Guideline: Routine Vitamin D Supplementation Unnecessary for the Prevention of Disease in Healthy Adults

From 1999 to 2014 the daily intake of vitamin D-containing supplements among U.S. adults increased from 0.3% to 18%.[1] The benefits of this surge, especially in those who are not vitamin D deficient and do not have related risk factors, are questionable.

A new guideline, funded by the Endocrine Society, recommends against empiric vitamin D supplementation to prevent diseases in healthy adults younger than 75 years, though it suggests that such supplementation may be helpful in other populations, including individuals aged 75 years and older.[2]

The guideline defined empiric vitamin D supplementation as taking additional vitamin D above the recommended daily allowance without testing blood levels of vitamin D. According to the guideline, the additional vitamin D intake is limited to consuming fortified vitamin D foods or taking a vitamin D supplement or vitamin formulations that contain vitamin D, usually in a pill or drop form.

Published in July 2024 in The Journal of Clinical Endocrinology & Metabolism, the guideline was developed by a diverse, 14-member expert panel, only one of whom had reported relevant conflicts of interest. Several U.S. and international organizations, including the American Association of Clinical Endocrinology and the European Society of Endocrinology, cosponsored the guideline.

About vitamin D

Vitamin D is a fat-soluble vitamin that promotes calcium absorption in the gut and maintains adequate blood levels of calcium and phosphate, which are necessary for normal bone mineralization.[3] It also plays other roles in the body, including reducing inflammation and regulating cell growth.



Vitamin D is found naturally in fatty fish (including trout and salmon) and fish liver oils (see Table below for examples). Beef liver, cheese and egg yolk contain small amounts of vitamin D. Fortified foods (including milk and breakfast cereals) are a major source of vitamin D in U.S. diets.

Importantly, vitamin D can be produced naturally in the skin during direct exposure to sunlight. Some experts suggest that 5 to 30 minutes of sun exposure (particularly between 10 a.m. and 4 p.m.) without sunscreen at least twice weekly to the arms, face, hands and legs produces sufficient vitamin D.

Nutritional guidelines recommend that healthy infants consume 400 international units (IU) of vitamin D daily and healthy individuals aged 1 to 70 years consume 600 IU of vitamin D daily. After age 70, the recommended daily allowance increases to 800 IU.

Two main forms of vitamin D are available: cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2). Most multivitamins contain about 800 to 1,000 IU of vitamin D.

Table: Examples of Vitamin D Food Sources and Their Vitamin D Content[4],[5]

New guideline recommendations

The Endocrine Society guideline recommendations[6] are based on a systematic review of evidence, primarily from randomized clinical trials, that focused on the use of vitamin D the general population without established indications for vitamin D treatment or testing.[7]

The guideline did not include infants because existing recommendations support routine empiric vitamin D supplementation in healthy infants to prevent rickets (weakened bones in children caused by vitamin D deficiency).

Based on low-certainty evidence, the guideline suggests daily empiric vitamin D supplementation in healthy children and adolescents (age 1 to 18 years) to prevent nutritional rickets and potentially lower the risk of respiratory tract infections.

In contrast, for healthy nonpregnant adults (age 19 to 74 years), the guideline suggests against routine empiric vitamin D supplementation. Instead, it suggests that adults in this broad age group should just stick to consuming the recommended daily allowance of vitamin D. This recommendation was based on the lack of conclusive evidence supporting the benefit of supplementation to lower risks of fractures, falls, infections or other outcomes in this age group. The guideline suggests routine empiric vitamin D supplementation in only two categories of healthy people in this age group: those at high risk of developing diabetes and pregnant females.

In healthy adults aged 75 and older, the guideline suggests routine empiric vitamin D supplementation because moderate-certainty evidence suggests that supplementation can potentially lower mortality.

When empiric dietary vitamin D supplements are considered, the guideline suggests low daily doses rather than high doses given intermittently (such as weekly or monthly) because evidence shows that high doses can cause adverse effects (such as high calcium blood levels and kidney stones).

Due to the lack of evidence supporting certain targets of vitamin D blood levels to prevent disease, the guideline suggests against routine testing to guide vitamin D dosing in healthy individuals.

The guideline does not suggest specific empiric vitamin D dosages to prevent disease because there is a wide range of supplementation doses in clinical trials.

Importantly, the guideline does not apply to individuals with clinical conditions that affect vitamin D physiology (including those with intestinal bypass surgery or inflammatory bowel disease or malabsorption) or those with bone symptoms that could be caused by osteomalacia (weakened bones in adults caused by vitamin D deficiency). In such individuals, higher doses of vitamin D supplementation and routine vitamin D testing can be essential.[8]

What You Can Do

Generally, Public Citizen’s Health Research Group recommends getting enough vitamin D from dietary sources and direct sun exposure rather than from supplements. Adults who are at risk of vitamin D deficiency, have osteoporosis or osteomalacia, or have other conditions should discuss vitamin D supplementation with their clinicians. Healthy adults over the age of 75 and parents or guardians of children and adolescents can discuss the new recommendations with their clinicians, keeping in mind that the evidence for empiric supplementation in these age groups is not strong.

For detailed information about important nutrition and health topics for each life stage, take a look at the Dietary Guidelines for Americans, 2020-2025, by the Departments of Agriculture and Health and Human Services (available at bit.ly/3Q8hmug).
 

References

[1] Rooney MR, Harnack L, Michos ED, et al. Trends in use of high-dose vitamin D supplements exceeding 1000 or 4000 international units daily, 1999-2014. JAMA. 2017;317(23):2448-2450.

[2] Demay MB, Pittas AG, Bikle DD, et al. Vitamin D for the prevention of disease: An Endocrine Society Clinical practice guideline. J Clin Endocrinol Metab. 2024;109(8):1907-1947.

[3] Office of Dietary Supplements. National Institutes of Health. Vitamin D: Fact sheet for health professionals. April 22, 2022. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/. Accessed December 31, 2024.

[4] Department of Agriculture. Food sources of vitamin D. August 2024. https://www.dietaryguidelines.gov/sites/default/files/2024-08/Food-Sources-Vitamin-D-Standard-508C.pdf. Accessed December 31, 2024.

[5] Office of Dietary Supplements. National Institutes of Health. Vitamin D: Fact sheet for health professionals. April 22, 2022. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/. Accessed December 31, 2024.

[6] Demay MB, Pittas AG, Bikle DD, et al. Vitamin D for the prevention of disease: An Endocrine Society Clinical practice guideline. J Clin Endocrinol Metab. 2024;109(8):1907-1947.

[7] Shah VP, Nayfeh T, Alsawaf Y, et al. A Systematic review supporting the Endocrine Society clinical practice guidelines on vitamin D. J Clin Endocrinol Metab. 2024;109(8):1961-1974.

[8] Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an endocrine society clinical practice guideline. J Clin Endocrinol Metab. 2011;96(7):1911-1930.