According to a recent study our genes have less than a 30 percent effect on how long we’ll live and in many cases this effect is as low as 7 percent. This study was conducted by scientists from Calico Life Sciences LLC, a company that studies the biology of aging who teamed up with researchers from Ancestry. The results showed that spouses typically have similar life spans likely due to lifestyle and dietary factors although siblings of the same sex don’t share this pattern. However, these researchers were surprised to find that siblings-in-law and first-cousins-in-law, like married couples, have similar life spans despite not being blood relatives or sharing households. J. Graham Ruby, the study’s lead author, attributed this to assortative mating, a pattern in which individuals with similar socioeconomic and lifestyles tend to mate with one another more frequently than expected under a random mating pattern.
Antiaging Clocks
While marriage has long been studied for its connection to longevity with happy couples tending to live longer, many other factors play a role, particularly epigenetic changes related to methylation. The first of these epigenetic associations with longevity was described in 2011 by the UCLA geneticist and biostatatician Steve Horvath, the creator of the epigenetic clock called GrimAge. Since then, a number of researchers including Horvath’s student Morgan Levine have devised aging clocks based on epigenetic factors associated with aging and various pathologies including various cancers, all-cause mortality, Huntington’s disease and Alzheimer’s disease. In epigenetic studies of Alzheimer’s disease patients show accelerated aging compared to subjects of the same age who are free of dementia.
Some of the most widely used clocks in medicine include Horvath’s GrimAge and Morgan Levine’s DNAm PhenoAge. With the exception of acquired mutations, human DNA is fixed. However the study of epigentics explores the factors that determine whether genes are turned on or turned off and how this influences longevity.
Epigenetics
Humans have approximately 22,000 genes, a small number compared to the 31,000 genes present in tiny water fleas. Single genes have minimal influence, and only about 2 percent of genetic diseases are directly caused by a single gene. In humans the DNA that comprises genes is located within 23 pairs of chromosomes. Each chromosome contains genes that provide instructions for producing the various proteins that make up our body’s cells.
As genes interact they produce physical traits such as eye color that make up an individual’s phenotype. Because a single gene can produce several different proteins the specific proteins produced by genes and their characteristic properties are significantly greater than the number of genes. When genes are turned on these properties are expressed. Epigenetic researchers study changes in gene expression and how they’re related to dietary and lifestyle factors.
Reliable biomarkers of aging and disease have been identified, particularly those caused by the effects of methylation. By studying these biomarkers, scientists have developed aging clocks that compare chronological and biological aging, thereby predicting longevity and a propensity for certain diseases. A number of companies such as Morgan Levine’s Elysium Health have also created blood and saliva tests that predict longevity based on measures of methylation or chemical molecules. An example is testing for the highly sensitive C-Reactive protein (hsCRP), which is an acute phase reactant and indicator of inflammation. Results compare one’s biological age to their chronological age. Tests for DNA age are available and expensive but regardless of results, the goal in antiaging programs is to lower one’s biological age with moderate but not excessive exercise, adequate sleep, proper nutrition, a healthy weight, and with dietary supplements.
DNA Methylation
DNA is composed of the amino acids adenosine, cytosine, guanine, and thymine. In human DNA there are more than 28 million CpG sites of attachment where cytosine precedes guanine. These are known sites where methyl groups can easily attach. Epigenetic clocks focus on only a few specific points of attachment in which methylation is known to turn off specific genes. An example of a change caused by methylation is one of the common methylenetetrahydrofolate reductase (MTHFR) mutations, which affects 60 percent of the US population and causes individuals to absorb only about 65 percent of the B vitamins that they ingest.
Causes of Methylation
Methylation is increased in obesity and diabetes; by insufficient sleep; in current smokers; by exposure to particulate air pollution; following a sedentary lifestyle; and by ingesting a diet devoid of nutrients; by eating genetically modified and processed foods foods containing antibiotics, pesticides, and hormones and by exposure to both physical and mental stress, including high intensity exercise. Changing these risk factors for methylation has been found to improve one’s biological age.
Improving Biological Age with Supplements
A small clinical study known as the thymus Regeneration, Immunorestoration, and Insulin Mitigation (TRIIM) trial tested 9 white men between 51 and 65 years of age to see if biological age could be reduced with the use of supplements. The study was conducted over the course of one year by the immunologist Gregory Fahy and his team at Intervene Immune in Los Angeles in conjunction with epigenetic monitoring by Steve Horvath.
Because growth hormone helps regenerate the thymus, an organ essential for a strong immune system, growth hormone was used along with two anti-diabetic drugs, dehydroepiandrosterone (DHEA) and metformin, a drug long associated with reduced mortality from all causes. The study used magnetic resonance imaging (MRI) to measure changes in the thymus. They noted that in 7 subjects the fat stores that normally accumulate in the thymus gland with age were replaced with regenerated thymus tissue. Steve Horvath used 4 different epigenetic clocks to assess each subject’s biological age and found significant reversal for each participant with an average reduction of 2.5 years in their biological age. Tests conducted 6 months after the trial showed that the effects persisted.
By using chlorella to increase growth hormone, DHEA, and metformin I’m hoping to see similar results.
No Limit to Longevity
A team led by Sapienza University demographer Elisabetta Barbi and University of Roma Tre statitician Francesco Lagona found that the risk of death, which typically increases with age up to around age 80, levels off after age 105. Like if you’ve made it this far you’re doing something right. In this mortality plateau, the odds of someone living another year are 50:50. This team from Rome and other researchers have concluded that the risk of death flattens out in one’s ultra golden years, and consequently there is no upper threshold for the human lifespan.
Resources
Levine, Morgan, et, al. 2018. “An Epigenetic Biomarker of Aging for Healthspan and Lifespan. Aging 10, No. 4: 573-91 doi: 10.18632/aging.101414.
Abbott Alison. 2019. “First Hint that Body’s 'Biological Age” Can Be Reversed.” Nature 573 173 Sept 5. doi: https://doi.org/10.1038/d41586-019-02638-w