Effects of Vitamin D on risk of breast cancer

Breast cancer is one of the most common cancers in women worldwide and Iran and According to the Ministry of Health more than 40000 people in Iran are now suffering from this disease. Obesity, physical activity, alcohol consumption, smoking, hormone therapy and diet are factors that have a significant role in breast cancer incidence. Studies show that the active form of vitamin D promotes cell differentiation and inhibits proliferation and have the potential to modify cancer risk. The results of some studies confirm an inverse association between dietary vitamin D intake and serum vitamin D concentration with the risk of breast cancer. Research results indicate a reduced risk of breast cancer with higher intake of vitamin D. Studies show that there is a significant inverse association between plasma calcidiol concentration and also exposure to the sun's ultraviolet radiation with the risk of breast cancer. Measurement of serum calcidiol long before cancer diagnosis leads to no significant relationship. Results of the studies suggest a protective effect of vitamin D intake from diet and supplements and exposure to ultraviolet rays of the sun against breast cancer incidence, especially in premenopausal women. On the other hand, based on measurement of plasma calcidiol concentration, the high prevalence of vitamin D in patients with breast cancer have been reported. Before achieving decisive results, adequate intake of vitamin D (600 IU/d for women younger than 71 years and 800 IU/d for women 71 and older) and maintenance of plasma calcidiol in the range of 30-49 ng / ml seems logical.