Breast Cancer Survivors and Soy Foods

Because we know that breast cancer is promoted by oestrogen, any woman who has had breast cancer tends to avoid foods that contain it such as tofu and soy milk. The most common source for many women is soy, a plant that has chemicals with oestrogen-like and anti-oestrogenic properties — which makes it a tricky area if you are a regular soy consumer.

A study has been ongoing since 2002 in China to study the effects of soy on breast cancer and analysis of the research suggests that eating soy, even in large amounts, may not be harmful after all, and may even reduce recurrence and death from the disease. Researchers based at Vanderbilt University in Houston, Texas and the Shanghai Institute of Preventive Medicine have looked at the first four years of follow-up of two groups of women breast cancer survivors. The first group consumed soy from naturally occurring sources, such as tofu or soybean and took in more than 15.3 g of soy protein a day and the others who had less than 5.3 g per day (less than half acup of soy milk, which has 7 g of soy protein.)

The women who had the higher intake had a risk of death from breast cancer four years after diagnosis of 7.4% and the risk of recurrence was 8%. Women who had the lower intake had higher risks: a 10.3% risk of death from breast cancer and an 11.2% risk of recurrence. Although not all experts are convinced that it’s safe to begin advising women to add soy to their diet, they do agree that there is no need to avoid soy altogether – particuarly in its natural forms – though supplements should be avoided by those who have had breast cancer until more analysis of the research has been done.