A report from Public Health England13 has said that the overuse of antibiotics is putting lives at risk. Studies have concluded that millions of routine operations could become life-threatening and experts have warned that a rise in drug-resistant bacterial infections risks pushing medicine “back to the dark ages”. The incidence of septicaemia, in which bacteria are resistant to at least one major antibiotic group, has risen by 35 per cent in four years. For vulnerable people, such as children, the elderly or people with compromised immune systems, antibiotic resistance can be life-threatening. It also significantly increases the risk of routine surgery, organ transplantations and childbirth.
Therefore, a new approach to protecting ourselves against bacterial infections is needed. The best way we can prevent and combat bacterial infections is by supporting our own excellent innate immune system to avoid initial infections and also to fight off infections by destroying pathogenic bacteria.
This blog focuses on the ability of specific polysaccharides, known as beta glucan, which are naturally found in certain foods such as mushrooms, yeast and oats, to support our immune function and therefore protect against infections.
what is beta glucan?
Beta glucan are an important structural component of cell walls in certain organisms such as bacteria, fungi and some plants. They come in different forms depending on the linkages between the monosaccharide (sugar) molecules. The numbers quoted after beta glucans refer to which carbon in the sugar ring the bond is formed between. For example in beta glucan 1-3 linkages there is a bond between the 1st carbon on one molecule and the 3rd carbon on another. Without getting bogged down in the biochemistry, this is important because research suggests that beta glucan with 1-3 and 1-6 linkages (referred to as beta glucan 1-3, 1-6), which can be found in the cell wall of a fungi known as Saccharomyces cerevisiae (also known as baker’s yeast), elicits the most potent effect on immune function when compared to other beta glucans with 1-3, 1-4 linkages (these latter are found in oats for example).
Beta glucan – how does it work?
Beta glucan are not synthesised by the human body and therefore are recognised as foreign. As they are found in the cell walls of fungi and bacteria the innate immune system recognises them as a potential pathogen, although they themselves do not possess the ability to cause an infection. The recognition of these specific molecules triggers the upregulation of the immune system.
Innate immune cells, unlike acquired immune cells, do not have the ability to recognise a wide range of antigens, however they carry on their surface an extremely important group of receptors called Toll-Like Receptors (TLR’s). TLR’s only respond to a limited number of compounds; but as these compounds are very basic elements in micro-organisms, and one or more of them occurs in every bacterium, virus and parasite, the TLR’s are able to recognise almost any infection and initiate an appropriate immune response. When they recognise a bacterial cell wall compound, for example lipopolysaccharide or a fungal wall compound such as a beta glucan 1-3, 1-6, they initiate an antimicrobial response involving heightened macrophage and dendritic cell activity (when the TLRs are exposed to viral DNA they elicit a different antiviral response). Therefore beta glucans stimulate the body’s own antibiotic reaction and are able to activate the innate immune response.1
After ingestion, beta glucan are taken up by macrophages in the gut associated lymphoid tissue (GALT) and are phagocytosed (eaten). Macrophages digest the beta glucan into smaller fragments and release these over time into the bloodstream. The fragments bind to receptors on neutrophil granulocytes and natural killer (NK) cells, priming them and making them more active. Neutrophils are involved in killing bacteria, and the NK cells destroy both virally infected cells and cancer cells; leading to increased resistance to infection, and enhanced apoptosis of abnormal cells.
Beta glucan can also evoke a response by the acquired immune system. When innate dendritic cells are activated they communicate the presence of a pathogen to the acquired immune system, warning that an infection is likely, and instruct naïve T helper cells to develop into TH1 cells, which have anti-microbial properties, rather than TH2 cells which are involved in allergic reactions. The resulting increase in the TH1/TH2 ratio has important anti-allergy effects.2,3
Intensive exercise, whilst excellent for health in many ways, is associated with reduced immune function due to increased cortisol release (an immune suppressor). Infections, particularly of the upper respiratory tract (URTIs), are common for endurance athletes. UTRIs are also significant in immunocompromised individuals particularly the elderly. Studies have shown that:
- Beta glucan supplementation maintains immune function in endurance athletes4
- Beta glucan supplementation reduces post-exercise URTIs in marathon runners4
- Daily oral beta 1-3, 1-6 glucan may protect against URTIs and reduce the duration of URTI symptoms in older individuals once infected5
- A study in healthy subjects showed a 20-25% reduction in common cold episodes with supplementation of yeast beta glucan 1-3, 1-6. It concluded that the yeast beta glucan preparation increased the body’s potential to defend against invading pathogens6
Further Support for the immune system:
Vitamin C – has multiple benefits for supporting immunity as it stimulates neutrophils and increases lymphocyte production, increases interferon production and has antioxidant and antihistamine properties. Vitamin C is found in most fruits, particularly berries and dark leafy green vegetables.
Zinc – improves cell-mediated immunity by increasing production of T-lymphocytes and regulating the function of white blood cells. Zinc can be found in meat, eggs, wholegrains and pumpkin seeds.
Vitamin D – is known to support healthy immune function and has been shown to be deficient in the majority of the population particularly over the winter months. Vitamin D can be manufactured by the skin from sunlight and obtained from the diet although it can be difficult to get sufficient from dietary sources; vitamin D is found in oily fish, butter and eggs. The government recommends supplementing 10ug of vitamin D all year round although many people may need a higher dose to maintain optimal vitamin D levels.
Vitamin A – is important for the function of neutrophils, macrophages and natural killer cells. Deficiency impairs innate immunity by impeding normal regeneration of mucosal barriers damaged by infection. Vitamin A is also required for adaptive immunity and plays a role in the development of both T helper (Th) cells and B cells.10 It is also essential for the maintenance and repair of epithelial tissue and therefore helps to maintain the integrity of the gastrointestinal lining. Oily fish and eggs are rich sources of vitamin A; orange and yellow vegetables provide beta-carotene, which can be converted to vitamin A in the body (although people with specific genetic mutations may be less efficient at making this conversion).
Selenium – studies have demonstrated an enhancement of both cell-mediated and humoral immune responses by increasing levels of selenium intake. Sources of selenium depend on the selenium content of soil and food but can be found in Brazil nuts, oily fish, eggs and seaweed.11
Iron – iron has been shown to enhance immune function and is particularly important in children, teenagers and women of reproductive age, who have increased iron requirement due to growth or menstruation, as well as being especially relevant for people with anaemia.
It is well understood that the gut plays an essential role in the health of the immune system and therefore when supporting immunity the gut should also be considered. The digestive system is home to 70% of our immune tissue, known as gut associated lymphoid tissue or GALT. GALT is comprised of lymphocytes in the mucosal epithelium and in the underlying connective tissue, mesenteric lymph nodes and Peyer’s patches (aggregates of lymphoid tissue). It is essential that such a large part of the immune system resides here as the lumen (inside) of the gut is in effect the external environment. The gut lining has an extremely large surface area, approximately the size of a tennis court, and therefore is the largest area of the body that is exposed to the outside world. The lumen is separated from the GALT by a single layer of epithelial cells which are infiltrated by B cells, T cells, macrophages, dendritic cells and M cells, all poised to ward off infection.8,9 It is also important to consider the microbiome (gut bacteria) which play an essential role in supporting and stimulating the immune system.
Healthy digestive function can be supported by:
- maintaining adequate zinc levels, zinc is very important for the production of stomach acid as well as for maintenance of epithelial tissue which lines the digestive system
- eating prebiotic foods such as baked apples, chicory and artichoke
- eating fermented foods such as kefir, sauerkraut and kimchi to support gut flora
- taking a multi-strain probiotic
- using digestive enzymes to improve nutrient digestion, if this is impaired
- drinking bone broths – make a broth from meat carcass (ideally organic) – this is high in the amino acid glutamine which supports the repair of the digestive lining
- increasing foods that support the liver such as brassicas, onions, garlic, rocket and watercress
- 1-3, 1-6 beta glucan are polysaccharides found in the cell wall of yeast and other fungi.
- 1-3, 1-6 beta glucan stimulate cells of our innate immune system, have anti-microbial properties and have therefore been shown to help support immune function.
- Studies have shown that 1-3, 1-6 beta glucan are able to prevent and reduce infections in both healthy and susceptible individuals.
- 1-3, 1-6 beta glucan also stimulate the acquired immune system and in doing so have demonstrated the ability to reduce atopic conditions such as allergies, eczema and asthma.
- The health of the gut is essential for immune function as 70% of our immune tissue is found in the gut. Gut health is heavily influenced by the microbiota, therefore, supporting a good balance of microflora is essential for immune function.
- Micronutrients which play specific roles in immune function include vitamins A, C and D and the minerals zinc, iron and selenium.
If you have any questions regarding the topics that have been raised, or any other health matters please do contact me (Helen) by phone or email at any time.
[email protected], 01684 310099
Helen Drake and the Cytoplan Editorial Team
Relevant Cytoplan Products
Immunovite – contains beta-glucan, vitamin C, zinc and selenium
Kid’s Immunovite – contains beta glucan, vitamin C, iron, zinc and selenium
Foundation Formula 1 – comprehensive multivitamin and mineral with iron for premenopausal women and teenagers
CoQ10 Multi – comprehensive multivitamin and mineral, additionally contains CoQ10 and beta glucan. Low iron. For postmenopausal women and men.
Cytobiotic Active – contains 8 strains of live native bacteria as well as prebiotic inulin
Vitamin D3 Drops – two drops contains 5ug (5ml contains 40ug). Alternative products: Vitamin D3 62.5 ug or Vitamin D3/K2 (100ug of each)
Vitamin A – Retinol Palmitate – 5000iu per capsule
Wholefood Zinc -7.5mg per capsule Alternative Products; Zinc Citrate – 30 mg per capsules Food State Zinc – 15mg zinc with 1mg copper
Wholefood Cherry C – vitamin C derived from acerola cherries. Alternative product: Organic Vitamin C
Wholefood Iron – 5mg per capsule
Food State Selenium – 100ug per tablet
- Stier H, Ebbeskotte V, Gruenwald J. Immune-modulatory effects of dietary Yeast Beta-1,3/1,6-D-glucan. Nutr J. 2014;13:38. doi:10.1186/1475-2891-13-38
- Hong F, Hansen RD, Yan J, et al. Beta-glucan functions as an adjuvant for monoclonal antibody immunotherapy by recruiting tumoricidal granulocytes as killer cells. Cancer Res. 2003;63(24):9023-9031. http://www.ncbi.nlm.nih.gov/pubmed/14695221. Accessed November 1, 2018.
- Inoue K, Takano H, Koike E, et al. Candida soluble cell wall β-glucan facilitates ovalbumin-induced allergic airway inflammation in mice: Possible role of antigen-presenting cells. Respir Res. 2009;10(1):68. doi:10.1186/1465-9921-10-68
- Talbott S, Talbott J. Effect of BETA 1, 3/1, 6 GLUCAN on Upper Respiratory Tract Infection Symptoms and Mood State in Marathon Athletes. J Sports Sci Med. 2009;8(4):509-515. http://www.ncbi.nlm.nih.gov/pubmed/24149590. Accessed November 1, 2018.
- Fuller R, Moore M V, Lewith G, et al. Yeast-derived β-1,3/1,6 glucan, upper respiratory tract infection and innate immunity in older adults. Nutrition. 2017;39-40:30-35. doi:10.1016/j.nut.2017.03.003
- Auinger A, Riede L, Bothe G, Busch R, Gruenwald J. Yeast (1,3)-(1,6)-beta-glucan helps to maintain the body’s defence against pathogens: a double-blind, randomized, placebo-controlled, multicentric study in healthy subjects. Eur J Nutr. 2013;52(8):1913-1918. doi:10.1007/s00394-013-0492-z
- Akramiene D, Kondrotas A, Didziapetriene J, Kevelaitis E. Effects of beta-glucans on the immune system. Medicina (Kaunas). 2007;43(8):597-606.
- Forchielli ML, Walker WA. The role of gut-associated lymphoid tissues and mucosal defence. Br J Nutr. 2005 Apr;93 Suppl 1:S41-8.
- Frei, Remo; Akdis, Mübeccel; O’Mahony, Liam (2015). Prebiotics, probiotics, synbiotics, and the immune system: experimental data and clinical evidence. Current Opinion in Gastroenterology, 31(2):153-158.
- Stephensen CB. Vitamin A, infection, and immune function. Annu Rev Nutr. 2001;21:167-92.
- Hoffmann PR, Berry MJ. The influence of selenium on immune responses. Molecular nutrition & food research. 2008;52(11):1273-1280.
- Stier H, Bischoff SC. Influence of Saccharomyces boulardii CNCM I-745on the gut-associated immune system. Clinical and Experimental Gastroenterology. 2016;9:269-279. doi:10.2147/CEG.S111003.