By Emily Murray

Women with breast cancer may want to rethink their diet if it includes soy products.

In the September issue of the Journal of the National Cancer Institute, new research reveals that in certain women with the disease, soy consumption could increase the activity of genes linked the growth of breast cancer.

Some of the most common soy products include tofu, tempeh and soy milk.

This research sprouted from a collection of research conducted by a breast cancer specialist in New York City who placed 140 newly diagnosed (and early-stage) women with breast cancer in to two groups. One group received soy milk capsules everyday for between 1 and 4 weeks. The other group was given a milk powder supplement.

The result was that nearly 20% of the women taking the soy supplement had an increase in the activity of genes recognized for their roles in tumor growth and spreading cancer.

Researchers cannot conclude that soy products cause cancer, but they have enough information to advise women with a current breast cancer diagnosis to avoid soy products, or consume them only in moderation.