NEW YORK (Reuters Health) — A nutritional supplement containing antioxidants, minerals and other nutrients can boost immune function in frail older people living in nursing homes, researchers report.Those who took eight ounces daily of the enriched supplement for ten weeks had fewer fevers and were less likely to require antibiotics than study participants given a standard nutritional supplement. They also responded more strongly to vaccination against influenza.

Older people living in nursing homes or long-term care facilities are at high risk of infection, Dr. Bobbi Longkamp-Henken of the University of Florida in Gainesville and colleagues note in the Journal of the American Geriatrics Society.

Given the similarity between declines in immune system function due to aging and to malnutrition, the researchers wanted to whether nutritional supplements might help strengthen older people’s immunity.

Fifty-two nursing home residents aged 65 and older were given the experimental formula, which contained protein, beta carotene, vitamins C and E, zinc, selenium, fructo-oligosaccharides (non-digestible sugars that help “feed” the good bacteria in the colon), and structured triacylglycerol. Forty received a standard liquid nutrition product, EnsurePlus.

Study participants were immunised against the flu after four weeks on the supplement, and then stayed on the supplements for an additional six weeks.

Columbus, Ohio-based Abbott Laboratories developed both the standard and experimental formulas, and also funded the study. Forty-three percent of those on the experimental formula achieved levels of antibodies sufficient to protect them against the flu, compared to 23 percent of study participants on the standard formula. They also showed higher production of white blood cells targeted to the flu virus.

Among those given the experimental formula, five percent required treatment for fever during the course of the study, compared with 16 percent of those on the standard formula. Study participants on the experimental formula were also less likely to require a new antibiotic prescription.

“The nutritional approach of this study demonstrated a collection of improvements that presumably could reduce the risk of infection and improve quality of life,” the researchers conclude.