A new study suggests that flaxseed lowers female hormone levels and may thereby reduce breast cancer risk.The flax plant has been used for thousands of years - the fibres to make linen and the ground seeds in bread and cereal.The seeds are rich in lignans, which resemble the female hormone oestrogen.
High levels of oestrogen are linked to breast cancer and lignans may lower levels by blocking oestrogen synthesis. Researchers at the University of Minnesota have studied the effect of flaxseed supplementation in a group of 28 postmenopausal nuns - chosen because of their strict dietary practices. They were given either zero, five or ten grams of flaxseed as a supplement for seven week cycles over a year. Both levels of supplementation gave significant decreases in oestrogen levels.
This does not show that flaxseed prevents cancer, the researchers caution. Further studies are needed to work out how the supplement lowers oestrogen and also to see if there is a link between flaxseed and cancer itself. Besides lignans, the fibre and omega-3 fatty acids in flaxseed could also be protective.