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Research on Beta Glucans:
A Healthy Natural Secret of Cereals
Beta Glucans - Beta glucans are large polysaccharide molecules that form the cell wall structures of some cereal grains, particularly barley and oats. Barley has been domesticated for over 10,000 years, and is thought to be the oldest continuously cultivated grain in the human diet. In more recent times, science has explored and identified many important nutritional and health benefits of these cereals. Oat bran, specifically as a rich source of beta glucans, was extensively studied and earned the first U.S. FDA Health Claim for its cardio-vascular benefits, along with a healthy, balanced diet that is low in fats. Unfortunately, much of the processed food in our everyday diets arrives at the table with little of the healthiest components that are found in the original whole grains.
Extensive research, including a large number of human and animal trials, have been conducted over the past 30 years to assess the effects of cereal beta glucan. These clinical trials have shown that there are significant bioactive effects on human and animal systems, ranging from improving digestive system functions to anti-tumor activity. Significant findings are also noted in studies of larger groups of people showing lower incidences of colorectal cancers and cardiovascular diseases among those who consume higher levels of soluble cereal fibers in their diets.
The evidence is mounting to suggest that the human body is designed to consume much higher levels of fiber (at least 25-30g/day), including the critical soluble fibers (beta glucan and similar polysaccharides), on a daily basis than most Americans get in their diets (the current average is about 12g/day). The evidence connects the low levels of fiber in our diet with increased odds of getting one or more of the chronic diseases of middle and later life. (for more detail, see scientific studies)
Dozens of research studies show that cereal beta glucans are an especially bioactive kind of soluble fiber. Their particular pattern of molecular bonds makes them totally resistant to our digestive enzymes, so they pass through the stomach and small intestine unchanged. On the journey however, they are remarkably adept at trapping and binding fats and other potentially harmful molecules in a web of active fibers. The primary activities that have been studied and documented are as follows:
- Satiety is the complex bodily sensation that indicates that the stomach is full and it is time to stop eating. When consumed 20-30 minutes ahead of mealtime, beta glucans that absorb many times their volume in water and form a thick, viscous fluid in the stomach and small intestine. The satiety effect reduces the body's desire for more food intake, helping to naturally control weight when combined with a healthy, balanced diet and adequate exercise.
- High serum cholesterol levels in the blood are a major risk factor for coronary heart disease. Research on large populations indicate that people who maintain the healthiest combinations of low LDL (bad) cholesterol, high HDL (good) cholesterol and low levels of triglycerides are 4 times less likely to die of heart attacks than those with unhealthy combinations.
Cereal beta glucans have been widely studied and shown to be very effective in helping to reduce LDL cholesterol and triglyceride levels. The viscous solution formed by beta glucans traveling through the digestive tract is effective in binding lipids (fats in foods) carrying them along in a dense web of fibers. Trapped lipids have limited exposure to the intestinal walls where nutrients are absorbed into the bloodstream and then to the liver, where they are made into LDL cholesterol. Scientific studies also shows that beta glucans are active in binding certain bile acids in the digestive tract that otherwise contribute to the synthesis of cholesterol. Numerous clinical research studies show LDL cholesterol-reducing effects (in the range of 8% - 20% reduction) from daily consumption just 3 to 6 grams of cereal beta glucan. The cholesterol lowering effect is best achieved by consuming beta glucans during or just prior to eating a meal.
- Blood sugar or blood glucose is the essential fuel that is used by all the cells in the body, in the presence of insulin. Most simple sugars in foods and beverages are quickly digested by enzymes in the stomach and are rapidly absorbed when exposed to the walls of the small intestine, raising blood sugar readings for several hours as cells absorb glucose. The same is true of most of the carbohydrates that are reduced to simple glucose by digestive enzymes in a relatively short time. The Glycemic Index has been developed as a measure of the effect of various foods on blood sugar. Sustained high levels of blood glucose are associated with diabetes and other serious health conditions.
Barley beta glucan increases the viscosity of the digestive tract trapping simple sugars along with water, which reduces the exposure of sugars to the intestinal wall. The result is that sugars are absorbed more slowly into the blood, and less of total sugar in foods is exposed to the intestinal walls before entering the colon. Research shows clearly that beta glucans can modulate the glycemic effect following meals, extending the length of blood sugar cycles - smoothing the peaks and valleys. Much of the research has been focused on mild type 2 diabetics and the effects of beta glucan on helping lower post-prandial (after meals) blood sugar levels. There is also good evidence that regular daily consumption of these soluble fibers can help susceptible individuals postpone or preclude progression to more serious health conditions. The glycemic effect is best achieved by consuming beta glucan along with healthy, well-balanced meal.
- Human immune cells, called macrophages, contain surface receptors for certain special carbohydrates, such as beta glucan. When beta glucans are present at those receptors, macrophages become more active in proliferating and releasing the multi-faceted immune response to pathogens. In fact the early scientific interest came about several decades ago when it was found that these molecules had strong bioactivity with cells in the immune system. For this effect beta glucans must enter the bloodstream through the intestinal walls or be in direct contact with immune cells, as might happen on an open skin wound.
Research studies over 40 years have demonstrated these effects for beta-glucans of cereal origin (with1-3, 1-4 linkage) and of yeast/mushroom origin (with 1-3, 1-6 linkage). The evidence indicates that all 1-3 linked beta glucans are effective, despite unsupported claims by yeast advocates to the contrary. Most research studies indicate that relatively small amounts (50 mg to 100mg) of beta glucan appear to be effective as an immune booster, when taken well before meals to ensure good uptake.
- Every human colon hosts vast numbers of bacterial organisms that are essential for life. Healthy bacteria, such as bifidobacteria and lactobacillus, live by fermentation of complex carbohydrates (glucans and some other fibers), and in turn make short chain fatty acids (butyrate, proprionate, etc.) that are critical raw materials needed to form the immune system. Beta glucan promotes the growth of the healthy bacteria, and in turn reduces the habitat for unhealthy bacteria (e.g. e.coli, clostridia) that can produce toxins.
Fermentation products, such as butyrate, that have been widely studied for their apparent capacity to inhibit the development of colon cancers and to promote a healthy environment in the colon. Epidemiology studies of large population groups a famous study of American nurses and another of Finnish men, show that consumption of higher levels of cereal fiber is associated with significantly reduced levels of digestive cancers, including colon cancers, as well as heart disease.
- The cereal antioxidants in Systane™ products are active chemical structures that are powerful scavengers of “free-radicals” that cause major damage to the body’s tissues. Free radicals are by-products of the basic chemical process of the body, the “burning” of nutrients to fuel the cells. These free radicals are chemically aggressive ions that bind with body tissues and can cause damage to organs and even modify DNA. They are one of the major forces in causing what we know as the aging process.
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