Healthy bacteria added to food or dietary supplements may keep colds and fevers at bay.

Probiotic food contains live bacteria, which is considered beneficial and not harmful to humans. Foods like curd, yoghurt and miso (soyabean and barley paste), fermented like dosa, dhoklas, idlis, and soya beverages are high in probiotics. Studies have shown that probiotics can benefit those who are already ill with various conditions, and the bacteria are thought to boost the immune system’s response to invaders. Whether they are effective at preventing sickness is unclear.

To explore the health benefits of probiotic food in keeping children safe from cold and fever during the winter season, researchers identified 326 children in China, aged between 3 and 5 years and randomly assigned them to three different groups: one given milk with a bacterium called Lactobacillus acidophilus mixed in, another that received the same organism along with a strain of another bacterium, Bifidobacterium animalis, and a third that received just milk with placebo. The test formulas were given twice daily for six months by school officials during the week and by parents or guardians on weekends.

Compared to the placebo group, the Lactobacillus group had 53 percent fewer fevers, 41 percent fewer cough episodes, and 28 percent fewer runny noses. The Lactobacillus + Bifidobacterium group had even larger reductions in symptom rates: 72 percent fewer fevers, 62 percent fewer coughs, and 59 percent fewer runny noses. All groups were comparable in size, with nearly 100 children each.

Furthermore, when children in any of the test groups did get fever, cough or a runny nose, they recovered significantly faster. Compared to placebo, the length of illness was decreased by 32 percent with Lactobacillus and by 48 percent with Lactobacillus + Bifidobacterium combination. The investigators also note that antibiotic use was 68 percent lower in the Lactobacillus group and 84 percent lower in the Lactobacillus + Bifidobacterium group, compared to the placebo group. Children who received the probiotics were absent from day care 28 to 32 percent less often than children in the placebo group.

It was concluded that children who drank probiotics with milk twice a day during the winter and spring had fewer colds, needed fewer antibiotics, and missed fewer days of school than other children who drank plain milk instead.