Evidence-based guide to vitamin D: cholecalciferol metabolism, calcium homeostasis, immune function, 25(OH)D blood testing, dosages, and toxicity risks.

September 2, 2026

Knowledge · Nutrition

Vitamin A in the Body: Why It Is Needed, Where It Is Found, and Why Too Much Can Be Dangerous

A practical guide to retinol and carotenoids, food sources, deficiency clues, testing, pregnancy precautions and overdose risk.

September 2, 2026

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Vitamin D, VDR and antimicrobial peptides: mechanisms and clinical limits

Vitamin D: Bones, Testing, Supplements, and the Risks of Megadoses

Vitamin A in the Body: Why It Is Needed, Where It Is Found, and Why Too Much Can Be Dangerous