Trial reportNutrients2023
Effects of an Individualized vs. Standardized Vitamin D Supplementation on the 25(OH)D Level in Athletes.
Trial report in Nutrients, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 9 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
9 citing papers in PubMed, 11 citations in OpenAlex.
- Eight-Week Vitamin DNutrients · 2026Trial
- The interplay between vitamin D status and exerkine signaling: implications for exercise adaptation in athletes: narrative review.Journal of the International Society of Sports Nutrition · 2026Review
- Review
- Improvements in competition performance of national-level track and field athletes following a personalized nutrition intervention: a mixed methods approach.BMC sports science, medicine & rehabilitation · 2025Article
- Data-augmented machine learning for personalized carbohydrate-protein supplement recommendation for endurance.Scientific reports · 2025Article
- Single-Nucleotide Polymorphisms (SNPs) in Vitamin D Physiology Genes May Modulate Serum 25(OH)D Levels in Well-Trained CrossFitInternational journal of molecular sciences · 2025Observational
- Vitamin D beyond the blood: Tissue distribution of vitamin D metabolites after supplementation.Life sciences · 2024Review
- A real-life snapshot: Evaluating exposures to low energy availability in male athletes from various sports.Physiological reports · 2024Article
- Patterns of energy availability and carbohydrate intake differentiate between adaptable and problematic low energy availability in female athletes.Frontiers in sports and active living · 2024Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Vitamin D is crucial to the health and performance of athletes. Although the exact vitamin D requirements for athletes have not been established, maintaining a 25(OH)D level of at least 40 ng/mL is considered beneficial. This randomized controlled intervention study aimed to determine whether an individual loading dose formula for vitamin D supplementation is more effective than standardized supplementation and suitable enough for athletes to meet a target value of 40 ng/mL. In a 10-week supplementation study conducted during the winter months in Germany, 90 athletes with insufficient vitamin D levels (25(OH)D < 30 ng/mL) were randomly assigned to receive either a universal dose of 2000 IU/day of vitamin D or a loading dose of 4000 IU/day, followed by a maintenance dose of 1000 IU/day. The total 25(OH)D concentration was measured from dried blood spots at three time points: at baseline, at the computed date of 40 ng/mL, and after the 10-week period. Additionally, a vitamin-D-specific questionnaire was issued. On the day when 25(OH)D blood concentrations of 40 ng/mL were calculated to prevail, the individualized group had a significantly higher 25(OH)D level than the standardized group (41.1 ± 10.9 ng/mL vs. 32.5 ± 6.4 ng/mL,
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.