Over 60% of immune health measures decreased during the winter months of the study in the placebo group, report scientists from Takanashi Milk Products Ltd report in Beneficial Microbes, but only 32% decreased in the TMC0356 group, and none of those were statistically significant.
In addition, the heat-killed bacteria group displayed increases in CD8+ T lymphocytes, a well-established diagnostic measure of immune system functioning. Lymphocytes are white blood cells that play a key role in immune response, and CD8+ refers to the presence of certain receptors on the surface of the cells.
“These results indicate that TMC0356 may positively alter human immune response,” wrote the researchers, led by Fang He, PhD, deputy manager of technical research at Takanashi Milk Products Co. “Considering that subjects who participated in the study were healthy before its commencement, the lack of significant change in the immune indexes can be considered as good evidence that TMC0356 treatment is safe.”
Although the strain seems to be beneficial it is not defined as probiotic because it is heat-killed, and not live. According the FAO/WHO, probiotics are defined as "live microorganisms which when administered in adequate amounts confer a health benefit on the host".
Other Japanese companies are researching the potential health benefits of heat-killed bacteria. In 2012, scientists from Tokyo Metropolitan Institute of Gerontology and Otsuka Pharmaceutical Company Limited reported that daily intakes of heat-treated Lactobacillus pentosus strain b240 were associated with a 39% reduction in the incidence of the common cold, compared to placebo.
That report, published in the British Journal of Nutrition, was said to be the “first to show that oral intake of heat-killed lactic acid bacteria dose-dependently reduces the incidence rate of the common cold in elderly adults.”
The researchers recruited 28 healthy people aged between 50 and 70 to participate in their double-blind, placebo-controlled clinical study. Participants were randomly assigned to receive supplements containing L. gasseri TMC0356 (one billion colony forming units per day) or placebo for four weeks.
Results showed that the number of CD8+ T cells increased by 13.7% in the TMC0356 group, while these decreased by 1% in the placebo group.
In addition, the population of CD8+CD28+ T cells was found to decreased significantly in peripheral blood mononuclear cells from the placebo group, which indicated that expression of CD28+ was partly impaired.
“Notably, this [impairment of CD28+ expression] is considered as one of the important aspects of age-associated immunosenescence in humans,” wrote the researchers. However, no such decreases were observed in the TMC0356 group. “These results indicate that TMC0356 may protect host animals from the loss of CD28 expression, and this alleviate age-associated immune senescence. Furthermore, our results may provide insights into the underlying mechanisms of TMC0356 immunity enhancement observed in previous studies.
“The effect of TMC0356 on immune responses in the elderly may enhance their natural defence mechanisms against pathogenic infections,” they concluded.
Source: Beneficial Microbes
Published online ahead of print, doi: 10.3920/BM2014.0108
“Heat-killed Lactobacillus gasseri can enhance immunity in the elderly in a double blind, placebo-controlled clinical study”
Authors: K. Miyazawa, M. Kawase, A. Kubota, K. Yoda, G. Harata, M. Hosada, F. He