Vitamin D may help delay or prevent the progression of prediabetes, but only in people with certain genetic variations, according to new study findings. The condition is typically marked by higher-than-normal blood sugar levels that often lead to type 2 diabetes.
More than two in five US adults have prediabetes, the study authors highlight. They discovered that prediabetic adults with certain variations in the vitamin D receptor gene had a 19% lower risk of developing diabetes when taking a high daily dose of vitamin D.
The findings may inform more personalized care in the future, which could potentially delay or prevent the onset of diabetes for the majority of the 115 million high-risk US citizens who are living with prediabetes.
“Part of what makes vitamin D appealing as a potential preventive tool is that it is inexpensive, widely available, and easy for people to take,” underscores senior author Anastassios Pittas, a professor of medicine at Tufts University School of Medicine, and chief of endocrinology, diabetes, and metabolism at Tufts Medical Center, US.
Vitamin D and prediabetes
The analysis published in JAMA Network Open looked at data from the “D2d” study, a large, multi-site clinical trial that tested the effect of 4,000 IU of vitamin D3 per day versus placebo in 2,098 prediabetic US adults. This earlier trial lasted between October 1, 2013 and November 28, 2018, with a median follow-up period of 2.5 years.
Although the original study did not find a significant reduction in diabetes risk across all participants, the authors of the new paper wondered if the vitamin could still benefit some people.
The researchers of the newer study were curious if genetic differences in this receptor might explain why some people benefited from vitamin D while others did not. They note that vitamin D circulating in the blood is first converted into its active form in the body before binding to the vitamin D receptor, which is a protein that helps cells respond to the vitamin.
For the new study, the research team analyzed genetic data from 2,098 trial participants who had consented to DNA testing according to two groups: participants who appeared to benefit from vitamin D supplementation and those who did not.
The scientists observed that the pancreas’ insulin-producing cells have vitamin D receptors, suggesting that the vitamin may help influence insulin release and blood sugar control.
The scientists also observed that the pancreas’ insulin-producing cells have vitamin D receptors, suggesting that the vitamin may help influence insulin release and blood sugar control.
They then compared response rates by subgroups of patients sorted according to three common variations in the vitamin D receptor gene.
This analysis revealed that adults with the AA variation of the ApaI vitamin D receptor gene — about 30% of the study population — did not respond to daily treatment with a high dose of vitamin D, compared with placebo.
In contrast, the analysis found that the same treatment in adults with the AC or CC variations of the vitamin D receptor gene saw a significantly reduced risk of developing diabetes compared with those taking a placebo.
The scientists also observed that the pancreas’ insulin-producing cells have vitamin D receptors, suggesting that the vitamin may help influence insulin release and blood sugar control.
Role of vitamin D receptor
Diabetes has so many serious complications that develop slowly over years, underscores lead author Bess Dawson-Hughes from Tufts University, US. “If we can delay the time period that an individual will spend living with diabetes, we can stop some of those harmful side effects or lessen their severity.”
Despite their promising findings, the authors do not advocate that people consume high doses of vitamin D on their own to prevent diabetes.
They highlight that current guidelines recommend 600 IU of vitamin D3 per day for people aged between one and 70, and 800 IU per day for those above 70.
Taking too much vitamin D can be harmful and has been linked to an increased risk of falls and fractures in older adults, they warn. More research is also required to better understand which individuals might benefit from a higher daily dose.
“Our findings suggest we may eventually be able to identify which patients with prediabetes are most likely to benefit from additional vitamin D supplementation,” concludes Dawson-Hughes. “In principle, this could involve a single, relatively inexpensive genetic test.”
In other research surrounding dietary interventions for diabetes, one paper recently found that the keto diet may improve beta-cell function in type 2 diabetics by reducing beta-cell stress. People following the high-fat, low-carbohydrate diet may have a higher chance of reversing their diabetes, compared to people on a low-fat diet.
Two papers published earlier this year revealed that a higher consumption of some preservatives widely found in industrially processed foods and beverages may raise the risk of type 2 diabetes and cancer. Drawing from the dietary data of more than 100,000 adults, the researchers urged regulators to revisit existing national food policies, such as setting stricter limits on certain additives.