Vitamin D Supplementation Is A Double-Edged Sword
A new randomized trial shows it can reduce the risk of cancer, while increasing the risk of heart disease.
Imagine, if you will, the great Cathedral of Our Lady of Correlation is Not Causation. You walk through the majestic oak doors depicting the link between ice cream sales and shark attacks, past the rose window depicting the cardiovascular benefits of red wine, and down the aisles frescoed in dramatic images showing how Facebook usage is associated with less life satisfaction. And then, you reach the altar. The holy of holies. Where, emblazoned in shimmering pyrite, you see the patron saint of this church. Vitamin D.
Yes, if you’ve watched this space you know I have little truck with the wildly popular supplement. In all of clinical research, I believe there is no molecule with stronger data for correlation and weaker data for causation.
Low serum vitamin D levels have been linked to higher risks of heart disease, cancer, falls, COVID, dementia, C. Diff, and others. And yet when we actually do randomized trials of Vitamin D supplementation — the thing that can prove that the low level was causally linked to the outcome of interest — we get negative results.
