A low-fat, fruit and vegetable-rich diet significantly lowers the risk of older women dying from breast cancer, according to long-term data from a US clinical trial.

Nearly 49,000 postmenopausal women aged 50-79 with no previous breast cancer and with dietary fat accounting for at least 32% of total daily calories were enrolled in the Women’s Health Initiative Dietary Modification trial.

From 1993-98, the women were randomly allocated to a usual-diet comparison group or a dietary intervention group that aimed to reduce fat intake to 20% of daily calories and increase consumption of vegetables, fruit and grains.

Women stuck to the diet for roughly 8.5 years. The majority increased their intake of fruits, vegetables and grains, and cut their daily fat intake to 25% or less, although most did not reach the 20% goal.