Sunday August 31, 2008 (foodconsumer.org) -- A higher intake of trans fat means a higher risk of colon cancer risk, according to a new study published in the August 1 2008 issue of the American Journal of Epidemiology.

The study showed people ate highest amounts of trans fat were more likely to have pre-cancerous lesions or polyps in their colons than those who consumed the least.

The finding by Dr. Lisa C. Vinikoor of the University of North Carolina in Chapel Hill and colleagues further justifies the government's recommendation to limit consumption of trans fat.

Trans fat, also known as partially hydrogenated vegetable oils, is formed during a process called hydrogenation. Trans fat is commonly used in processed food such as baked goods, crackers, snacks and other packaged foods because it renders longer shelf-life and certain mouth feel among others.  Trans fat is also used in fried foods and others served in restaurants.

Trans fat has been known to cause an increase in bad cholesterol and a drop in good cholesterol.   It has been associated with increased risk of heart disease and possibly diabetes.   Harvard epidemiologists have estimated that trans fat may be involved in 100,000 deaths from heart disease each year. The link between trans fat and cancer is relatively unknown.

Currently, the government does not recommend a complete elimination of trans fat because it fears that by doing so, consumers would avoid eating certain foods causing nutrition-imbalance.   It recommends that people should not eat more than 2 grams a day.   The average daily intake for Americans is about 6 to 8 grams.   However, experts have warned that there is no safe threshold meaning intake of any could have an impact.

The association between trans fat and cancer has not been extensively studied.   Studies on whether trans fat boost colorectal cancer risk has been almost none, according to the authors of the study who suspect such an association may exist because trans fat could change the normal balance of fatty or bile acids in the colon.

For the study, the investigators surveyed 622 people who received colonoscopies at University of North Carolina Hospitals in 2001 and 2002 for their diet, physical activity and other health issues within 12 weeks of having the screening test.   Of the participants, 38 percent were found with polyps.

Subjects in the quartile eating the highest amounts of trans fatty acids, about 6.5 grams a day, were at an 86 percent increased risk of having colon polyps compared to those who were in the quartile consuming the lowest amounts of trans fat, about 3.63 grams per day, the investigators found.

The results suggest that eating trans fat increases of developing polyps, precursors of colon cancer.