Nature or Nurture?

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Which has the greatest effect when it comes to the cause of disease? Although only a few statistical studies try to answer this question, one recent study suggests that about 5% of obesity is caused by genetics. That means 95% of the overweight problem is a result of environment – cultural patterns, economic constraints, formal and informal educational levels, health intervention awareness, parental modeling, social pressures, advertising and personal choices.

This is an amazing statistic – especially when so many overweight people tend to say: “It runs in my family.” So we have to ask: “What runs in the family? Genetics or habit patterns? Are these problems from the gene pool or from cultivated cultural/familial choice patterns?”

Clearly, most of the problem lies with the habits we have learned, not the DNA we were born with.

Although there are no other similar measurable statistics for the most common diseases, it is easy to understand that the same magnitude of effect (5-20%) is the probable contribution. Like obesity, most common deadly diseases – heart disease, stroke, cancer, diabetes II, metabolic syndrome, arthritis, mental illness – are multifactorial. That means they are caused by different components, and genetics is only one of them.

Very few diseases (Huntington’s chorea comes to mind) which are 100% caused by genetics. In fact, no major diseases have genetics as the overwhelming cause. Do some people have a greater genetic tendency to have hypertension, obesity, ovarian cancer, diabetes or heart disease than others? Do some people have to work harder at avoiding these problems? Yes, but the majority of those with a genetic predisposition for these diseases don’t actually manifest the disease – because their lifestyle choices have improved their chances of avoiding it.

“The devil made me do it!” The famous laugh line of a 1970’s comedian points out how we love to blame our choices on someone else, anyone except ourselves. Funny? Yes, until a disease process sets in.

Even more attention-getting is the new understanding that lifestyle choices can affect our genes, causing some to switch on and others to switch off, setting a new genetic pattern which can be passed on to succeeding generations. Our genetics are not chiseled in stone; they are affected by our lifestyle choices.

Don’t be a victim of your genetic code. For the most part, genetics plays only a small part in your risk of contracting one of the major diseases. Just because you have a genetic predisposition for a particular disease generally does not mean that you are doomed to get it.

Lifestyle choices are far more powerful than genetics and can even modify the genetics that you pass on to your children. In fact, your lifestyle choices have a much higher impact on your children than the genes you pass to them.

If you make good lifestyle choices, someday your children will thank you.

Author

Max Wayne Hammonds was born Aug 3, 1943, in northeastern Indiana, in the county hospital in Wabash. He attended high school and college in his home town of North Manchester and attended Indiana University Medical School in Indianapolis. Following an internship in South Bend, IN and a year of flight medicine in the Air Force, he took a residency in anesthesiology at Wilford Hall Medical Center at Lackland Air Force Base in San Antonio, TX.