Life without French fries is unfathomable for most junk food addicts. Nevertheless, ingesting them means more than just making one obese (with all the accompanying health related issues): a new Dutch research published in the American Journal of Clinical Nutrition shows that acrylamide, a chemical abundant in French fries, cakes, snacks and coffee, boosts the risk of kidney cancer, especially in smokers.

"Ours is the first report of a positive association between dietary acrylamide intake and renal cell [kidney] cancer," said co-author Janneke Hogervorst, a researcher at Maastricht University.

Since 1994, acrylamide has been classified as a probable human carcinogen, and the main exposure sources were considered to be cigarette smoke and cosmetics. A 2002 Swedish research signaled the presence of acrylamide in carbohydrate-rich foods cooked at high temperatures, like French fries and potato chips. Along the years, researches investigating the connection between various cancers and acrylamide have come up with mixed results.

The new study was made on a batch of 5,000 men and women, aged 55 to 69, monitored for over 13 years for kidney, bladder and prostate cancers. The team focused on their diets and found that the daily average consumption of acrylamide was 21.8 mg, just below the amount found in a 70 g serving of French fries. Subjects with the highest intake (an 40.8 mg daily average) had a 59% increased risk of kidney cancer (but only of this particular type of cancer) compared to the others.

Most subjects listed coffee as the main acrylamide source, but Dutch spiced cake, a popular snack, was also mentioned. Each additional 10 mg boosted the probability of developing kidney cancer risk by 10%. The connection acrylamide-kidney cancer was even more pregnant in the case of smokers.

Other recent researches failed to connect acrylamide to prostate, colon, rectum, bladder or breast cancer. A previous South African study showed that varying amounts of acrylamide are found in 40% of the food supply. The best solution seems to be a balanced diet, "rich in fruit and vegetables and eat[ing] fried, fatty, char-grilled and fermented foods in moderation."

"Smoking is a [known] risk factor for this [kidney] cancer. Exactly how the acrylamide boosts cancer risk isn't known, but the hypothesis is that metabolites [breakdown products] of the acrylamide cause DNA damage," said Marji McCullough, a nutritional epidemiologist for the American Cancer Society.

"Limiting the consumption of foods containing the chemical is wise. Also, in preparing food at home, fry potatoes at temperatures below 175o C and fry them to gold-yellow, not dark brown [the more brown, the more acrylamide]. The same goes for making toast and cookies," Hogervorst concluded by saying.