Oat beta-glucan is a soluble fiber that is found in the cell wall of whole oats. It is comprised of long chains of glucose and is a polysaccharide. This fiber is not digested. It binds toxins and cholesterol in the digestive tract and helps them to be excreted. This compound has been shown to help lower the levels of cholesterol in the blood.
The United States Food and Drug Administration (FDA) allows some food labels to claim that they may reduce the risk of heart disease, if certain conditions are met. To do this, one serving of a food must contain 3g of whole oat fiber, and be eaten daily in combination with an overall diet low in cholesterol, saturated fat, and fat. Whole oats include rolled oats, oat bran, and oat flour.
The mechanism by which oat beta-glucan is thought to lower cholesterol involves the secretion of bile from the gall bladder into the digestive tract. Bile contains toxins and cholesterol. If there is soluble fiber, such as oat beta-glucan, in the digestive tract, it can bind these compounds and excrete them in bowel movements. Otherwise, they may be reabsorbed by the liver and end up circulating in the blood. High levels of cholesterol can contribute to coronary artery disease.
There are other health benefits claimed for oat beta-glucan. For instance, there is some research that it can improve the immune system. This is the case for a number of beta-glucans. Also, it has been thought to improve blood sugar levels, which can help diabetics. It is also supposed to reduce hypertension.
One can buy supplemental oat beta-glucan powder to add to food, to increase the consumption of this compound. Its solubility is a great help in consuming it in this manner. Food manufacturers also use such a powder to increase the oat beta-glucan content of some foods. When used in this manner, it is thought to retain its ability to lower cholesterol levels.
Theoretically, oats should be a good source of fiber for those with Celiac disease. They do not contain gluten, the compound in wheat that aggravates this autoimmune disorder. They do, however, have another protein that can trigger a reaction in some people with Celiac disease. Unfortunately, in the United States, oat is often manufactured near wheat and becomes contaminated with it. For this reason, oats from certain European countries, where wheat is rarely grown, may be a better source of oat products for people who suffer from this condition.
There are a variety of beta-glucans — produced by grains, like oats and barley, as well as yeast and mushrooms — that vary in their solubility. These are all chains of glucose with a type of linkage, known as a beta linkage, that makes them indigestible. This is in contrast to polysaccharides of glucose, such as starch and glycogen, which are easily degraded as an energy source. Oat beta-glucan has a mix of two types of beta linkages, which cause branching and account for its solubility in water.