Results from the Women's Intervention Nutrition Study show that women who survived breast cancer and followed a low-fat diet reduced their risk of a recurrence of breast cancer by 24% during the 5 years after treatment. The study included 2 groups of women, aged 48 to 79 years, and followed their progress for 5 years after treatment for early breast cancers. One group received nutrition counseling on how to reduce their fat consumption. The other group was merely told about healthful eating without fat reduction.
The first group of women decreased their fat intake from ~29% of total calories to ~20%, consuming an average of close to 33 g/day. The other group averaged 51 g/day.
The impact of dietary fat on breast cancer risk and recurrence still remains unclear, however. Different types of fat or proportions of fat may result in different effects. For example, omega-3 fats?found in certain fish, walnuts, and flaxseed?may protect women against breast cancer. The overall risk from fat also may vary with a woman's stage of life.
Other factors that could explain the lower cancer risk include overall weight loss, which is a recommended cancer-prevention strategy, and increased consumption of fruits, vegetables, and cereal, which carry a great deal of cancer-protective nutrients and fiber.