Though consumers sometimes struggle in stating why a healthy immune system is important, the medical community knows that infection, poor diet, stress, smoking, and other lifestyle-related choices can have a detrimental effect on immune health.

Healthcare professionals are increasingly aware that the immune system is vital to mitigating many chronic health issues. Research shows that nearly every area of health is affected by the immune system, including digestive, cardiovascular, cognition, and risk of chronic disease.

Immune health is one of the top five reasons people take dietary supplements. According to the Council for Responsible Nutrition’s (CRN) 2019 Consumer Survey on Dietary Supplements, immune health is one of the top reasons survey responders said they take supplements. In the same survey, 27% of those who use dietary supplements cited immune health as a reason they take supplements.

Market sales reflect this interest. According to IRI, U.S. sales of immune health dietary supplements grew 12% annually in 2019. Global market sales of immune health supplements are also climbing. The sector was valued at $14 billion in 2017 and is expected to reach $25 billion by 2025, according to a forecast by Persistence Market Research.

Many health issues drive interest in immune support, but in 2020 people around the world are especially worried in light of the coronavirus outbreak.

The number of deaths and infections was rising daily and containment measures were getting more drastic around the world. Experts also said it’s possible that, like influenza, outbreaks of COVID-19, the disease caused by the coronavirus, may occur seasonally.

These concerns compound consumers’ existing worries about negative influences on their immune health, such as:

• The growing global population (crowding and competition for resources cause physiologic stress)
• An aging world population (the immune system gets weaker with aging)
• Increasing environmental stresses

Immune System Support
Currently no vaccine exists for the coronavirus, but development has top priority. Still, the availability of a vaccine could be a year off. Further, U.S. agencies regulating dietary supplements (e.g., FDA, FTC) have made it abundantly clear that supplements are not allowed to make any claims whatsoever for prevention or treatment of coronavirus, or any diseases.

With that said, medical experts have routinely stated that having a strong immune system is important for all people, especially for those most vulnerable to illness (e.g., the elderly, the chronically ill, the immune compromised). There are numerous nutritional ingredients supported by scientific evidence shown to help support a healthy immune system. It is well beyond the scope of this column to address these; however, a summary of one class may be insightful.

It’s no surprise that consumers are looking for products and ingredients to get help for their immune systems. Beta glucans are one of the newest. They’re well-grounded in science with more than 1,000 published articles in the scientific literature attesting to their efficacy.

Beta glucans are chains of glucose molecules linked by 1,3; 1,4 or 1,6 β-glycosidic bonds. [Glycosidic bonds connect a carbohydrate molecule (such as glucose) to another molecule.] Beta glucans are naturally present and act as storage depots and structural components in bacteria, fungi, algae, and cereals.¹ The physical conformation of 1,3 beta glucans, their chemical structure and composition, and their molecular weight affect the extent to which they can stimulate and support the immune system.²

Among the existing configurations of beta glucans, only 1,3 beta glucans stimulate and support the human immune system. They do this in three important ways:
1) 1,3 beta glucans directly prime B cells (components of the innate immune system), activating them to release chemokines and proinflammatory cytokines as a first line defense. Chemokines attract immune cells that destroy invaders. Proinflammatory cytokines provoke inflammation, a normal part of the immune response.³  

2) Recognition of 1,3 beta glucan by Dectin-1 (a protein in white blood cell membranes) activates the adaptive immune system by “turning on” genes that direct a rapid increase of T and B lymphocytes capable of attacking the specific pathogen. Each of the new T and B lymphocytes are identical to the original and fight the same pathogen. The effect is long-lasting, antigen-specific, and maintained over time by memory T cells.⁴

3) 1,3 beta glucans exert a prebiotic effect on the GI tract. Prebiotics are a substrate that is selectively utilized by host microorganisms conferring a health benefit.⁵ The prebiotic activity of 1,3 beta glucans act in two important ways in the GI tract: they specifically fuel beneficial GI microbiota, enabling them to flourish and compete against pathogenic bacteria for space and food; and they travel undigested to the large intestine where microbiota metabolize them, producing short chain fatty acids (SCFA) that intestinal cells use for fuel. 

Feeding and maintaining the health of intestinal cells maintains GI tract integrity so it can act as a physical barrier to invading pathogens. Barrier function is critical because the GI tract is not sterile. Its 25-foot length is open at both ends, exposing it to environmental microbes and pathogens. Once these entities enter the GI tract, they can easily pass through the single cell wall thickness of the GI tract to enter general circulation. Fortunately, they are met on the other side and disposed of by gut-associated lymphoid tissue (GALT).⁶ Keeping the GI tract healthy keeps GALT healthy and functioning.

While we think of the digestive tract primarily as the organ for digesting food and absorbing nutrients, it’s also the body’s largest immune organ. Approximately 70% of immune cells reside in the human intestine.⁷

1,3 beta glucans enter the proximal small intestine where they are captured by GALT macrophages. After the 1,3 beta glucans are released from the macrophages, they are taken up by circulating immune cells—granulocytes, monocytes and dendritic cells, stimulating the immune response.⁸

One of the newest sources of 1,3 beta glucans is Euglena gracilis. This microalgae produces 1,3 beta glucans, storing them in cellular granules called paramylon. E. gracilis is attractive because it sustainably produces a biomass that is high in 1,3 beta glucans and is a source of protein and micronutrients. Because paramylon is surrounded by a simple cell membrane and the 1,3 beta glucans are highly crystalline, harsh solvents and extraction processes aren’t required. This is beneficial because chemical, physical, and enzymatic treatments can alter the molecular structure and functionalities of β-glucans.² 

As important as a healthy immune system is, science supports the fact that constant boosting of the immune system is not always beneficial. It can be contraindicated for people with allergies or autoimmune disease. Research also shows that continual stimulation of the immune system may be detrimental because it may cause immune fatigue. While there is promise, our best advice continues to be to consult with healthcare providers regarding ways to improve immune health. Overall, supporting the immune system through lifestyle choices, nutritional enhancements and, when indicated, pharmaceutical interventions can be important to a healthy and long life. And don’t forget to wash your hands! 

References

1. Bashir KMI, et al. Clinical and physiological perspectives of β-Glucans: The past, present, and future. Int J Mol Sci. 2017;18(9):1906. doi:10.3390/ijms18091906.
2. Bin D, et al. A Concise Review on the Molecular Structure and Function Relationship of β-Glucan Int. J. Mol. Sci. 2019, 20(16), 4032; https://doi.org/10.3390/ijms20164032
3. Ali MF, et al.  β-Glucan–Activated Human B Lymphocytes Participate in Innate Immune Responses by Releasing Proinflammatory Cytokines and Stimulating Neutrophil Chemotaxis. J Immunol.  2015; 195 (11): 5318-5326; DOI: https://doi.org/10.4049/jimmunol.1500559.
4. Sun L, et al. The Biological Role of Dectin-1 in Immune Response.  Int Rev Immuno. 2007; 26:5-6, 349-364, DOI: 10.1080/08830180701690793
5. Prebiotics Nature Reviews: Gastroenterology & Hepatology (2017). DOI: 10.1038/nrgastro.2017.75. Expert consensus document.
6. Erickson KL, et al.  Assessing mucosal immunity with new concepts and innovative, time-honored strategies. Nutr Rev. 2009;67 Suppl 2:S172-82. doi: 10.1111/j.1753-4887.2009.00238.x.
7. Chan, GCF. et al.  The effects of 1,3 beta-glucan on human immune and cancer cells. J Hematol Onc. 2009; 2(1):25 DOI: 10.1186/1756-8722-2-25.
8. Barsanti L, et al. Chemistry, physico-chemistry and applications linked to biological activities of β-glucans.  Nat Prod Rep. Mar;28(3):457-66. doi: 10.1039/c0np00018c. Epub 2011 Jan 17.

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Gregory Stephens
Windrose Partners

Greg Stephens, RD, is president of Windrose Partners, a company serving clients in the the dietary supplement, functional food and natural product industries. Formerly vice president of strategic consulting with The Natural Marketing Institute (NMI) and Vice President of Sales and Marketing for Nurture, Inc (OatVantage), he has 25 years of specialized expertise in the nutritional and pharmaceutical industries. His prior experience includes a progressive series of senior management positions with Abbott Nutrition (Ross Products Division of Abbott Laboratories), including development of global nutrition strategies for disease-specific growth platforms and business development for Abbott’s medical foods portfolio. He can be reached at 267-432-2696; E-mail: gregstephens@windrosepartners.com.

Sheila Campbell, PhD, RD

Sheila Campbell, PhD, RD, has practiced in the field of clinical nutrition for more than 30 years, including 17 years with Ross Products Division of Abbott Laboratories. She has authored more than 70 publications on scientific, clinical and medical topics and has presented 60 domestic and international lectures on health-related topics. She can be reached at smcampbellphdrd@gmail.com.