Blocking carbohydrate absorption and weight loss: a clinical trial using phase 2™ brand proprietary fractionated white bean extract

Alternative Medicine Review,  March, 2004  by Jay Udani,  Mary Hardy,  Damian C. Madsen

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Abstract

Background: Phase 2[TM] starch neutralizer brand bean extract product ("Phase 2") is a water-extract of a common white bean (Phaseolus vulgaris) that has been shown in vitro to inhibit the digestive enzyme alpha-amylase. Inhibiting this enzyme may prevent the digestion of complex carbohydrates, thus decreasing the number of carbohydrate calories absorbed and potentially promoting weight loss. Methods: Fifty obese adults were screened to participate in a randomized, double-blind, placebo-controlled study evaluating the effects of treatment with Phase 2 versus placebo on weight loss. Participants were randomized to receive either 1500 mg Phase 2 or an identical placebo twice daily with meals. The active study period was eight weeks. Thirty-nine subjects completed the initial screening process and 27 subjects completed the study. Results: The results after eight weeks demonstrated the Phase 2 group lost an average of 3.79 lbs (average of 0.47 lb per week) compared with the placebo group, which lost an average of 1.65 lbs (average of 0.21 lb per week), representing a difference of 129 percent (p=0.35). Triglyceride levels in the Phase 2 group were reduced an average of 26.3 mg/dL, more than three times greater a reduction than observed in the placebo group (8.2 mg/dL) (p=0.07). No adverse events during the study were attributed to the study medication. Conclusion: Clinical trends were identified for weight loss and a decrease in triglycerides, although statistical significance was not reached. Phase 2 shows potential promise as an adjunct therapy in the treatment of obesity and hypertriglyceridemia and further studies with larger numbers of subjects are warranted to conclusively demonstrate effectiveness. (Altern Med Rev 2004;9(1):63-69)

Introduction

Obesity is a dangerous and highly prevalent condition in the United States. Almost 61 percent of the U.S. population is either overweight (defined as a Body Mass Index (BMI) >25 kg/[m.sup.2]) or obese (defined as a BMI >30 kg/[m.sup.2]). Obesity increases the risk of several co-morbidities, including degenerative arthritis, obstructive sleep apnea, dyslipidemia, hypertension, diabetes mellitus, and coronary artery disease. In addition to health risks, obese individuals have lower quality of life evaluation scores (SF12) than their non-obese counterparts. (1) Fortunately, obesity is treatable and there is strong evidence that even modest weight loss

(5% of body weight) significantly decreases the risk of these diseases, especially diabetes and cardiovascular disease.

Pharmacological treatments are currently available for obesity, including serotoninergic agents (dexfenfluramine, fluoxetine), noradrenergic agents (sibutramine) and lipase inhibitors (orlistat). While each of these drugs has been shown to be effective as an adjunct to dietary modification and exercise, their utility is limited by side effects that include cardiac valvular disease, hypertension, seizures, sexual dysfunction, and fecal incontinence. (2)

The general public uses many other methods for weight loss, including non-prescription weight loss products (herbs, vitamins, and nutritional supplements) and meal replacement preparations. Scientifically rigorous studies have not been performed on these products, and in many cases safety and efficacy take a back seat to marketing.

The Phase 2[TM] starch neutralizer brand bean extract product ("Phase 2") is a water extract of a common white bean (Phaseolus vulgaris) that has been shown in vitro to inhibit the digestive enzyme alpha-amylase. (3-6) Phase 2 was previously sold as Phaseolamin 2250, purportedly referring to 1 g of the product blocking 2,250 starch calories. Alpha-amylase, secreted in saliva and by the pancreas, is responsible for breaking down starch to simple sugars that are absorbed in the small intestine. Blocking this digestive enzyme may prevent the digestion of complex carbohydrates, allowing them to pass through the digestive system. The end result of blocking alpha-amylase would logically be a decrease in the number of calories absorbed, potentially promoting weight loss.

Acute and chronic (90 day) animal toxicity studies to date have demonstrated no clinical or pathological toxicity associated with ingestion of Phase 2. (7,8)

A 2003 double-blind, placebo-controlled clinical trial (n=60) of Phase 2 versus placebo for weight loss documented a 4.0-percent loss of body weight compared with 0.47 percent in the placebo group after 30 days (p < 0.05). In addition, the experimental group demonstrated a 10.45-percent reduction of body fat. (9)

An earlier controlled crossover study (n=10) of Phase 2 versus placebo in normoglycemic individuals measured pre- and postprandial glucose levels. (10) The glucose levels of the Phase 2 group returned to baseline 20 minutes earlier than the placebo group. In addition. the area under the plasma glucose versus time curve (a measure of glucose absorption and metabolism) was 57-percent lower with Phase 2. These results suggest less glucose is absorbed in subjects taking Phase 2 and the absorbed glucose is cleared from the bloodstream more rapidly.