Scientists from the Institute of Pharmacological Research in Milan, Italy, studied more than 2,300 Italians to determine the link between eating white bread and developing cancer. Nearly 770 of the participants had the disease already, while more than 1,530 did not.
The researchers gave the participants detailed questionnaires about their dietary habits over the previous two years, and found that those who reported eating the most white bread ran the highest risk of developing renal cell carcinoma.
The participants who ate 35 slices of white bread per week -- five slices per day -- were nearly twice as likely to develop the cancer compared to those who ate 11 slices a week. Those who ate high quantities of poultry, meat and vegetables ran a low risk of kidney cancer.
The researchers believe that development of the cancer may be linked to high-glycemic foods that rapidly increase blood sugar in the body. High-glycemic-index foods cause the body to release excess insulin to help process the extra sugar in the blood. Cancer cells can use the chemical byproducts of insulin, as well as the excess blood glucose caused by consumption of refined grains, to fuel unchecked growth.
The study's lead researcher, Dr. Francesca Bravi, said that based on her study, consumers should consume fewer cereals and refined grains, and eat more vegetables to reduce their risk of renal cell carcinoma. If consumers choose to eat cereals, Bravi said focusing on those made with whole grains could help reduce cancer risk.
Previous studies have shown that postmenopausal women with low-glycemic diets run a lower risk of developing breast cancer compared to women eating high-GI diets. Low-glycemic foods are also recommended for diabetics, to prevent peaks and troughs in blood sugar levels.
Natural health advocate Mike Adams, author of "Grocery Warning," says that in addition to promoting kidney cancer, white bread also causes nutritional deficiencies and increases the risk of developing diabetes.
"The only bread suitable for human consumption is whole-grain bread," Adams said.