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Routine use of vitamin D or omega-3 fatty acid supplements did not prevent frailty among older healthy adults, an ancillary study of the randomized VITAL trial showed.

In an intention-to-treat analysis involving over 25,000 participants ages 50 and up, neither 2,000 IU of vitamin D₃ nor 840 mg of omega-3 fatty acids daily affected mean Rockwood frailty index scores compared with placebo at a median follow-up of 5 years:

• Vitamin D: mean difference -0.0002, P=0.85
• Omega-3 fatty acids: mean difference -0.0001, P=0.90

The rate of change in mean frailty scores (interaction with time for vitamin D: P=0.98; for omega-3 fatty acids: P=0.13) and incident frailty (vitamin D: P=0.90; omega-3 fatty acids: P=0.32) were also similar over time, reported Ariela Orkaby, MD, MPH, of Harvard Medical School in Boston, and colleagues in .

"These new findings from VITAL are an important reminder that dietary supplements are not miracle pills or elixirs of youth," co-author JoAnn Manson, MD, DrPH, of Brigham and Women's Hospital in Boston, said in a press release.

"We should consider deprescribing unnecessary pills, and instead promote healthy lifestyle habits," Orkaby suggested. "Regular exercise and the Mediterranean diet are proven strategies for prevention of frailty and should be encouraged for all older adults."

In an , Elizabeth Eckstrom, MD, MPH, and Bryanna De Lima, MPH, both of the Oregon Health & Science University in Portland, noted that "African American individuals and older adults, who are underrepresented populations at risk for frailty due to a marked burden of chronic illness, tended to have higher adherence to the Mediterranean diet," which was a "positive finding."

"Shifting our attention to an active, engaged lifestyle and the Mediterranean diet might improve longevity; reduce heart disease, dementia, and diabetes; and perhaps most important to older adults, reduce frailty and loss of independence," they wrote.

Frailty is marked by a reduction in physiologic reserve, which is worsened by poor diets, Orkaby's group explained. Even though frailty is independent of age, its prevalence increases with age, and it is estimated to affect about half of all elderly adults ages 85 and up.

have shown that vitamin D may slow the development of frailty, while studies in humans have been mixed. Omega-3 fatty acids have previously demonstrated potential benefits in , "which shares a bidirectional association with frailty," the authors wrote.

Other studies among VITAL participants have shown that vitamin D and omega-3 fatty acids did not prevent fractures.

For this ancillary study, Orkaby and colleagues examined data on 25,057 adults without cancer and cardiovascular disease across all 50 states. Mean age was 67, 50.7% were women, and 70.4% were white. Mean Rockwood frailty index score was 0.109 at baseline, and 12.7% were frail.

Participants received 2,000 IU of vitamin D and/or 840 mg of marine omega-3 fatty acids (460 mg of eicosapentaenoic acid and 380 mg of docosahexaenoic acid) or placebo daily from November 2011 to March 2014.

Over a median follow-up of 5.3 years, mean frailty score increased to 0.121, while 11.3% became frail.

A subgroup analysis showed no change in mean scores with an alternative frailty definition, the Fried physical phenotype. In addition, there were no significant interactions seen with either intervention for sex, BMI, race/ethnicity, weekly fish consumption, or low serum 25-hydroxyvitamin D levels, though a significant interaction by age was observed with omega-3 fatty acid supplements (P=0.01).

Orkaby and team acknowledged that the doses used in the study may not have been optimal for frailty prevention, and only a single dose was studied. Furthermore, frailty rates were lower than those of the general population, which may have led to possible healthy volunteer bias.

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