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How DNA Changes with Age
As we age, our DNA changes, leading to numerous age-related health concerns. The smoking gun of age-related DNA alterations is something called DNA methylation, which has been found to modify some people’s DNA by as much as 20 percent.
In a study published in the journal Aging, more than 13,000 people were evaluated for their epigenetic age–an age measurement based on the amount of harmful methylation that has impacted someone’s genome.
Epigenetics is the study of changes in organisms based on modifications to gene expression (the result of aging, pollution, stress, and more), rather than changes to genetic codes. (Methylation is the key mechanism of epigenetics, however, methylation can also occur without creating genetic alterations.)
After adjusting for traditional risk factors, including age, gender, smoking habits, body-mass index, and disease history, researchers were able to use each individual’s epigenetic clock (the amount of methylation) as a predictor of lifespan.
What is Methylation?
Methylation does not change the basic structure of DNA nucleotides (adenine (A), thymine (T), guanine (G), and cytosine (C)), rather it changes the way genes are expressed.
DNA is made up of repeating sets of A, T, G, and C. Each gene has a certain number of these nucleotides in a certain order. Methylation is when a methyl group– a carbon with three hydrogens (CH3)–attaches typically to the cytosine nucleotide, or C, and alters genetic expression.
As we age, hundreds of thousands of genes can be altered as a result of methylation. This process can also be accelerated by environmental, chemical, or even emotional stress.
The body’s typical response to over-methylation, as is the case above, is to destroy these mutated or methylated cells—a process called senescence, or apoptosis.
This is happening throughout your life, but as methylation accelerates with age, your body loses the ability to destroy all of the mutated cells. These mutated cells further perpetuate DNA damage and aging.
What is Optimal Methylation?
Methylation can also be a good thing. A balanced amount of it is actually necessary for a healthy liver, fat and estrogen metabolism, and creating cellular energy.
The key is to have balanced methylation, which means not too much and not too little. A clean, healthy lifestyle and low stress are linked to balanced methylation, while aging, stress, processed foods, and environmental pollutants are all linked to unbalanced methylation.
Optimal methylation is needed for the body to manufacture:
- Coenzyme Q10
- Nitric oxide
- Norepinephrine and epinephrine
- L-Carnitine, cysteine, and taurine
How Methylation Changes DNA with Age
In a study with 111 Icelanders and 125 people from Utah who were followed for 11 and 16 years respectively, researchers measured age-related alterations in DNA from methylation.
In the Icelandic group, 70 of the volunteers showed at least a 5 percent shift in DNA, 33 showed at least a 10 percent shift, and 9 showed a whopping 20 percent shift. Of the 126 study subjects from Utah, 50 showed at least a 5 percent shift in DNA, 23 showed at least a 10 percent shift, and 13 showed a 20 percent shift.
While not everyone’s DNA was altered as a result of methylation, this was one of the first studies that linked age-related concerns with increased methylation.
Today, science has confirmed that behavior, emotional stress, nutrition, and exposure to pollutants are among the lifestyle factors associated with harmful epigenetic modifications via methylation.
Nutrition and DNA Damage
Nutrition throughout one’s lifetime is a key environmental risk factor for harmful epigenetic changes.
If you’re lacking certain nutrients, your ability to adapt to environmental stressors can be severely compromised. Research shows that exposure to pollutants such as endocrine-disrupting chemicals (EDCs) has been linked to an increased incidence of cancer, which can be considered a type of epigenetic alteration.
A diet high in methyl-donating nutrients has been shown to protect against the effects of either hypo-methylation (too little) or hyper-methylation (too much).
The body’s primary methyl-donating nutrient is SAMe (S-adenosyl-L-methionine).
For SAMe to spur balanced methylation, folic acid, which is commonly used in dietary supplements, must be converted to an active form or folate, or 5-MTHF.
Approximately 60 percent of people in the United States have a genetic mutation called MTHFR that alters their ability to create enough 5-MTHF. You can find out if you’re part of this group through genetic testing.
Foods for Balanced Methylation
The nutritional requirements needed to maintain healthy levels of methylation and ward off harmful epigenetic changes has been well established.
Studies have shown that a diet lacking in methyl-donated nutrients like vitamin B12 and folate is linked to harmful methylation-related alterations. When these nutrients were supplemented back into the diet, methylation-related changes were reversed.
In one study, in which a group of mice were fed a diet rich in BPA (bisphenol), found in plastics, they were more likely to be unhealthy (yellow, obese, and prone to cancer and diabetes). When another group of mice were fed the same diet, but were also supplemented with methyl-rich nutrients like folate and vitamin B12, the mice were healthy (brown, with healthy weight and metabolism).
- Sesame seeds
- Brazil nuts
- Sunflower seeds
- Baker’s yeast
- Whole grains
- Red wine
If stressors are persistent enough during someone’s reproductive years then these epigenetic alternations to DNA, including accelerated aging, may be passed down to subsequent generations.
In Ayurveda, these intergenerational epigenetic changes are called samskaras, and are thought of as impressions that are passed on in the genetic code from generation to generation.
Many studies have documented the passing down of epigenetic changes as a way to inform the next generation of a potential species-threatening stressor.
For example, in a 2014 study, stressed male mice passed down the fear to explore new environments. This trait in the offspring was attributed to genetics because the mice pups did not have any contact with the dad.
Or in another well-known, and more blatant epigenetics study, if mouse mothers ate one type of food the pups were yellow but if they ate another type of food the pups were black.
What traits have you inherited from the environment your parents survived or thrived in?