In the Journals

Lycopene-rich diet increased adiponectin, may protect against breast cancer

Women at high risk for breast cancer produced higher levels of adiponectin after maintaining a lycopene-rich diet for 10 weeks, according to findings in a recently published study. Researchers hypothesized that this could, in turn, offer protection against breast cancer.

“Our findings demonstrate that serum adiponectin increased after the consumption of the lycopene-rich diet and decreased after the consumption of the isoflavone-rich diet,” Adana A. Llanos, MD, of the Ohio State University Comprehensive Cancer Center, and colleagues wrote. “Interestingly, the individual effects of these interventions on adiponectin concentration were stronger among nonobese women.”

The prospective study looked at 70 postmenopausal women (mean age, 57.2 years; mean BMI, 30) recruited between February 2003 and September 2004 as they consumed a tomato-based diet (≥25 mg lycopene daily) for 10 weeks, followed by a 2-week “wash-out” period and another 10 weeks of a soy-based diet (≥40 g soy protein daily). These women were considered high risk for breast cancer due to higher BMI (range, 25-42) or having a first-degree relative with breast cancer.

Looking at blood serum specimens, the researchers found a 9% overall adiponectin concentration increase (ratio 1.09; 95% CI, 1-1.18) and more so in nonobese women (ratio 1.13, 95% CI, 1.02-1.25) after the lycopene-rich diet. After the soy-rich diet, adiponectin decreased by 9% overall (ratio 0.91, 95% CI, 0.84-0.97) with a greater reduction in nonobese women (ratio 0.89, 95% CI, 0.81-0.98).

Researchers said although women consumed more than the recommended amount of lycopene (approximately six to 15 times a normal daily intake), they did not adhere as well to the soy recommendations, consuming only three-quarters of the recommended amount. Additionally, participants did not lose weight while following either dietary intervention.

“Adiponectin plays a role in regulating glucose homeostasis and fatty acid metabolism. Thus, the increase in adiponectin observed among nonobese women during the tomato intervention suggests that lycopene may effectively improve insulin sensitivity in this subgroup, which could reduce their breast cancer risk,” the researchers wrote.

Disclosure: This study was supported by grants from the Breast Cancer Research Foundation and the Ohio State University Clinical and Translational Science Award.