Beta-glucan is a large molecule that occurs in nature, made up from several sugar molecules. Such a compound is known in nature as a polysaccharide. There are several types of food that are rich in beta-glucan, among them cereals (in particular oats and barley) and some species of mushroom. Research has shown that beta-glucan might provide important health benefits and boost the activity and response of the human immune system.
The compounds grouped under the umbrella term beta-glucans (?-glucans) are actually several different types. What they usually have in common is the structure, with 1-3 ?-glycosidic bonds forming a straight linear backbone. However, their other properties vary depending on their origin. They can have different molecular mass, while viscosity, branching structure, gelation factor and solubility are also variable.
This group of ?-D-glucose polysaccharides is part of the cell walls of plants (in particular cereals), lichens, yeasts, algae, bacteria and fungi. There can be serious physicochemical differences between them, depending on the source. Their effects on animals can also be very different, with some having a significant bioactive influence, and can be used in human medicine as well.
?-glucans are considered to be part of the so-called "biological response modifiers". These can be found in the cell wall structure of several organisms, with the highest concentration in seaweed, yeast and fungi. They exhibit strong conservation characteristics and are physiologically active.
In human food, some of the richest sources for soluble beta glucans are cereals like oats and barley. These are popular for breakfast and can provide important health benefits. Scientific research has discovered that eating such cereals daily or taking supplements containing beta-glucan from cereals can decrease the levels of bad cholesterol (LDL) in the blood. According to these studies, the minimum oatmeal needed to provide the decreased cholesterol is 84 grams per day, while the minimum daily supplement is between 3 and 9 grams. However, the studies failed to confirm consistent results, these depend on several factors. Research has also found that beta-glucan consumption might lower sugar blood levels and increase overall stamina.
As for the insoluble variant of beta-glucan, the best sources are yeast and mushrooms. Very conveniently, the yeast with the highest beta-glucan content is the variety used in bakeries all around the world. The best mushrooms are the white mushrooms found in every supermarket, as well as varieties like shitake and crimini. The insoluble type found in yeast and mushrooms has a powerful effect on the human immune system, greatly boosting our defence against germs and confirming the old belief that mushroom consumption is beneficial for immunity. According to modern research, beta-glucan stimulates the response of white and killer-t cells in the blood stream. New studies have found that a stronger immune system might help in the fight against cancer and viral infections, while further research is still needed to confirm these results, it seems that beta-glucan might be a useful tool in the search of a cure for cancer.
At the same time, beta glucan might stop some unwanted immune responses of our body. Studies suggest that this compound not only boosts the immune system, but it also inhibits the production of super oxide anion or hydrogen peroxide. This could have far-reaching consequences and greatly reduce the severity of the widespread respiratory allergies that affect many people all around the world.
The mechanism behind these beneficial effects is that beta glucan acts like an immuno-modulator that raises the response time of the immune system and makes it adapt to external threats. This ability to modulate is the key, the immune system doesn't overreact, and it's activated just as much as needed. It never stimulates the immune response more than required, which makes it a very safe bioactive compound. A smarter immune response has been linked to the body's ability to fight against cancer.
Overall, studies have revealed the benefits of using beta glucans in the treatment of several serious and lethal diseases, including cancer, diabetes and even HIV/AIDS. They are very good in the treatment of numerous infectious diseases like the common winter cold, influenza, allergies, hepatitis, Lyme disease, aging-related infections, ulcerative colitis, rheumatoid arthritis, multiple sclerosis, otitis, asthma, Crohn's disease, fibromyalgia and even special deadly viruses like H1N1. Beta glucans are especially valuable for people who have a damaged immune system due to various causes like radiotherapy, chemotherapy, extreme stress or the chronic fatigue syndrome.
One of the most important benefits of beta glucan consumption is the reduction of the level of cholesterol. The mechanism is quite interesting: this compound is a soluble fiber that becomes a thick gel after being digested. The gel then absorbs excess cholesterol and prevents it from being released in the blood. This makes it extremely valuable in a balanced diet, for both patients with heart diseases and normal people.
The other major use of beta glucan is as a booster of the immune system. Clinical tests have shown that it stimulates the bone marrow, in particular the immune stem cells clustered in there. This increases the production and release of fresh immunocites in the organs of the lymphatic system and the blood stream, massively boosting the body's response against pathogens as well as cancer cells. This is crucial for people who undergo radiotherapy or chemotherapy, since it both attacks cancer cells supplementing the conventional treatment, as well as stimulates the weakened immune system. The conventional treatment is known to have the nasty side effect of decreasing the number of immunocytes, thus leaving the body vulnerable to infection.
A parallel anti-cancer effect of beta glucan is the release of other molecules that fight this lethal disease. This happens by stimulating various cells and organs to produce such compounds. Some of the substances are hydrogen peroxide, gamma interferon, as well as interleukins 1 and 6, which strengthen immunity and destroy tumours.
A constant supply of beta glucan is known to stimulate while cells like macrophages and neutrophils which are the body's first line of defence against viruses and germs. Besides fighting pathogens, these cells have other important functions. They repair damaged tissues, purify the blood stream by ingesting various impurities that are by-products of cellular metabolism and also identify and eliminate deviant cells that the ones that cause cancer.
Like some other soluble fibers, beta glucan is slowly digested and is released at a constant rate into the blood. This limits the rate of glucose absorption and prevents a massive spike in sugar levels, which can be very dangerous or even lethal. Balanced levels of blood sugar are the cornerstone of modern treatment of Type 2 diabetes and insulin resistance and might even stop both diseases from occurring in the first place. At least 4 grams of beta glucan are required every day in order to keep glucose under control, but this is a lower amount when compared to other types of fiber. This effect has been confirmed by a number of independent studies, which concluded that diabetes patients should include beta glucan in their diets in order to treat the disease.
The consumption of carbohydrates can increase the level of blood sugar, the chance of this happening is measured by the so-called glycemic response. In order to keep diabetes under control, it is very important to eat foods that result in a glycemic response as low as possible. Being a soluble type of fiber, beta glucan decreases the sugar intake and it has been proven that eating cereals can greatly decrease the body's glycemic response.
A low level of cholesterol is extremely important even for people who don't suffer from any type of heart disease. This is because lower levels of LDL cholesterol greatly reduce the chance to have a sudden stroke or heart attack. By becoming a thick gel during the process of digestion, beta glucan is able to bind with the bad cholesterol and prevent it from being processed by the body. This greatly lowers the stress on the heart and arteries and thus boosts the overall health of the human body.
Since long beta glucan has been known to be useful against cold and even cancer. It is still used empirically to treat infection and can be applied on the skin to reduce and eliminate problems like wounds, burns, diabetic ulcers, eczema, bedsores, dermatitis, radiation damage and even to get rid of wrinkles.
Products rich in beta glucan can also become part of a very successful diet. Like all fibers, it is slowly digested by the stomach. It takes longer to process it, which means more nutrients are absorbed but it also stays more in the stomach, which provides a sensation of fullness and prevents undesired snacks between meals. Its beneficial effects on the immune system are known but haven't been fully studied, so there is still potential for even further discoveries.