Phaseolamin starch blocker supplement, benefit and side effects, how well does it work? Will it help you lose weight?
September 20 2016 by Ray Sahelian, M.D.

Kidney beans, Phaseolus vulgaris (also called kintoki beans) contain an inhibitor of alpha-amylase, which has been named phaseolamin. Alpha-amylase is an enzyme that helps the breakdown of starches.
   Phaseolamin may reduce the rate or thoroughness of starches such as potatoes, pasta, bread, etc. from being broken down in the digestive tract into sugars.

Phaseolamin and weight loss
Do supplements of phaseolamin produce weight loss in humans? I am aware of one human research study with phaseolamin that has evaluated the effectiveness of this substance in weight loss. Another study used the combination of phaseolus with artichoke leaf extract for weight reduction.

Phaseolamin weight loss study
A Dietary Supplement Containing Standardized Phaseolus vulgaris Extract Influences Body Composition of Overweight Men and Women.
Int J Med Sci 2007. Cosmetic Research Center, dell'UniversitÓ Cattolica di Roma, Rome, Italy
A randomized, double-blinded, placebo-controlled study was done on 60 pre-selected, slightly overweight volunteers. The volunteers were divided into two groups, homogeneous for age, gender, and body weight. Phaseolus vulgaris extract and the placebo were taken one tablet per day for 30 consecutive days before a main meal rich in carbohydrates. After 30 days, subjects receiving Phaseolus vulgaris extract with a carbohydrate-rich, 2000- to 2200-calorie diet had greater reduction of body weight, BMI, fat mass, adipose tissue thickness, and waist,/hip/ thigh circumferences while maintaining lean body mass compared to subjects receiving placebo.
   Comments: This one study is encouraging, and I would like to see two or three more studies from independent centers to have a better understanding of the benefits and side effects of phaseolamin.

Diet Rx weight control management -
This natural appetite suppressant works without stimulants. Diet Rx has no phaseolamin, added caffeine, ephedra, ephedrine alkaloids, synephrine, hormones, guarana, ginseng, or stimulating amino acids. 

Benefits of Diet Rx - An effective diet pill
Decreases appetite so you eat less
Helps you maintain healthy blood sugar levels
Helps you maintain healthy cholesterol and lipid levels
Provides healthy fiber
Improves energy
Balances mood
Improves mental concentration and focus
Improves will power and choice of food selection

Other Weight control options to consider
Green tea extract is popular
Garcinia cambogia could help certain individuals
5-HTP is a nutrient that helps curb appetite in some individuals. 5-HTP, by converting into serotonin, can be used temporarily to improve will power and decrease the urge to eat until more established weight loss habits are in place.
Acetyl-l-Carnitine with lipoic acid, formulated by Dr. Sahelian is another option. Some users have reported an all day decrease in appetite when this product was taken before breakfast.
Hoodia is a cactus plant extract from the Kalahari desert in South Africa that has been getting a lot of attention lately.
Use stevia as a substitute for sugar.

Phaseolamin supplement summary
At this point I would like to see a couple of additional studies before I wholeheartedly recommend the use of phaseolamin for the purposes of weight loss. Losing weight is difficult and we have to go back to the true and proven methods of caloric restriction and exercise. The temporary use of certain nutrients, herbs, and combination products is justified. Phaseolamin may be one of these nutrients, particularly in combination with others.

Phaseolamin Research
J Med Food. 2014. An in vitro and in vivo study of the α-amylase activity of phaseolamin. We evaluated the polypeptide profiles, inhibition of human salivary α-amylase activity, and hemagglutination properties of a commercial phaseolamin sample. We also performed an in vivo assay to investigate the effects of a commercial phaseolamin treatment (100, 500, or 1500 mg/kg) over 20 days on the glycemia, body weight, and serum biochemical parameters (total cholesterol, triglycerides, alanine aminotransferase, and aspartate aminotransferase) of nondiabetic and streptozotocin-induced diabetic rats. The in vitro evaluation showed defined protein profiles, low hemagglutination activity, and high α-amylase inhibition. None of the experimental groups treated with phaseolamin or acarbose showed decreases in body weight. Our data demonstrate that phaseolamin inhibits amylase activity in vitro, reduces blood glucose levels, decreases or attenuates some of the renal and hepatic effects of diabetes in streptozotocin-induced rats, and could therefore have therapeutic potential in the treatment or prevention of the complications of diabetes.

Anal Chim Acta. 2008. Determination of alpha-amylase inhibitor activity of phaseolamin from kidney bean (Phaseolus vulgaris) in dietary supplements by HPAEC-PAD. Some dietary supplements, so-called 'starch-blockers', used to control overweight, are based on the protein concentrate of the kidney bean, known to contain high levels of the alpha-amylase inhibitor phaseolamin, which may hinder the digestion of complex carbohydrates, thereby promoting or supporting weight loss. Currently, methods to determine the levels of alpha-amylase inhibitor are based on the measurement of alpha-amylase activity using colorimetric methods that cannot be applied to dietary supplements because they are complex mixtures of different ingredients that may interfere with the measurement. The aim of this study was to develop an alternative method to determine the level of phaseolamin in dietary supplements, using high-performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD) to measure the amount of maltose resulting from the action of the enzyme porcine alpha-amylase on soluble starch in the presence and absence of the inhibitor. The assay described proved sensitive and accurate for use with both dietary supplements and raw materials.

Effects of decreasing intraluminal amylase activity on starch digestion and postprandial gastrointestinal function in humans.
Layer P,. Gastroenterology. 1986.
We used an amylase inhibitor preparation that markedly improves postprandial carbohydrate tolerance in humans to investigate the effects of decreased intraluminal amylase activity on digestion of starch and postprandial gastrointestinal and hormonal responses. Four fasting volunteers were intubated with an oroileal tube to obtain duodenal, jejunal, and terminal ileal samples. After intubation, subjects ingested 50 g of rice starch given with placebo; on the second day, starch was given with the amylase inhibitor. Compared with placebo, the amylase inhibitor significantly reduced duodenal, jejunal, and ileal intraluminal amylase activity by more than 95% for 1-2 h; increased postprandial delivery of total carbohydrate (glucose polymers in particular) to the distal small bowel; increased breath hydrogen concentrations; decreased intestinal water absorption and increased distal intestinal volume delivery to the distal bowel; shortened duodenoileal transit time but doubled postprandial gastric emptying time; reduced the early postprandial plasma glucose rise by 85% and eliminated the late postprandial glucose fall to below fasting levels; and abolished postprandial plasma concentrations of insulin, C-peptide, and gastric inhibitory polypeptide. Postprandial trypsin output was not influenced. We conclude that more than 95% inhibition of amylase reduces dietary starch digestion within the small intestine and uptake of dietary starch from the small intestine, markedly decreases postprandial release of insulin and gastric inhibitory polypeptide, and may alter postprandial upper gastrointestinal motor function.