Effects of vitamin D3, omega-3 fatty acids and a simple home exercise program on change in physical activity among generally healthy and active older adults: The 3-year DO-HEALTH trial.
Level 2 - randomized trial
Multicenter randomized controlled trial
PubMed 40054416 · doi:10.1016/j.jnha.2025.100528
What was done
The DO-HEALTH multi-center, 2 × 2 × 2 factorial randomized controlled trial assessed the individual and combined effects of vitamin D3 (2000 IU/day), marine omega-3 fatty acids (1 g/day), and a simple home exercise program (SHEP, 3 × 30 min/week) across eight treatment arms over three years. Participants were 2,157 community-dwelling adults aged ≥70 years (mean age 75 years; 83% physically active; 59% vitamin D3 replete) without major comorbidities. Pre-defined outcomes were changes from baseline to 12, 24, and 36 months in self-reported physical activity (MET-h/week) and objective physical function (five times sit-to-stand test, handgrip strength, and gait speed), evaluated using adjusted mixed-effects models.
What was found
Baseline physical activity averaged 75 MET-h/week. Over three years, neither marine omega-3s nor SHEP significantly changed physical activity or physical function compared to controls. Vitamin D3 supplementation was associated with a statistically significant decline in physical activity compared to no vitamin D3 (adjusted mean difference: -7.1 MET-h/week [95% CI: -12.7, -1.5], P = 0.01). Subgroup analyses across age groups (70–74 vs. ≥75 years) and sex showed no differences. None of the three interventions, alone or in combination, improved the objective physical function metrics.
Why it matters
Routine supplementation with vitamin D3 or omega-3s, as well as simple home exercise regimens, provides no functional or activity benefit to older adults who are already healthy, physically active, and largely vitamin D replete. The observed reduction in physical activity with high-dose vitamin D3 warrants caution against unindicated supplementation in this population.
Limits
Physical activity was measured via self-report rather than device-based tracking (such as accelerometry). The study cohort was predominantly active and vitamin D replete at baseline, precluding generalization to frail, sedentary, or severely vitamin D-deficient older populations. Exact numerical values and effect sizes for the objective physical function tests were not reported in the abstract.
Cited by
- partial In the DO-HEALTH clinical trial cohort of older adults in Switzerland, approximately 88% of participants self-identified as physically active at baseline.