Yeast beta-glucan: An immunomodulator or just a food supplement?

The health of an individual is mostly attributed to the role of a strong immune system. Yeast beta-glucan is considered to strengthen the body’s immunity not only in healthy adults but also in children and older adults.

A recent article on the Journal of Dietary Supplements elucidated the enhanced immune health effect of a dairy-based beverage supplemented with yeast beta-glucan. Mah E et al.1 researched 370 healthy participants aged 18-65 years for 91 days who were participants of Austin 2017 full marathon. The participants were instructed to consume 250 mg/day dispersible baker’s yeast beta-glucan (BYBG) or 0 mg BYBG (control) for 45 days before, day of and 45 days after the marathon.

Although the result did not show any difference in the number and duration of episodes of upper respiratory tract infection (URTI), there was 11% decrease in the number of URTI symptomatic days in the participants who consumed BYBG (3.43 ± 6.44 days, max 27 days) versus the control group (3.84 ± 6.84 days, max 49 days). Furthermore, there was also a reduction in the severity of the URTI symptoms and the number of missed workout days for participants who consumed BYBG (4.52 ± 1.61; 0.09 ± 0.38 days, max 2 days) versus control (5.60 ± 2.23; 0.36 ± 1.40 days, max 10 days). 

Similarly, a study in 156 children of 1-4 years of age supplemented with 75 mg/day and 35 mg/day BYBG were compared with the placebo group for 12-weeks. The incidence of childhood infectious episodes in children supplemented with 75 mg/day and 35 mg/day BYBG decreased to 47% and 32%, respectively versus 85% in placebo. Likewise, the duration (3.47 and 2.87) and number (0.7 and 0.5) of URTIs and duration (3.6 and 4.7) and number (0.7 and 0.7) of all infectious illness episodes also decreased in 75 mg/day and 35 mg/day BYBG supplemented children, respectively as compared to placebo for URTI duration (8.85) and number of episodes (1.5) and duration (9.9) and number (1.6) of childhood illnesses².

Another study conducted in older adults (aged 50-70 years) supplemented with 250 mg/day BYBG for 90 days during winters showed fewer illnesses (odds ratio 0.55; 95% CI 0.24,1.26) (p= 0.149) and number of symptomatic days (p= 0.067) versus placebo group. In this study, the effect of BYBG was attributed to innate immune response (increased interferon-gamma concentrations and decreased monokine)³.

The immunomodulatory effect of beta-glucan has been attributed to the activation of innate as well as cellular and humoral immunity that includes monocytes/macrophages, neutrophils, natural killer cells, complementary systems, CD4 and CD8 cells and antibodies⁴.

Although the health benefits of beta-glucan are varied, not all beta-glucans bestow such benefits. Beta-glucan exists as (1,3)-, (1,4)-, and (1,6)-linked beta-glucan and only (1,3)-beta-glucan derived glucans, either as linear, branched or chemically-modified structures have immune-enhancing effects^5,6.

The benefits of beta-glucan surpass immune health to include anti-inflammatory, antitumor, antiallergic, antiobesity, antidiabetic, antiosteoporotic, antihypertensive, antimicrobial, antihypercholesterolemic and antioxidative effects⁷.

Apart from being derived from the cell walls of yeast (Saccharomyces cerevisiae), they are also derived from the cell walls of fungi (Scizophyllum commune, Sclerotiniasclerotiorum) and mushrooms (Maitake and Shiitake), seaweeds (Laminaria species) and cereals (barley, oat, sorghum, rye, wheat, maize, rice and triticale)⁷.

Given the extensive documentation of enhanced immune health and other health claims, economic nature and safety profile of beta-glucans, they are permitted in several products and food supplements in various countries including China, Japan, Korea, United States, Canada, Sweden and Finland⁷. The abundance of data in literature cannot help rule out that increased intake of dietary beta-glucan might enhance immune function in healthy adults, children and older adults too.