Improvement after a supplement is not the same as a comparative result
Start with the comparison. A before-and-after change alone cannot isolate the contribution of an ingredient.
Vitamin D
Selected research topic
Bone, joint, and mobility
Findings differ across measurements or study conditions. The results below keep them separate.
Findings from a combination study cannot be attributed to this ingredient alone.
Some findings concern patients or people with a deficiency.
- Publications for this topic
- 10
- Human comparison publications
- 2
- Publications needing review
- 5
Findings in the studies
Non-vertebral fractures
- No clear difference from the comparison group was found.General population · Single ingredient
Measurement and study conditions
- Study type
- Randomized controlled trial: subjects were randomly assigned to groups for comparison.
- Study population
- Human participants · General population
- Ingredients tested
- Single ingredient
- How results were compared
- Results were compared between groups. · Between-group comparison
- Additional measurement information
- Secondary outcome
- Measurement time
- mean treatment duration 3.4 years
radial volumetric BMD
- A worse result than the comparison group was reported.General population · Single ingredient · 3 years
Measurement and study conditions
- Study type
- Randomized controlled trial: subjects were randomly assigned to groups for comparison.
- Study population
- Human participants · General population
- Ingredients tested
- Single ingredient
- How results were compared
- Results were compared between groups. · Study comparison: 4000 or 10,000 IU/day vitamin D3 versus 400 IU/day; calcium provided to participants with low dietar
- Additional measurement information
- Primary outcome
- Measurement time
- 3 years
falls
Other human research, including observational studies and reviews
- A change was reported, but the comparison could not be confirmed.Deficiency group · Single ingredient · 12 months
Measurement and study conditions
- Study type
- Randomized controlled trial: subjects were randomly assigned to groups for comparison.
- Study population
- Human participants · Deficiency group
- Ingredients tested
- Single ingredient
- How results were compared
- Study comparison: Seven dose levels versus placebo showed a U-shaped fall response: medium doses reduced falls, low/hi
- Additional measurement information
- Secondary outcome
- Measurement time
- 12 months
Research with unclear study subject or type
- No clear difference in this measurement was found between the compared groups.
What the comparison group used was not confirmed.
Single ingredientMeasurement and study conditions
- Study type
- Meta-analysis
- Study population
- Study subject not identified
- Ingredients tested
- Single ingredient
- How results were compared
- Results were compared between groups.
- Measurement time
- Not confirmed.
bone mineral density
Research with unclear study subject or type
- No clear difference in this measurement was found between the compared groups.Single ingredient · one to five years
Measurement and study conditions
- Study type
- Meta-analysis
- Study population
- Recorded population category: General population. Whether the research involved humans needs confirmation.
- Ingredients tested
- Single ingredient
- How results were compared
- Results were compared between groups. · Study comparison: Pooled vitamin D versus untreated, placebo, or lower-dose controls
- Additional measurement information
- Biomarker
- Measurement time
- one to five years
Other measured outcomes (4)
hip fracture
Research with unclear study subject or type
- No clear difference in this measurement was found between the compared groups.Single ingredient · varied across included trials
Measurement and study conditions
- Study type
- Meta-analysis
- Study population
- Recorded population category: General population. Whether the research involved humans needs confirmation.
- Ingredients tested
- Single ingredient
- How results were compared
- Results were compared between groups. · Study comparison: Pooled vitamin D versus untreated, placebo, or lower-dose controls
- Additional measurement information
- Primary outcome
- Measurement time
- varied across included trials
hip fractures
Research with unclear study subject or type
- A change was reported, but the comparison could not be confirmed.
Several ingredients were tested together, so this ingredient’s individual effect is unknown.
Combination studyMeasurement and study conditions
- Study type
- Meta-analysis
- Study population
- Recorded population category: General population. Whether the research involved humans needs confirmation.
- Ingredients tested
- Ingredient combination
- How results were compared
- Study comparison: Calcium plus vitamin D supplementation in pooled RCTs; comparator not specified in abstract
- Additional measurement information
- Primary outcome
- Measurement time
- Not confirmed.
total fracture
Research with unclear study subject or type
- No clear difference in this measurement was found between the compared groups.
What the comparison group used was not confirmed.
Single ingredientMeasurement and study conditions
- Study type
- Meta-analysis
- Study population
- Study subject not identified
- Ingredients tested
- Single ingredient
- How results were compared
- Results were compared between groups.
- Measurement time
- Not confirmed.
total fractures
Research with unclear study subject or type
- A change was reported, but the comparison could not be confirmed.
Several ingredients were tested together, so this ingredient’s individual effect is unknown.
Combination studyMeasurement and study conditions
- Study type
- Meta-analysis
- Study population
- Recorded population category: General population. Whether the research involved humans needs confirmation.
- Ingredients tested
- Ingredient combination
- How results were compared
- Study comparison: Calcium plus vitamin D supplementation in pooled RCTs; comparator not specified in abstract
- Additional measurement information
- Primary outcome
- Measurement time
- Not confirmed.
This result is held for interpretation. That does not mean research found no effect.
Outcome groups needing additional review (3)
- bone mass · Distinct papers needing additional review: 1Evidence criteria check: 1
- incident symptomatic fracture · Distinct papers needing additional review: 1Evidence criteria check: 1
- proportion having 2 or more falls · Distinct papers needing additional review: 1Evidence criteria check: 1
One paper can appear under multiple measured outcomes or review reasons, so these counts should not be added together.
Representative outcome and study details
Human studies reported a change with no confirmed comparison group in falls; while Studies with an unspecified organism reported no clear between-group difference in falls.
These conditions come from related studies and may not describe a single paper.
Single-ingredient studies · Human studies · Includes deficiency groups · Population not specified · between-group comparison · comparator not confirmed
2 publications linked to this result
- Study conditions differ; results are shown descriptively and are not pooled.
Data coverage and detailed study classifications
Paper counts are separated by research topic below. One paper may contribute to multiple findings.
Analysis status: Public-ready
Ingredient analysis date:
How the grade was determined: C
The 49.3 evidence score includes 2 independent human studies and 2 clinical studies in the representative benefit area. The C tier remains conservative because of the evidence centers on contextual or measured outcomes rather than general-use effects, limited repetition across independent human clinical studies.
The grade is based mainly on the research area with the most evidence. It does not mean the same result was found in other areas.
Papers linked to this ingredient overall: 126
Papers linked to this topic 10 · distinct papers 10 · papers with a confirmed human comparison 2 · papers needing additional review 5
A publication may appear in more than one count. These numbers should not be added. Ingredient-wide papers, topic-linked papers, and sources in outcome groups use different scopes. Adding source counts may count the same paper more than once.
- bone mass: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- bone mineral density: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- falls: Sources represented in this measurement group: 2 · Distinct papers with human comparisons for this outcome: 0
- hip fracture: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- hip fractures: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- incident symptomatic fracture: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- Non-vertebral fractures: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 1
- proportion having 2 or more falls: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- radial volumetric BMD: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 1
- total fracture: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- total fractures: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
What the research found
Non-vertebral fractures
No clear difference in this measurement was found between the compared groups.
Controlled study in people · Single ingredient · General population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
radial volumetric BMD
The study reported worsening in this measurement.
Controlled study in people · Single ingredient · General population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
bone mineral density
No clear difference in this measurement was found between the compared groups.
Meta-analysis · Single ingredient · General population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
falls
No clear difference in this measurement was found between the compared groups.
Meta-analysis · Single ingredient · Unspecified population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
hip fracture
No clear difference in this measurement was found between the compared groups.
Meta-analysis · Single ingredient · General population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
total fracture
No clear difference in this measurement was found between the compared groups.
Meta-analysis · Single ingredient · Unspecified population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
falls
A change was reported, but the comparison could not be confirmed.
Controlled study in people · Single ingredient · Deficiency group
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
hip fractures
A change was reported, but the comparison could not be confirmed.
Meta-analysis · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Analysis coverage and paper counts
1 paper · 1 measured outcome
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
total fractures
A change was reported, but the comparison could not be confirmed.
Meta-analysis · Ingredient combination · General population
Several ingredients were used together. This does not establish the effect of this ingredient alone or synergy.
Analysis coverage and paper counts
1 paper · 1 measured outcome
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
bone mass
The study needs further checking before its result can be interpreted.
Review · Single ingredient · Patient group
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
incident symptomatic fracture
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · Deficiency group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
proportion having 2 or more falls
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · General population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · Unspecified population
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Review · Unknown intervention · Unspecified population
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
How to read research findings
How should I read research findings?
Research guidesNo clear difference and an uninterpretable result are different
A reported null comparison contains a result. An abstract without an interpretable comparison leaves a question unresolved.
Paper counts and study counts are different
Count original research separately from research that reanalyzes it. Publication volume is neither replication nor a quality rating.
Side effects and combination findings
Findings from this ingredient alone are shown separately from those involving another supplement or medication.
No reviewed caution rules are available yet. Reported caution findings are shown below.
Review 3 combination findings and 0 findings that outperformed an ingredient alone.
Findings to review with care
Side effects reported for the ingredient alone are separated from findings involving another supplement or medication.
Side effects reported with this ingredient alone
Symptoms or adverse events reported in studies without another active ingredient.
adverse reactions (e.g., hypercalciuria, hypervitaminosis D, kidney stones, gastrointestinal symptoms, mild itch)1 papers
Six studies reported adverse reactions potentially attributable to vitamin D, occurring across treatment and control arms.Human studies · Meta-analysisReported improvements with combinations
Combination findings are grouped by how the study compared them. This is not a recommendation to combine ingredients.
Combinations with reported improvement
The combination showed improvement, but each ingredient's contribution is unclear.
오메가-3Combined vitamin D and omega-3 fatty acids showed a 31% reduction in autoimmune disease incidence compared to placebo, suggesting a potential additive effect.
BCAACombination with Vitamin D significantly improved appendicular skeletal muscle mass/height2 compared to control.
마그네슘Co-supplementation with Vitamin D and Magnesium resulted in significant improvements in behavioral function and mental health scores compared to placebo.