Shocking news: Vitamin D is not a vitamin. Vitamins are defined as chemical components from food that are required by our bodies to function. Vitamin D is more like a hormone – produced by our body (our skin specifically) when exposed to ultraviolet light. Oh well, we often get things wrong – Pluto is no longer a planet and the Women’s Weekly is now monthly.

But the recent prominence of Vitamin D is worth highlighting – it is critical in the absorption of calcium and phosphate. Deficiency in Vitamin D can lead to Ricketts (bone softening and deformities in kids, which is how Vitamin D was discovered in Poland in 1822),

Furthermore, complications of pregnancies can be associated with Vitamin D deficiency, including gestational diabetes (85% with Vitamin D deficiency) and pre-eclampsia (40% more likely to develop this with Vitamin D deficiency).

Other studies have shown high Vitamin D levels are correlated with half the incidence of colon cancer and lower rates of prostate cancer in men. In colon cancer, high levels of Vitamin D can double the survival rate compared to low levels of Vitamin D. In prostate cancer, adding Vitamin D to prostate cancer cells inhibits growth, and giving Vitamin D in high doses to prostate cancer patients can reduce or prevent increases in the cancer marker Prostate Specific Antigen.

Risk of other cancers can be reduced as well, including ovarian, kidney, bladder, uterine, oesophageal, rectal and breast cancer.

And Vitamin D deficiency is also correlated with  higher risks of hypertension, heart attack, heart failure, stroke, diabetes and dementia.

Well worth considering as a top-up if you’re not getting enough sunlight (but of course beware of sun risks as well).


  • The big 5 – Dr Sanjiv Chopra, Professor of Medicine at Harvard Medical School, 2016, Thomas Dunn Books.