook on life were particularly distinct. He says that the older people whom he has worked with have a keen interest in being happy and that getting them there doesn’t take much, especially as compared with younger generations. Having a positive outlook and relaxed approach to life seem prevalent among the longest-lived people.
It may be a relief that, based on the current research, we no longer need to be resigned to the diseases of our forefathers. How long and, perhaps more importantly, how well we live is, instead, a combination of our genes, environment, lifestyle, and attitude. Thankfully, that means our choices have a much more significant impact on our health than do the genes we carry, and that our health is predominantly in our hands.
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Why Mushrooms Increase Longevity
Mushrooms produce millions of microscopic spores that are spread by animals or the wind. Once these have germinated in wood or soil, they send out a network of rooting threads called mycelium that can persist for many years. Mycelium digests the surrounding nutrients externally and then absorbs those nutrients.
Scientists do not believe that all mushroom species have been identified. Neither do they agree on how many species there may be, with estimations ranging from a low of 45,000 catalogued species in 2015 to a high of 1.5 million to 5.1 million yet to be discovered and named. According to a paper in the American Society for Microbiology, in 2017 there were 120,000 identified species, which the researchers estimated may be just 3% to 8% of the population of mushrooms.
In ancient Egypt, mushrooms were thought to bring long life and have been used for centuries by Chinese medicine practitioners. Greek physician Hippocrates used the Amadou mushroom for cauterizing wounds and as a potent anti-inflammatory. The first people populating North America used puffball mushrooms to heal wounds.
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READ MORE: Stepping Toward Longevity
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