A new meta-analysis of previous prospective studies has reported that women with relatively high levels of circulating carotenoids have a 19% lower risk of breast cancer compared to those with low levels. To conduct the analysis, the authors performed a pooled analysis of eight prospective studies concerning circulating carotenoids and risk of breast cancer. The studies included a total of 3,055 breast cancer cases and 3,956 matched cancer-free controls. To ensure that the data was comparable across the eight studies, the authors recalibrated study participant carotenoid levels to a common standard by retesting 20 plasma or serum samples from each study at the same laboratory.
Women in the top fifth (quintile) of total circulating carotenoids were found to have a 19% lower risk of breast cancer compared to those in the lowest quintile. When carotenoids were considered individually, women in the top quintile of lycopene were found to have a 22% lower risk of breast cancer than those in the bottom quintile.
The comparable reductions in risk were 17% for high levels of beta-carotene, 16% for lutein+zeaxanthin (which are often found together in foods), and 13% for alpha-carotene. Beta-cryptoxanthin was not found to be significantly associated with breast cancer risk.
The link to lower breast cancer risk was found to be stronger for estrogen receptor negative (ER-) than for ER+ disease for several carotenoids. For example, high levels of beta-carotene were associated with a 48% lower risk of ER- breast cancer compared to a 17% lower risk of ER+ breast cancer. The authors conclude that women with relatively high circulating levels of alpha-carotene, beta-carotene, lutein and zeaxanthin, lycopene, and total carotenoids may be at reduced risk of breast cancer.
Please see our article on how to optimize your breast cancer diet for information on what to eat during all stages of treatment and recovery.