Abstract
- Background
Lentinus edodes (commonly known as Shiitake) is a prominent medicinal mushroom boasting a long-standing tradition of therapeutic use across Asian populations. The major pharmacologically active substance isolated from L. edodes is a high-molecular-weight (1$\to$6, 1$\to$3)-$\beta$-glucan known as lentinan, which exhibits robust immunomodulatory properties. As human populations age, immunosenescence leads to a natural decline in immune competence, yet no prior clinical controlled studies had investigated the targeted immunological effects of orally administered lentinan on immune responses specifically in healthy, elderly Caucasian subjects. This randomized trial was designed to evaluate the immunological efficacy, safety profile, and physiological tolerability of a standardized $\beta$-glucan extract derived from L. edodes mycelium (marketed as Lentinex) administered orally to healthy elderly participants.
- Methods
A rigorous double-blind, randomized, crossover, placebo-controlled clinical trial was conducted. A total of forty-two healthy elderly human subjects were randomly allocated into two parallel treatment sequences. Participants received either a daily oral dose of 2.5 mg Lentinex or an organoleptically matched placebo for a duration of six weeks. Following a subsequent four-week washout period, subjects crossed over to receive the alternate supplementation for an additional six weeks. Comprehensive clinical, hematological, and immunological evaluations were systematically performed. Evaluated primary and secondary endpoints included circulating lymphocyte subsets (specifically B-cells and natural killer [NK] cells), humoral immunity factors (immunoglobulins and complement proteins), systemic cytokine profiles, and comprehensive safety blood parameters (differential white blood cell counts, hepatic function markers, renal function panels, and clinical blood chemistry), alongside the continuous recording of adverse events and tolerability.
- Results
Administration of oral Lentinex demonstrated specific immunomodulatory activity alongside an exemplary safety profile:
Modulation of B-Cell Counts: The changes in circulating B-cell numbers demonstrated a statistically significant difference between the Lentinex and placebo intervention groups.
Natural Killer (NK) Cell Dynamics: The absolute number of circulating NK cells increased significantly following supplementation in both groups, though the net difference between the active and placebo groups did not reach statistical significance.
Humoral & Cytokine Stability: Other systemic immune response parameters—including serum immunoglobulins, complement proteins, and circulating cytokines—remained unaltered by the intervention.
Biosafety & Tolerability: Comprehensive safety blood variables, including differential cell counts, liver function tests, and kidney function metrics, were entirely unaffected by Lentinex. Furthermore, the frequency, nature, and severity of reported adverse events were comparable to the placebo condition.
- Conclusions
Oral administration of Lentinex ($\beta$-glucan derived from Lentinus edodes mycelium) to healthy elderly subjects is exceptionally safe, well-tolerated, and induces a statistically significant increase in the number of circulating B-cells. These clinical findings highlight oral $\beta$-glucan supplementation as a safe and effective nutritional strategy to support immune competence and modulate cellular immunity in aging populations.
https://pubmed.ncbi.nlm.nih.gov/22164761/