Researchers Say People with Prediabetes May Want to Take Vitamin D — Here’s Why

•    Past research indicates that vitamin D can positively affect blood sugar levels, inflammation, and insulin production.
•    It can be difficult to obtain enough vitamin D through your diet, so sunshine and supplements can be options.
People with prediabetes who supplement with at least 1,000 units per day of vitamin D may significantly reduce their risk of progressing to a diagnosis of type 2 diabetes.
That’s the conclusion of recent research published in The Journal of Clinical Endocrinology & Metabolism.
The meta-analysis included nearly 45,000 participants from nine previous clinical trials. Those participating had an average age of 65 years.
With the large sample size, the researchers said they were striving to determine more clearly if a deficiency in vitamin D increases the risk of type 2 diabetes and if supplements taken by people with prediabetes could prevent further progression of the disease.
Past research has determined that about 41 percentTrusted Source of the U.S. population has lower than normal vitamin D levels.
When focusing on specific ethnicities, nearly 82 percent of African American adults and 62 percent of Hispanic adults were found to be deficient in vitamin D. The factors for those percentages included obesity, lack of college education, and lack of daily milk consumption.
Dr. Zachary Bloomgarden, a professor at Mount Sinai Hospital in New York City specializing in endocrine and diabetes care, says the association between vitamin D and type 2 diabetes has been studied many times.
“The random controlled trials have not convincingly showed that vitamin D prevents diabetes, but subset analogies suggest that the group of individuals with low vitamin D levels are protected from diabetes by taking a vitamin D supplement,” Bloomgarden told Healthline.
A 2017 studyTrusted Source posed theories that vitamin D affects blood sugar levels and reduces the risk of type 2 diabetes in three ways: insulin production, insulin sensitivity, and overall inflammation.
And this doesn’t just apply to adults.
In a studyTrusted Source focused on Swedish youth who have obesity, vitamin D deficiency and prediabetes were identified in 33 percent of the participants.
“Vitamin D is really a prohormone,” explained Bloomgarden. “Chemically, it’s a steroid hormone.”
The fact that insulin is also a hormone convinces some experts that there is a relationship between insulin and vitamin D. Many people with low vitamin D levels have also been found to have overall immune deficiencies.
Bloomgarden adds, however, that while vitamin D deficiency is common in people with obesity and type 2 diabetes, it’s difficult to say what causes what.