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In recent years, vitamin D supplements have been widely used in the general population, even among individuals who are not vitamin D deficient. However, evidence from a large, U.S. federally funded, randomized, placebo-controlled trial called VITAL has not found benefits of routine daily vitamin D supplementation in generally healthy middle-aged and older adults for preventing chronic conditions, mainly cardiovascular disease, cancer[1] and depression[2] as well as other health outcomes, such...
In recent years, vitamin D supplements have been widely used in the general population, even among individuals who are not vitamin D deficient. However, evidence from a large, U.S. federally funded, randomized, placebo-controlled trial called VITAL has not found benefits of routine daily vitamin D supplementation in generally healthy middle-aged and older adults for preventing chronic conditions, mainly cardiovascular disease, cancer[1] and depression[2] as well as other health outcomes, such as falls.[3]
In addition, recent evidence from an ancillary study of the VITAL trial showed that daily vitamin D supplementation does not lower the risk of new fractures.[4] This evidence was published in the July 28, 2022, issue of the New England Journal of Medicine.
About vitamin D
The human body needs small daily amounts of vitamin D: 600 international units (IU) for healthy adults up to age 70 years and 800 IU for those older than 70 years.[5] These amounts can be met in three ways. First, by consuming foods that are naturally rich in vitamin D, including fatty fish (such as mackerel, salmon, trout and tuna), fish-liver oils and mushrooms (beef liver and egg yolks provide modest amounts of vitamin D). Second, by consuming vitamin D-fortified foods, such as milk, certain orange juice products and breakfast cereals. Third, vitamin D is produced naturally in the skin during direct exposure to sunlight. Some experts suggest that up to 30 minutes of sun exposure, particularly between 10 a.m. and 4 p.m., at least twice weekly to the face, arms, hands and legs without sunscreen often generates adequate amounts of vitamin D.
Vitamin D dietary supplements are available in two main forms: cholecalciferol (vitamin D3) and ergocalciferol (vitamin D2).[6]
Although there is no consensus about the threshold of vitamin D sufficiency, 25-hydroxyvitamin D blood levels of 20 nanograms (ng) per milliliter (mL) or more generally are considered adequate for most people.[7]
The VITAL ancillary study[8]
Approximately 25,900 generally healthy, community-dwelling men (aged 50 years or older) and women (aged 55 years or older) from all 50 states — 20% of whom were Black — without a history of cardiovascular disease (such as heart attack or stroke) or cancer (except nonmelanoma skin cancer) enrolled in the main VITAL trial. Selection of these subjects was not based on whether they had vitamin D deficiency, low bone mass or osteoporosis.
Trial staff randomly assigned the subjects to receive either a once-daily, 2,000-IU vitamin D3 soft gel or a placebo for a median of five years.[9] The study did not involve calcium supplementation; however, subjects who wanted to take a calcium supplement on their own (20%) agreed not to take more than 1,200 milligrams of such a supplement per day.
In this ancillary study, the researchers examined the effects of the vitamin D supplement on new fractures, which were reported by the subjects and verified by medical-record and radiologic-image reviews. They found that the vitamin D supplement did not lower the risk of new total fractures, hip fractures or nonvertebral fractures (fractures not occurring in the spine) — the primary study endpoint — compared with the placebo, even after adjusting for age, sex, race and ethnicity, and personal use of supplemental calcium.
Moreover, there were no significant differences in the risk of new fractures between the trial groups according to various 25-hydroxyvitamin D blood levels, even among about 400 subjects who had very low levels (less than 12 ng/mL) at baseline.
With respect to safety outcomes, there were no substantial differences in the rates of hypercalcemia (high blood calcium levels) and kidney stones between the vitamin D and placebo groups.
Based on their findings, the researchers for the ancillary study recommended cutting back on widespread routine screening and supplementation of vitamin D in the generally healthy population.[10] Nonetheless, they still recommended vitamin D supplementation in individuals with very low vitamin D levels to avoid osteomalacia (bone softening). They also recommended sufficient calcium and vitamin D intake and supplementation in patients with low bone mass and osteoporosis.
Notably, the VITAL trial involved a group of subjects who were randomized to receive an oral omega-3 fatty acid supplement (in addition to vitamin D or a placebo). However, there were no benefits for the omega-3 fatty acid supplement with regards to reducing fracture risk.
What You Can Do
Unless you have osteoporosis or osteomalacia, or are at risk of vitamin D deficiency (due to lack of sun exposure, malabsorption or other factors), you generally do not need to take vitamin D supplements to prevent factures or other conditions. Instead, try to obtain enough vitamin D from dietary sources and by spending time outdoors. As a general rule, do not use any dietary supplement as replacement for a healthy diet and active lifestyle.
References
[1] Manson JE, Cook NR, Lee IM, et al. Vitamin D supplements and prevention of cardiovascular disease. N Engl J Med. 2019;380(1):33-44.
[2] Okereke OI, Reynolds CF, Mischoulon D, et al. Effect of long-term vitamin D3 supplementation vs placebo on risk of depression or clinically relevant depressive symptoms and on change in mood scores: A randomized clinical trial. JAMA. 2020;324(5):471-480.
[3] LeBoff MS, Murata EM, Cook NR, et al. Vitamin D and omega-3 trial (VITAL): Effects of vitamin D supplements on risk of falls in the US population. J Clin Endocrinol Metab. 2020;105(9):2929-2938.
[4] LeBoff MS, Chou SH, Ratliff KA, et al. Supplemental vitamin D and incident fractures in midlife and older adults. N Engl J Med. 2022;387(4):299-309.
[5] Office of Dietary Supplements. National Institutes of Health. Vitamin D: Fact sheet for health professionals. August 12, 2022. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/. Accessed December 8, 2022.
[6] Ibid.
[7] Ibid.
[8] LeBoff MS, Chou SH, Ratliff KA, et al. Supplemental vitamin D and incident fractures in midlife and older adults. N Engl J Med. 2022;387(4):299-309.
[9] VITAL researchers announce landmark trial findings. https://www.vitalstudy.org/findings.html. Accessed December 7, 2022.
[10] LeBoff MS, Chou SH, Manson JE. Vitamin D and incident fractures. Reply. N Engl J Med. 2022;387(17):1626-1627.
