Are there benefits to Vitamin D supplements?

Interest in vitamin D supplements grew dramatically from 2007 to 2017. Sales jumped from $107 million to $936 million.

Early on, we lacked large-scale clinical trials. Many claims were based on observational studies that showed associations, not proof of benefit. Now in 2025, we have better data. The picture is more nuanced than early claims suggested.

Most of the research we found early on were observational studies. That's where researchers identified associations between things rather than controlled clinical trials. For example, in an observational study, researchers found that people who were at greater risk of cancer, cardiovascular disease, diabetes or obesity had lower levels of vitamin D in their blood. So the assumption was made that if we increase the vitamin D, those people would decrease their risk of those diseases or conditions.

We saw those very same assumptions made in the late 1990s and early 2000s. The vitamins of choice back then were vitamin A, E and beta-carotene. People who experienced health issues, had lower levels of those vitamins in their system. Supplement companies promoted vitamins A, E and beta-carotene as healthy pills that would help you live longer.

Long-term clinical trials found those vitamins weren't helping at all. People who took vitamin A, E or beta-carotene supplements were dying younger than non-vitamin taking groups. People were paying money to take pills that killed them sooner.

There appear to be many similarities with vitamin D. Sick people stay indoors more than healthy people, reducing their exposure to the sun and reducing the amount of vitamin D in their bodies. Low vitamin D levels don't cause disease, they're the result of having a disease.

Let's look at vitamin D and obesity. Since vitamin D is absorbed in the skin, you would think that an obese person who lays in the sun would get MORE vitamin D than a skinny person. After all, an obese person has more skin surface area to soak up the suns rays. BUT, vitamin D is fat-soluble. That means all that excess fat absorbs the vitamin D first, before the body can take it and put it to good use.

Researchers found that obese people may need two to three times the vitamin D dose of a fit person. Being obese causes lower levels of vitamin D. Low vitamin D doesn't cause obesity.

In the June 19th, 2019 issue of JAMA Cardiology, the results of a large vitamin D supplementation study was released. Researchers looked at 83,291 participants in 21 clinical trials. After going through all the data, the researchers concluded: “...vitamin D supplementation was not associated with reduced risks of major adverse cardiovascular events, myocardial infarction, stroke, cardiovascular disease mortality, or all-cause mortality compared with placebo.”

That means people who took vitamin D weren't protected against heart attacks or stroke any better than people who took a placebo.

A 2019 Tufts University analysis found nutrients from food were associated with lower mortality, while supplement use showed no benefit in people who already met their nutritional needs.

One subset analysis suggested possible harm from high-dose calcium and vitamin D supplementation in people without deficiency. However, this finding conflicts with other large trials. A 2023 meta-analysis of 105,000 participants found daily vitamin D reduced cancer mortality by 10 to 15 percent in some studies, though other analyses found no effect.

The evidence on vitamin D and mortality remains mixed. What is clear: supplementation does not benefit people who already meet their vitamin D needs through diet.

Vitamin D helps your body absorb calcium and maintain bone health. It prevents rickets in children and osteomalacia in adults when deficiency exists.

Most healthy adults under 75 need 600 IU daily until age 70, then 800 IU after that. You get this from fortified milk, orange juice, cereals, fatty fish, and supplements when needed.

Some groups may need higher amounts based on individual circumstances. These include breastfed infants, children and adolescents, pregnant people, adults over 75, people with prediabetes, and people with obesity, dark skin, malabsorption disorders, or limited sun exposure.

Do not rely on sun exposure for vitamin D. Dermatology groups recommend getting vitamin D from food and supplements instead because skin cancer risk outweighs the vitamin D benefit from unprotected sun exposure.

Vitamin D supplements do not prevent cancer, heart disease, or diabetes in adults who already meet basic needs. They do not help with weight loss. They are not cure-alls.

For specific populations at risk of deficiency, supplementation prevents serious health problems. Talk with your doctor about whether you need testing or supplementation.

---

Reference Links:

Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline

Marie B. Demay (Chair), Anastassios G. Pittas (Co-Chair), Daniel D. Bikle, Dima L. Diab, Mairead E. Kiely, Marise Lazaretti-Castro, Paul Lips, Deborah M. Mitchell, M. Hassan Murad, Shelley Powers, Sudhaker D. Rao, Robert Scragg, John A. Tayek, Amy M. Valent, Judith M. E. Walsh, Christopher R. McCartney
The Journal of Clinical Endocrinology & Metabolism, Published August 2024 (online June 2024)

Click Here for the Study: https://www.endocrine.org/clinical-practice-guidelines/vitamin-d-for-prevention-of-disease

 

Vitamin D - Fact Sheet for Health Professionals

National Institutes of Health Office of Dietary Supplements, Published Update June 27, 2025

Click Here for the Study: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/

 

Vitamin D Deficiency

Jasleen Kaur, Swapnil Khare, Omeed Sizar, Amy Givler
StatPearls Publishing, Last Update: February 15, 2025

Click Here for the Study: https://www.ncbi.nlm.nih.gov/books/NBK532266/

 

Association of Body Weight With Response to Vitamin D Supplementation and Metabolism

Deirdre K. Tobias, JoAnn E. Manson, and the VITAL Research Group
JAMA Network Open, Published January 17, 2023

Click Here for the Study: https://doi.org/10.1001/jamanetworkopen.2022.50681

 

Vitamin D, Calcium, or Combined Supplementation for the Primary Prevention of Fractures in Community-Dwelling Adults

US Preventive Services Task Force Recommendation Statement, Published Online: April 17, 2018

Click Here for the Study: https://doi.org/10.1001/jama.2018.3185

 

Efficacy of vitamin D3 supplementation on cancer mortality: Systematic review and individual patient data meta-analysis of randomised controlled trials

Sabine Kuznia, Anna Zhu, Taisuke Akutsu, Julie E. Buring, Carlos A. Camargo Jr, Nancy R. Cook, Li-Ju Chen a, Ting-Yuan David Cheng, Sari Hantunen, I.-Min Lee, JoAnn E. Manson, Rachel E. Neale, Robert Scragg, Aladdin H. Shadyab, Sha Sha, John Sluyter, Tomi-Pekka Tuomainen, Mitsuyoshi Urashima, Jyrki K. Virtanen, Ari Voutilainen, Jean Wactawski-Wende, Mary Waterhouse, Hermann Brenner, Ben Schöttker
Ageing Research Reviews, Published Volume 87, June 2023, 101923

Click Here for the Study: https://doi.org/10.1016/j.arr.2023.101923

 

Effect of Vitamin D3 Supplements on Development of Advanced Cancer - A Secondary Analysis of the VITAL Randomized Clinical Trial

Paulette D Chandler, Wendy Y Chen, Oluremi N Ajala, Aditi Hazra, Nancy Cook, Vadim Bubes, I-Min Lee, Edward L Giovannucci, Walter Willett, Julie E Buring, JoAnn E Manson; VITAL Research Group
JAMA Network Open, Published Online: November 18, 2020

Click Here for the Study: https://doi.org/10.1001/jamanetworkopen.2020.25850

 

Effects of Supplemental Vitamin D on Bone Health Outcomes in Women and Men in the VITamin D and OmegA‐3 TriaL (VITAL)

Meryl S LeBoff, Sharon H Chou, Elle M Murata, Catherine M Donlon, Nancy R Cook, Samia Mora, I‐Min Lee, Gregory Kotler, Vadim Bubes, Julie E Buring, JoAnn E Manson
Journal of Bone and Mineral Research, Published Volume 35, Issue 5, 1 May 2020

Click Here for the Study: https://doi.org/10.1002/jbmr.3958

 

Vitamin D and Calcium in Osteoporosis, and the Role of Bone Turnover Markers: A Narrative Review of Recent Data from RCTs

Gavriela Voulgaridou, Sousana K Papadopoulou, Paraskevi Detopoulou, Despoina Tsoumana, Constantinos Giaginis, Foivi S Kondyli, Evgenia Lymperaki, Agathi Pritsa
Diseases, Published 2023 Feb 8

Click Here for the Study: https://doi.org/10.3390/diseases11010029

 

Vitamin D Synthesis Following a Single Bout of Sun Exposure in Older and Younger Men and Women

Jenna R Chalcraft, Linda M Cardinal, Perry J Wechsler, Bruce W Hollis, Kenneth G Gerow, Brenda M Alexander, Jill F Keith, D Enette Larson-Meyer
Nutrients, Published 2020 Jul 27

Click Here for the Study: https://doi.org/10.3390/nu12082237

 

Effect of High-Dose Vitamin D Supplementation on Volumetric Bone Density and Bone Strength - A Randomized Clinical Trial

Lauren A. Burt, Emma O. Billington, Marianne S. Rose, Duncan A. Raymond, David A. Hanley, Steven K. Boyd
JAMA Network, Published Online: August 27, 2019

Click Here for the Study: https://doi.org/10.1001/jama.2019.11889

 

Vitamin D Toxicity–A Clinical Perspective

Ewa Marcinowska-Suchowierska, Małgorzata Kupisz-Urbańska, Jacek Łukaszkiewicz, Paweł Płudowski, Glenville Jones
Frontiers in Endocrinology, Published 2018 Sep 20

Click Here for the Study: https://doi.org/10.3389/fendo.2018.00550

 

The D-Health Trial: a randomised controlled trial of the effect of vitamin D on mortality

Prof Rachel E Neale, PhDa, ∙ Catherine Baxter, BA ∙ Briony Duarte Romero, BA ∙ Donald S A McLeod, PhD, ∙ Prof Dallas R English, PhDd, ∙ Prof Bruce K Armstrong, D Philf, ∙ Prof Peter R Ebeling, MD ∙ Gunter Hartel, PhD ∙ Prof Michael G Kimlin, PhD ∙ Rachel O'Connell, PhD ∙ Jolieke C van der Pols, PhD ∙ Prof Alison J Venn, PhD ∙ Prof Penelope M Webb, D Phil, ∙ Prof David C Whiteman, PhD, ∙ Mary Waterhouse, PhD
The Lancet Diabetes & Endocrinology, Published February 2022

Click Here for the Study: https://doi.org/10.1016/s2213-8587(21)00345-4

---

Vitamin D Supplements Do NOT Improve Bone Health - Update 9/12/19

Large trials show vitamin D alone does not prevent fractures or falls in community-dwelling older adults who meet basic intake levels. The US Preventive Services Task Force recommends against taking vitamin D supplements to prevent fractures if you live independently and do not have deficiency.

A 2019 trial found high-dose vitamin D (4,000 to 10,000 IU daily) did not improve bone density in healthy adults compared to standard doses. Some measures showed slightly lower density with very high doses.

Vitamin D combined with calcium does reduce fracture risk in older adults in institutional care settings like nursing homes. The combination shows little benefit for healthy adults living independently.

Vitamin D prevents rickets in children and osteomalacia in adults when deficiency exists. For people taking osteoporosis medication, doctors prescribe vitamin D and calcium together as part of treatment.

Effect of High-Dose Vitamin D Supplementation on Volumetric Bone Density and Bone Strength - A Randomized Clinical Trial

Lauren A. Burt, Emma O. Billington, Marianne S. Rose, Duncan A. Raymond, David A. Hanley, Steven K. Boyd
JAMA Network, Published Online: August 27, 2019

Click Here for the Study: https://doi.org/10.1001/jama.2019.11889

---

Vitamin D3 supplementation did not result in a significantly lower risk of fractures than placebo among generally healthy midlife and older adults who were not selected for vitamin D deficiency, low bone mass, or osteoporosis. - Update 7/29/2022

Among 25,871 participants (50.6% women [13,085 of 25,871] and 20.2% Black [5106 of 25,304]), we confirmed 1991 incident fractures in 1551 participants over a median follow-up of 5.3 years. Supplemental vitamin D3, as compared with placebo, did not have a significant effect on total fractures (which occurred in 769 of 12,927 participants in the vitamin D group and in 782 of 12,944 participants in the placebo group; hazard ratio, 0.98; 95% confidence interval [CI], 0.89 to 1.08; P=0.70), nonvertebral fractures (hazard ratio, 0.97; 95% CI, 0.87 to 1.07; P=0.50), or hip fractures (hazard ratio, 1.01; 95% CI, 0.70 to 1.47; P=0.96). There was no modification of the treatment effect according to baseline characteristics, including age, sex, race or ethnic group, body-mass index, or serum 25-hydroxyvitamin D levels. There were no substantial between-group differences in adverse events as assessed in the parent trial.

Supplemental Vitamin D and Incident Fractures in Midlife and Older Adults

Meryl S. LeBoff, M.D., Sharon H. Chou, M.D., Kristin A. Ratliff, B.A., Nancy R. Cook, Sc.D., Bharti Khurana, M.D., Eunjung Kim, M.S., Peggy M. Cawthon, Ph.D., M.P.H., Douglas C. Bauer, M.D., Dennis Black, Ph.D., J. Chris Gallagher, M.D., I-Min Lee, M.B., B.S., Sc.D., Julie E. Buring, Sc.D., and JoAnn E. Manson, M.D., Dr.P.H.
The New England Journal of Medicine, Published July 28, 2022

Click Here for the Study: https://www.nejm.org/doi/full/10.1056/NEJMoa2202106

Call for a FREE Consultation (305) 296-3434
CAUTION: Check with your doctor before
beginning any diet or exercise program.

11/30/2019
Updated 9/12/2019
Updated 7/29/2022
Updated 10/15/2025