Abstract
RationaleTo prevent or combat infection, increasing the effectiveness of the immune response is highly desirable, especially in case of compromised immune system function. However, immunostimulatory therapies are scarce, expensive, and often have unwanted side-effects. β-glucans have been shown to exert immunostimulatory effects in vitro and in vivo in experimental animal models. Oral β-glucan is inexpensive and well-tolerated, and therefore may represent a promising immunostimulatory compound for human use.MethodsWe performed a randomized open-label intervention pilot-study in 15 healthy male volunteers. Subjects were randomized to either the β -glucan (n = 10) or the control group (n = 5). Subjects in the β-glucan group ingested β-glucan 1000 mg once daily for 7 days. Blood was sampled at various time-points to determine β-glucan serum levels, perform ex vivo stimulation of leukocytes, and analyze microbicidal activity.Resultsβ-glucan was barely detectable in serum of volunteers at all time-points. Furthermore, neither cytokine production nor microbicidal activity of leukocytes were affected by orally administered β-glucan.ConclusionThe present study does not support the use of oral β-glucan to enhance innate immune responses in humans.Trial RegistrationClinicalTrials.gov NCT01727895
Highlights
Defense mechanisms against invading pathogens are of vital importance to our survival
The advent of molecular immunology has provided rigorous mechanistic explanations for how humans recognize glucans and how this may influence the immune system [6]. bglucan is already applied as a food additive in animal feed to enhance the immune response [7] and it is widely offered on the internet as a dietary supplement for humans, advertised to have beneficial immunostimulatory effects
The only evidence of immunological effects of oral b-glucan in humans to date is derived from a study in patients with advanced breast cancer, in which oral b-glucans enhanced expression of surface molecules associated with macrophage proliferation and activation in peripheral blood mononuclear cells (PBMCs) [8]
Summary
Defense mechanisms against invading pathogens are of vital importance to our survival. Since the early 1900s, numerous in vitro and animal studies have demonstrated immunostimulatory effects of b-glucans [5]. Bglucan is already applied as a food additive in animal feed to enhance the immune response [7] and it is widely offered on the internet as a dietary supplement for humans, advertised to have beneficial immunostimulatory effects. There are no studies to substantiate the putative immunostimulatory effects of orally administered b-glucan in humans. The only evidence of immunological effects of oral b-glucan in humans to date is derived from a study in patients with advanced breast cancer, in which oral b-glucans enhanced expression of surface molecules associated with macrophage proliferation and activation in peripheral blood mononuclear cells (PBMCs) [8]
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