Trans Fats Linked to Pre-Cancerous Colon Growths

A high intake of trans fats could increase colon cancer risk, according to
new research published in the American Journal of Epidemiology.

People who ate the most trans fatty acids were more likely to have
pre-cancerous growths or polyps in their colons than those who consumed the
least, Dr. Lisa C. Vinikoor of the University of North Carolina in Chapel
Hill and colleagues found. "These results provide further support for
recommendations to limit consumption of trans-fatty acids," they conclude.

Trans fats are formed by processing vegetable oils to increase their
shelf-life, and are found in many baked goods, crackers, snacks and other
packaged foods. Eating them increases levels of "bad" LDL-cholesterol, and
hence heart disease risk. US food producers are now required to list the
amount of trans fat contained in their products, and health authorities
recommend people avoid eating trans fats entirely.

While there has been little research on whether trans fats boost colorectal
cancer risk, there are many possible ways that they could do so, for example
by changing the normal balance of fatty or bile acids in the colon, Vinikoor
and her colleagues say.

To investigate a possible link, they looked at 622 people who had
colonoscopies at University of North Carolina Hospitals in 2001 and 2002.
Study participants were interviewed about their diet, physical activity and
other health issues within 12 weeks of having the screening test.

People in the top fourth based on trans-fatty acid consumption, most of whom
took in 6.54 grams daily, were 86 percent more likely to have colon polyps
than those in the bottom quartile for trans fat intake, for whom median
intake was 3.63 g, the researchers found. There appeared to be a threshold
effect, with no increased risk seen for people in the bottom three quarters
of fatty acid consumption.

Among the 38.5 percent of study participants found to have colon polyps,
average trans fatty acid intake was 4.97 g, while most consumed 4.12 g.
Average intakes for people who were free of the colon growths was 4.42 g,
while the median was 3.61 g.

These results suggest that consumption of high amounts of trans-fatty acid
may increase the risk of colorectal polyps, the researchers write, adding
that the findings also back current recommendations to limit trans fat
intake.

SOURCE: American Journal of Epidemiology, August 1, 2008.
Copyright Reuters