VITAL — Vitamin D and Omega-3 in Primary Prevention

Design

VITAL randomised 25,871 generally healthy adults (men ≥50, women ≥55) in a 2×2 factorial design to:

• Vitamin D₃ 2,000 IU/day or placebo
• Marine omega-3 (840 mg EPA+DHA/day) or placebo

Median follow-up 5.3 years.

Findings (primary)

• Vitamin D: no significant reduction in incident invasive cancer or major cardiovascular events.
• Omega-3: no significant reduction in primary cardiovascular endpoint; subgroup signals for MI reduction.
• No effect on all-cause mortality for either.

Secondary / follow-up findings

• Autoimmune disease: vitamin D (and to a lesser extent omega-3) reduced incident autoimmune disease by ~22% over 5 years (Hahn et al., 2022).
• Cancer mortality: vitamin D associated with reduced cancer death after exclusion of early follow-up years.
• Fracture: no clear reduction in fracture risk in this generally vitamin-D-replete population (separate analysis).

Implication

For most generally-healthy, vitamin-D-replete adults, routine vitamin D and omega-3 supplementation does not deliver clear primary-prevention benefit. Targeted use in deficient individuals or for specific endpoints (autoimmune disease, hypertriglyceridaemia) may still be justified.

Related entries

Vitamin D, Omega-3, DO-HEALTH.