Phase 2 Clinical Evidence

International Journal of Medical Sciences
Celleno L, et al. A dietary supplement containing standardized Phaseolus vulgaris extract influences body composition of overweight men and women. 2007 4(1):45-52. 

Topic: 
Can white bean extract help overweight adults lose weight?

Background:
White bean extract is believed to promote weight loss by interfering with the digestion of carbohydrates.

Study Type:
Human clinical intervention trial

Study Design:
Randomized, double-blind, placebo-controlled. Subjects took white bean extract or a placebo before a carbohydrate-rich meal, were weighed and had other body measurements taken.

Subjects:
60 slightly overweight subjects, whose weight had been stable for at least 6 months

Dosage:
445 mg/day for 30 days

Results:
Compared to subjects in the placebo group, subjects in the treatment group had greater reductions in weight, BMI, fat mass, adipose tissue thickness, and the circumference of their waists, hips, and thighs. On average, they lost almost 4.5 lbs of fat while maintaining lean body tissue.

Conclusion:
Compared to subjects in the placebo group, subjects in the treatment group had greater reductions in weight, BMI, fat mass, adipose tissue thickness, and the circumference of their waists, hips, and thighs. On average, they lost almost 4.5 lbs of fat while maintaining lean body tissue. 

The Open Nutraceuticals Journal 
Vinson J, Hassan A, and Shuta D. Investigation of an Amylase Inhibitor on Human Glucose Absorption after Starch Consumption. 2009;2:88-91. 

Topic: 
How effective is white bean extract at inhibiting carbohydrate absorption?

Background:
Blocking the absorption of carbohydrates can reduce calorie intake and promote weight loss. In vitro studies have shown white bean extract can inhibit the action of amylase, an extract that converts starches to sugars. How effective is white bean extract at reducing carbohydrate absorption (as glucose) in humans?

Study Type:
Human clinical observation trial

Study Design:
In the first phase of the trial, subjects fasted and then consumed bread and margarine with and without white bean extract. Their carbohydrate absorption was measured as area under the plasma glucose time curve. In the second phase of the trial, subjects ate a full meal, with and without the white bean extract, after which their glucose levels were measured.

Subjects:
11 subjects in first phase, 7 subjects in second phase

Dosage:
In the first phase, subjects who took the white bean extract absorbed 66% less carbohydrate (as glucose). In second phase, carbohydrate absorption was reduced by a non-significant 28-41%. Thus, the decrease in absorption was dose-dependent.

Results:
In the first phase, subjects who took the white bean extract absorbed 66% less carbohydrate (as glucose). In second phase, carbohydrate absorption was reduced by a non-significant 28-41%. Thus, the decrease in absorption was dose-dependent.

Conclusion:
The bean extract has in vivo efficacy for inhibition of starch absorption and may prove beneficial in weight reduction in individuals consuming large amounts of starch. It also may inhibit starch-induced hyperglycemia in normal and diabetic subjects.

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Alternative Therapies 
Udani J and Singh B. Blocking carbohydrate absorption and weight loss: a clinical trial using a proprietary fractionated white bean extract. Jul/Aug 2007;13(4):32-37. 

Topic: 
Does white bean extract promote weight loss?

Background:
White bean extract has been shown to inhibit the digestive enzyme alpha-amylase in vitro. Can this effect lead to weight loss in humans?

Study Type:
Human clinical observation trial

Study Design:
Randomized, double-blind, placebo-controlled. Subjects took a dose of white bean extract twice a day before meals in conjunction with a weight loss program including diet, exercise and behavior changes.

Subjects:
25 healthy subjects

Dosage:
1,000 mg/2 times a day for 4 weeks

Results:
Both the treatment and control groups saw significant weight loss and reduction of waist size. The treatment group lost more weight than the control group (6 lbs versus 4.7 lbs) but this difference was not statistically significant. However, further analysis of the date revealed that subjects in the treatment group who ate the most carbohydrates lost the most weight (8.7 lbs) compared to those in the placebo group who ate the most carbohydrates (1.7 lbs). Waist size also decreased significantly (3.3 inches versus 1.3 inches) in the high-carbohydrate white bean extract group, compared to the high-carbohydrate placebo group.

Conclusion:
Both the treatment and control groups saw significant weight loss and reduction of waist size. The treatment group lost more weight than the control group (6 lbs versus 4.7 lbs) but this difference was not statistically significant. However, further analysis of the date revealed that subjects in the treatment group who ate the most carbohydrates lost the most weight (8.7 lbs) compared to those in the placebo group who ate the most carbohydrates (1.7 lbs). Waist size also decreased significantly (3.3 inches versus 1.3 inches) in the high-carbohydrate white bean extract group, compared to the high-carbohydrate placebo group. 

Alternative Medicine Review 
Udani J, Hardy M,Madsen DC. Blocking carbohydrate absorption and weight loss: a clinical trial using Phase 2 brand proprietary fractionated white bean extract. 2004 Mar;9(1):63-9. 

Topic: 
Can white bean extract help obese adults lose weight and lower their trigylcerides?

Background:
High levels of triglycerides are a risk factor for hardening of the arteries, heart disease and stroke. Obese people are at higher risk for all these maladies. Can white bean extract help?

Study Type:
Human clinical observation trial

Study Design:
Randomized, double-blind, placebo-controlled. Subjects took white bean extract twice daily with meals.

Subjects:
27 obese adults completed study.

Dosage:
1,500 mg/2 times a day, for 8 weeks

Results:
Subjects in the treatment group lost an average of 3.79 lbs, compared to 1.65 lbs in the placebo group. Triglyceride levels in the treatment group fell by 26.3 ml/dl, compared to 8.2 ml/dl in the control group. The results were not statistically significant, possibly due to the small sample size.

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.

 

 

Phase 2 Mechanism of Action

White kidney beans (Phaseolus vulgaris) contain natural glycoproteins also known as phaseolamin, which inhibit the starch-digesting enzyme alpha-amylase. Because starch consists of glucose molecules joined together into very large starch molecules (glucose polymers), the starch must first be converted to glucose before it can cross the intestinal wall into the bloodstream and be absorbed. By interfering with this conversion and thus reducing the calories that can be absorbed from carbohydrates, white kidney bean extract may help promote weight loss. Also, slowing of the rapid absorption of carbohydrates should have a beneficial influence on the insulin system that could, in turn, lead to less fat accumulation. 

Some carbohydrates have a naturally occurring form that makes them resistant to alpha-amylase and thus they enter the colon mostly undigested, where they are fermented by bacteria. These resistant starches promote fat burning. Starch blockers like white kidney beans may have a similar effect.