Vitamin D in health and disease
Heaney RP • Clin J Am Soc Nephrol
Key Finding
Optimal serum 25(OH)D threshold >32 ng/mL (80 nmol/L); serum rises ~1 ng/mL per 100 IU daily intake; safe upper limit 10,000 IU/day
Key Findings
- 1Optimal serum 25(OH)D: >32 ng/mL (80 nmol/L)
- 2Serum rises ~1 ng/mL per 100 IU daily vitamin D intake
- 3Autocrine mechanisms account for >80% of daily vitamin D utilization
- 4Safe upper intake: 10,000 IU/day; D3 more potent than D2
Original title: “Vitamin D in health and disease”
Plain English Summary
Review examining vitamin D metabolism, optimal serum levels, and health associations. Emphasizes that autocrine mechanisms account for more than 80% of daily vitamin D utilization.
In-Depth Analysis
Study Details
Author: Robert P Heaney
Institution: Creighton University, Omaha, NE
Journal: Clinical Journal of the American Society of Nephrology, 2008 Sep; 3(5):1535-41
PMID: 18525006 | PMCID: PMC4571146
Key Points (from abstract)
Optimal Levels
- •Optimal serum 25(OH)D: >32 ng/mL (80 nmol/L)
Metabolic Utilization
- •Autocrine mechanism accounts for "more than 80% of the metabolic utilization of the vitamin each day"
Dosing Relationship
- •"Serum 25(OH)D can be expected to rise by about 1 ng/mL (2.5 nmol/L) for every 100 IU of additional vitamin D each day"
Safety
- •Safe upper intake level: 10,000 IU/day for cholecalciferol (vitamin D₃)
Forms
- •Cholecalciferol (D₃) is "substantially more potent than ergocalciferol (D₂)"
Disease Associations
- •Low vitamin D status increases risk of hypertension, diabetes, and cancer
Source: PubMed abstract (PMID 18525006) and PMC full text (PMC4571146)
Paradigm Relevance
How this study applies to different clinical perspectives:
Standard Medical
RelevantConventional clinical guidelines used by most doctors
Why it matters:
Establishes 32 ng/mL threshold now used in some clinical guidelines
Research Consensus
RelevantCurrent scientific understanding, often ahead of guidelines
Why it matters:
Key paper explaining autocrine mechanism—why 25(OH)D levels matter independent of calcitriol
Metabolic Optimization
RelevantProactive targets for optimal health, not just disease absence
Why it matters:
Supports 4,000+ IU daily dosing and 10,000 IU safety ceiling
Study Details
- Type
- Review Article
- Methodology
- Review article covering vitamin D metabolism, optimal levels, dosing relationships, and disease associations.
Evidence Quality
Review from PMC4571146. Author Robert P Heaney from Creighton University.
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Original Source
DOI (Digital Object Identifier) is a permanent link to this publication. Unlike website URLs that can change, a DOI always resolves to the correct source.
Related Studies
Health Effects of Vitamin D supplementation: Lessons Learned from Randomized Controlled Trials and Mendelian Randomization Studies
Bouillon R, et al • J Bone Miner Res • 2023
Cancer mortality: daily dosing RR 0.88 (95% CI 0.78-0.98, 10 trials); bolus RR 1.07 (ineffective); VITAL: normal BMI cancer OR 0.76; shift focus to deficient individuals
Vitamin D supplementation and total cancer incidence and mortality: a meta-analysis of randomized controlled trials
Keum N, et al • Annals of Oncology • 2019
Cancer mortality: 13% reduction (RR 0.87, 95% CI 0.79-0.96, p=0.005); Cancer incidence: no effect (RR 0.98, 95% CI 0.93-1.03, p=0.42)
International Vitamin D Supplementation Guidelines
Pludowski P, et al • Journal of Steroid Biochemistry and Molecular Biology • 2018
Target 25(OH)D levels of 30-50 ng/mL (75-125 nmol/L) recommended for general health; higher targets (40-60 ng/mL) for specific conditions.