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Wellness Corner August 2015 -The Genetic Basis of Disease


Wellness Corner August 2015

The Genetic Basis of Disease

by Dr. Gary Pace

Let’s face it, modern medicine is not helping us to become healthier. Medical costs are spiraling out of control, but physically and emotionally, many people are feeling worse. Our current medical system focuses on the biochemical expressions of disease, yet new understandings in genetics suggest the possibility to affect deeper causations. 


Completed in 2003, the Human Genome Project was designed to map all human genes in the hope that through identifying the gene/disease template, effective diagnostic and treatment strategies could be developed.  This hope has not been realized, but many other important discoveries have emerged. 

We had mistakenly thought that human genes were more numerous than other species’ since we are more complex. The total number of genes in the human genome is about 25,000. Many plants actually have more genes, and our closest relative, the chimpanzee, has a genetic correlation with humans of 96%, somehow not explaining the big differences between species. Initial scientific interest was on the other 4%, but now attention has focused on single nucleotide polymorphisms (SNPs)—small mutations that allow for most of the variation in humans. In any individual, there are an estimated 3 million of these changes in the genetic code. These variations in the DNA act as the source of individual complexity, and they provide an evolutionary opportunity to allow for more nuanced interactions between the genetic code and the environment.

Also from the HGP, we gained an understanding of epigenetics, the study of how environmental factors like diet, stress, and toxin exposure are able to turn different genes on or off selectively. The different SNPs lead to a huge spectrum of response to these different exposures. One example is a study by Drs. Jittle and Waterland at Duke which demonstrated that a specific dietary supplement could turn off specific genes that would ordinarily have expressed themselves. They used special lab mice who were bred for tan fur, obesity, and diabetes, and who died young from their genetic heritage. When the diets were supplemented with folate, they would have mottled fur, normal weight, and no diabetes. Even more impressive, subsequent generations expressed the healthier genetic directions. Think about this—rather than treating the diabetes with a lifelong medication, they added targeted dietary supplements that actually turned off the disease-causing genes in the rats and their offspring.

Medically, we had been thinking that lifestyle choices influenced health by direct effects on our chemistry, i.e., by eating fewer calories and getting more bloodflow to different parts of the body our cells were healthier. Actually, evidence is accumulating that specific diets, stress, and exercise work at a deeper level. These changes can actually turn on disease-preventing genes and turn off the disease-causing genes (including cancer genes, or ‘oncogenes’).  This is being demonstrated in prostate and breast cancers, coronary artery disease, diabetes, and other chronic disease states. Dr. Dean Ornish is a pioneer in this work and he has a website that outlines much of the current research on lifestyle effects on health outcomes. 


These are mind-boggling findings to me. It means that lifestyle modifications lead to profound changes in our health through alterations in our genetic expression. Contemporary medical care really tends to focus on symptoms—in diabetes, we lower the sugars, but we don’t really get at the core problem. The body is still programmed to respond in the same way, and it often tries to overcome the effects of medication, essentially working against the treatment. Yet if we can turn the proper genes on and off through environmental cues that have developed evolutionarily over eons, we can truly get at the root of the problem.

So, if we have “bad genes” from our family history, it doesn’t necessarily mean that we are doomed. Rather, we could benefit by learning the specific lifestyle changes that will prevent the problems from appearing. There is a great deal of interest now in developing genetic tests to learn about these individual variations and what the implications are for a given individual. But until we figure all of this out, maybe we need to continue to follow our Grandmothers’ advice: eat well, exercise, and get a good night’s sleep.