January 28, 2014 Sophie Langley
Eating a diet rich in tomatoes may protect against breast cancer
A tomato-rich diet may help protect at-risk postmenopausal women from breast cancer, according to research from Ohio State University.
The study, which was published 1 January 2014 online in the Endocrine Society’s Journal of Clinical Endocrinology and Metabolism, found that eating a diet high in tomatoes had a positive effect on the level of hormones that play a role in regulating fat and sugar metabolism. Breast cancer risk rises in postmenopausal women as their body mass index climbs.
“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, PhD MPH, Assistant Professor of Epidemiology at Rutgers University and the study’s first author.
Dr Llanos complete the research while she was a postdoctoral fellow with Electra Paskett, PhD, at the Ohio State University Comprehensive Cancer Centre Arthur G. James Cancer Hospital and Richard J. Solove Research Institute.
“Eating fruits and vegetables, which are rich in essential nutrients, vitamins, minerals and phytochemicals such as lycopene, conveys significant benefits,” Dr Llanos said. “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,” she said.
Study method
The longitudinal cross-over study examined the effects of both tomato-rich and soy-rich diets in a group of 70 postmenopausal women. For 10 weeks, the women ate tomato products containing at least 25 milligrams of lycopene daily. For a separate 10-week period, the participants consumed at least 40 grams of soy protein daily. Before each test period began, the women were instructed to abstain from eating both tomato and soy products for two weeks.
When the women followed the tomato-rich diet, their levels of adiponectin — a hormone involved in regulating blood sugar and fat levels — climbed 9 per cent. The effect was slightly stronger in women who had a lower body mass index.
“The findings demonstrate the importance of obesity prevention,” Dr Llanos said. “Consuming a diet rich in tomatoes had a larger impact on hormone levels in women who maintained a healthy weight,” she said.
Soy-rich diet may only be helpful to some ethnic groups
The soy diet was linked to a reduction in participants’ adiponectin levels. Researcher originally theorised that a diet containing large amounts of soy could be part of the reason that Asian women have lower rates of breast cancer than women in the US, but any beneficial effect may be limited to certain ethnic groups, Dr Llanos said.
Other authors of the study included: J.Peng and M.L. Pennell of the Ohio State University; M.Z. Vitolins of Wake Forest School of Medicine in Winston-Salem, NC; and J.L. Krok, C.R. Degraffinreid and E.D. Paskett of the Ohio State University Comprehensive Cancer Centre. The study was funded with grants from the Breast Cancer Research Foundation and the Ohio State University Clinical and Translational Science Award.
