Over the past several years, several studies appear to indicate that vitamin D supplementation may reduce cancer risk. Already considered a crucial element in supporting bone health and the immune system, it’s worth taking a look at what else it can do.
Vitamin D and Cancer Prevention
Vitamin D has played a role in several recent studies, including one that appeared to reduce the severity of COVID-19. Vitamin D’s role as a cancer prevention tool has a much longer – and murkier – history. The evidence starts with sun exposure, which is the natural source of vitamin D. Individuals living in areas with increased sun exposure have lower cancer and cardiovascular deaths, leading some to associate vitamin D with increased cancer resilience.
A Correlation, Not a Cause
Some researchers believe this link is tenuous, at best. Active individuals have a lower cancer risk and tend to spend more time outdoors. As a result, they tend to have increased levels of vitamin D. Even when accounting for vitamin D supplementations, evidence is weak that the vitamin has any impact on cancer resistance.
Perhaps the most robust study, published in 2019 in the New England Journal of Medicine evaluated more than 25,000 subjects. The comprehensive study failed to find any convincing evidence that vitamin D supplementation had any impact on cancer incidence.
Vitamin D and Cancer Progression
Among cancer patients, vitamin D may be a viable tool. One trial showed a 17% reduction in cancer reduction, which slowed the progression of certain types of cancer. The data are still too thin to make any strong recommendations around vitamin D supplementation.
There isn’t enough evidence to support vitamin D having any meaningful impact on cancer prevention or reducing the severity or spread of cancer in confirmed diagnosis.
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