Probiotics can help prevent upper respiratory infections (URTIs), which include the common cold, and improve the response to flu vaccines, according to new clinical trials. Probiotics are micro-organisms that can exert beneficial effects on our health.
Probiotics prevent the common cold and other upper respiratory tract infections
New clinical trials show that probiotics help to prevent the common cold and its symptoms. A randomized controlled study on children tested the effects of two probiotics administered together (Lactobacillus acidophilus and Bifidobacterium bifidum). One group of children received the probiotics twice a day, and another group received a placebo, for three months. Fewer children in the probiotics group developed at least one symptom of the cold than in the placebo group. Those who used probiotics had a significant lower risk of runny nose, fever, and cough, and school absence due to the cold. The study was conducted by Dr. Sanguansak Rerksuppaphol, MD, of the Department of Pediatrics, Faculty of Medicine, in Srinakhariwirot University, NakornNayok, Thailand, and published in the journal Pediatrics International.
A recent study on elderly subjects also showed that those who used heat-killed Lactobacillus pentosus had a reduced incidence of the common cold, compared to those on placebo. The study was published in the British Journal of Nutrition.
Probiotics improve immune response to flu vaccine
A recent randomized placebo-controlled clinical trial examined the effects of two strains of probiotics on immune response to flu vaccination. The study, led by Dr. Giuliano Rizzardini of the Department of Infectious Diseases, Luigi Sacco Hospital in Milan, Italy, involved 211 humans. Subjects were administered probiotic capsules of Bifidobacterium animalis ssp. lactis (BB-12), or a dairy drink with Lactobacillus paracasei ssp. paracasei (L. casei 431), or a placebo, once a day for six weeks. After two weeks, subjects were vaccinated against influenza. After six weeks those who received the probiotics had significantly greater increases in vaccine specific immune responses, compared to those on placebo. Total antibody concentrations were also higher in those who used probiotics. The study was published in the British Journal of Nutrition.
Review of clinical trials
A recent review of 21 clinical trials on probiotics’ effects on URTIs and otitis was conducted. Most of the trials, except four, showed that probiotics have a beneficial effect on URTIs. One of the trials that used a four probiotic combination product showed an increased prevalence of Moraxella catarrhalis in the probiotic group. This bacterium can cause respiratory infections. This effect was maybe due to the fact that some strains of bacteria can inhibit the effects of another strain. The review was published in the Journal of Applied Microbiology.
Although most probiotics are safe, speak with your doctor if you have particular health issues, are immunocompromised, or if your child is very young. The most common probiotics are Lactobacilli and Bifidobacteria and these are found in yogurts and as supplements. Many strains of these bacteria have shown beneficial effects on upper respiratory tract infections in clinical trials. Probiotics can prevent cold symptoms and potentially improve the efficacy of the flu vaccine.