News & Updates

The Buzz on Beta-Glucans

Are beta-glucans poised to be the next it ingredient? A growing body of science indicates that beta-glucans promote health in a number of important ways. Some scientists even believe that beta-glucans show promise in reducing the risk of metabolic syndrome, a cluster of conditionsincluding obesity, high blood sugar, dyslipidemia and high blood pressurethat often occur together and can lead to heart disease. Since about 25% of Americans suffer from metabolic syndrome (a number that’s expected to double over the next 15 years), and coronary heart disease is the leading cause of death and permanent disability in the United States, beta-glucan is big news. It’s going to take some long-term studies to pull some of this information out, but I see barley and oats incorporated into an overall healthy diet that is high in beta-glucans as having a positive impact on metabolic syndrome, says Christine Fastnaught, Ph.D., barley food consultant, Fargo, ND.

In December 2005, FDA amended its regulation authorizing a health claim on the relationship between oat beta-glucan soluble fiber and reduced coronary heart disease by adding whole grain barley and certain drymilled barley grain products as additional eligible sources of that same fiber. The health claim is based on consuming 3 grams of beta-glucan soluble fiber daily; that can be divided into sub-doses as small as 0.75 grams each.

Beta-glucans occur in the bran of grasses such as barley, oats, rye and wheat, in amounts of about 7%, 5%, 2% and less than 1%, respectively. Yeast and mushrooms also contain this fiber. Glucans are polysaccharides made up of chains of glucose molecules. The term beta refers to the steric position of the glucose hydroxyl group involved in the chain formation. The terms beta-1,3- and beta-1,6-glucans are often used, with the numbers referring to the positions on the glucose molecules that link them together. Beta-glucans are considered to be water-soluble fiber in the diet and are non-digestible, due to the absence in the human body of an enzyme capable of hydrolyzing the beta-glucosidic linkage.

Dietary oats, oat bran, purified beta-glucans from yeast, and barley beta-glucans have been studied for their hypocholesterolemic effects. Proposed mechanisms that may account for their cholesterol-lowering properties include: reducing the intestinal absorption of cholesterol and bile acids by binding to glucans; shifting the liver from cholesterol syntheses to bile acid production; and fermentation by intestinal bacteria to short-chain fatty acids, which are absorbed and inhibit hepatic cholesterol syntheses.

Various studies have also shown that oat beta-glucans blunt the glycemic and insulin response. Oat extracts rich in beta-glucans were found to improve glucose tolerance and lower insulin output in moderately hypercholesterolemic men and women consuming a normal diet. In another study, oat beta-glucan reduced the glycemic index (GI) of a 50-gram carbohydrate portion by 4 units for each gram of beta-glucan. Modulating blood glucose concentrations following consumption of a carbohydrate-containing meal is another potential benefit area which holds promise for beta-glucans, says Mark Andon, Ph.D., director of nutrition at Quaker/Tropicana/Gatorade, Chicago.

In addition, beta-glucans have been linked to enhanced macrophage, B lymphocyte and suppressor T cell action, and increased non-specific-host resistance to a variety of bacterial, viral, fungal and parasitic infections. Beta-glucans have also been linked to reducing blood pressure and inducing satiety that can lead to weight loss.

Will the day come when beta-glucans are splashed on food labels as prominently as antioxidants? While Quaker extols the heart-healthy benefits of oats on product labels, they have steered clear of the word betaglucan, instead choosing the term soluble fiber as easier to mentally digest. Lisa Carlson, M.S., R.D., director of professional marketing at Quaker, believes that consumers understand the message that soluble fiber helps lower cholesterol, but most don’t understand the benefits of beta-glucans.

Much of the evidence on beta-glucan promotes a food-based approach of increasing whole-grain cereal consumption for heart-disease prevention. Beta-glucan supplements will not deliver the same benefits as consuming beta-glucan-containing whole foods, such as oatmeal, says Andon. Old-fashioned oats contain about 2 grams of soluble fiber in 12 cup (uncooked), and steel-cut oatmeal contains about 2 grams of soluble fiber in 14 cup (uncooked).

Manufacturers can rely on ingredients such as barley flour or oat bran to pump beta-glucan levels in foods. A number of new products are poised to push beta-glucans even further. Cargill, Minneapolis, announced its new barley product, Barliv, with a 70% concentration of beta-glucans. George E. Inglett, an Agricultural Research Service chemist at the National Center for Agricultural Utilization Research in Peoria, IL, recently developed a barley and oat bran ingredient called Nutrim. ARS scientists at North Dakota Agricultural Experiment Station, North Dakota State University, published their joint registration of HiFi, a new spring oat cultivar with 50% more beta-glucan than regular oats. Nutritech International, Kristianstad, Sweden, launched Aktiv barley powder. OatVantage, made by Nurture, Inc., Missoula, MT, is an oat-bran concentrate containing 54% beta-glucans. Cevena, Edmonton, Alberta, created Viscofiber, a barley concentrate with 60% beta-glucans, or oat concentrate with 50% beta-glucans. Takeda-Kirin Foods Corporation, Tokyo, developed Pureglucan curdlan, which has a minimum content of 90% beta-glucans derived from microbial fermentation of glucose.

While research has focused primarily on the health benefits of beta-glucans from whole foods, some scientists are now exploring the effects of beta glucan-enriched products. Researchers from Lund University, Sweden, isolated beta-glucan from oats and incorporated it into three foods that do not normally contain beta-glucans: fruit beverages, readymeals and feta cheese. Results indicated that the isolate could be used in low amounts in such foods.

In a study performed at Maastricht University, Netherlands, researchers concluded that beta-glucan lowers serum concentrations of total and LDL cholesterol when incorporated into a fruit drink, without affecting plasma concentration of lipid-soluble antioxidants.

Beta-glucan appears to have all the earmarks of a winning functional food ingredient, as long as consumers are ready to recognize it by name.