Quality, dose, use

I'm interested in the differences between glucans from yeasts and from oyster mushroom. I've read that glucans are extracted from oyster mushroom along with other substances contained in the mushroom, so they have synergic effects, unlike pure glucan from yeasts.

A simple question that necessitates a longer answer. It is true that mushroom glucans, including those from oyster mushroom, are often isolated together with many other substances. This is the main reason why mushroom glucans often have a very intense odour, which producers often conceal by adding all kinds of flavours or even alcohol.

But the other part of the question is not really true, the other isolated additives are basically impurities. Personally I'm not aware of any publication that would prove that other biological substances isolated from mushrooms together with glucan have synergic effects. It is not even possible in practice. There are too many substances (and different in case of each isolation and from each mushroom), let's say twenty, for simplification. And to prove the fact that the individual substances have synergic effects, I would have to characterize all twenty substances to full extent (i.e. knowing exactly what substances these are and how much of them there is in the product), and isolate and test them. And not only alone, but also with glucan and with all other nineteen substances. This is virtually impossible because the very number of combinations would employ a well-furnished laboratory for a long time. Of course, the producers of mushroom glucans did not do that and defend themselves in advance against possible questions on why here are so many impurities by stating that they are bio-active and beneficial. But it is just an excuse, used when the producer is not able or willing to isolate glucan better.

So far there are only four types of substances that we can demonstrably describe as having synergic effects with glucan - antibodies, antibiotics, vitamin C and resveratrol. Quite likely, there will be more of them but simply we do not have any proof. Even though work with glucan have been very intensive for over 30 years.

You mention the importance of the purity of the preparation. Why is it important and what is unclean glucan causes?

Of course, the purity of the product is essential for several reasons. Most producers honestly specify the mg content of glucans in one lozenge, and they have to do so legally. However, they are less active in specifying the percentage of impurities, while it is clear that if a lozenge contains 100mg of 50% glucan, the actual content is almost half of that in a lozenge with 100mg of 95% glucan. For your money, you therefore get only a half of the active substance.

However, there is another reason - we almost never know what the rest is. Sometimes they can be substances without any biological activity, and in that case there is only the problem mentioned above. However, impurities can also contain biological substances that can in essence reduce immunity, and then glucan can be virtually worthless. A part of the glucan molecule that binds to the immune cells can be wrapped up to some extent, so even a top-quality glucan will have a poorer efficacy. And the fact that glucans often contain impurities can be evidenced on glucans isolated from mushrooms, which often have an intense odour that producers sometimes try to conceal by adding alcohol or some flavourings.

After all, there are studies that pointed out that swallowing 2 tablets of 50% glucan is not the same as swallowing one tablet of 90% glucan. And because of such impurities, this "logical" approach does not work.

What is the highest purity achievable in glucan?

Theoretically, purity can near 100%, but practically this level of purity is not achievable. The yield would be so low that glucan would not be commercially saleable. We have to realize that the value on the vial, let's say 80%, does not fully reflect the reality. I don't mean that the producer would like, rather that 80% glucan A can be much more potent than 90% glucan B. The reason is, in addition to the differences in the individual glucans, also the fact that in some cases impurities can mean an addition of other substances (something similar to mixing flour with sugar - we still have 80% of flour). In other cases, however, sugar attaches to the flour and changes its properties, even though theoretically the ampoule also contains 80% of flour. And the same applies to glucan.

And what about the long-term use of beta-glucan and subsequent interruption of its use? Will the strength of the immune system drop back below the original level before the use of beta-glucan started, i.e. will the body be so used to beta-glucan and much weaker without it even than at the beginning?

Long-term use of beta-glucan in people has not been tested by anyone so far, all tests have rather dealt with the possible negative effect of long-term feeding to animals (where no problems were identified). However, we can derive with a significant level of certainty from our knowledge of the immune system that any fear is groundless. Although the immune system knows the term "memory", therefore the defensive system responds faster when it encounters an infection repeatedly, but this does not apply to the case you've mentioned. The defensive mechanisms will work better with glucan and when you interrupt using it, they will restore the level before glucan. The use of glucan can rather be compared to a situation when you give a better gun to a guard - he will guard better. However, if we take the gun back, he will guard just like in the past, before ho got the gun in the first place.

Dear Professor, at your website I read something to the sense that some preparations with beta-glucan are of a high quality, some not, or that it's worthless to buy products with crushed dried whole mushrooms etc. I would like to ask you if e.g. dried shiitake mushroom in the form of capsules is a useless investment in your opinion - regardless of the producer - and also if there is a magazine or something where everyone can learn non-commercial information on the efficacy of specific products and on products that just pull money out of people's pockets. Not only as regards beta-glucan, but nutritional supplements in general.

You're right, I say repeatedly that in case of beta-glucans (just like in case of most other products, and not only nutritional supplements, the same applies also to sausages) there are excellent products, but also average and absolutely worthless. And I also say, and can experimentally prove, that products containing only crushed mushrooms have minimum (or none at all) efficacy. By the way, it is the same with yeasts, otherwise pure kitchen yeast would already be a medicine. The problem is that our stomach cannot fully digest polysaccharides, only herbivores can do it, and we have to help it through isolation. Complicated isolation and purification constitute the biggest part of the price of beta-glucan.

As regards the other part of the question, there is no summary information available. Although I was thinking about establishing a kind of reference laboratory for some time that would test individual glucans and publish quality certificates, but it turned out that some producers known to offer glucans at lower end of the range of quality were not interested in any testing at all. It is possible that in the near future the Regulatory Commission of the EU will listen to you; it is preparing the obligation of producers of dietary supplements to prove what they promise on the package. But it won't be immediately.

And as regards pulling money out of our pockets - there is never enough caution. Although it is very hard to say which firm is good and which is not somewhere in a pharmacy or at the Internet, but there are many warning signs. Understandably, there is a difference if in its materials, a company offers publications that describe experiments on its glucan or if it only offers a nice-sounding marketing advertisement. Likewise, a text we have read three times somewhere is also a good warning. It is then clear that the firm copies texts from others without consulting an expert. And so, if we want to do something for our health without throwing money down the gutter, it is advisable to study the offer in detail. In case of glucan as well as sausages.

Are there any interactions between glucan and medicaments?

In spite of thousands of available publications on glucan, only very few interactions between glucan and medicaments have been described in literature. In fact, there is only one study in this vein that has been published several times. In all cases, it was the same group of researchers and no one has ever repeated the results. It dealt with interactions between injected glucan and indomethacin; the study pointed at the negative effects of the products administered simultaneously. Since these results were repeated in literature so many times and nobody tried to confirm if it is actually true, we tried to repeat this work of Japanese scientists this year. To make sure, we tested four different types of glucan and monitored injected as well as oral glucan. We did not observe any negative effects in any of the tested groups.