There's promising news for breast health. Secoisolariciresinol diglucoside (SDG), abundant in flaxseed, belongs to a class of phytochemicals called lignans and is chemically similar to the breast cancer drug tamoxifen. Researchers are finding that SDG has a potent effect on estrogen levels.

Postmenopausal women consuming 5 or 10 grams of ground flaxseed over seven weeks showed significant reductions in blood concentrations of the most potent estrogen, estradiol, and its less potent sister, estrone. This may be desirable for postmenopausal women who have a high risk of breast cancer.

The effects of flax on premenopausal breast cancer risk are less clear. A recent study of 116 premenopausal women found those eating 25 grams of ground flax each day for one year showed no reductions in estradiol or breast density (dense breasts are associated with increased breast cancer risk). But a lengthening of the menstrual cycle was noted.

The most promising research with flax lignans revealed that women with breast cancer who ate flax muffins showed notable reductions in breast cancer cell growth.

Another study found that premenopausal women with menstrual cycle-associated breast pain (cyclical mastalgia) experienced a significant reduction in pain after eating 25 grams of freshly ground flaxseed in muffins each day for four months.

Nutrition and exercise biochemist Anthony Almada, MS, has collaborated on more than 45 university-based studies, is cofounder of Experimental and Applied Sciences (EAS), and founder and chief scientific officer of IMAGINutrition (www.imaginutrition.com).