How Epigenetics Makes a Practical Difference in Your Life

Just about any outside stimulus, an infection, a chemical, a life experience, or even an emotion, has the potential to make an epigenetic change in your DNA. The precise ways certain life experiences change which genes are activated and which genes are not is still poorly understood, but there is mounting evidence for epigenetic changes caused by several common experiences.

• Exercise has been known to be beneficial for decades, but only since 2000 have scientists begun to understand that exercise marks DNA not just in muscle but also in fatty tissue.
• Childhood abuse causes lifetime changes. Some of them are even encoded into DNA.
• Bisphenol A (BPA) is a chemical added to plastic that is known to interfere with the action of sex hormones, to accelerate deposition of fat, and to increase the risk of cancer. Some of its effects are the result of DNA methylation that causes epigenetic changes.

There is a widely accepted body of evidence for epigenetic changes that happen during the lifetime of an individual. There is less evidence for passing epigenetic changes from grandparents to parents to children.

• Much of the early study of epigenetics concerned the agouti gene. Both normal-weight brown mice and yellow obese mice can have the same gene (or genotype) but very different outward characteristics (or phenotype) depending on whether this gene has been methylated. Folic acid is a source of the methyl groups that act on this gene. If the mother mouse gets more folic acid, her pups will tend to have brown coats and to be normal weight. If she gets less folic acid, her pups will tend to have yellow coats and to be obese.
• Studies of prairie voles (a kind of field "mouse") in Florida have found that when DNA in brain cells in the animal’s nucleus accumbens, a kind of traffic control center in the brain, are methylated, the animal mates for life. As long as the DNA in these cells is not methylated, it literally and figuratively “plays the field.”
• Many people scoff at the idea that marijuana is a gateway drug. However, there is a growing body of evidence that smoking marijuana during adolescence activates a gene that increases the likelihood of heroin addiction in adulthood.

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• Studies of survivors of famine in Sweden and in the Netherlands have found that epigenetic activation by starvation can be passed down for at least three generations. It’s a very common observation that people who survived starvation in World War II and other conflicts of the twentieth century tend to have weight problems once they can get normal amounts of food again, and their children and grandchildren tend to have weight problems, too. Research is ongoing to figure out how to deactivate these genes that set the stage for obesity.

Studies of over 1,000 patterns of epigenetic activation in humans are underway, but it’s too early to generalize their results. However, medical science is finding more and more significance for methylation, and for folic acid metabolism, every year. Just don’t assume that more folic acid is always better, at least not yet.