Vitamin d supplement
Pro Research Analysisby 
Searched over 200M research papers
The Impact of Vitamin D Supplementation: A Comprehensive Review
Vitamin D Supplementation and Cancer Prevention
Cancer Risk Reduction
Research on the role of vitamin D supplementation in cancer prevention has yielded mixed results. A large-scale randomized controlled trial (RCT) involving 25,871 participants found that vitamin D supplementation did not significantly reduce the risk of invasive cancer compared to a placebo1. Similarly, a meta-analysis of various studies indicated that while high-dose vitamin D supplementation might reduce the risk of total cancer, the evidence is not robust enough to draw definitive conclusions2.
Site-Specific Cancer Outcomes
Further analysis of site-specific cancers, such as breast, prostate, and colorectal cancer, showed no significant reduction in risk with vitamin D supplementation1 2. This suggests that while vitamin D may have some role in cancer prevention, its effects are not strong enough to warrant its use as a primary preventive measure.
Vitamin D and Cardiovascular Health
Cardiovascular Disease (CVD) Risks
The relationship between vitamin D supplementation and cardiovascular health has been extensively studied. A meta-analysis of 21 RCTs involving over 83,000 individuals found no significant association between vitamin D supplementation and reduced major adverse cardiovascular events, including myocardial infarction and stroke7. Another large RCT confirmed these findings, showing no significant reduction in cardiovascular events with vitamin D supplementation1.
Serum Lipid Profiles
Vitamin D supplementation has shown some promise in improving serum lipid profiles. A systematic review and meta-analysis revealed that vitamin D supplementation could reduce total cholesterol, LDL cholesterol, and triglyceride levels, although it did not significantly affect HDL cholesterol levels6. These improvements were more pronounced in individuals with baseline vitamin D deficiency.
Bone Health and Fracture Prevention
Fracture Risk Reduction
Vitamin D is widely recommended for bone health, particularly in older adults. A meta-analysis found that combined vitamin D and calcium supplementation could reduce fracture risk, especially in institutionalized elderly individuals2. However, another study reported that vitamin D supplementation alone did not significantly reduce the risk of total, nonvertebral, or hip fractures in generally healthy midlife and older adults5.
Muscle Strength and Function
Vitamin D supplementation has a small but significant positive effect on muscle strength, particularly in individuals with low baseline vitamin D levels and those aged 65 years or older4. However, it does not significantly impact muscle mass or muscle power.
Vitamin D and Immune Function
Tuberculosis and Respiratory Infections
Vitamin D's role in immune function has been explored in various contexts. A study on Mongolian schoolchildren found that vitamin D supplementation did not significantly reduce the risk of tuberculosis infection or acute respiratory infections compared to a placebo3. This suggests that while vitamin D supports immune function, its supplementation may not be effective in preventing these specific infections.
Immune-Related Diseases
Low levels of serum 25-hydroxyvitamin D have been associated with an increased risk of several immune-related diseases, including psoriasis, type 1 diabetes, multiple sclerosis, and respiratory infections10. Clinical trials have shown variable outcomes, indicating that while vitamin D has immunomodulatory effects, its supplementation may benefit some individuals more than others.
Conclusion
Vitamin D supplementation has diverse effects on health, with some benefits in specific areas such as lipid profile improvement and muscle strength enhancement. However, its role in cancer prevention, cardiovascular health, and fracture risk reduction remains inconclusive. Further research is needed to determine optimal dosing and target populations that may benefit the most from vitamin D supplementation.
Sources and full results
Most relevant research papers on this topic
Vitamin D Supplements and Prevention of Cancer and Cardiovascular Disease
Vitamin D supplementation did not result in a lower incidence of invasive cancer or cardiovascular events compared to placebo.
RCT
Large Human Trial
Rigorous Journal
Highly CitedVitamin D With or Without Calcium Supplementation for Prevention of Cancer and Fractures: An Updated Meta-analysis for the U.S. Preventive Services Task Force
Combined vitamin D and calcium supplementation can reduce fracture risk in older adults, but the effects may be smaller in community-dwelling settings than in institutionalized elderly individuals.
Meta-AnalysisHighly CitedVitamin D Supplements for Prevention of Tuberculosis Infection and Disease.
Vitamin D supplementation did not significantly reduce the risk of tuberculosis infection, tuberculosis disease, or acute respiratory infection in vitamin D-deficient schoolchildren in Mongolia.
RCTLarge Human TrialRigorous JournalHighly CitedThe effects of vitamin D on skeletal muscle strength, muscle mass, and muscle power: a systematic review and meta-analysis of randomized controlled trials.
Vitamin D supplementation has a small positive impact on muscle strength, but no significant effect on muscle mass or muscle power.
Meta-AnalysisRigorous JournalHighly CitedSupplemental Vitamin D and Incident Fractures in Midlife and Older Adults.
Supplemental vitamin D3 does not significantly lower the risk of fractures in generally healthy midlife and older adults without vitamin D deficiency, low bone mass, or osteoporosis.
RCTLarge Human TrialRigorous JournalHighly CitedEffect of vitamin D supplementation on serum lipid profiles: a systematic review and meta-analysis.
Vitamin D supplementation may help reduce serum total cholesterol, LDL cholesterol, and triglyceride levels, but not HDL cholesterol levels, potentially benefiting hypercholesterolemia.
Meta-AnalysisHighly CitedVitamin D Supplementation and Cardiovascular Disease Risks in More Than 83 000 Individuals in 21 Randomized Clinical Trials: A Meta-analysis.
Vitamin D supplementation does not reduce major adverse cardiovascular events, individual CVD end points, or all-cause mortality.
Meta-AnalysisHighly CitedVitamin D supplementation guidelines
Higher vitamin D levels are associated with improved outcomes for various chronic diseases, and supplementation is recommended based on individual factors like age, body weight, and latitude.
Highly CitedVitamin D supplementation in chronic kidney disease: a systematic review and meta-analysis of observational studies and randomized controlled trials.
Vitamin D supplementation improves biochemical endpoints in chronic kidney disease patients, but its clinical significance remains unclear.
Meta-AnalysisHighly CitedImmunologic Effects of Vitamin D on Human Health and Disease
Optimal vitamin D intake and sensible sunlight exposure can maintain optimal immune system function and reduce the risk of immune-related diseases.
Very Rigorous JournalHighly Cited