Tomatoes could protect you against breast cancer. In a new study, researchers at Rutgers University and Ohio State University show that a diet rich in tomatoes corresponds to a lower incidence of breast cancer in at-risk postmenopausal women. The findings add to the growing list of lifestyle changes associated with higher protection against the disease that kills nearly 40,000 Americans each year.

Previous studies have shown that women who are genetically predisposed to breast cancer can partially offset their elevated risk by taking certain preventative measures. Exercise, vitamins, and long walks are thought to decrease the risk by as much as 25 percent. The study, published in the Journal of Clinical Endocrinology & Metabolism, sought to determine whether a tomato-rich diet can have a similar protective effect.

So far, the results look promising. "The advantages of eating plenty of tomatoes and tomato-based products, even for a short period, were clearly evident in our findings," lead author Adana Llanos said in a press 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 the study, Llanos and her colleagues enrolled a group of 70 postmenopausal women in an experiment. Over 10 weeks, the subjects adhered to a tomato-rich diet corresponding to at least 25 milligrams of lycopene per day. At the end of the experiment, the researchers assessed changes in the subjects’ levels of adiponectin — a glucose-regulating hormone known to influence the risk of breast cancer.

They found that after sticking to the lycopene-rich tomato diet for 10 weeks, the average subject showed a nine percent increase in her adiponectin levels. This protective effect was slightly more pronounced in women with a lower body mass index (BMI). According to the researchers, this suggests that the diet may work even better in combination with other risk-reducing habits. "The findings demonstrate the importance of obesity prevention," Llanos explained. "Consuming a diet rich in tomatoes had a larger impact on hormone levels in women who maintained a healthy weight."

Breast cancer is currently the second most deadly cancer among women, affecting over 200,000 and killing 40,000 each year. National Institutes of Health (NIH) says that one in every eight women will develop the disease at some point in their life. While the cause remains unknown, risk factors include early puberty, late menopause, and certain genes. Lifestyle factors like calorie intake and alcohol consumption have also been implicated in higher risk for diagnosis.

Source: Llanos A, et al."Effects of Tomato and Soy on Serum Adipokine Concentrations in Postmenopausal Women at Increased Breast Cancer Risk: A Cross-over Dietary Intervention Trial," [published online ahead of print].Journal of Clinical Endocrinology & Metabolism.2013.