The guidelines recommend that healthy people under 75 years of age take a daily allowance of vitamin D

Healthy adults under age 75 generally do not need to exceed the daily allowance for vitamin D recommended by the Institutes of Medicine (IOM) and do not need to be tested for vitamin D levels, according to a new Endocrine Society Clinical Practice Guideline.

For children, pregnant women, adults over age 75, and people at high risk of prediabetes, the guidelines suggest vitamin D doses higher than the IOM recommendations.

Vitamin D levels and intake have been linked to many common diseases. However, whether taking vitamin D reduces the risk of these diseases and what levels of vitamin D are needed for health have long been debated.

In the new guidelines, the expert group made recommendations for the use of vitamin D and testing of levels in healthy people without an obvious medical indication. The recommendations are based on clinical research data.

The guideline, "Vitamin D for Disease Prevention: An Endocrine Society Clinical Practice Guideline," was published online and will appear in print in the August 2024 issue of The Journal of Clinical Endocrinology & Metabolism (JCEM).

"The purpose of these guidelines is to determine the vitamin D requirements for disease prevention in healthy individuals who do not have conditions that might interfere with the absorption or action of vitamin D," said Marie Demay, MD, of Harvard Medical School and Massachusetts General Hospital in Boston. Demay led the group that developed the guidelines.

"Healthy groups that may benefit from higher doses of vitamin D include people over 75 years of age, pregnant women, adults with prediabetes, and children and adolescents under 18 years of age. However, we do not recommend routine testing of vitamin D levels in any of these groups."

Key recommendations from the guide:

• We do not recommend taking vitamin D supplements in doses higher than the IOM recommendations for healthy adults under 75 years of age.

The following groups have been identified as those that may benefit from higher doses of vitamin D, above the IOM recommendation, to reduce specific health risks:

• Children and adolescents under 18 years of age - potential to prevent vitamin D deficiency and reduce the risk of respiratory infections.
• People over 75 years of age - potential for reduced mortality risk.
• Pregnant women - potential for reduced risk of preeclampsia, intrauterine mortality, preterm birth, small for gestational age infants and neonatal mortality.
• People with prediabetes have the potential to reduce progression to diabetes.
• For adults over 50 years of age who require vitamin D treatment, we recommend daily low-dose vitamin D rather than non-daily high-dose vitamin D.
• We do not recommend routine testing of 25-hydroxyvitamin D levels in any of the groups studied, as no specific benefits associated with these levels have been identified. This includes screening for 25-hydroxyvitamin D in people with dark skin or obesity.

Despite the increasing evidence on the role of vitamin D in health and disease over the past decade, the panel noted many limitations in the available data. For example, many large clinical trials were not designed to assess some of the outcomes reported, and the populations studied had adequate blood levels of vitamin D at baseline.

Due to lack of evidence, the group was unable to identify specific blood 25-hydroxyvitamin D levels for adequacy or target levels for disease prevention.

The guidelines were developed using a rigorous methodology, incorporating improvements initiated in 2019. The chairs of our guidelines development panels cannot have significant conflicts of interest, and more than half of the writing panel members must be free of any significant conflicts.