Increased vitamin D intakes may reduce lung cancer risk

A new US study has linked intakes higher than 800 IU of vitamin D per day with an up to 63% decreased risk of developing lung cancer in never-smoking, postmenopausal women.

The study analyzed the dietary and supplement intakes of vitamin D of 128,779 postmenopausal women, including 1,771 women who developed lung cancer within 17 years (1). While no significant association betwe-en vitamin D intakes and lung cancer risk was observed overall, a clear association with a lower risk of de-veloping lung cancer was seen among participants who never smoked in their lives and had a total vitamin D intake higher than 400 IU/day. Participants who took more than 800 IU per day had a 63% decreased risk of lung cancer compared to those who took less than 100 IU/day. Among the participants who had received a daily supplementation of 1 gram of calcium plus 400 IU of vitamin D3 or a placebo, a lung cancer risk reduc-tion was only observed in those who had a daily vitamin A intake lower than 1000 micrograms of retinol equivalents.

The researchers commented that vitamin D has been suggested to have cancer-preventing effects by regulating cell division and growth (proliferation) as well as the development of new blood vessels (angio-genesis) (2, 3). The observation that increased vitamin D intakes only showed efficacy among study partici-pants who never smoked may indicate that vitamin D may be more effective at preventing or reversing tumor development which is not tobacco-related. According to the scientists, the association between comb-ined vitamin D and calcium supplementation and lung cancer risk reduction observed in a subgroup of smo-king and non-smoking participants with lower vitamin A intake must be interpreted with caution because of the small number of lung cancer cases in this group. Increased intakes of beta-carotene in supplements did not influence lung cancer risk.

1. Cheng T.-Y. D. et al. Vitamin D intake and lung cancer risk in the Women’s Health Initiative. American Journal of Clinical Nutrition. Published online August 2013.
2. Deeb K. K. et al. Vitamin D signalling pathways in cancer: potential for anticancer therapeutics. Nat Rev Cancer. 2007; 7:684–700.
3. Königshoff M. and Eickelberg O. WNT signaling in lung disease: a failure or a regeneration signal? Am J Respir Cell Mol Biol. 2010; 42:21–31.