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Probiotic plus vitamin/mineral supplement reduces upper respiratory tract infection incidence and symptoms
Although the role of nutrition in preventing colds and flu has been questioned, a study published in the July 2005 issue of the International Journal of Clinical Pharmacology and Therapeutics found that supplementing with a probiotic plus vitamins and minerals for at least three months reduced the incidence of upper respiratory tract infections as well as lessened their symptoms.
For the current double-blind trial, J. Schrezenmeir, MD and colleagues at the Institute for Physiology and Biochemistry of Nutrition, Federal Research Center for Nutrition and Food in Kiel, Germany enrolled 477 health men and women who had not been vaccinated against influenza. The participants were randomized to receive a placebo or a probiotic containing Lactobacillus gasseri, Bifidobacterium longum and Bifidobacterium bifidum in addition to 13 vitamins and 13 minerals commonly included in multinutrient supplements. The subjects were divided to receive their regimens for 3 months in the spring or 5.5 months in winter through spring. Questionnaires were used by the participants to record respiratory tract infection symptoms. Immune response was evaluated in a group of 120 subjects before and two weeks after the beginning of the study.
It was found that the incidence of viral respiratory tract infections was 13.6 percent lower in the group that received the supplements compared to those who received the placebo. For those who received the supplements and acquired an infection, symptoms were reduced by an average of 19 percent, with this group suffering half the amount of days spent with a fever than the number of days reported by the placebo group. Immune response as determined by white blood cells (particularly T-lymphocytes) was significantly higher in the supplemented group than the placebo group.
The authors conclude that these results provide “some evidence of the positive effects of long-term consumption of a dietary supplement containing probiotic bacteria plus vitamins and minerals on the symptoms of respiratory tract infections, particularly influenza symptoms, and the occurrence of fever in otherwise health adults.” They attribute these benefits to stimulated cellular immunity.