BRYSTKREFT: Hvordan virker antioksidanter forebyggende, og har frukt og grønt en reell effekt?

Abstract

Title: BREAST CANCER: What is the mechanism behind antioxidants anticarsinogenic effect, and do fruits and vegetables have a protective role?

Author: Kristiane Woie, University of Oslo, Norway Advisor: Giske Ursin

The effect of fruit and vegetable consumption on breast cancer risk is controversial. This paper summarizes current knowledge on the association between fruit and vegetable intake and breast cancer risk. Vegetables and fruits are rich in antioxidants, and may therefore prevent cancer development by reducing oxidative damage caused by reactive species. In addition, they may also upregulate expression of tumor suppressor genes, downregulate oncogenes, modulate cancer cell proliferation and induce apoptosis. This paper mainly focuses on the effects of dietary intake of antioxidants such as carotenoids and breast cancer risk. The latest four case-control studies recently published on the topic were compared; 1)Mignone et al. (2009) 2) Wang et al. (2009) 3) Huang et al. (2007) and 4) Zhang et al. (2009). Even though they all examined the intake of carotenoids and the risk of breast cancer, their results differ immensely. The first study carried out in the U.S found that high consumption of carotenoids may reduce the risk of premenopausal, but not postmenopausal cancer. The second study, also carried out in the U.S, did not find a protective effect of dietary antioxidants. On the other hand, both studies (3rd and 4th) among Chinese women, found an inverse association between intake of carotenoid rich fruits and vegetables and breast cancer risk. The potential effects of dietary antioxidants on breast cancer risk have been considered in many epidemiological studies during the last 25 years, but results are still inconsistent and inconclusive.