A large Swedish study has once again shown a link between the quantity of food consumed with a high glycemic index and the risk of developing breast cancer.

Researchers at the Karolinska Institute (which gives out the Nobel prize for Medicine every year) followed 61,000 women for 17 years. Using detailed nutritional questionnaires, they were able to measure each woman's "glycemic load" (the quantity of food consumed that had a high glycemic index) at the beginning of the study. [1] According to their results, the risk of developing an estrogen-positive and progesterone-negative breast cancer increased in an almost linear fashion with the glycemic load. In other words, the higher the glycemic load, the higher the risk.

As I explained in Anticancer, food with a high glycemic index (white sugar, white flour and bread, pastries, white rice, sweet drinks, desserts etc) lead to the release of hormones such as insulin and IGF growth factor. In turn, these hormones stimulate factors for inflammation and the growth of cancerous cells. In 2002, researchers from the University of Toronto reported on women in remission for breast cancer who had been followed for a number of years. Those with the highest levels of insulin at the beginning of the study were twice as likely to suffer a relapse and three times more likely to develop metastases than women whose diet contained less sugars and who thus had lower levels of insulin. [2]

It's not just breast cancer. Colon cancer is also sensitive to the effect of sugars in the diet. It's very likely that other cancers are too, although the association has not been systematically studied in most of them.

To avoid increasing the levels of glucose and insulin in your blood, eat mostly  whole grain cereals in combination:
-   Multi-grain bread (containing at least four different wholegrain flours if possible); wholegrain pasta (or, if you eat pasta made from refined flour, cooked al dente; brown rice (or, if you must absolutely eat refined rice, basmati or Thai varieties); wholegrain couscous; quinoa (the cereal of the Incas, which delivers more protein than rice and can agreably replace it); buckwheat; rye; oats, linseed flour. The presence of more fiber in food contributes to eliminating toxins and carcinogens that penetrate the body by nutritional or other means. In addition fibers also contribute to reducing spikes in blood-sugar levels, and thus insulin and IGF.

In addition
-    Combine your meals with garlic, onions, and shallots, which decrease the glycemic index of the food that is eaten. Absolutely avoid sweet drinks and prefer green tea, or water flavored with a little lemon, mint, orange or tangerine peel (organic!). Avoid sweet desserts and prefer desserts based on fruit, perhaps together with a little melted or grated dark chocolate (more than 70% cocoa content), or with ginger; you can add some agave syrup or acacia honey if you really find it difficult to do without the sweet taste of sugar.

1.    Larsson, S.C. et. al., Glycemic load, glycemic index and breast cancer risk in a prospective cohort of Swedish women. Int J Cancer, 2009. 125: p. 153-157.
2.    Goodwin, P.J., et al., Fasting Insulin and Outcome in Early-Stage Breast Cancer: Results of a Prospective Cohort Study. Journal of Clinical Oncology, 2002. 20: p. 42-51.