The results suggested a “protective role” of alpha-carotene, beta-carotene, lycopene and lutein/zeaxanthin, but not beta-cryptoxanthin in the risk of breast cancer.
Published in the British Journal of Nutrition, the study looked at 521 women aged 25–70 years diagnosed with breast cancer within three months and 521 age-matched controls.
The researchers from the Sun Yat-sen University and Guangzhou Medical University in China said the study built on epidemiological studies suggesting “anti-cancer effects” of dietary circulating carotenoids – but this was the first to examine specific types.
“To the best of our knowledge, only one previous study has investigated the association between specific circulating carotenoids and the risk for breast cancer in the Chinese population, and evidence for the protective effect of each individual serum carotenoid is inconsistent,” they wrote.
They suggested previous studies that "failed to find evidence for a protective role" of specific serum or plasma carotenoids may have been limited by small numbers and restricted representation of socioeconomic groups.
"A protective role for carotenoids in breast cancer aetiology is biologically plausible. Carotenoids may protect against DNA damage by neutralising oxygen species and activating the antioxidant response element transcription system. Besides their antioxidant potential, some carotenoids such as α-carotene, β-carotene and β-cryptoxanthin are metabolised to retinol, which is involved in cell differentiation."
Second most-common cancer globally
According to the World Cancer Research Fund International, breast cancer is the most common cancer in women worldwide.
Nearly 1.7 million new cases were diagnosed in 2012, representing about 12% of all new cancer cases and 25% of all cancers in women.
It is the second most common type of cancer overall after lung cancer.
The researchers behind this latest paper said the incidence rate of female breast cancer in China was still significantly lower than in western countries but rates had seen a “rapid increase”.
Source: British Journal of Nutrition
Published online ahead of print, doi:10.1017/S000711451500416X
“Specific serum carotenoids are inversely associated with breast cancer risk among Chinese women: a case–control study”
Authors: B. Yan, M.S. Lu, L. Wang, X.F. Mo, W.P. Luo, Y.F. Du and C.X. Zhang