Researchers know that genes can influence who may develop alcoholism. Although both animal and human research has also found an association between a liking for sweets and alcohol intake, it has been unclear if a liking for sweets among humans was caused by years of drinking or was linked to a genetic predisposition for alcoholism. Findings published in the November issue of Alcoholism: Clinical & Experimental Research indicate that a liking for sweets precedes alcoholism and may in fact serve as a "marker" for the genetic risk for developing alcoholism.
"Previous research has established that in mammals such as mice, rats and monkeys, the preference for and consumption of sweet fluids are strongly correlated with voluntary alcohol intake," said Alexei B. Kampov-Polevoy, assistant professor of psychiatry at Mt. Sinai School of Medicine and first author of the study. "It is thus possible to measure the amount of sweet solution that an animal drinks per day and accurately predict how much alcohol it will drink if given a chance."
Kampov’s prior research also showed that alcoholic patients prefer stronger sweet solutions than do non-alcoholics. "However," said Kampov, "it was not clear whether the increase in sweet preference was caused by a long history of drinking or if a higher sweet preference existed before the onset of alcoholism and somehow reflects predisposition for this disease. Our present manuscript is focused on resolving this issue."
Researchers recruited 163 social drinkers from a university setting, dividing them into two groups: 81 (27 males, 54 females) had a paternal history of alcoholism; 82 (38 males, 44 females) did not. Each study participant rated a series of sucrose solutions for intensity of sweetness and palatability.
"Because humans consume their food based on both biological and environmental factors," said Kampov, "we study the hedonic or pleasurable response to various concentrations of the sugar solutions. This trait is much less controlled by environmental factors. People may regulate the amount of sweet foods they consume, but they usually have less concern about their hedonic reaction to various sweet tastes. Thus, this test better reflects the biological reaction to sweet taste."
Individuals with a paternal history of alcoholism were 2.5 times more likely to like sweets than those who did not have a paternal history of alcoholism.
"This finding indicates that sweet liking precedes alcoholism," said David Overstreet, associate professor of psychiatry with the Bowles Center for Alcohol Studies at the University of North Carolina at Chapel Hill, "and suggests that the association previously reported is unlikely to be due to differential histories of alcohol exposure. This finding adds further weight to the hypothesis for the association between the liking for sweets and the genetic risk for alcoholism. However, it does not provide definitive proof."
The present study produced some unexpected results as well: individuals with a paternal history of alcoholism disliked the tastes of the two weakest sucrose concentrations, while individuals without a paternal history of alcoholism rated the tastes as neutral.
"This finding may provide a mechanistic explanation of the association between sweet preference and risk for alcoholism," explained Kampov. "Pleasurable reactions to both alcohol and sweet substances are regulated by the same mechanism, namely, the brain’s opioid system. Activation of this system results in increased consumption of both alcohol and sweets, while blockade of this system causes the opposite effect. The latter is used in medicine when opioid antagonists such as Naltrexone ™ are prescribed to alcoholics to reduce their drinking. We believe that children of alcoholics have a genetic abnormality of the brain opioid system, which leads to an increased sensitivity to the rewarding effects of alcohol. The same abnormality of the brain opioid system may also lead to a preference for stronger sweet solutions."
"These studies imply that a person whose relatives are alcoholics may be at greater risk for developing alcoholism if he or she likes sweets," said Overstreet. "By demonstrating that a liking for sweets is dependent on the family history of alcoholism in young individuals, this paper has provided one further step in developing ‘sweet-liking’ as a ‘marker’ for alcoholism. However, there are still problems to overcome, since some sweet likers are observed in families without a history of alcoholism, and some sweet dislikers are observed in families with a history of alcoholism."
Overstreet suggested that future research be long-term in nature. "The current study could follow these individuals for a period of five or 10 years and repeat the assessments," he said. "If the liking of sweets is predictive of the later development of alcoholism, then sweet likers with a positive family history of alcoholism will exhibit more drinks and/or problems related to alcohol drinking. Another area that could be explored is conducting the sweet test in even younger individuals. It is not uncommon for children of alcoholics to have started heavy drinking during their teenage years. Being able to advise and counsel individuals at risk before alcohol abuse has started may help prevent its onset and/or progression."
"A sweet-preference test is a simple and benign test that can be done at any age," added Kampov. "If our findings are confirmed by future studies, a test may help to identify an individual at risk for the development of alcoholism early in life, way before the first drink. With advanced knowledge, it will be easier to develop effective preventive measures. As with any other disease in the world, alcoholism is easier to prevent than to treat. It should also be noted that hedonic response to sweets reflects the activity of the brain opioid system that is involved in the pathogenesis of not only alcoholism but many other medical conditions, including drug addiction, eating disorders, and pain-related disorders. Therefore, the use of a sweet-preference test may be beneficial for other medical conditions, but these applications have yet to be explored."
Funding for this Addiction Science Made Easy project is provided by the Addiction Technology Transfer Center National Office, under the cooperative agreement from the Center for Substance Abuse Treatment of SAMHSA.
Articles were written based on the following published research:
Kampov-Polevoy, A.B., Garbutt, J.C., Khalitov, E. (November 2003). Family history of alcoholism and response to sweets.Alcoholism: Clinical & Experimental Research, 27(11), 1743-1750.