Looking for changes in healthy active people
The study included 465 healthy people who had engaged in at least 30 minutes of exercise per week during the previous three months. They were divided into three groups:
one group received 2 billion CFU (colony-forming units) of Bifidobacterium animalis, subspecies lactis, per day;
one group received 5 billion CFU of Bifidobacterium animalis, subspecies lactis, plus 5 billion CFU of Lactobacillus acidophilus NCFM per day; and,
the third group received a placebo.
Each group took their supplements for five months (150 days), beginning in the autumn and ending in the spring.
Probiotics delay and prevent colds
The participants kept daily records showing their physical activity, symptoms of common cold or other upper respiratory infection (such as sneezing, sore throat, congestion, and runny nose), and symptoms of intestinal infection (such as diarrhea, constipation, bloating, nausea, and abdominal pain). From these records, the researchers determined the following:
People in the Bifidobacterium group had a 27% lower risk of upper respiratory infection than people in the placebo group. (People in the combined Bifidobacterium/Lactobacillus group had a 19% lower risk, but this degree of protection was not considered statistically significant.)
The average length of time between the beginning of the study and the first infection was 24 days longer for both probiotic groups, compared with placebo.
In the combined Bifidobacterium/Lactobacillus group, people's time spent exercising increased, while exercise time in the other two groups held steady.
There were too few intestinal infections among the participants to notice any differences in risk.
Avoiding colds allows for more exercise
"The positive effects of probiotic supplementation appear to extend beyond individuals considered to have a higher susceptibility to illness," the study's authors said. They also point out that the increase in exercise seen in the combination probiotic group suggests that probiotic protection may allow increased activity, "which will be of interest to those involved in competitive sport."
Stay healthy all winter
This study's findings add to the evidence that probiotics can help us avoid infections. Here are some other ways to lower your cold and flu risk:
- Eat your veggies. While vegetables are rich in immune-enhancing chemicals, excessive sugar, alcohol, and dietary fat appear to be immune-inhibiting and may contribute to your infection risk.
- Exercise and rest. Getting enough physical activity and enough sleep will go a long way toward keeping your immune system strong and keeping you cold-free.
- Wash your hands and throat. Frequent hand washing and daily gargling with tap water can reduce your germ load and prevent colds.
(Clin Nutr 2013; http://dx.doi.org/10.1016/j.clnu.2013.10.002)