Calcium vitamin d supplement
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Calcium and Vitamin D Supplementation: Benefits and Risks
Calcium and Vitamin D for Fracture Prevention
Hip and Spine Fractures
Calcium and vitamin D supplementation has been extensively studied for its potential to prevent fractures, particularly in postmenopausal women. A large-scale study involving 36,282 postmenopausal women found that supplementation with 1000 mg of calcium and 400 IU of vitamin D daily resulted in a modest increase in hip bone density by 1.06% compared to placebo. However, the reduction in hip fracture risk was not statistically significant, with a hazard ratio of 0.881. Another meta-analysis supported these findings, showing a 15% reduction in total fractures and a 30% reduction in hip fractures with combined supplementation4.
Osteoporosis and Bone Mineral Density
A systematic review and meta-analysis of randomized controlled trials concluded that combined calcium and vitamin D supplementation significantly increased bone mineral density (BMD) in various parts of the body, including the lumbar spine and femoral neck. This supplementation also reduced the incidence of hip fractures6. These findings suggest that while the impact on fracture risk may be modest, the improvement in BMD is more pronounced.
Cancer Risk Reduction
Colorectal Cancer
The relationship between calcium and vitamin D supplementation and colorectal cancer risk has been explored, but results are inconclusive. A study involving 36,282 postmenopausal women found no significant difference in the incidence of colorectal cancer between the supplementation group and the placebo group over seven years2. This suggests that the duration of the study may have been insufficient to observe a potential protective effect.
General Cancer Risk
In contrast, another study found that calcium and vitamin D supplementation significantly reduced the risk of all types of cancer in postmenopausal women. The relative risk of incident cancer was lower in the group receiving both supplements compared to the placebo group, particularly when cancers diagnosed after the first 12 months were considered3. This indicates a potential long-term benefit of supplementation in reducing overall cancer risk.
Metabolic Health and Diabetes
Glucose Metabolism and Lipid Profiles
Calcium and vitamin D supplementation has also been studied for its effects on glucose metabolism and lipid profiles, particularly in populations at risk for type 2 diabetes. In overweight and obese women with polycystic ovary syndrome (PCOS), supplementation led to improved insulin sensitivity and reduced serum insulin levels, as well as lower triglycerides and VLDL-cholesterol levels5. Another study found that supplementation improved insulin sensitivity in individuals with prediabetes, although no significant changes were observed in the general population at risk for type 2 diabetes10.
Type 2 Diabetes Prevention
A systematic review and meta-analysis indicated that low vitamin D and calcium levels are associated with an increased risk of type 2 diabetes. Combined supplementation may help in optimizing glucose metabolism, particularly in high-risk populations9.
Cardiovascular Risks
Cardiovascular Events
The potential cardiovascular risks associated with calcium and vitamin D supplementation have been a topic of debate. A reanalysis of the Women's Health Initiative dataset and a meta-analysis of other studies found that calcium supplements, with or without vitamin D, modestly increased the risk of cardiovascular events, including myocardial infarction and stroke8. This finding suggests that while supplementation may have benefits for bone health, it could pose risks for cardiovascular health, necessitating a careful evaluation of the risk-benefit ratio.
Conclusion
Calcium and vitamin D supplementation offers several health benefits, including modest improvements in bone mineral density and potential reductions in fracture and cancer risks. However, the benefits must be weighed against potential risks, such as an increased likelihood of kidney stones and cardiovascular events. Further research is needed to clarify these risks and to optimize supplementation strategies for different populations.
Sources and full results
Most relevant research papers on this topic
Calcium plus vitamin D supplementation and the risk of fractures.
Calcium with vitamin D supplementation improved hip bone density in healthy postmenopausal women, but did not significantly reduce hip fracture risk and increased the risk of kidney stones.
RCT
Large Human Trial
Highly CitedCalcium plus vitamin D supplementation and the risk of colorectal cancer.
Daily calcium and vitamin D supplementation for seven years did not significantly reduce the incidence of colorectal cancer in postmenopausal women.
RCTLarge Human TrialHighly CitedVitamin D and calcium supplementation reduces cancer risk: results of a randomized trial.
Improving calcium and vitamin D nutritional status significantly reduces all-cancer risk in postmenopausal women.
RCTLarge Human Trial
Very Rigorous JournalHighly CitedCalcium plus vitamin D supplementation and risk of fractures: an updated meta-analysis from the National Osteoporosis Foundation
Calcium plus vitamin D supplementation significantly reduces the risk of total fractures and hip fractures in middle-aged to older adults.
Meta-Analysis
Rigorous JournalHighly CitedCalcium plus vitamin D supplementation affects glucose metabolism and lipid concentrations in overweight and obese vitamin D deficient women with polycystic ovary syndrome.
Calcium plus vitamin D supplementation for eight weeks in overweight and obese vitamin D deficient women with PCOS improved glucose metabolism and lipid levels, but did not affect FPG or other lipid profiles.
RCTVery Rigorous JournalHighly CitedEffects of combined calcium and vitamin D supplementation on osteoporosis in postmenopausal women: a systematic review and meta-analysis of randomized controlled trials.
Combined calcium and vitamin D supplementation significantly increases bone mineral density and reduces hip fracture risk in postmenopausal women.
Meta-AnalysisHighly CitedThe vitamin D and calcium controversy: an update
Vitamin D and calcium supplements are uncertain for fall and fracture prevention, with high-dose vitamin D potentially having adverse musculoskeletal effects, and inconsistent findings on adverse cardiovascular effects.
Systematic ReviewCalcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women’s Health Initiative limited access dataset and meta-analysis
Calcium supplements with or without vitamin D modestly increase the risk of cardiovascular events, particularly myocardial infarction, warranting a reassessment of their role in osteoporosis management.
Meta-AnalysisRigorous JournalHighly CitedThe role of vitamin D and calcium in type 2 diabetes. A systematic review and meta-analysis.
Combined vitamin D and calcium supplementation may help optimize glucose metabolism and prevent type 2 diabetes in high-risk populations.
Meta-AnalysisHighly CitedEffects of Combined Calcium and Vitamin D Supplementation on Insulin Secretion, Insulin Sensitivity and β-Cell Function in Multi-Ethnic Vitamin D-Deficient Adults at Risk for Type 2 Diabetes: A Pilot Randomized, Placebo-Controlled Trial
Daily vitamin D and calcium supplementation for 6 months may not improve insulin sensitivity, secretion, and -cell function in multi-ethnic adults at risk for type 2 diabetes, but may improve insulin sensitivity in those with prediabetes.
RCTRigorous JournalHighly Cited