MILAN, ITALY. A group of Italian researchers recently reported that consumption of whole-grain foods helps protect against cancer, particularly cancers involving the digestive system. This adds to the evidence that diet is an important factor in cancer prevention. Diets high in fruits and vegetables have also been found to be protective while alcohol consumption and smoking are risk factors for certain cancers, particularly those involving the mouth, esophagus, and lungs (smoking). Now the same researchers report that while whole-grain foods protect against cancer, foods based on processed grains, e.g. pasta and bread, may actually increase the risk of cancer. Their study involved 3336 patients diagnosed with cancer at various sites and 3526 people without cancer.
Based on food frequency questionnaires completed two years before the diagnosis of cancer the researchers conclude that people with a high consumption of bread, pasta, and rice have a 60 per cent higher risk of developing cancer of the oral cavity, pharynx, esophagus or larynx than do people who consume only one serving or less per day of refined cereal products. The estimated risk increase for stomach and colon cancer was 50 per cent and for thyroid cancer it was 100 per cent.
The researchers point out that a high consumption of refined sugar produces similar
increases in cancer risk and speculate that the detrimental effect of refined cereals is due
to their rapid digestion. This tends to cause glycemic overload and a subsequent increase
in insulin and IGF-1 (insulin-like growth factor 1) which is known to stimulate tumour
growth. They also suggest that the substantial increase in thyroid cancer observed
among frequent consumers of refined cereals may be due to the low iodine content of
these foods. The researchers conclude that replacing meat and fat with refined cereals in the diet may
not have the intended effect of reducing cancer risk.