On the other hand, he said, vitamin D supplements might have more of an impact on the odds of dying from a disease.
His team found a clear relationship between blood vitamin D levels and the risk of early death — especially among people who were younger than 60: Those with levels of 10 nmol/L (nanomoles per liter) or less had almost a three-times higher risk of dying during the study, versus those with adequate levels (50 nmol/L).
In contrast, middle-aged and younger people with vitamin D levels at or above 90 nmol/L had a lower death risk than those at the 50 mark.
In general, vitamin D concentrations of 50 nmol/L or higher are considered to be high enough for overall health, according to the U.S. National Institutes of Health.
When the researchers zeroed in on causes of death, it turned out that vitamin D levels showed only weak connections to heart disease and cancer. Instead, people with low levels (below 50) had a more than fourfold higher risk of dying from diabetes complications, versus those with adequate levels.
It’s not clear why. But, Marculescu said, there are plausible reasons that vitamin D levels would be particularly linked to diabetes: The vitamin, which acts as a hormone in the body, helps regulate the immune system. That’s relevant to type 1 diabetes, Marculescu noted, because it is an autoimmune disease.
Vitamin D is also important to the cells that produce the hormone insulin — which regulates blood sugar — and to the body’s sensitivity to insulin. That’s relevant to type 2 diabetes, Marculescu pointed out.
For now, he said, the findings “further strengthen the already very strong rationale for intensifying vitamin D supplementation, especially during childhood and at younger ages.”
Specifically, he pointed to recommendations from the Endocrine Society. They suggest that adults get 1,500 to 2,000 IU of vitamin D per day, while children and teenagers get 600 to 1,000 IU.
The body naturally synthesizes vitamin D when sunlight hits the skin, but cold climates — and concerns about sun exposure — can limit that source.
Diekman suggested that people have their blood vitamin D level checked. If it’s low, she said, talk to your doctor about how to boost it — whether through supplements or foods such as vitamin D-fortified dairy products, juice or cereal.