By Jennifer Reilly, R.D., and Neal D. Barnard, M.D.

Broccoli Compound Helps Destroy Breast Cancer Cells
New research suggests that a specific compound in cruciferous vegetables (broccoli, cauliflower, Brussels sprouts, cabbage, kale, etc.) may be especially helpful in inhibiting breast cancer development. Researchers at the University of Leicester looked at the effect of indole-3-carbinol (I3C) on four different types of breast cancer cells. Previous studies have shown that foods rich in indoles may help to kill breast cancer cells by diminishing the expression of the epidermal growth factor receptor, which protects cancer cells. This study found that I3C helped to reduce these receptors in three of the four types of breast cancer cells. Consuming cruciferous vegetables daily may significantly lower breast cancer risk and increase survival.

Moiseeva EP, Heukers R, Manson MM. EGFR and Src are involved in indole-3-carbinol-induced death and cell cycle arrest of human breast cancer cells. Carcinogenesis 2007. Feb;28:435-45.

Fiber Lowers Breast Cancer Risk
A follow-up of the U.K. Women’s Cohort Study involving more than 35,000 women found that premenopausal women who ate 30 grams of fiber a day had half the risk of breast cancer compared with those who ate less than 20 grams per day. In addition, high protein consumption and low vitamin C intake were associated with increased breast cancer risk among premenopausal women. Researchers suspect that since estrogen levels are higher in premenopausal women, dietary fiber earlier in life may be more important for regulating female hormones and lowering breast cancer risk. Fiber helps the body remove excess hormones, carcinogens, and toxic compounds. Fiber is not present in animal products, but is found in virtually all plant foods: whole grains, legumes, vegetables, and fruit.

Cade JE, Burley VJ, Greenwood DC. Dietary fibre and risk of breast cancer in the UK Women’s Cohort Study. Int J Epidemiology. Advance Access published on January 24, 2007.

Cancer-Related Hormones Associated with Protein and Dairy Consumption
A study recently published in the European Journal of Clinical Nutrition found that elevated insulin-like growth factor-1 (IGF-1) levels were positively associated with the consumption of protein (mainly from animal sources), milk, cheese, calcium, magnesium, phosphorous, potassium, and vitamins B2 and B6. The study examined 2,109 women from eight European countries who had been subjects in a previous breast cancer study (the European Prospective Investigation into Cancer and Nutrition). Inverse relationships were found between IGF-1 levels and the intake of vegetables and beta-carotene (found in orange-colored fruits and vegetables as well as dark leafy greens). Previous evidence has revealed that elevated IGF-1 levels are associated with a variety of cancers, including colorectal, prostate, and premenopausal breast cancer.

Norat T, Dossus L, Rinaldi S, et al. Diet, serum insulin-like growth factor-1 and IGF-binding protein-3 in European women. Eur J Clin Nutr. January 2007; 61:91-98.  

The Cancer Project is a nonprofit PCRM subsidiary that advances cancer prevention and survival through nutrition education and research.