Could vitamin D supplements prevent adult onset type 1 diabetes?

by Barbara Hewitt on March 6, 2013

Among the new drugs is Forxiga, an oral diabetes drug

Could vitamin D supplements prevent adult onset type 1 diabetes?

The risk of developing type 1 diabetes may be cut by up to 50% by having adequate levels of vitamin D during young adulthood, scientists have discovered. The findings from a team at the Harvard School of Public Health (HSPH), if confirmed in future studies, could lead to a role for vitamin D supplementation in preventing the condition in adults.

‘It is surprising that a serious disease such as type 1 diabetes could perhaps be prevented by a simple and safe intervention,’ said lead author Kassandra Munger, research associate in the Department of Nutrition at HSPH.

This study provides the strongest findings to date to suggest that vitamin D may be protective against type 1 diabetes. This occurs when the body’s immune system attacks and permanently disables the insulin making cells in the pancreas and, although it often starts in childhood, about 60% of type 1 diabetes cases occur after the age 20.

Previous studies have suggested that a shortage of vitamin D might boost type 1 diabetes risk, although those studies mostly examined the link between vitamin D levels in pregnancy or childhood and the risk of type 1 diabetes in children. Other research, in young adults, uncovered an association between high vitamin D levels and a lowered risk of multiple sclerosis, an autoimmune disease genetically and epidemiologically related to type 1 diabetes, suggesting that inadequate vitamin D in adulthood may be an important risk factor for autoimmune diseases in general.

The researchers undertook a control study of US military personnel on active duty, using blood samples from the Department of Defense Serum Repository, which contains more than 40 million samples collected from eight million military personnel since the middle of the 1980s. They identified 310 individuals diagnosed with type 1 diabetes between 1997 and 2009 and examined blood samples taken before the onset of the disease, and compared the samples with those of 613 people in a control group.

Quote from DiabetesForum.com : “Nearly a year ago I read an article about how important vitamin D was, and it suggested large dosages for maximum effect.”

The researchers found that white, non-Hispanic, healthy young adults with higher serum levels (>75 nmol/L) of vitamin D had about half the risk of developing type 1 diabetes than those with the lowest levels of vitamin D (

‘The risk of type 1 diabetes appears to be increased even at vitamin D levels that are commonly regarded as normal, suggesting that a substantial proportion of the population could benefit from increased vitamin D intake,’ said Alberto Ascherio, professor of epidemiology and nutrition at HSPH, the study’s senior author.

It is estimated that worldwide around a billion people have inadequate levels of vitamin D in their blood, and deficiencies can be found in all ethnicities and age groups. While sun exposure is an excellent source of vitamin D, sunscreen, clothing, skin pigmentation, and winter months reduce vitamin D production.

‘Whereas it is premature to recommend universal use of vitamin D supplements for prevention of type 1 diabetes, the possibility that many cases could be prevented by supplementation with 1,000-4,000 IU/day, which is largely considered safe, is enticing,’ the authors said.


The opinions expressed in this article do not necessarily reflect the views of the DiabetesForum.com Community and should not be interpreted as medical advice. Please see your doctor before making any changes to your diabetes management plan.

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