Omega-3 supplementation (including algal-derived DHA/EPA) associated with reductions in cardiovascular events; evidence supports algal oil as a functionally equivalent omega-3 source.

DHA levels in plasma phospholipids increased ~80% and in erythrocytes ~25% with both algal-oil capsules and cooked salmon; the two sources were bioequivalent in raising plasma and red blood cell DHA, supporting algal oil as a non-fish DHA source.

Vitamin D supplementation reduced risk of acute respiratory tract infection (adjusted OR 0.88, 95% CI 0.81–0.96); greatest benefit in those with baseline deficiency (<25 nmol/L) and those receiving daily or weekly dosing rather than bolus doses.

Vitamin D at 700–800 IU/day reduced hip fracture risk by 26% (RR 0.74) and any nonvertebral fracture by 23% (RR 0.77); no significant benefit was observed at 400 IU/day.

Vitamin D insufficiency is prevalent among athletes, particularly indoor athletes and those in northern latitudes in winter. Insufficiency is associated with reduced muscle strength, power, and endurance; supplementation of 2,000–6,000 IU/day recommended to maintain 25(OH)D >40 ng/mL.