NORTH RIDGE—Arabinogalactan from Larch tree (Larix spp.) bark has have been shown to stimulate the immune system; therefore, researchers tested whether ingestion of a proprietary arabinogalactan extract—ResistAid™—would selectively enhance the antibody response to the pneumonia (pneumococcal) vaccine in healthy adults. According to results published in Nutrition Journal, arabinogalactan extract increased the antibody response of healthy volunteers to the 23-valent pneumococcal vaccine compared to placebo (2010;9(32). The randomized, double blind, placebo-controlled, parallel group pilot study was conducted in 45 healthy adults who had not previously been vaccinated against Streptococcus pneumoniae. The volunteers began taking 4.5 g/d of the larch tree bark or placebo at the screening visit (V1-Day 0) and continued over the entire 72-day study period. After 30 days the subjects received the 23-valent pneumococcal vaccine (V2). They were monitored the following day (V3-Day 31), as well as 21 days (V4-Day 51) and 42 days (V5-Day 72) after vaccination.
As expected, vaccination significantly increased pneumococcal IgG levels. The larch tree group demonstrated a statistically significant greater IgG antibody response than the placebo group in two antibodies subtypes (18C and 23F) at both Day 51 (P=0.006 and P=0.002) and at Day 72 (p=0.008 and p=0.041). These same subtypes (18C and 23F) also demonstrated change scores from baseline which were significant, in favor of the larch tree group, at Day 51 (P=0.033 and 0.001) and at Day 72 (P=0.012 and P=0.003). Change scores from baseline and mean values were greater in the larch tree group than placebo for most time points in antibody subtypes 4, 6B, 9V and 19F, but these differences did not reach statistical significance. There was no effect from the vaccine or larch tree group on salivary IgA, white blood cell count, inflammatory cytokines or complement, markers of the innate immune system.