The gastrointestinal tract’s surface lining (mucosa) covers an area over 300 meters squared. It is constantly bombarded by many foreign substances from dietary and bacterial origin. Together with the skin, the gastrointestinal tract is the first line of defense against these potential foreign invaders. It is a very important immune organ, because it houses 80% of the B-lymphocytes and 60% of the T-lymphocytes in the body. This part of my series is about the natural supplement you can use that targets this area: probiotics.
Probiotics are actually live bacteria or yeast that are/is healthy for human beings. Thus, they are considered dietary supplements. Lactic acid bacteria are most commonly used by the food industry to help convert sugars and carbohydrates into lactic acid. The sour taste of fermented dairy products such as yogurt is the result of the lactic acid. Among the many strains of bacteria in probiotics, those belonging to “Lactobacillus” and “Bifidobacterium” are most widely used.
“Lactobacillus plantarum” has been shown to suppress immunoglobulin E production, which reduces the immune response to food allergens. In a study from Japan, 60 healthy individuals were randomly assigned to get a capsule with 10 mg of a strain of this bacterium labeled “HK-LP” or a placebo daily for 12 weeks. HK-LP was shown to augment the acquired immunity and improved health-related quality of life.
There are several high-quality clinical trials that studied the effect of probiotics in common cold:
In one study, 477 healthy men and women who did not have the flu vaccine were randomly assigned to either daily probiotic multivitamin and mineral supplement or placebo for up to 5.5 months. In the group treated with probiotics, there was a reduction in flu symptoms by 25%. However, the duration of infections was unaffected. Moreover, the white blood cells, lymphocytes, especially the T-lymphocytes were greatly increased by the probiotics treatment.
In another, 479 healthy adults between the ages of 18 and 67 were given probiotics with vitamins and mineral or just vitamins and minerals for three months. In the probiotic-treated group, the duration of common cold episodes, and days with fever were lower as compared to the control group. Moreover, in the probiotic-treated group, there was a significantly higher number of lymphocytes. These authors concluded that treatment with probiotic bacteria for three months significantly shortened common cold episodes by two days and reduced the severity of cold symptoms.
A meta-analysis was recently published that looked at all available studies that tested probiotics against respiratory infections. Five of six studies saw a reduction in severity of respiratory symptoms. Probiotics shortened the length of the respiratory tract infections in three of nine studies. The overall conclusion was that probiotics may have a beneficial effect on the severity and duration of symptoms of respiratory tract infections.