People who are at risk of alcoholism may also have a greater risk of being obese, researchers from Washington University School of Medicine in St. Louis reveal in an article published in Archives of General Psychiatry. The authors explained that the link between a family history of alcohol dependency and obesity risk has become more prominent over the last few years. A higher percentage of males and females with a family history of alcoholism were found to be obese in 2002 than in 1992.
First author, Richard A. Grucza, PhD., said:
“In addiction research, we often look at what we call cross-heritability, which addresses the question of whether the predisposition to one condition also might contribute to other conditions. For example, alcoholism and drug abuse are cross-heritable. This new study demonstrates a cross-heritability between alcoholism and obesity, but it also says – and this is very important – that some of the risks must be a function of the environment. The environment is what changed between the 1990s and the 2000s. It wasn’t people’s genes.”
15% of the US population was obese in the late 1970s, compared to 33% in 2004. An obese individual has a BMI (body mass index) of at least 30, and has a significantly higher risk of developing hypertension (high blood pressure), several cancers, stroke, heart disease and diabetes.
In this latest study, researchers found that individuals with a family history of alcoholism had a higher risk of obesity, especially females. Grucza explains that this risk is growing and may be partly caused by dietary changes and the availability of more foods which interact with the same brain areas as addictive drugs.
“Much of what we eat nowadays contains more calories than the food we ate in the 1970s and 1980s, but it also contains the sorts of calories – particularly a combination of sugar, salt and fat – that appeal to what are commonly called the reward centers in the brain. Alcohol and drugs affect those same parts of the brain, and our thinking was that because the same brain structures are being stimulated, overconsumption of those foods might be greater in people with a predisposition to addiction.”
As Americans eat high-calorie and hyper-palatable foods which hit the reward centers in the brain with greater impact, individuals with a higher genetic risk for addiction may face a greater risk of obesity, Grucza suggests.
The team gathered data from the 1991-1992 National Longitudinal Alcohol Epidemiologic Survey, and the 2001-2002 National Epidemiologic Survey on Alcohol and Related Conditions, involving approximately 80,000 individuals.
“We looked particularly at family history of alcoholism as a marker of risk. And we found that in 2001 and 2002, women with that history were 49 percent more likely to be obese than those without a family history of alcoholism. We also noticed a relationship in men, but it was not as striking in men as in women.”
Some people may be swapping one addiction for another, Grucza suggests, hence explaining why obesity occurs more frequently in those with a family history of alcoholism. Some individuals may resist alcohol after witnessing the devastating effects of alcoholism on a family member. However, hyper-palatable high-calorie foods might substitute alcohol because they stimulate reward centers in the brain, giving them a similar experience to what they would have obtained from alcohol.
“Ironically, people with alcoholism tend not to be obese. They tend to be malnourished, or at least under-nourished because many replace their food intake with alcohol. One might think that the excess calories associated with alcohol consumption could, in theory, contribute to obesity, but that’s not what we saw in these individuals.”
Other factors, such as smoking, alcohol intake, age and education cannot explain the link between alcoholism risk and obesity, the researchers explained.
“It really does appear to be a change in the environment. I would speculate, although I can’t really prove this, that a change in the food environment brought this association about. There is a whole slew of literature out there suggesting these hyper-palatable foods appeal to people with addictive tendencies, and I would guess that’s what we’re seeing in our study.”
Alcohol, addiction and obesity researchers should be liaising more, Grucza believes. Treating one of the disorders may result in helping prevent or treat the other.