A carcinogen found in grilled chicken may worsen breast cancer, according to new research. In the October issue of Toxicology, Imperial College London researchers shared results of a study treating human breast cancer cell lines with PhIP, one of a group of carcinogens called heterocyclic amines. PhIP is commonly found in grilled and barbecued meats, especially chicken. The researchers found that very small doses of PhIP caused the cells to exhibit extracellular invasive behavior. The invasiveness of the cells increased with increasing doses of PhIP, with some doses of PhIP surpassing the positive control, 17B-estradiol, the most common form of estrogen. Estrogen is a major promoter of breast cancer cells.

The authors concluded that PhIP is not only a potent breast cancer culprit due to its ability to damage DNA, but could also increase the likelihood that breast cancer cells will become metastatic, worsening existing disease.

Lauber SN, Gooderham NJ. The cooked meat-derived mammary carcinogen 2-amino-1-methyl-6- phenylimidazo[4,5-b]pyridine promotes invasive behaviour of breast cancer cells. Toxicology. Published ahead of print October 15, 2010. doi:10.1016/j.tox.2010.10.004

Women consuming the most soy products have a lower risk of breast cancer recurrence, according to a new study published in the Canadian Medical Association Journal. Researchers observed the amounts of soy isoflavones consumed by 524 women with breast cancer. Postmenopausal women who ate more than 42.3 milligrams of soy isoflavones daily had a 33 percent decreased risk of recurrence, compared with women who ate less than 15.2 milligrams per day. Sources of soy isoflavones included soy milk, tofu, and edamame. Eight ounces of soymilk contains roughly 20 milligrams of soy isoflavones.

Kang X, Zhang Q, Wang S, Huang X, Jin S. Effect of soy isoflavones on breast cancer recurrence and death for patients receiving adjuvant endocrine therapy. CMAJ. Published ahead of print October 18, 2010: doi:10.1503/cmaj.091298.

Consumption of fish oil during pregnancy does not benefit babies’ cognitive development or mothers’ mood, according to a new study in the Journal of the American Medical Association. Pregnant women who consumed 800 mg of a DHA-rich fish oil supplement each day during pregnancy showed no benefits for depression, and their babies did not differ cognitively from children born from women who consumed a vegetable oil (rapeseed, sunflower, and palm) supplement. A team of researchers in Australia evaluated depression in 2,320 women six months postpartum and cognitive scores including memory, problem solving, and language for 694 children at 18 months.

Makrides M, Gibson RA, McPhee AJ, et al. Effect of DHA Supplementation During Pregnancy on Maternal Depression and Neurodevelopment of Young Children. JAMA. 2010;304:1675-1683.

New evidence contradicts the notion that early humans were mainly hunters. Archeological findings recently unearthed in Italy, Russia, and the Czech Republic show evidence that grains were ground into flour as far back as 30,000 years ago. The findings were presented in the Proceedings of the National Academy of Sciences.

Revedin A, Aranguren B, Becattini R, et al. Thirty thousand-year-old evidence of plant food processing. Proc Natl Acad Sci. 2010. Published ahead of print October 19, 2010: doi: 10.1073/pnas.1006993107.

Women consuming more vegetables have a decreased risk of breast cancer, according to a new study published in the American Journal of Epidemiology. Researchers followed the diets of 51,928 participants in the Black Women’s Health Study. Participants who ate two or more servings of vegetables per day had a 43 percent decreased breast cancer risk, compared with those who ate less than four servings per week. Cruciferous vegetables (e.g., broccoli, cauliflower, and kale) and carrots had the largest impact on breast cancer risk.

Boggs DA, Palmer JR, Wise LA, et al. Fruit and Vegetable Intake in Relation to Risk of Breast Cancer in the Black Women’s Health Study. Am J Epidemiol. Published ahead of print October 11, 2010. doi: 10.1093/aje/kwq293.