Dietary supplements and food ingredients are being developed to enhance the immune system, the biological processes which provide protectionagainst disease by identifying and destroying pathogens and tumor cells. Colds, which are the most common infection in humans, are a viral immune disease of the upper respiratory system and can result in significant impacts on productivity. A study reported that among 3,249 university students surveyed, 91% had more than one upper respiratory tract infection (URTI) within a six month period. The cumulative effects of the URTI were estimated at 6,023 bed days, 4,263 days of missed school, and 45,219 days of illness. Academic performance was compromised with 27.8% and 46.3% of the study population reporting less than optimal performance on exams and assignments, respectively, due to illness(1).
Chicken Soup

Allergic rhinitis (inflammation of the nasal passages), also known as hay fever, affects about 8% of adults and 9% of children in the U.S.(2). The affliction was reported to be responsible for a decrease in concentration, increased stress, alteration in mood, and a decrease in career performance in over 1,200 health care practitioners surveyed(3).

Weakening of the immune heath represents a particular challenge to athletes because of the physical demands associated with exertion. In particular, reductions in immune enhancing natural killer T cells, immunoglobulin A, macrophages, neutrophils and monocytes have been observed. These immune system alterations result in athletes being more susceptible to contracting colds and flu(4).

Disorders in the immune system can result in more serious diseases, including autoimmune diseases, inflammatory diseases and even cancer. Immunodeficiency diseases occur when the activity of the immune system is compromised.

Natural health products that can selectively stimulate or modulate the immune system in response to pathogens and allergens are being actively investigated. An important focus is the improvement of the quality of life for people with allergies as well as for those who frequently contract colds or the flu.

ß-glucans are polysaccharides comprised of the sugar glucose linked by β-glycosidic bonds. They are most commonly found in oats, barley, baker’s yeast, and mushrooms, and are being studied for immunomodulating effects. ß-glucans from yeast and mushrooms are linked in the ß-1,3 position, whereas, ß-glucans from oats and barley are mostly ß-1,4 and ß-1,3 linkages.

ß-glucans From Oats and Yeast

Nieman investigated the potential of oat ß-glucans to improve resting immunity, exercise-induced alterations in immunity, and self-reported URTI in athletes(4). Twenty-six male cyclists were randomly assigned to consume either 5.6g/day of oat ß-glucans or a placebo two weeks before, during, and one day after, a three day cycling event. Blood was collected at several time points: before and after the two week supplementation, immediately after the three hour cycling on the third day, and 14 hours after exercise. After analysis of many markers of immunity, including natural killer T cells, interleukin-6, interleukin-10, interleukin-1, and polymorphonuclear respiratory burst activity, no significant differences between the placebo and treatment groups were noted.

In contrast, the supplementation of ß-glucans (ß-1,3 and ß-1,6 linkages) derived from a proprietary trademarked baker’s yeast resulted in an improvement in immunity in athletes(5). The trial included 29 men and 31 women that were required to cycle for approximately 49 minutes at 37°C. Significantly greater monocyte and plasma cytokine levels two hours post-exercise were reported. Lipopolysaccharide stimulated cytokine production during or post exercise was also improved. This research suggests that yeast ß-glucans can stimulate the innate and humoral dependent immune system resulting in a strengthening of defences against pathogens.

In other research, the administration of the proprietary trademarked baker’s yeast ß-glucans at a level of 500mg/day for 12 weeks did not result in significant improvements in the incidence of URTI’s(6). However, the placebo group missed on average 1.38 days of work or school due to colds or flus, whereas the treatment group did not miss any days. Additionally, the treatment group had a significantly lower fever, and a better quality of life, scores. 

A placebo controlled, double blinded study of the same product in 48 individuals subjected to high pollen counts has recently been conducted(7). The treatment group received 250 mg daily for four weeks and showed significantly fewer, and less severe, allergy symptoms at the end of the trial. In particular, the treatment group experienced reductions in nasal and eye related allergy symptoms, and an improvement in their quality of life.

ß-glucans from Mushrooms

Proprietary, trademarked ß-glucans (ß-1,3 and ß-1,6) from mycelia of shitake mushrooms have been investigated in 42 elderly subjects(8). The study was a cross-over, double blind, placebo-controlled assessment of 2.5 mg/day for 6 weeks.  The results showed an increase in the number of circulating B-cells (+0.44%) which are involved in antibody production, compared to placebo    (-0.57%). There were no significant differences between other markers of immunity.

Proprietary, trademarked ß-glucans from another the mushroom Pleurotus ostreatus  have beenexamined for immuno-stimulatory effects inadouble blind study of 20 athletes receiving 100 mg daily for two months(9). Natural killer T cells, cytotoxic lymphocytes that play an important role in immune responses to stressors, were measured.  In the placebo group, natural killer T cell activity was reduced by 28% after 20 minutes of exercise and no decrease was observed in the treatment group. Other immune cell counts were not significantly different between groups.

ß-glucans derived from oats, yeast and mushrooms appear to play a positiverole in modulating the immune system in athletes, allergy sufferers, and those who frequently contract colds and flus. Strengthening the immune system can have significant impact on overall well-being, mood, and performance. Further investigation into the effects of ß-glucans extracted from different food sources holds promise in the promotion of health promotion and in the treatment of diseases.



1.      Nichol KL, D’Heilly S, Ehlinger E. 2005. Colds and influenza-like illnesses in university students: impact on health, academic and work performance, and health care use. Clin Infect Dis. 40(9):1253-70.

2.      Pleis JR and Lethbridge-Çejku M. 2007. Summary health statistics for U.S. adults: National Health Interview Survey, 2006. National Center for Health Statistics. Vital Health Stat 10 (235).

3.      Van Cauwenberge P, Van Hoecke H, Kardos P, et al. 2009. The current burden of allergic rhinitis amongst primary care practitioners and its impact on patient management. Prim Care Respir J.18(1):27-33.

4.      NiemanDC, Henson DA, McMahon M, et al. 2008. ß-glucan, immune function, and upper respiratory tract infections in athletes. Med Sci Sports Exerc.40(8):1463-71.

5.      Carpenter KC, Breslin WL, Davidson T, et al. 2011. The effects of yeast ß-glucan supplementation on monocytes and cytokine response to exercise. Biothera News Release.

6.      Feldman S, Schwartz HI, Kalman DS, et al. 2009. Randomized phase II clinical trials of Wellmune WGP® for immune support during cold and flu season. J of Appl Res. 9(1,2):30-42.

7.      Wellmune WGP® . Presentation by Biothera. Experimental Biology Conference. Washington DC. April 2011.

8.      Gaullier JM, Sleboda J, Snorre Ofjord E, et al. 2011. Supplementation with a soluble beta-glucan exported from shitake medicinal mushroom, Lentinus edodes (Berk.) Singer Mycelium: a crossover, placebo-controlled study in healthy elderly.

9.      Bobovčák M, Kuniaková R, Gabriž J, Majtán J. 2010. Effect of Pleuran (ß-glucan from Pleurotus ostreatus) supplementation on cellular immune response after intensive exercise in elite athletes. Appl Physiol Nutr Metab. 35:755-762.