|October 2002 Vol. 1 No. 10|
Acrylamide – Do Carbohydrates Cause Cancer?
Recent headlines have suggested that eating cooked carbohydrates (starchy vegetables) can raise your risk of cancer. This is the first time a cancer-causing substance has been found in our staple foods. More specifically, carbohydrates, such as fried potatoes, potato chips, some types of breakfast cereals and baked goods contain a high level of a powerful cancer causing substance called acrylamide. Heating the amino acid asparagine with sugars at temperatures above 185 degrees centigrade (365 F) produces this unwanted substance. The minimal temperature to cause this conversion is 120 degrees centigrade, with temperatures of 140 to 180 degrees centigrade (284 to 356 F) optimal for the formation. Acrylamide cannot be detected in unheated and boiled foods.1 Therefore, frying, baking, and most likely, roasting and grilling are the cooking methods most likely to reach these high temperatures and be harmful.
The risk of acrylamide has only recently come to the attention of scientists and its discovery was accidental. Swedish tunnel workers exposed to large amounts of acrylamide from a water sealant in 1997 were studied and compared to unexposed people. The control group, who had not been exposed to acrylamide at work, showed evidence of unexpectedly high levels of acrylamide in their bodies. This caused investigators to look for other sources of this substance – and they have discovered it in their diet of overcooked foods. Acrylamide is a white, crystalline substance used in industry to produce dyes and to purify drinking water by removing particulate matters – it combines with solid materials making them more easily filtered out of the water. Cigarette smoke also contains acrylamide.
In large doses this substance can damage the nervous system and has been found to impair fertility. Acrylamide damages genetic material and induces the formation of tumors in rats following long-term administration. This cancer-causing substance tends to attack the thyroid gland, female breast tissues, male testicles, and mouth.2 Investigation of populations of people has, so far, failed to confirm or disprove that this substance causes cancer. The WHO estimates the lifelong (70 years) risk of cancer from consuming 1 microgram a day is about 1 in 100,000.1
So how do you protect yourself?
Don’t eat fried or baked carbohydrates – like French fries and potato chips (duh!). Since high temperatures are required to make acrylamide, cooking at low temperatures will keep your starches, vegetables and fruits healthy and tasty. Cooking is an important part of food preparation – one reason is because heating breaks down complex sugars to make sweet-tasting simple sugars – adding more flavors, and also causing browning of the food. Fortunately, you can keep your food from forming acrylamide by avoiding the overcooking and overheating of that food. There is a 10-fold difference in the amount of acrylamide between normal cooked and overcooked foods.2 You will always be safe boiling and steaming foods because the temperature reached is only 100 degrees centigrade (212 F). Microwaving should also be safe, because of the low food temperatures reached – but more research needs to be done.
So far the official recommendations have been very general, but reassuring for those of us who eat a healthy vegetarian diet. The British government’s Food Standards Agency recommends, “A healthy well-balanced diet, including plenty of fruits and vegetables, will help protect against some cancers.” Experts reporting in the British Medical Journal recommend “a diet with plenty of fresh fruits and vegetables.”
One reason this issue reached national headlines so quickly, and was misunderstood by many people to mean potatoes, corn, and other grains are unsafe to eat and “everything causes cancer so why should I bother,” is people love to hear good news about their bad habits. Now I don’t have to eat my vegetables – meat is no worse than potatoes. But that is simply not true – and believing so puts you at great risk for our common cancers and other health problems like heart disease, diabetes and obesity. Cooking meat has been recognized for decades to produce many very powerful cancer-causing substances including heterocyclic amines and polycyclic aromatic hydrocarbons (benzopyrene).3
1) Tareke E. Analysis of acrylamide, a carcinogen formed in heated foodstuffs. J Agric Food Chem. 2002 Aug 14;50(17):4998-5006.
2) Fleck F. Experts launch action on acrylamide in staple foods. BMJ. 2002 Jul 20;325(7356):120.
3) Bingham SA. High-meat diets and cancer risk. Proc Nutr Soc. 1999 May;58(2):243-8.
John McDougall All Rights Reserved