Beta-Glucans and Immune Function

November 16, 2015

Beta Glucan: Immune Booster 

  Reference: Nutrition Journal 2014 

 Published:  Nov 16, 2015 

 Ever heard of the immune boosting effect of mushrooms? Of course. Shiitake mushrooms from Japan or Lengzhi from China have been used in Asia for millennia to boost immune function. They exist in the cell walls of yeast, fungi, and some seaweeds. They play an important role in the building blocks of the cell wall of yeast and fungi.   We are familiar with cellulose, the building block of wood and trees.   That is a β-glucan linked from the 1 to the 4 positions of adjacent glucose molecules.   It plays no role in immune modulation, but it sure holds trees together nicely.   

The β-glucans we are interested in are linked at the 1-3 position.   What we call starch or glycogen is made of glucoses hooked together at the 1-4 or 1-6 site. So, β-glucan is only slightly different than cellulose (wood) or glycogen (human) or starch (potato, rice, bread). They are all glucose molecules hooked together at different places on the glucose molecule. Humans can neither digest or synthesize β-glucans, hence we have to recognize them as foreign. And that is precisely what your immune system measures and evaluates – the different structures and connections of glucose on the surface of various invaders – bacteria in particular.

 It only makes sense that your immune system would get a boost. Yeast have β- glucan on their surface.   We don’t want yeast to invade you. Β-glucan becomes a useful tool to “boost” your immune system.  And yeast becomes the means by which we can “manufacture” it as a supplement. What do they do inside you? Well, your gut M cells (FBI of the gut) identify them, capture them, transport them into your Peyer’s patches in your gut from whence they are transported to local lymph nodes, spleen, and bone marrow.   In the bone marrow, you can show that granulocytes get activated and proceed to go out and kill tumor cells.  

But wait, there is more. You also activate the B cell branch of your immune system that makes antibodies.   That requires you to absorb bigger chunks of β-glucan that are too big to dissolve in water. And your phagocytes (those cells that gobble up bacteria whole) get equally turned on with β-glucan.   This means that just about every arm of your immune system gets activated, turned on, focused. Is there research to support that taking β-glucan as a supplement will reduce illness? 

Well yes.   Auinger showed decreased colds in a randomized, controlled trial from Europe in 2013. Graubaum showed the same in 2012. He gave 100 subjects β-glucan for 26 weeks and demonstrated a significant reduction in colds and progression of colds to severe symptoms. And then there is cancer.   We don’t have good randomized studies yet, but tons of testimonials claiming otherwise unexplained improvement. Testimonials shouldn’t be taken as proof, but they should be taken seriously as cause for curiosity. The mechanisms make sense. And cancer succeeds by tamping down the immune system, reducing fever and generally hiding from the immune system. 

Β-glucans reawaken that masking effect. Now, the European Food Safety panel has evaluated the efficacy of β-glucan for the prevention of colds and rejected the claim based on criticism that the questionnaire used to evaluate cold symptoms has not been validated.   So, there you have it. There is pretty good evidence that it works, with in-vivo experiments down to the bone marrow. There are statistical studies showing fewer colds, but using research methods that don’t quite pass muster.   And you have a couple thousand years of Chinese and Japanese healers noting that it works. You decide. 

 WWW. What will work for me.   Well, I’m stymied by the number of colds I get when I travel. Sitting on an airplane with 300 other people in close quarters seems to be risky. I’m going to try it this winter. And I think it makes sense for anyone with cancer to add Shiitake mushrooms or β-glucan supplements to their regimen. Maybe not every day, but at least once a week.   

 Pop Quiz  

  1. β-glucans are closely related to glucose? T or F                         Answer:  True. They are branched strings of glucose hooked together in a way we can’t digest.
  1. In nature, β-glucans show up in mushrooms, fungi, yeast and seaweed. T or F               Answer:    True
  1. Our gut immune system rejects β-glucans and refuses to digest them. T or F                Answer:   False. We don’t digest them, that’s true but we take them up and ship them all over our bodies, even to our bone marrow where we turn on our immune system to recognize them.
  1. There are pretty good studies that show they reduce the symptoms of the common cold. T or F                   Answer:   True, if you accept the questionnaire that has not been validated as good enough.
  1. There is no evidence that β-glucans are toxic.                     Answer:   Yup.
  1. If you had cancer, there are plausible mechanisms shown to explain why so many people claim to have great results with β-glucans in slowing down their cancer.                 Answer:   True. With a lot less toxicity than many of our current chemo drugs.