Folate reduces bowel cancer risks

West Australian researchers are urging people to increase their intake of green leafy vegetables after breakthrough research has revealed folate can significantly cut the risk of bowel cancer.

In a world first, a team of WA researchers from the University of Western Australia and the Western Australian Institute for Medical Research (WAIMR) has shown that a common version of the MTHFR gene – carried by about half the population – increases a person’s chance of developing colon cancer by nearly a third.

Lead author Professor Barry Iacopetta, from the UWA School of Surgery, said the study also provided clear evidence that tumours arising in different parts of the large bowel had different risk factors.

The MTHFR gene variant increased the risk of developing cancers only in the right side of the large bowel, Professor Iacopetta said.

"Partly because of our research findings, other workers around the world now also consider the site at which bowel tumours arise when investigating dietary and genetic risk factors for this disease," he said.

Report co-author and WAIMR Associate Professor Lin Fritschi said the study found the risk of colon cancer in the right side of the bowel jumped to 70 percent if there was not enough folate in a person’s diet.

"But, in a fascinating discovery, we’ve also found that by boosting their folate intake, people with the high-risk version of the MTHFR gene might be able to lower that 70 per cent risk down to nothing," A/Prof Fritschi said.

She said the research – recently published in the prestigious International Journal of Cancer – showed that in order to get enough folate, people should eat more than 200 mg of folate a day and limit their consumption of alcohol.

"Folate is found in many everyday foods including spinach, brussel sprouts, lentils and peanuts and eating the right daily amount is as simple as eating an orange, a cup of cooked broccoli and a cup of baked beans," A/Prof Fritschi said.

"And, because alcohol tends to block the absorption of folate, it is also recommended that people drink it in moderation if they want to boost their levels of the vitamin."

Prof Iacopetta said that while folic acid supplements had been shown to provide sufficient amounts of folate for other medical purposes, the best way to reduce the risk of bowel cancer was by eating folate-rich foods.

"Folate from food provides a protective mechanism before cancer cells begin to divide – which is the stage when the body needs folate the most – whereas the folate from supplements tend to act later in the process and so may not be as effective."

The study of more than 1,800 people was carried out by researchers from the Schools of Surgery and Population Health at UWA and WAIMR. The research was supported by a grant from the NHMRC.

(Source: Western Australian Institute for Medical Research (WAIMR): International Journal of Cancer: July 2009)