Genotypes, Stress and Emotions. Oh My!

The human genome is on everyone’s mind with recent advances by Craig Venter’s team. Let’s look at how reducing mental and other stress may be especially important for a genetic group of which you just might be a member.

Research into cancer has shown that oxidative stress affects DNA, and that this can lead to cancer (1). It has also shown that DNA damage can be reduced by cutting oxidative stress. Dietary research has gone a long way in opening our eyes to the how and why of all this. I hope you’re already eating your share of fruits and vegetables, but not going overboard with fruit or especially fruit juice, since there’s an epidemic of diabetes.

Emotional stress appears to increase oxidative stress as well — the same oxidative stress that contributes to cancer (2). Reducing stress has been shown to improve health in thousands of studies, though a direct, general stress-cancer link is controversial. This might be because the subtypes of people most vulnerable to such a link may need to be identified first. Once such group may already have been identified, as we’ll see below.

A recently published study has shown that yoga can reduce the DNA-damaging effect of radiation therapy (3).

Despite the quantity of research, we are far from teasing out the “active ingredients” for producing the most powerful stress-reducing mind-style. For example, there is much research on using music to reduce stress and improve healing. But music and sound have many elements, some cultural, others more directly a matter of physiological impact. This has only begun to be explored in a useful way. But that’s for another post.

Let’s talk about a genetic connection. People who are members of genotypes (GSTM1 and GSTT1) that lack genes for glutathione S-transferase are more vulnerable to oxidative damage and cancer from effects such as smoking, according to a recent study (1). The same study found that four cups a day of green tea were especially helpful for this genetic group in reducing the oxidative damage.

Perhaps one day there will be enough research, and cheap, accurate genetic analysis, that you will have a report that tells you what your ideal healthy lifestyle should be, and what factors are the most important. This isn’t completely science fiction. Craig Venter is taking statins, despite the fact that his cholesterol levels are good, because his genome told him he was at risk for heart trouble (4,5). But is there any reason to believe that taking a cholesterol-lowering drug can prevent heart attacks in people with normal cholesterol, whether or not they have a genetic risk factor?

That question aside, perhaps highly individualized genetic information will come to be one more tool that public health information outlets can use to influence people. Some day, genetic subtypes may be considered a demographic element, like age and education. Maybe we’ll come up with cute names for them, just like we have with personality types (e.g., Type A). I’m sure there will be books and services long before there’s much validity to it. As for issues of discrimination, see this post, Genetic Discrimination: A Real Threat? by Sudip Gosh. It’s refreshingly non-paranoid, compared to what I’d come up with. But then, I have worked in and with managed care.

But, as far as potential health alerts go, I’m all for another healthy scare tactic that will reduce smoking. I’m all for the fear of smoking. But isn’t fear a stressful cancer risk factor, itself? Maybe so, but some fears are real.

But what about psychological measures to reduce oxidative stress? Research is beginning to look at this as well. Perhaps we will have stress management mind-styles as well as lifestyles that are custom designed for genetic groups. But I wouldn’t wait around for science to create a customized stress solution. After all, you’re an N (number of subjects) of one in your own personal experiments. That means no statistical validity, but high stakes. As for me, I’ll use what I know: advanced mental stress management practices, yoga, diet, exercise, great conversations, and the love of learning, as my favorite stress fighters.

Citations

1. Iman A., et. al. Effect of a 4-Month Tea Intervention on Oxidative DNA Damage among Heavy Smokers
Role of Glutathione S-Transferase Genotypes. Cancer Epidemiology Biomarkers & Prevention Vol. 13, 242-249, February 2004.

2. Sivonová M, et. al. Oxidative stress in university students during examinations. Stress. 2004 Sep;7(3):183-8.

3. Banerjee B, et. al. Effects of an Integrated Yoga Program in Modulating Psychological Stress and Radiation-Induced Genotoxic Stress in Breast Cancer Patients Undergoing Radiotherapy. Integr Cancer Ther. 2007 Sep;6(3):242-250.

4. Marlowe Hood. Individual human genome decoded, key step in nature/nurture debate. AFP, Yahoo News. Sep 4, 2007.

5. Maggie Fox. One man’s genes show DNA is still a mystery. Health and Science Editor, Reuters, 9/4/2007.