Glucans are part of a group of biologically active natural molecules and are steadily gaining strong attention not only as an important food supplement, but also as an immunostimulant and potential drug. This paper represents an up-to-date review of glucans (β-1,3-glucans) and their role in various immune reactions and the treatment of cancer. With more than 80 clinical trials evaluating their biological effects, the question is not if glucans will move from food supplement to widely accepted drug, but how soon.

Background:Diabetes mellitus is a chronic disease manifested by an increase of blood glucose.Objective:To evaluate the effects of glucan and vitamin D supplementation in patients with diabetic retinopathy.Method:We evaluated the effects of 3-month supplementation with glucan and vitamin D in 54 patients with diabetic retinopathy. We measured levels of vitamin D, cholesterol, HDL cholesterol, and triglycerides.Results:The supplementation strongly decreased the cholesterol levels and improved the levels of HDL cholesterol. In addition, vitamin D levels were strongly improved, but still not at optimal values.Conclusion:From our data, we concluded that glucan and vitamin D supplementation strongly influence lipid metabolism and have positive effects on human health.

The role of glucan in stimulation of immune reactions has been well-established. In this report, we focused on the antibody production in glucan-supplemented children with chronic respiratory problems. We measured the levels of salivary IgA, IgM and IgG in 40 children aged 8-12 years and evaluated the effects of 100 mg d^-1 oral dose of glucan. We found a significant increase in production of all tested antibodies in the glucan-stimulated group, but a decrease of antibody production in the control group. A thirty-day oral application of yeast-based natural immunomodulator β-glucan strongly stimulated the mucosal immunity of children with chronic respiratory problems

The objective of this article is to evaluate the potential effects of beta-glucan and vitamin D supplementation in patients with diabetic retinopathy. We evaluated the levels of several parameters of inflammatory reactions (C-reactive protein [CRP], serum amyloid A [SAA], and interleukin- [IL-] 6), leptin, and vitamin D. Using a 3-month interval, we divided the patients into three groups: (1) supplemented with beta-glucan and vitamin D, (2) supplemented with vitamin D and placebo, and (3) supplemented with vitamin D alone. By this division, we aim not only to observe whether beta-glucan can increase the effects of vitamin D, but also to eliminate the potential effects of placebo. The doses of vitamin D corresponded to phototype, weight, age, and sex of the individual. Fifty-two diabetic retinopathy patients were selected for our study. We found significant vitamin D deficits in all cases, even after three months of supplementation with vitamin D. Significant changes in levels of CRP were observed in the beta-glucan-supplemented group; levels of SAA and IL-6 were not changed. Leptin levels were significantly lowered in the beta-glucan-supplemented group and increased in the other groups. More detailed studies and/or longer supplementation is necessary.

For decades, glucans have been studied for their biological and immunological activities. The scientific community has mainly focused on immune reactions, but other areas, such as cholesterol levels and diabetic retinopathy, have shown the positive effects of glucan supplementation. However, the majority of studies focused on possible cancer suppression, where glucans showed clear and significant effects on numerous types of cancers, leading not only to clinical trials, but to approval as an official drug. The aim of this review is to describe the current knowledge of this field.