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January 2008 Research Behind the News
practice applications
RESEARCH BEHIND THE NEWS
The following capsule news summaries reflect emerging areas of research that will likely capture the attention of various media and news outlets. These capsule reviews are derived from the New in Review section of the Journal on page 165.
Jeans Feeling Tight? It May Be Your Genes
G
enetics might help drive chronic overeating, according to a study published in the October 2007 issue of Behavioral Neuroscience. Researchers at the University of Buffalo, the State University of New York, have discovered that individuals with genetically lower dopamine—a neurotransmitter that helps make behaviors and substances more rewarding—find food to be more reinforcing than people without that genotype. The research team studied 29 obese and 45 nonobese men and women, aged 18 to
40, and examined genes associated with differences in brain activity, in particular the influence of a genetic variation linked to a lower number of dopamine D2 receptors on cells. About half the population has this variation, called the taq1A1 allele. Researchers measured participants’ body mass, swabbed DNA samples from inside their cheeks, and had participants fill out eating questionnaires. There were two behavioral tasks completed for taste and personal preference using both food and computer rewards. Food
reinforcement, defined as the trend to be more motivated to consume food for multiple reasons, was found to be higher in obese individuals and correlated highest with food intake. Bottom Line: The reinforcing value of food, which may be influenced by dopamine genotypes, appeared to be a significantly stronger predictor of consumption than self-reported preference for a favorite food. The authors conclude, “Food is a powerful reinforcer that can be as reinforcing as drugs of abuse.”
“C” for Yourself: Vitamin C May Slow Skin Wrinkling
C
an an orange a day help keep the wrinkles at bay? Reporting in the October 2007 issue of the American Journal of Clinical Nutrition, researchers at Unilever Corporate Research (UK) found that higher dietary intakes of vitamin C and linoleic acid are associated with better visual signs of skin aging. Researchers analyzed data from 4,025 women who participated in the first National Health and Nutrition Examination Survey (NHANES I) con-
ducted in the US between 1971 and 1974. The women, ages 40-74, had extensive dermatological exams designed to evaluate skin wrinkling, senile dryness, and skin atrophy (or thinning). The women also completed a 24-hour recall survey listing all of the foods they consumed during a particular day. After adjusting for potential confounding factors such as sun exposure, race, and cigarette smoking, lower vitamin C intakes were associated with greater risks of
wrinkling and senile dryness, while higher dietary intakes of linoleic acid (an essential fatty acid found in many plant foods) were associated with lower risks of senile dryness and skin atrophy. Bottom Line: “Perhaps appealing benefits such as reducing skin-aging appearance may motivate healthy eating,” note the authors in the study’s closing comments, “and new campaigns to promote healthy dietary behaviors could consider this issue.”
Small Changes Can Remedy Big Problem for Obese Children mall changes in lifestyle and diet may help prevent excessive weight gain in children. Researchers at the University of Colorado Health Sciences Center, Center for Nutrition, examined 200 families, all of which had at least one overweight child between the ages of 7 and 14 years. One hundred families following the America on the Move Foundation’s “Families on the Move Program” were asked to substitute at least 100 kcal/day of sugar intake
S
with sugar substitute Splenda (McNeil Nutritionals, Fort Washington, PA) and to walk an additional 2,000 steps per day over baseline. Ninetytwo families were asked to self-monitor their usual calorie intake and activity levels. After 6 months, researchers found that that the America on the Move group compared with the self-monitoring group had a statistically higher percentage of children who maintained or reduced weight and a higher percentage of
This article was written by Tony Peregrin, a freelance writer in Chicago, IL.
children who decreased body mass index. The findings appear in the October 2007 issue of Pediatrics. (Funding was provided by both McNeil Nutritionals and the National Institutes of Health.) Bottom Line: “A small-changes approach to lifestyle modification can be easily implemented in families and could, over time, help to reduce excessive weight gain in all family members, regardless of weight status,” write the authors.
Journal of the AMERICAN DIETETIC ASSOCIATION
17
RESEARCH BEHIND THE NEWS
The following capsule news summaries reflect emerging areas of research that will likely capture the attention of various media and news outlets. These capsule reviews are derived from the New in Review section of the Journal on page 165.
Jeans Feeling Tight? It May Be Your Genes
G
enetics might help drive chronic overeating, according to a study published in the October 2007 issue of Behavioral Neuroscience. Researchers at the University of Buffalo, the State University of New York, have discovered that individuals with genetically lower dopamine—a neurotransmitter that helps make behaviors and substances more rewarding—find food to be more reinforcing than people without that genotype. The research team studied 29 obese and 45 nonobese men and women, aged 18 to
40, and examined genes associated with differences in brain activity, in particular the influence of a genetic variation linked to a lower number of dopamine D2 receptors on cells. About half the population has this variation, called the taq1A1 allele. Researchers measured participants’ body mass, swabbed DNA samples from inside their cheeks, and had participants fill out eating questionnaires. There were two behavioral tasks completed for taste and personal preference using both food and computer rewards. Food
reinforcement, defined as the trend to be more motivated to consume food for multiple reasons, was found to be higher in obese individuals and correlated highest with food intake. Bottom Line: The reinforcing value of food, which may be influenced by dopamine genotypes, appeared to be a significantly stronger predictor of consumption than self-reported preference for a favorite food. The authors conclude, “Food is a powerful reinforcer that can be as reinforcing as drugs of abuse.”
“C” for Yourself: Vitamin C May Slow Skin Wrinkling
C
an an orange a day help keep the wrinkles at bay? Reporting in the October 2007 issue of the American Journal of Clinical Nutrition, researchers at Unilever Corporate Research (UK) found that higher dietary intakes of vitamin C and linoleic acid are associated with better visual signs of skin aging. Researchers analyzed data from 4,025 women who participated in the first National Health and Nutrition Examination Survey (NHANES I) con-
ducted in the US between 1971 and 1974. The women, ages 40-74, had extensive dermatological exams designed to evaluate skin wrinkling, senile dryness, and skin atrophy (or thinning). The women also completed a 24-hour recall survey listing all of the foods they consumed during a particular day. After adjusting for potential confounding factors such as sun exposure, race, and cigarette smoking, lower vitamin C intakes were associated with greater risks of
wrinkling and senile dryness, while higher dietary intakes of linoleic acid (an essential fatty acid found in many plant foods) were associated with lower risks of senile dryness and skin atrophy. Bottom Line: “Perhaps appealing benefits such as reducing skin-aging appearance may motivate healthy eating,” note the authors in the study’s closing comments, “and new campaigns to promote healthy dietary behaviors could consider this issue.”
Small Changes Can Remedy Big Problem for Obese Children mall changes in lifestyle and diet may help prevent excessive weight gain in children. Researchers at the University of Colorado Health Sciences Center, Center for Nutrition, examined 200 families, all of which had at least one overweight child between the ages of 7 and 14 years. One hundred families following the America on the Move Foundation’s “Families on the Move Program” were asked to substitute at least 100 kcal/day of sugar intake
S
with sugar substitute Splenda (McNeil Nutritionals, Fort Washington, PA) and to walk an additional 2,000 steps per day over baseline. Ninetytwo families were asked to self-monitor their usual calorie intake and activity levels. After 6 months, researchers found that that the America on the Move group compared with the self-monitoring group had a statistically higher percentage of children who maintained or reduced weight and a higher percentage of
This article was written by Tony Peregrin, a freelance writer in Chicago, IL.
children who decreased body mass index. The findings appear in the October 2007 issue of Pediatrics. (Funding was provided by both McNeil Nutritionals and the National Institutes of Health.) Bottom Line: “A small-changes approach to lifestyle modification can be easily implemented in families and could, over time, help to reduce excessive weight gain in all family members, regardless of weight status,” write the authors.
Journal of the AMERICAN DIETETIC ASSOCIATION
17