A special fiber from the bark of the larch tree, called arabinogalactan, may be another weapon in the arsenal against the common cold, according to a study that found that people who supplemented with arabinogalactan got fewer colds.
The study, published in Current Medical Research and Opinion, included 199 people who reported getting colds frequently—at least three times in six months. They were assigned to receive either 4.5 grams (about 1 teaspoon) of larch arabinogalactan powder per day or placebo and were monitored for 12 weeks.
Larch arabinogalactan increased the body’s potential to defend against infection
Arabinogalactan appeared to make a small difference: 60% of the people in the supplement group got a cold during the study compared to 74% in the placebo group and the arabinogalactan users had more cold-symptom-free days (77 days) compared to placebo (74 days). The duration and severity of symptoms was the same in both groups.
The study’s authors comment that “larch arabinogalactan increased the body’s potential to defend against common cold infection,” noting that both groups had fewer colds than expected during the study, suggesting that the protective effect of arabinogalactan may have been more pronounced if the rate of colds had been higher.
While scientists still don’t know exactly how larch arabinogalactan works, studies done in test tubes have found that it can increase the activity of specific immune cells and increase antibody production. It is also known to act as a prebiotic, increasing populations of friendly bacteria in the large intestine. These bacteria help keep the immune system working properly, and studies have shown that increasing the number of friendly bacteria in the gut can reduce susceptibility to some infections, including colds.
Larch arabinogalactan may help your immune system better fight off cold viruses, but viruses are very clever and you might improve your odds staying healthy if you use multiple weapons to keep them at bay:
(Curr Med Res Opin 2013;29:1–8)