Heavy Drinkers' Genes May Cut Cancer Risk

Researchers find a tweaked gene that may help some heavy drinkers dodge cancer.

May 26, 2008— -- Could your genes actually help lower the risk of getting cancer when drinking alcohol? A new study says that this may be possible.

Researchers from Lyon, France, found that some people with certain variations in a gene involved in breaking down alcohol in the body appear to have a lower risk for developing certain alcohol-related cancers.

Paul Brennan, head of the genetic epidemiology group at the International Agency for Research on Cancer, and his colleagues studied more than 3,800 people in Europe and Latin America who had cancers of the respiratory tract and upper digestive tract. What they found is that those who had a particular variation in the genes known as ADH1B and ADH7 metabolized alcohol much faster than those without the variation -- about 100 times faster, to be exact.

The results were released Sunday in the journal Nature Genetics.

A Balance of Risk and Benefit

Several studies have shown that there are both risks and benefits to moderate alcohol intake. But past research has also found that alcohol consumption is a risk factor for oral cancer.

However, this study found that having a variation of ADH1B or ADH7 may be "cancer protective" in people who are moderate to heavy drinkers. The greater the amount of alcohol the people with the variant gene consumed, the more significant the protective effect researchers saw.

The study did not see the variant gene provide cancer protection in nondrinkers. It's like our bodies were designed to have this protective mechanism "kick in" in the event that we overindulge.

Now the bad news: The benefits extend only to those of us who carry the gene. In the study population, only approximately 3 percent to 12 percent were so lucky.

Take That Shot -- With a Grain of Salt

According to the United States Centers for Disease Control and Prevention, about 79,000 Americans die every year because of excessive alcohol use, making it the third-leading lifestyle-related cause of death for the nation.

Could this variant gene somehow help to minimize the negative effect of excessive alcohol intake? Maybe, and maybe not.

Many mixed messages exist when it comes to drinking. In 2001, researchers at the Harvard School of Public Health and Brigham and Women's Hospital found that moderate alcohol consumption in people who have another version of this gene had lowered risk of heart disease.

However, they cautioned, "Heavy consumption of alcohol can lead to negative cardiovascular outcomes such as high blood pressure, heart attacks and sudden cardiac death. Other doctors warn that even moderate drinking may raise the risks of colon and breast cancer, some types of stroke, fetal damage, driving accidents, abusive behavior and criminal activities."

The study released Sunday may only marginally advance the debate over the balance between the risk and benefit of alcohol consumption, since this study was conducted in only two population groups -- Europeans and Latin Americans.

Still, Brennan notes in the study, "These results provide strong evidence that both ADH1B and ADH7 have an important association with susceptibility to [upper] digestive cancer. The strong similarity of the results from different studies argues against population stratification or other biases."

In other words, he explains, because these results are similar in studies around the world, their results could be applied globally.

But more evidence may be necessary to change the view of the World Health Organization, which states that light drinking is unlikely to lower heart disease risks in people who are already taking other lifestyle precautions, such as exercising regularly, not smoking and eating less fat. According to WHO, the less you drink the better.

Drink to Your Health?

The U.S. Department of Agriculture and Department of and Health and Human Services defines moderate drinking as no more than one drink a day for women and people over 60, and two drinks a day for men. They recommend the following people should not drink at all:

Women who are pregnant or trying to conceive

People who plan to drive or engage in other activities that require attention or skill

People taking medication, including over-the-counter medications

Recovering alcoholics

People under the age of 21

As for cancer, there is good news. The National Cancer Institute at the National Institutes of Health said that "the rate of cancer incidence has declined since the early 1990s." With that in mind, this new study may suggest an added avenue of decline for alcohol-related cancers.

Sherine Brown Jennels, Ph.D., is an adjunct faculty at Morgan State University in Baltimore, Md.

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