Doubt cast over vit D supplements for disease prevention
The review showed the link between vitamin D and disease prevention was not backed by intervention studies.
It was conducted by the International Prevention Research Institute in Lyon, France, and showed that across 290 observational prospective studies, high vitamin D concentrations reduced cardiovascular disease by up to 58%, diabetes by up to 38% and colorectal cancer by up to 34%.
In contrast, analysis of 172 randomised controlled trials showed vitamin D supplementation did not have any effect on these disorders.
The authors concluded the discrepancy between observational and intervention studies suggested that low vitamin D was a marker for ill health.
“Inflammatory processes involved in disease occurrence and clinical course would reduce vitamin D, which would explain why low vitamin D status is reported in a wide range of disorders,” they wrote.
A slight reduction in all-cause mortality was only demonstrated