Vitamin D supplementation found to reduce cancer risk in women

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On Monday, I wrote about sunscreen, and in particular the apparent hazards associated with their use. One potential effect associated with sunscreen use if the blocking of vitamin D production in the skin. This is a shame, as this nutrient has a number of health-promoting properties, including relative protection from several forms of cancer.

I was therefore interested to read this week a study in which women were supplemented with vitamin D over a 4-year period [1]. This research, conducted in Nebraska, USA, treated almost 1200 women with either a combination of vitamin D and calcium, calcium alone, or placebo (inactive medication).

At the end of the study, women taking the vitamin D and calcium combination were found to be at 60 per cent reduced risk of cancer. Women taking calcium alone, on the other hand, did not enjoy a statistically significant reduce risk of cancer.

The researchers involved in this study went on to analyse data from just the last 3 years from the study. They did this in an attempt to exclude from the data women who might have had undetected cancer at the start of the study. In this way, the researchers were hoping to get an even more accurate picture of the effects of nutrient supplementation on cancer risk.

Having performed an analysis on just the last 3-years worth of data the researchers found that women taking vitamin D and calcium were at a 73 per cent reduced risk of cancer.

Analysis also revealed that there was an important correlation between blood vitamin D level and cancer risk ” basically higher vitamin D levels were associated with reduced risk.

While this may only be one study, let’s remember that it comes on the back a stack of science linking sunlight exposure and vitamin D with a reduced risk of cancer.

To my mind, therefore, this most current research is utterly consistent with what science has shown before: that vitamin D has the ability to afford us some protection from cancer.

Need for more vitamin D will generally be greatest in individuals living in areas where sunlight can be in short supply ” and this is particularly the case during the darker winter months.

Such individuals may consider supplementing with vitamin D. The dose, incidentally, used in the study referred to here was 1,100 IU (international units) per day.


1. Lappe JL, et al. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. American Journal of Clinical Nutrition 2007;85(6):1586-1591

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