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Novel Fiber Limits Sugar Absorption

September 2004

Correlating Food Type and Obesity
According to the US Surgeon General, 60% of adult Americans are clinically overweight, having a body mass index of 25 or greater. Obesity has become so common that those who are not grotesquely overweight appear to look normal. These “normal” heavy people, however, suffer significantly greater incidences of disability and premature death.

Mounting evidence points to hyperinsulinemia as being a culprit in today’s obesity epidemic. One way to help reduce excessive insulin is by eating a low-glycemic diet. This means eliminating foods that induce the pancreas to over-secrete insulin. While people seeking to lose body fat know they should avoid sucrose and fructose, too often the craving for sugar (induced by hyperinsulinemia) results in binging on carbohydrate-rich food.

The food industry misleads the public into thinking that high-glycemic foods are healthy. Fruit juices, for instance, are promoted as a concentrated source of nutrients contained in fruit. The downside to juice, however, is that it is a concentrated form of quick-release fructose that can spike serum insulin. Eating whole fruit produces a gradual release of sugar into the blood. Once most fruits are juiced, however, they become catalysts for insulin overload because of their concentration of rapidly absorbable sugar.

Carrots rank high on the glycemic index, but because their glycemic load is very low, there is nothing wrong with eating carrots. Once carrots are juiced, however, the sugar is concentrated into a form that instantly hits the bloodstream and provokes an insulin spike. The moral to this story is to eat lots of fruits and vegetables, but avoid the juice. A look at the calorie content of a glass of fruit or vegetable juice confirms its fat-potentiating effects. For those concerned about obtaining adequate folic acid, vitamin C, alpha carotene, and similar nutrients, these can be obtained by eating whole fruits and vegetables and by taking supplements.

As shown in the sidebar on the previous page, foods that were once considered part of a healthy “low-fat diet” have a high glycemic index and high glycemic load. Ingesting these kinds of foods helps you gain weight, even though you think you are eating right.

The message for those seeking to lose some pounds is to reduce or avoid consumption of foods with a higher glycemic index/load. While this is not the entire solution to the obesity crisis, it is an important component. The problem is that it is difficult to suppress carbohydrate craving. Even when people know they should avoid sucrose-fructose foods, they too often succumb to an insulin-induced addiction and gorge themselves with ice cream, chocolate, and other sugar-laden desserts.

When it comes to the problem of high-glycemic diets, two obstacles must be overcome: cutting the craving for sugar, and changing eating patterns to avoid high-glycemic foods. A partial solution is to impede the rapid absorption of sugars into the bloodstream in order to reduce the accompanying insulin spike. This reduction in postprandial insulin secretion can help induce satiety and somewhat inhibit calorie intake. After six years of intensive research, a supplement is now available that interferes with the rapid absorption of sugar, thus reducing after-meal blood glucose and insulin levels by 23% and 40%, respectively.


While “low fat” or “fat free”appear on more and more food labels, a record number of Americans are overweight. The problem is that “low fat” often means “high sugar.” If you examine the labels of fat-free salad dressings, for example, you can see that they are loaded with sucrose or fructose.

Sugar is cheap and is a palatable alternative to oils that add fat calories. If you look at pasta sauce labels, for instance, you will find that most of them are loaded with “high-fructose corn syrup” or just plain old sucrose. Eating these sugar-fortified sauces with high-glycemic pastas and bread can create an enormous insulin spike. Fruit and vegetable juices feature healthy looking photos on their labels, but when you look at the calorie content of these sugar concentrates, you should seek to consume the actual fruit or vegetable in lieu of the juice. Even products that purport to have health benefits like tea beverages are usually loaded with sugar.

Food companies have duped Americans into believing that anything that is low in fat is beneficial. Consumers should carefully read food labels to make sure they are not inadvertently loading up on insulin-spiking sugar calories.

The Search for a Better Fiber
Scientific studies consistently document the ability of water-soluble fibers to inhibit carbohydrate absorption, reduce cholesterol and low-density lipoprotein (LDL), and induce some weight loss.33,34 When taken before meals, these fiber sources bind to water in the stomach and small intestine to form a gelatinous, viscous mass that slows the absorption of sugars and inhibits the re-absorption of intestinal cholesterol excreted from the liver. The net effect is a reduction in the number of absorbed calories and an induction of a feeling of satiety.

The problem until now is that the large quantity of fiber required to produce a meaningful effect has resulted in poor compliance, primarily because of upper and lower gastrointestinal-related discomfort.

In the early 1990s, scientists at the University of Toronto began to investigate a novel class of viscous fibers in order to identify a low-dose blend that would reduce blood glucose, insulin, cholesterol, and LDL levels. Initial studies confirmed the beneficial effects of these soluble fibers. Compared to placebo, those consuming highly viscous fibers before meals showed improvement in glycemic control, blood lipid levels, and blood pressure.35,36 The problem, however, remained—these beneficial effects could be produced only by ingesting large amounts of this fiber.

To overcome this problem, the scientists tested hundreds of different fiber blends with the objective of achieving significant benefits from only a few grams of soluble fiber per meal.

One of the initial findings that motivated the University of Toronto scientists to pursue this research occurred during a study that measured the glycemic-index response to different forms of fiber (or no fiber). In this study, three grams of various fibers were administered prior to a 20-gram glucose challenge. As expected, the glycemic index of the control group receiving no fiber was 100. Those receiving three grams of psyllium and xanthan showed only negligible glycemic index reductions (3% and 6%, respectively). By contrast, test subjects receiving three grams of a novel fiber blend showed a remarkable 39% reduction in their glycemic index. This finding demonstrated that consuming just three grams of this highly viscous fiber before a meal could significantly reduce the number of insulin-spiking carbohydrate calories absorbed.37

Using the Most Viscous Fibers
Glucomannan possesses the greatest viscosity (gelling property) of all known soluble fibers.37,38

Four to five grams of glucomannan blended into fluid or mixed with food can slow carbohydrate absorption into the bloodstream and dampen the ensuing insulin spike by up to 50%.39 Controlled clinical studies document that glucomannan can promote satiety and induce modest weight loss.40-43 It has been shown to significantly lower LDL and total cholesterol, improve diabetic control, and correct constipation.29-31,33-38,40-43

The reason glucomannan has fallen by the wayside is that in the 1980s, programs promoting quick weight loss advertised glucomannan as a supplement that could make obese people thin. The FTC stepped in and aggressively attacked those who were making exaggerated fat-loss claims for glucomannan. The subsequent negative reports by the news media caused glucomannan to be viewed by the public as a worthless dietary supplement.


The glycemic index is a way of calculating the rate by which blood glucose levels rise in response to different food types, with pure glucose producing a reading of 100. The glycemic index measures how fast a particular food triggers a spike in blood glucose. Higher-glycemic foods prompt an elevated insulin release because the pancreas is stimulated to metabolize the sudden surge of glucose into the blood.

The published scientific studies on glucomannan, however, are quite impressive. Although it does not make fat people thin, a double-blind trial showed that compared to placebo, obese subjects taking one gram of glucomannan before each meal lost 5.5 pounds after only eight weeks.40 The subjects were instructed not to change their eating or exercise patterns. Total cholesterol and LDL also were reduced (by 21.7 and 15.0 mg/dL, respectively) in the glucomannan-supplemented group. No adverse reactions to glucomannan were reported.

Several other published studies confirm that glucomannan modestly reduces weight compared to placebo or diet alone.41-43 Total cholesterol and LDL, along with after-meal insulin and glucose blood levels, are significantly reduced when glucomannan is taken before meals.41-43

With this knowledge of glucomannan as a foundation, University of Toronto scientists led by Vladimir Vuksan, PhD, combined glucomannan with two other viscous fibers (xanthan and alginate) in an exact ratio to increase the viscosity of the original glucomannan material by 2.5-5 times.44 A mulberry concentrate (20:1) was added to enhance the glycemic-control and lipid-lowering effects.48

The primary benefit of this proprietary fiber blend lies in its superior viscosity. This means that it is better able to expand in the gastrointestinal tract to inhibit sugar absorption and bind cholesterol. This enables much smaller quantities to be taken than of other viscous dietary fibers to achieve comparable health benefits. The fiber blend’s trade name is PGX™, which stands for “polyglycoplex.”

Studies Confirm Effectiveness
At last June’s 64th Annual Meeting of the American Diabetes Association, held in Orlando, FL, the results of two studies using the PGX™ fiber blend were presented by researchers from the Risk Factor Modification Centre at St. Michael’s Hospital and the University of Toronto.53 The first study reported on test subjects who took three grams of the fiber blend, followed by a huge 50-gram acute glucose challenge. Compared to the control group, those taking the fiber blend had a 65% reduction in postprandial glucose elevation.

The second study was performed over a three-week period to better reflect real-life experiences. Study subjects took three grams of the fiber blend three times a day before meals. After three weeks, there was a 23% reduction in postprandial glucose, a 40% reduction in after-meal insulin release, and a 55.9% improvement in whole-body insulin sensitivity scores. In addition, this proprietary fiber blend reduced body fat by 2.8% from baseline by the end of the three-week study period.

As a result of these findings, a large, longer-term clinical study has been initiated to further evaluate this unique fiber blend’s effects on weight loss.

By Dale Kiefer

Type II diabetes is reaching epidemic proportions in the developed world as obesity rates continue to climb. While the American Diabetes Association estimates that diabetes affects about 17 million Americans, some medical professionals believe this figure vastly underestimates the true scope of the pandemic. An additional 16-20 million people probably suffer from a precursor condition known as pre-diabetes.45

Patients with glucose-handling difficulties are at increased risk of developing life-threatening conditions ranging from heart disease and stroke to blindness, nerve damage, depression, and kidney disease. These dire secondary complications are the result of excess glucose in the bloodstream (hyperglycemia). Too much “sugar” (glucose) damages blood vessels and the tissues they support.

Blood sugar rises when cells become “resistant” to the normal effects of insulin, which ordinarily shepherds glucose molecules across the cell membrane into the cell’s interior, where it is burned for energy. As body fat rises, production of a hormone called resistin increases, rendering cells deaf, so to speak, to insulin’s knock at the door.46,47

Evidently, mulberry leaves contain substances that reverse this defect. In a study conducted in India, patients with type II diabetes were randomly assigned to one of two groups.48 One group took glibenclamide, a drug that stimulates pancreatic insulin secretion and is prescribed to certain type II diabetics. Patients in the second group received three grams of mulberry leaf powder taken with each of three daily meals. Treatment continued for 30 days.

Before treatment began, researchers measured a variety of parameters that collectively provide a detailed picture of a patient’s lipid status and glucose-handling abilities. These parameters were measured again at the end of the 30-day trial.

Patients taking mulberry leaf had significantly lower fasting glucose, while the decrease in the glibenclamide group was statistically insignificant.

While glibenclamide subjects enjoyed some minimal improvements in their blood lipid profile, the changes were not statistically significant, except for triglycerides, which fell by 10%. Mulberry patients, on the other hand, experienced striking improvements across all lipid parameters, including a remarkable 18% increase in highly desirable HDL. The biggest change was a dramatic drop in harmful LDL. While glibenclamide patients saw no significant change in their levels of this artery-clogging lipid, mulberry patients saw their LDL decline by 23%.

The research team also measured changes in lipid peroxidation in plasma, urine, and red blood cell membranes. Lipid peroxidation occurs when lipids are oxidized in the body, rendering them yet more harmful. One of the goals of antioxidant therapy is to prevent this harmful process (common among diabetics) from occurring. Plasma and urinary lipid peroxidation dropped significantly in both groups, but the effect was stronger among mulberry patients. Only mulberry significantly improved lipid peroxidation and decreased cholesterol in red blood cell membranes. As the researchers noted: “Mulberry therapy is highly effective against lipid peroxidation when compared with glibenclamide treatment.”48 This finding has also been seen in diabetic rats.49 These results indicate that mulberry not only reduces harmful lipids and apparently improves sensitivity to glucose, but also possesses beneficial antioxidant properties.

This antioxidant activity probably reflects mulberry’s own defense and repair mechanism at work. Japanese researchers showed in 2001 that stressed mulberry leaves produce chemicals that mop up free radicals in leaf tissue.50 Free radicals, which are responsible for harmful lipid peroxidation in humans, are also damaging to plant tissue.

Previous (and subsequent) research has shown that rodents with experimentally induced diabetes also experience dramatic improvements when fed mulberry leaf.49, 51,52