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Oct. 17, 2005 -- No. 499
UNC research team identifies gene variant
indicating women who need more choline in diet
CHAPEL HILL -- Scientists at the University of North Carolina at Chapel Hill have identified a common gene variation that occurs in about one-third of all premenopausal woman, a variant that greatly increases susceptibility to dietary deficiency of the essential nutrient choline.
Choline is a vitamin-like substance that is sometimes treated like B vitamins and folic acid in dietary recommendations. The body uses it to make the nerve messenger chemical known as acetylcholine, to make 1-carbon building blocks for other reactions in the body (methylation), and to build cell membrane Ė the biological "wrapper" that keeps cells from leaking.
Choline deficiency can cause significant liver and muscle damage, and this nutrient also is needed for optimal fetal development during pregnancy.
The findings, published today (Oct. 17) in the Proceedings of the National Academy of Sciences (PNAS), not only provide information identifying women who need to eat more choline-rich foods, such as eggs, meat and wheat germ, but also provide evidence that genetics may determine what specific nutrients individuals need to keep their bodies healthy.
"Within the next decade, I foresee hundreds of genetic variations being uncovered that will identify individuals with special nutritional needs," said Dr. Steven Zeisel, associate dean for research at UNCís School of Public Health and a principal investigator on the study. "This is a glimpse into what clinical nutrition will be one day Ė allowing more personal, individual nutrition advice."
Zeisel also is a professor of nutrition in UNCís School of Public Health and director of the UNC Clinical Nutrition Research Center, housed jointly in UNCís schools of public health and medicine.
This latest study adds to the body of evidence that Zeisel and other scientists at UNC, Boston University and Duke University have uncovered about the vital role of choline in physical development of the brain, specifically concerning memory and brain function.
Other authors of the study, all with the department of nutrition, are: Dr. Martin Kohlmeier, research professor; Dr. Kerry-Ann da Costa, research assistant professor; and Dr. Leslie M. Fischer, research assistant professor.
The study shows that a common genetic variation influences whether or not a lack of choline in the diet of an individual will cause fatty liver and damage to liver and muscle cells. These changes are reversible by adding choline back to the diet.
The clinical trial participants were 31 women and 31 men, all healthy and between the ages of 18 and 70. The researchers found that premenopausal women with a variant in a gene important in metabolism of the vitamin folic acid were 15 times more likely to develop liver or muscle problems when placed on a low-choline diet.
The participants stayed at the UNC General Clinical Research Center for the duration of the study and could leave only for brief periods under the supervision of study staff. All food was prepared on-site. Participants ate a choline-containing diet for 10 days, and then were switched to a low-choline diet. Participants stayed on this choline-depletion diet until they developed signs of liver or muscle problems or for 42 days if they did not develop any signs. Damage healed when choline was restored to the diet.
"We will continue to study the role of choline and other nutrients in developing and maintaining good health," Zeisel said.
"Previous studies have shown how vital choline is for pregnant women, to promote good brain development and reduce birth defects. We now are seeing increasing evidence that choline is needed in the diets of all women and men. I expect that, as we look further, weíll find other genetic variations that increase a personís requirement for choline. This will allow us to alert people who are better off with choline-rich diets."
A list of foods high in choline is available at the U.S. Department of Agricultureís Web site: http://www.nal.usda.gov/fnic/foodcomp/Data/Choline/Choline.html.
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Note: Zeisel can be reached at (919) 843-4731 or email@example.com.
School of Public Health contact: Ramona DuBose, (919) 966-7467 or firstname.lastname@example.org
UNC News Services contact: Deb Saine, (919) 962-8415 or email@example.com