WASHINGTON (Reuters) - The essential nutrient choline -- found in red meat, poultry, eggs and milk -- may increase the risk of colon polyps, at least for women, U.S. researchers said on Tuesday.
The findings were the opposite of what they expected, said Eunyoung Cho, the epidemiologist at Harvard’s Brigham and Women’s Hospital in Boston, who led the study.
Because choline is involved in similar processes as folate, a vitamin known to protect against genetic changes that can lead to cancer, researchers had thought choline might also have a protective effect.
But it turns out that choline actually may be encouraging the growth of polyps, Cho said in a telephone interview. That’s because choline also helps form the outer coating of cells, said Cho, whose work appears in the Journal of the National Cancer Institute.
Cho and colleagues analyzed the diet and colon health of nearly 40,000 female nurses whom they followed since 1984.
Women who ate the most choline -- based on food questionnaires filled out every two years -- were 45 percent more likely to develop polyps than those who consumed the smallest amount.
Choline has a number of important functions in the body, including roles in brain development and memory function. Less is known about its association with cancer.
Researchers said other nutrients found in choline-rich foods may explain the increased polyp risk.
“We know that red meat intake has been associated with increased risk of colorectal cancer. We are concerned that there may be other components in red meat and animal-based food that may be responsible for this association,” Cho said.
Colorectal adenomas -- the type of polyps studied -- are found in up to 40 percent of adults over 50. Fewer than 5 percent of them turn cancerous, experts said.
“It’s probably too early to worry about choline,” added Cho, who is now looking for a similar association in men.
The average choline intake in this study was lower than the Institute of Medicine’s daily recommendation of 425 mg.