Probiotics fail to reduce risk of cold and ‘flu in seniors

Drinking Yakult daily did not affect the risk of developing upper respiratory tract infections like the cold and ‘flu, according to randomized, double-blind, placebo-controlled trial.

Results published in the American Journal of Clinical Nutrition indicated that daily consumption of a fermented milk product containing 6.5 billion units of Lactobacillus casei Shirota failed to affect the probability of respiratory symptoms in 737 elderly people.

“To the best of our knowledge, this was the first large RCT in which the effect of probiotics on respiratory symptoms in institutionalized elderly people over a 6-month period was studied,” wrote the researchers, led by Karolien Van Puyenbroeck from the University of Antwerp in Belgium.

“The study was based on the notion that probiotics are believed to influence immunoregulatory pathways, mainly by stimulating regulatory T cell responses.

“There are some possible factors that could have contributed to these negative results in this population. First, the study was conducted in elderly individuals with a mean age greater than 80 years old. One could question whether the immune system in the very elderly is still sensitive for stimulation.

“Second, the winter of 2007–2008 was a very mild influenza season, although in our study population we showed more RTIs than expected.”

Source: American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.3945/ajcn.111.026831
“Efficacy of daily intake of Lactobacillus casei Shirota on respiratory symptoms and influenza vaccination immune response: a randomized, double-blind, placebo-controlled trial in healthy elderly nursing home residents”
Authors: K. Van Puyenbroeck, N. Hens, S. Coenen,et al.