Smoking, drinking alcoholic beverages, eating foods high in all the things (fat, sugar, sodium, etc.) that we are told to avoid: any damage to our health only happens to us and then is over and done with, right?
Possibly not, at least in regard to smoking. Scientists from the Los Angeles Biomedical Institute have found that if you smoke, you could be putting your grandchildren at risk for some of the effects.
The reason lies in epigenetics, the study of how changes in your environment and your own lifestyle choices can affect how your genes are expressed, through modifications of the network of chemical “switches” within our cells. That is, epigenetics studies not changes in the underlying DNA sequence, but others including DNA methylation (the addition of methyl groups to the DNA) and histone modification (the addition of acetyl groups to the histones, the proteins in which DNA is wrapped). As The Economist puts it,
Methylation switches genes off. Acetylation switches them on. Since, in a multicellular organism, different cells need different genes to be active, such regulation is vital.
The Los Angeles Biomedical Institute scientists’ research suggests that epigenetic switches can be passed on and for more than one generation.
Virender Rehan, M.D. studied the intergenerational effects of nicotine. He and his colleagues injected pregnant rats with nicotine and found that not only their offspring, but their offspring’s offspring developed asthma from the drug. The Economist describes the study:
The pups of the treated mothers had asthmatic lungs. The organs’ airways were constricted, and molecular analysis showed abnormally high levels of fibronectin and collagen—which would stiffen the lung tissue—and also high levels of receptor molecules for nicotine. That was expected, since the developing embryos were exposed to the nicotine when their mothers were treated. However, when the team did similar tests on the grand-offspring of the treated mothers, they got similar results. Those grand-offspring had not been exposed to nicotine.
The cause of the grand-offsprings’ asthma, Dr Rehan believes, is epigenetic modification. Nicotine is not only affecting lung cells, but also affecting sex cells in ways that cause the lungs which ultimately develop from those cells to express their genes in the same abnormal ways.
Epigenetics suggests that the choices you make in your diet and lifestyle can, possibly, lead to changes in how your cells express their genes, with implications for your children and other descendants. As The Economist notes, it is not that your DNA sequence is changed; other studies suggest that inherited epigenetic changes can be reversed. But Rehan’s study shows that, to invoke a Biblical tone, “the sins of the fathers (or, in this case, the mothers) will be visited on the sons, even unto the third and fourth generations.”
Epigenetics is a reminder that when making choices about what you eat and drink and put into your body, and what you do (go for that daily walk or hunker down on the couch with a bowl of something salty), you’re not only doing it for yourself, but for future generations and for the future of all of us.
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