Vitamin D3 Research
40 peer-reviewed studies · Evidence score: 9/10
Vitamin D supplementation vs. placebo and incident type 2 diabetes in an ancillary study of the randomized Vitamin D and Omega-3 Trial
Tobias DK et al. • Nature communications (2025)
This meta-analysis examined the effects of Omega-3.
- Mean body mass index (BMI) was 27.5 kg/m2 (SD = 5.3), with 51% female and 17% Black race/ethnicity.
- T2D incidence (cases/1000py) at median follow-up of 5.3 y was 3.98 for vitamin D and 4.37 for placebo (hazard ratio [HR] = 0.91; 95% confidence interval [CI] = 0.76, 1.09).
- In conclusion, Vitamin D supplementation did not reduce T2D in older US adults, but a modest reduction was observed when meta-analyzed with prior trials.
Vitamin D supplementation decrease asthma exacerbations in children: a systematic review and meta-analysis of randomized controlled trials
Fedora K et al. • Annals of medicine (2024)
Vitamin D supplementation can lower the occurrence of exacerbations in children with asthma, along with the improvement of FEV1.
- Our pooled analysis found that VD supplementation had a significant effect on lowering the total number of asthma exacerbations (RR 0.62; 95% CI: 0.44, 0.87; p = 0.01).
- Subgroup analysis revealed that a daily dose of VD given based on standard daily dose recommendation had a significant improvement on asthma exacerbations [(RR 0.41; 95% CI: 0,18, 0,92; p = 0.03).
- Vitamin D supplementation can lower the occurrence of exacerbations in children with asthma, along with the improvement of FEV1.
What is the impact of daily oral supplementation of vitamin D3 (cholecalciferol) plus calcium on the incidence of hip fracture in older people? A systematic review and meta-analysis
Manoj P et al. • International journal of older people nursing (2023)
Daily oral supplementation 800 IU of vitamin D3 plus 1200 mg of calcium reduces hip fracture and non-vertebral fracture in older people.
- The meta-analysis of seven RCTs on vitamin D3 plus calcium supplementation and hip fracture (n = 12,620) identified odds ratio (OR) of 0.75; 95% Confidence interval (CI): 0.64, 0.87; p = .0003.
- A meta-analysis of the seven RCTs to identify the incidence of non-vertebral fracture gave the OR of 0.80; 95% CI: 0.72, 0.89; p < .0001.
- A meta-analysis of three RCTs on femoral neck bone mineral density (BMD) (n = 483) gave a mean difference of 1.21; 95% CI: -0.79, 3.20; p = .24.
Preventive Vitamin D Supplementation and Risk for COVID-19 Infection: A Systematic Review and Meta-Analysis
D'Ecclesiis O et al. • Nutrients (2024)
Vitamin D may play a protective role in COVID-19, particularly in those with deficiency.
- Potential protective effect against infection
- Benefits linked to correcting deficiency
- Immune function support in deficient individuals
Vitamin D Supplementation for Patients with Dysmenorrhoea: A Meta-Analysis with Trial Sequential Analysis of Randomised Controlled Trials
Lin KC et al. • Nutrients (2024)
In conclusion, although substantial heterogeneity persists, vitamin D supplementation decreased pain intensity in patients with dysmenorrhea, especially in those with primary dysmenorrhoea.
- TSA revealed that the current RCTs provide sufficient information.
- In subgroup analyses, vitamin D supplement reduced primary dysmenorrhoea pain but not secondary dysmenorrhoea pain.
- In conclusion, although substantial heterogeneity persists, vitamin D supplementation decreased pain intensity in patients with dysmenorrhea, especially in those with primary dysmenorrhoea.
Effect of Vitamin D Supplementation in Early Life on Children's Growth and Body Composition: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Ma K et al. • Nutrients (2021)
Vitamin D supplementation during pregnancy or infancy may be associated with reduced adiposity in childhood.
- Vitamin D supplementation during pregnancy was associated with higher triceps skinfold thickness (mm) (MD 0.33, 95% CI, 0.12, 0.54; I2 = 34%) in neonates.
- Vitamin D supplementation during pregnancy or infancy may be associated with reduced adiposity in childhood.
- Further large clinical trials of the effects of vitamin D supplementation on childhood body composition are warranted.
Efficacy of weekly versus daily cholecalciferol for repleting serum vitamin D (25(OH)D) deficiency: A systematic review and meta-analysis of randomized controlled trials
Bortolussi-Courval É et al. • Basic & clinical pharmacology & toxicology (2024)
Limited direct evidence supports a switch from daily to weekly cholecalciferol dosing; however, weekly supplementation was not demonstrably worse at repleting levels and decreased a patient's daily pill burden.
- Limited direct evidence supports a switch from daily to weekly cholecalciferol dosing; however, weekly supplementation was not demonstrably worse at repleting levels and decreased a patient's daily pill burden.
- Published in Basic & clinical pharmacology & toxicology (2024)
- Further research warranted to confirm findings
Effects of vitamin D supplementation during pregnancy on bone health and offspring growth: A systematic review and meta-analysis of randomized controlled trials
Luo T et al. • PloS one (2022)
Vitamin D supplementation during pregnancy may be associated with increased humeral length (HL) in the uterus, increased body length at birth and higher cord blood 25(OH)D concentration.
- Vitamin D supplementation during pregnancy was associated with increased humeral length (HL) (MD 0.13, 95% CI 0.06, 0.21, I2 = 0, P = 0.0007) during the fetal period (third trimester).
- Vitamin D supplementation during pregnancy was associated with a significantly increased length at birth (MD 0.14, 95% CI 0.04, 0.24, I2 = 24%, P = 0.005) and was associated with a higher cord blood 25(OH)D concentration (MD 48.74, 95% CI 8.47, 89.01, I2 = 100%, P = 0.02).
- Prenatal (third trimester) vitamin D supplementation was associated with a significant increase in birth length, while prenatal (second trimester) vitamin D supplementation was associated with a significant increase in birth weight.
Vitamin D and respiratory tract infections
Martineau AR et al. • BMJ (2017)
Vitamin D supplementation reduced the risk of acute respiratory tract infection, with stronger effects in those with profound deficiency.
- 12% reduction in respiratory infections overall
- 70% reduction in severely deficient individuals
- Daily/weekly dosing more effective than large boluses
Vitamin D and depression
Anglin RE et al. • British Journal of Psychiatry (2013)
Low vitamin D levels are associated with depression, and supplementation may improve symptoms in deficient individuals.
- Low vitamin D associated with depression
- Supplementation benefits those who are deficient
- Effect strongest when correcting deficiency
Vitamin D and muscle function
Stockton KA et al. • Osteoporosis International (2011)
Vitamin D supplementation improves muscle strength, particularly in individuals with baseline vitamin D deficiency.
- Improves muscle strength in deficient individuals
- Reduces fall risk in elderly
- Effects on strength in non-deficient unclear
Is Vitamin D Supplementation Useful for Weight Loss Programs? A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Perna S • Medicina (Kaunas, Lithuania) (2019)
Conclusions: This meta-analysis lays the foundation for defining the potential clinical efficacy of vitamin D supplementation as a potential therapeutic option for weight loss programs, but further studies are needed to confirm the validity of these findings and delineate potential underlying mechanisms.
- The selected articles focused on vitamin D supplementation in overweight and obese individuals with different conditions.
- Eleven RCTs were included into this meta-analysis with a total of 947 subjects, with a mean of the follow-up from 1 to 12 months and different vitamin D interventions (from 25,000 to 600,000 IU/monthly of cholecalciferol).
- Further research warranted to confirm findings
Vitamin D supplementation in the critically ill: A systematic review and meta-analysis
Langlois PL et al. • Clinical nutrition (Edinburgh, Scotland) (2018)
In critically ill patients, Vitamin D administration does not improve clinical outcomes.
- In critically ill patients, Vitamin D administration does not improve clinical outcomes.
- The statistical imprecision could be explained by the sparse number of trials.
- Further research warranted to confirm findings
Effect of vitamin D supplementation on knee osteoarthritis: A systematic review and meta-analysis of randomized clinical trials
Diao N et al. • Clinical biochemistry (2017)
The results of this study indicate that vitamin D supplementation may not have a clinically significant effect on pain control or structure progression among patients with knee OA.
- The results indicated that vitamin D supplementation had a statistically significant but small-to-moderate effect on pain control in patients with knee OA (SMD=-0.32, 95% CI: -0.63 to -0.02).
- However, no effects were observed for the change in tibial cartilage volume (SMD=0.12, 95% CI: -0.05 to 0.29) or joint space width (SMD=0.07, 95% CI: -0.08 to 0.23).
- Longer-term clinical trials with rigorous measurement of symptom and radiologic changes are required to further clarify the effect of vitamin D supplementation in patients with symptomatic knee OA and low serum 25(OH)D levels.
Effect of vitamin D supplementation on polycystic ovary syndrome: A systematic review and meta-analysis of randomized controlled trials
Fang F et al. • Complementary therapies in clinical practice (2017)
Evidence from available RCTs suggests vitamin D supplementation may be beneficial for follicular development and menstrual cycle regulation in patients with PCOS.
- Vitamin D supplementation had significant effect on the improvement of follicular development with a higher number of dominant follicles (OR, 2.34; 95% CI, 1.39 to 3.92).
- Differences in regular menstrual cycles were also observed when metformin plus vitamin D was compared with metformin alone (OR, 1.85; 95% CI, 1.01 to 3.39).
- Evidence from available RCTs suggests vitamin D supplementation may be beneficial for follicular development and menstrual cycle regulation in patients with PCOS.
Vitamin D Supplementation and Allergic Rhinitis: A Systematic Review and Meta-Analysis
Kawada K et al. • Medicina (Kaunas, Lithuania) (2025)
Conclusions: The study results suggest that vitamin D supplementation alleviates allergic rhinitis symptoms, although the effects differ according to the patient's sex and concomitant medications.
- Compared with placebos, vitamin D supplementation alleviated allergic rhinitis symptoms, although the difference was not significant; there was significant heterogeneity among studies (standardized mean difference [SMD] = -2.69, 95% confidence interval [CI]: -6.20 to 0.82, I2 = 98%, p < 0.01).
- The proportion of female participants in the RCTs (slope: 0.21, p = 0.026) and concomitant corticosteroid use (slope: -9.16, p = 0.005) influenced the vitamin D response.
- Compared with the placebos, vitamin D supplementation without corticosteroids alleviated the allergic rhinitis symptoms (SMD = -0.56, 95% CI: -0.90 to -0.23).
Effect of Vitamin D Supplementation on Lipid Profile in Overweight or Obese Women: A Meta-analysis and Systematic Review of Randomized Controlled Trials
Hu L et al. • Nutrition reviews (2025)
According to our findings, vitamin D has a significant effect on hypertriglyceridemia in individuals who are overweight or obese.
- According to our findings, vitamin D has a significant effect on hypertriglyceridemia in individuals who are overweight or obese.
- However, vitamin D has no significant effect on LDL-C concentrations in this population.
- Further research warranted to confirm findings
Health Effects of Vitamin D Supplementation: Lessons Learned From Randomized Controlled Trials and Mendelian Randomization Studies
Bouillon R et al. • Endocrine Reviews (2023)
Vitamin D supplementation does not benefit bone or reduce fractures in vitamin D-replete adults, but correcting deficiency is essential.
- No benefit in vitamin D-replete individuals
- Correcting deficiency remains important
- Benefits seen primarily in those with severe deficiency
The effect of vitamin D supplementation on depressive symptoms in adults: A systematic review and meta-analysis of randomized controlled trials
Mikola T et al. • Critical reviews in food science and nutrition (2023)
Funding: Finnish Medical Foundation, grant 4120 and Juho Vainio Foundation, grant 202100353.
- Results for main outcome (n = 53,235) revealed a positive effect of vitamin D on depressive symptoms (Hedges' g = -0.317, 95% CI [-0.405, -0.230], p < 0.001, I2 = 88.16%; GRADE: very low certainty).
- Notwithstanding high heterogeneity, vitamin D supplementation ≥ 2,000 IU/day appears to reduce depressive symptoms.
- Future research should investigate possible benefits of augmenting standard treatments with vitamin D in clinical depression.
Comparison of the Effect of Daily Vitamin D2 and Vitamin D3 Supplementation on Serum 25-Hydroxyvitamin D Concentration (Total 25(OH)D, 25(OH)D2, and 25(OH)D3) and Importance of Body Mass Index: A Systematic Review and Meta-Analysis
van den Heuvel EG et al. • Advances in nutrition (Bethesda, Md.) (2024)
Vitamin D3 leads to a greater increase of 25(OH)D than vitamin D2, even if limited to daily dose studies, but vitamin D2 and vitamin D3 had similar positive impacts on their corresponding 25(OH)D hydroxylated forms.
- Body mass index (BMI) appeared to be the strongest response modifier, reducing heterogeneity to 0% in both subgroups.
- The vitamin D2- and vitamin D3-induced change in total 25(OH)D lost significance predominantly in subjects with a BMI >25 kg/m2 (P = 0.99).
- Vitamin D3 leads to a greater increase of 25(OH)D than vitamin D2, even if limited to daily dose studies, but vitamin D2 and vitamin D3 had similar positive impacts on their corresponding 25(OH)D hydroxylated forms.