Supplements that claim to block carbohydrate absorption, known as carb blockers or more scientifically as amylase inhibitors, are sold as weight-loss aids. Blocking carbohydrate absorption lowers daily calorie intake, which results in weight loss. Ingredients vary from one product to another, allowing some to advertise their products as having the "most powerful" or "secret" weapons against weight gain. Most have several elements in common. More studies are needed to prove their benefit in weight loss.
Amylase Inhibitors
White kidney bean extract, also known as phaseolus vulgaris or phaseolamin, is the active amylase inhibitor in carb blockers. Phaseolus vulgaris binds with enzymes that break down carbohydrates so your body can use them for energy. The maker of Calorie Quencher, Vitamin Sources, suggests taking six capsules per day. A three-capsule serving contains 1,000 mg of phaseolamin, which they call Phase 2. Vitamin Sources also claim that 1,000 mg of phaseolamin blocks absorption of 2,250 starch calories, a difficult-to-prove claim. The average daily diet of 2,000 calories should contain between 50 and 55 percent carbohydrates, or around 1,000 calories from carbohydrate, according to the Merck Manual of Medical Information. In testing done in 1986 and 1987 at the Mayo Clinic and Boston Medical Center, considerably higher doses of purified amylase inhibitors, 2,900 mg and 3,800 mg in a single dose, showed some benefit in carbohydrate malabsorption. Do not take higher doses than specified on the supplement labels because higher doses can also cause side effects.
Chromium
Chromium, often in the form of chromium picolinate, is a common ingredient in carb blockers. Chromium, a trace element, helps metabolize carbohydrates. A 2008 Louisiana State University study demonstrated that 1,000 mg a day of chromium picolinate decreased food intake by between 200 and 400 calories per day in an eight-week study of 42 overweight women. Women felt less hungry and lost more weight than those taking placebo, lead author Stephen Anton, Ph.D., reported.
Chitosan
Chitosan, made from the shells of shrimp, crab, lobster or other shellfish, finds its way into some carb blockers, although the product is touted as a fat blocker. Several studies have shown no benefit in chitosan as a fat blocker, at least in the amounts normally contained in weight-loss aids. Taking 10 capsules of chitosan per day resulted in an increased fat excretion of only nine calories per day, Stephen Barrett, M.D. reports on Quackwatch. Because it takes a decrease of 3,500 calories to lose a single pound, decreasing calorie intake by nine calories per day does not increase weight loss.
References
- Vitamin Source: Calorie Quencher
- PubMed: Effect of a Purified Amylase Inhibitor on Carbohydrate Metabolism After a Mixed Meal in Healthy Humans; M. Boivin; 1987
- PubMed: Effects of Chromium Picolinate on Food Intake and Satiety; Stephen Anton; 2008
- PubMed: Impairment of Starch Absorption by a Potent Amylase Inhibitor; W.R. Brugge; 1987
- QuackWatch: Is Chitosan a "Fat Magnet?"; Stephen Barrett
- MetaboGold: Phase 2 Premium Carb Blocker
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