Having discovered The Cochrane Library, I thought I'd see what was in it regarding Vitamin D & Cancer. I found the following Protocol Vitamin D supplementation for prevention of cancer in adults.
"Why it is important to do this review
The available evidence on vitamin D and cancer incidence is intriguing but inconclusive. Results of recently completed randomised clinical trials testing the influence of vitamin D supplementation for cancer prevention are inconsistent. Lappe et al found that vitamin D supplementation is associated with significantly decreased cancer incidence (Lappe 2007). On the contrary, another large randomised clinical trial found no effect of vitamin D and calcium supplementation on cancer incidence (Wactawski-Wende 2006). A recent meta-analysis by Autier and Gandini of 18 randomised clinical trials found significantly lower mortality in vitamin D supplemented participants (Autier 2007). We have been unable to identify any systematic reviews of randomised trials on vitamin D supplementation for cancer prevention."
I took a closer look at the Wactawski-Wende trial. In this trial, a daily Vitamin D dose of 400IU was used. That's less than one tenth of an effective dose (5,000IU/day). What happens when you take less than one tenth of an effective dose of a medication? Nothing. Which is exactly what they found. Like, Duh!
The randomised trials in the Autier meta-analysis used daily Vitamin D doses of 300 to 2000IU. The trial size–adjusted mean daily vitamin D dose was 528IU. Once again, mostly pathetically inadequate doses were used.
The Lappe trial used a daily Vitamin D dose of 1,100IU (+ Calcium). It's a bit low, but there was a beneficial effect. When analysis was confined to cancers diagnosed after the first 12 months (to allow time for serum 25(OH)D levels to stabilise and ignore results from subjects who started the trial with undiagnosed cancers), there was a 77% reduction in cancer diagnoses (RR for the Ca + D group fell to 0.232 (CI: 0.09, 0.60; P < 0.005)).
No cancer trials have yet been done using 5,000IU/day of Vitamin D3.
So, thanks to eejit researchers testing ineffective doses, there is no conclusive evidence supporting Vitamin D3. People continue to die from cancer unnecessarily. What is Cancer Research doing with all of the money that they get?