Beta-glucan works, but how?
We know that β-glucan has a favourable effect on cholesterol and blood sugar level. Several studies have shown that β-glucans also have a positive effect on immune defences, but the mechanism behind this potential immune-modulating effect is not known.
What is beta-glucan?
β-glucan is a group of dietary fibres and is found in barley, oats, fungi and yeast, among other things. β-glucan consists of glucose molecules that are joined in such a way that they cannot be broken down by the body’s own enzymes. They can have different branching and chain length, depending on their biological source and the way in which they have been produced.
These are the mechanisms that Ph.D. Student Anne Rieder at the Nofima food research institute has been working on mapping. She has developed a new method that makes it possible to see if the measured effect is related to the β-glucan itself.
The method is based on enzymatic degradation. “This means that specially selected enzymes are used to cut the chain length of the β-glucan. If the desired effect disappears when the chain is cut, we know that it is the chain, and consequently the β-glucan, that works,” says Anne Rieder.
Developed a generic method
The method is generic, which means that it can be very useful for any research that wishes to study which macro molecules in food and dietary supplements could have a specific effect on immune defences.
A method has also been developed that can measure very small quantities of β-glucans in cell cultures and biological fluids.
“It has been shown that mice that eat β-glucan from grain or yeast are less often ill, and our studies have shown that β-glucans from grain can activate the complement system, which is a key part of immune defences”, explains tutor and research scientist Svein Halvor Knutsen of Nofima.
This knowledge was the starting point of the survey of how β-glucan ingested via food affects the immune defences in humans. “We found that the effective mechanism for grain β-glucans was different from what we thought, so we must continue to search for what other mechanism grain β-glucans might have,” says Anne Rieder.
The mechanism the researchers studied was the extent to which β-glucans from grain and yeast contribute to the secretion of certain immune response related signal substances from intestinal epithelial cells. It was found that only particle yeast β-glucan has such an effect. When the researchers arrive at the correct effective mechanism for the various β-glucans, the next step is to create β-glucans with special properties so as to maximise the effect.
Facts about the doctorate
Anne Rieder qualified as a food technologist at Universität Hohenheim in Germany. Her disputation was on 12 April at the University of Oslo’s Institute of Basic Medical Sciences. The title of the thesis is “Dietary immune-modulation – carbohydrate specific effects of cereal and yeast β-glucans” and the tutors are Professor Svein Olav Kolset, Institute of Basic Medical Sciences, University of Oslo, and research scientists Svein Halvor Knutsen and Stine Grimmer of Nofima.
This doctorate has been financed by the Foundation for Research Levy on Agricultural Products.
Anne Rieder is continuing at Nofima as a postdoctoral researcher. She will begin by working on analysis methods for investigating the effects of adding β-glucan to juice and grain products.