Postmenopausal women are known to be at higher risk for breast cancer, and a new study offers a simple way they may be able to offset that risk: Eat more tomatoes.

The antioxidants in tomatoes, particularly lycopene, seem to offer protection against a variety of diseases and health conditions. The new research suggests that a tomato-rich diet can help increase the levels of a hormone that improves insulin sensitivity, and which in turn reduces the risk of breast cancer, particularly among postmenopausal women.

Eating a tomato-rich diet increased women's levels of adiponectin, a hormone found in the bloodstream that originates in fat tissue. Low levels of adiponectin are associated with obesity, diabetes and heart disease as well as the development of breast cancer.

The advantages of eating plenty of tomatoes and tomato-based products, even for a short period, were clearly evident in our findings.

“The advantages of eating plenty of tomatoes and tomato-based products, even for a short period, were clearly evident in our findings,” said Adana Llanos, Ph.D., M.P.H., Assistant Professor of Epidemiology at Rutgers University and lead author of the study, in a news release.

“Eating fruits and vegetables, which are rich in essential nutrients, vitamins, minerals and phytochemicals such as lycopene, conveys significant benefits. Based on this data, we believe regular consumption of at least the daily recommended servings of fruits and vegetables would promote breast cancer prevention in an at-risk population.”

For 10 weeks, 70 women ate two or more tomato products containing at least 25 milligrams of lycopene daily. The women's levels of adiponectin increased by nine percent, the researchers, from Rutgers University and Ohio State University, found.

The protective effect was slightly higher in women with a lower body mass index (BMI). A separate aspect of the study looked at soy consumption, also for 10 weeks, but found no rise in adiponectin levels.

The researchers concluded that increasing adiponectin levels through the consumption of lycopene may be an effective way to improve insulin sensitivity and reduce the risk of obesity-related breast cancer.

An increasing BMI is one of the hazards women face in the postmenopausal years, and this raises the risk for breast cancer.

In addition, the findings point to the importance of obesity prevention. Llanos believes that, “Consuming a diet rich in tomatoes had a larger impact on hormone levels in women who maintained a healthy weight.”

The study is published online in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism.