Green Tea and Glucomannan

Rates of overweight and obesity have risen dramatically in recent years and continue to climb for many segments of the population. Recommendations for weight loss and weight management are to eat less and be more physically active.

Sounds simple…but many of you know this is much easier said than done. The truth of the matter is that eating less and exercising regularly are very challenging in the environment we live in today with busy schedules and access to many unhealthy foods.

Therefore, it is reasonable to consider strategies that are easily implemented that can give people an edge when it comes to achieving weight control. A super-class polysacharide called KGM-90, which is the highest potency, highest viscosity source available of konjac glucomannan, and green tea extremely rich in EGCG and total polyphenols.

These two complementary supplements are a proven to be effective, and most important an easy way to help promote safe weight loss and maintenance and enhance energy levels. Specific to weight control, KGM helps to inhibit appetite making it easier to restrict calories, whereas green tea primarily acts as a thermogenic to increase calories burned. Thus, together they make a perfect combination to facilitate weight loss. Following is some general information on each of these ingredients including a synopsis of the scientific evidence supporting their use for weight control.

KGM

Fibers are widely touted as having numerous health benefits[1-3], but not all fibers have the same physiological effects. Soluble fibers (such as those found in oats, dried beans and peas, barley, fruits such as oranges and apples) tend to form a gel when mixed with liquid, which results in several beneficial effects in the body such as lowering cholesterol levels, regulating blood sugar and insulin levels, decreasing appetite and promoting weight loss.

KGM is a type of soluble fiber with particularly potent effects. KGM is a storage form of energy in the plant Amorphophallus Konjac or konjac plant made of several simple sugars like starch, but it cannot be digested. KGM is very unique due to its tremendous water-holding capacity, up to 100 times its own weight.

Research has shown that in head to head comparisons, KGM has greater gel volume and viscosity properties compared to other soluble fibers[4]. Therefore it appears to be the ideal soluble fiber for assisting the promotion of weight and fat loss, suppressing appetite, controlling glucose and insulin surges, and lowering cholesterol.

The primary sources of KGM powder come from China and Japan. Because of the complex processing involved, it is not surprising that the quality of KGM powder varies widely in products sold and marketed to consumers in the US. Because the health benefits of KGM, and other soluble fibers, are directly linked to their viscosity (gel-forming capacity), it is critical that this characteristic is maintained during processing.

The highest quality KGM comes from a state-of-the-art manufacturing facility in Japan. They use advanced processing technology that effectively purifies the KGM without losing its molecular weight and viscous properties. Their highly refined KGM is a white powder that is virtually flavorless and odorless. In laboratory tests, the viscosity of this specific KGM is over 7x that of Chinese origin (120,800 vs. 15,700 mPa?s). Researchers in Japan have clearly shown that high-viscosity KGM is much more effective at reducing the increase in blood sugar to a meal compared to low-viscosity, commonly used glucomannan[5].

Since KGM works physically (by forming a gel), not enzymatically or chemically like other nutrients and drugs, it is an ideal supplement to promote weight loss without any side effects whatsoever. KGM primarily works by delaying stomach emptying and triggering satiety (a feeling of fullness). The viscosity of KGM is magnitudes higher than other soluble fibers like guar gum and pectin so this appetite reducing effect can be achieved with much smaller doses. A number of placebo-controlled studies have shown that relatively small amounts of KGM (1 to 4 g/day) enhance weight loss[6-11].

These effects are seen in studies that involved diets that were restricted in calories or free-living where no guidance to restrict calories was provided. In one study, it was shown that obese subjects provided 3 g of highly purified KGM/day for 8 weeks had a 5.5 pound weight loss and significant improvements in total and LDL cholesterol[11]. Subjects in this study were specifically instructed not to change their normal eating and exercise patterns and so it was not surprising that the placebo group experienced no changes in weight or cholesterol. In another double-blind, placebo-controlled study, overweight subjects provided 3 g of highly purified KGM/day for 8 weeks lost more than 8 pounds without any instructions to modify their diet[6].

This study had the strength of using a cross-over study design (all subjects participated in both the KGM and a placebo trial), which removes the problem of potential differences between groups because each subject serves as their own control. In a study of overweight patients with high blood pressure, KGM (3 g/day) provided to a group that restricted calories and a group with no caloric restriction, both lost more weight than a placebo group[8]. Weight loss after 4 weeks was slightly higher in the KGM group that also restricted calories (-5.3 pounds) compared to unrestricted group (-3 pounds).

In a follow-up study, these authors again showed superior weight loss and decreased cholesterol levels after 8 weeks of KGM (3 g/day) combined with a caloric restriction[9]. In a study of obese children provided highly-purified Japanese KGM and prescribed a balanced diet, weight loss, cholesterol and triglyceride decreases were significantly greater than a control group[7]. Other studies testing the combination of KGM with a reduced calorie diet show greater weight loss than caloric restriction alone[10, 12].

A recent randomized, placebo-controlled study compared the effects of different KGM supplements versus a placebo on weight loss[13]. Three groups took various doses of KGM ranging from 420 to 4320 mg/day and weight loss determined after 5 weeks of treatment. All the KGM groups experienced significantly greater weight loss compared to placebo (about 2-fold greater weight loss), but there was no difference between the various doses of KGM. The results suggest that KGM enhances weight loss and that relatively small doses (420 mg) are as effective as larger doses. Considering that most people regain weight because they cannot maintain caloric restriction over the long-term, the fact that KGM reduces food intake on the subject’s own volition is a major advantage over other diet approaches that rely on will power.

Further, KGM works through its high viscosity and gel-forming properties, not the sympathetic nervous system like other weight loss stimulants. KGM is believed to promote feelings of fullness by forming a gel in the stomach, which in turn sends signals to the appetite center in the brain that control hunger and satiation. Several subjects in the above studies reported feeling more satiated after taking KGM with water before meals.

KGM has other major health benefits that are independent of its effects on weight loss. A large number of studies have consistently shown that KGM taken prior to or with a meal significantly reduces the glucose and insulin response by as much as one-half[11, 12, 14-18]. This again is due to its powerful bulk-forming properties in the stomach, a function of the viscosity of the KGM product.

Green Tea

Green tea extract contains several polyphenolic compounds that have been shown in a large number of studies to have wide-ranging health effects including augmenting weight and fat loss[19]. The primary way in which green tea works is by increasing energy expenditure, rather than decreasing energy intake.

The bioactive compounds in green tea, polyphenols, account for a third of the dry weight of the leaves. The predominant polyphenols are the catechins and include epicatechin, epicatechin-3-gallate, epigallocatechin, and epigallocatechin-3-gallate (EGCG). Most research has focused on EGCG as the predominant active ingredient in green tea responsible for the thermogenic, antioxidant and anticarcinogenic effects.

In one of the first studies, green tea was examined for its ability to stimulate thermogenesis and fat oxidation[20]. Ten health men with a wide range of body fatness spent 24 hours in a whole room respiratory chamber on three different occasions. During these experiments, they consumed either 1) green tea extract containing 150 mg caffeine and 270 mg epigallocatechin gallate (EGCG), 2) 150 mg caffeine, or 3) a placebo.

The whole room respiratory chamber allows for continual measurements of energy expenditure and fat oxidation over a 24 hour period, as opposed to shorter time periods. There were no effects of caffeine compared to placebo but treatment with green tea extract was shown to increase 24 hour metabolic rate by 4% compared to a placebo. This amounted to an increase in energy expenditure of about 80 kcal/day. Furthermore, green tea caused a shift to greater fat oxidation over carbohydrate oxidation as evidenced by a significantly lower respiratory exchange ratio. There was also a greater urinary excretion of norepinephrine over 24 hours during treatment with green tea extract.

There were no adverse side effects including no differences between treatments in heart rate. These findings indicate that ingredients in green tea extract in addition to caffeine acutely stimulate thermogenesis and fat oxidation.

Several cell culture and animal studies provide clues to the mode of action by which green tea extract could stimulate thermogenesis and fat oxidation. Catechins inhibit catechol O-methyltransferase (COMT), the enzyme that breaks down norepinephrine[21]. Norepinephrine is a hormone that is released primarily from sympathetic nerves that stimulates cellular events that that lead to increases in cellular levels of cyclic AMP (cAMP), which in turn increases metabolic rate and breakdown of fat in cells.

Green tea also contains caffeine, which inhibits the enzyme phosphodiesterase. Phosphodiesterase breaks down cAMP in cells and thus can dampen the stimulatory effects of norepinephrine. Thus, green tea is hypothesized to work through the interaction of catechins and caffeine, which in synergy inhibit COMT (thus allowing norepinephrine to work longer) and phosphodiesterase (thus allowing cAMP to work longer in the cell)[22].

An inhibitory effect on COMT as a mechanism is supported by the finding in the study by Dulloo et al.[20] showing that green tea extract resulted in significantly greater urine norepinephrine levels, presumably reflecting less degradation and spillover into the circulation.

Other mechanisms of action that make green tea extract attractive as a weight loss agent have been identified. Researchers have shown that injections of EGCG cause fast weight loss in rats and that EGCG prevented further weight gain in obese rats[23, 24]. The mechanism in these studies was attributed to a significant decrease in food intake. In cell culture studies with fat cells, EGCG showed inhibitory effects on acetyl-CoA carboxylase (ACC), a rate-limiting enzyme in the biosynthesis of fatty acids[25].

In another study, green tea extract was shown to have potent inhibitory effects on fatty acid synthase, another rate limiting enzyme in biosynthesis of fatty acids[26]. In the same study, oral administration of the same green tea extract to overweight rats resulted in significant weight loss compared to controls. Collectively, these studies provide strong evidence that green tea contains bioactive and bioavailable substances that can help in the management of obesity through multiple mechanisms.

Importantly, while green tea appears to work primarily through the sympathetic nervous system hormone norepinephrine, it is distinct from other similar substances (e.g., ephedrine) that act through adrenergic receptors, in that green tea does not have adverse cardiovascular effects (e.g., increased heart rate, blood pressure, etc.).

Another study examined the effects of 12 weeks of green tea (containing 690 mg catechins/day) versus placebo on weight loss and several measures of body fat in men. After 12 weeks, men consuming the green tea had two-fold greater weight loss (-2.4 vs -1.3 kg) and fat loss (-1.4 vs -0.7 kg). Additionally, this study also assessed both subcutaneous and visceral fat in the abdominal region using computed tomography imaging. Compared to placebo, green tea had a four-fold greater effect on reductions in subcutaneous and visceral fat in the abdomen. The study shows that green tea is an effective method for losing fat, particularly in the mid-section[27].

Green tea capsules appear to be more bioavailable than liquid teas. In one study green and black tea were prepared with boiling water and allowed to steep for 5 min and compared to a green tea supplement as capsules[28]. All 3 teas had the same EGCG content. Flavanol absorption was greatest with the supplement in capsule form compared to the green and black tea. The green tea supplement also resulted in greater blood antioxidant activity. The study suggests that green tea supplements in capsule form are more bioavailability than green tea or black tea.

Summary

A high potency, high viscosity KGM and green tea rich in EGCG and total polyphenols, are a potent combination of ingredients found in Tetrazene ES-50 in ideal concentrations that ultimately work together to assist in restricting caloric intake while maintaining metabolic rate to achieve an ideal state conducive to weight and fat loss. The safety of these ingredients is well documented.