Obesity and drug addiction share brain chemistry and genetics

The biggest contributor to the growing obesity epidemic may be that we alter our brain chemistry by what we eat.

by Dr. Martha Grout — 

For many people, food and drug addictions are a function of individual brain chemistry. For example, brain-imaging studies conducted by the Brookhaven National Laboratory suggest that many overweight people, like drug addicts, have fewer brain receptors for dopamine — the neurotransmitter that signals feelings of satisfaction and pleasure.

The more you eat, the more dopamine you release. The science suggests that obese people may be overeating to get a feel-good feeling, much as a drug addict does with drugs. The good news here is that exercise also triggers the release of dopamine.

Since the early 1990s, we have been learning about the genetic component that food and drug addictions share. Most recently, a study of 31,000 people of European origin, ages 45 to 76, found that people who inherited the gene variant NRXN3 have a 10 to 15 percent increased risk of being obese, compared with people who do not have the variant. About 20 percent of the people studied had the gene variant.

The NRXN3 gene variant also is associated with alcohol dependence, cocaine addiction and other substance abuse. NRXN3 is the third obesity-associated gene to be identified; all three are highly active in encoding brain proteins.

In the families of alcoholics and drug addicts, there are often many more blood relatives who also have addictions to alcohol and/or drugs than would be possible by chance. For a long time, it was assumed that less than 10 percent of the U.S. population was alcoholic. But in single families with one diagnosed alcoholic, frequently half of the blood relatives are alcoholic or otherwise addicted. That strongly suggests a genetic connection.

The biggest contributor to the growing obesity epidemic, however, may be that we alter our brain chemistry by what we eat. Doing drugs such as cocaine and eating too much junk food both gradually overload the so-called pleasure centers in the brain, according to Paul J. Kenny, an associate professor of molecular therapeutics at the Scripps Research Institute.

Eventually it takes increasing amounts of the drug or food to get the same pleasurable feelings. Kenny found that rats that gorge themselves on human food quickly became obese. But their brains also changed. By monitoring implanted brain electrodes, the researchers found that the rats gradually developed a tolerance to the pleasure the food gave them and had to eat more to experience a high. They began to eat compulsively, to the point where they continued to do so in the face of pain.

What is happening in the nation of Qatar suggests that “modern food” is the biggest part of the obesity equation. Qatar ranks sixth globally for prevalence of obesity and has the highest rate of obesity among boys in the Middle East and North African region. As The New York Times reported earlier this year, “Like other oil-rich nations, Qatar has leaped across decades of development in a short time, leaving behind the physically demanding life of the desert for air-conditioned comfort, servants and fast food.”


Martha Grout, M.D., M.D.(H), specializes in the reversal of chronic disease and uses homeopathic hCG for weight loss, combined with ongoing nutritional therapy. Arizona Center for Advanced Medicine, 480-240-2600 or www.ArizonaAdvancedMedicine.com.

Reprinted from AzNetNews, Volume 29, Number 6, Dec 2010/Jan 2011.

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