A Letter to The Editor:
White Bean Extract Safely Decreases Starch Absorption, Promotes Weight Loss
by Dennis Meiss, PhD
ProThera, Inc.

Editor:
The recent article, "Natural Weight-Loss Supplements: Are Safe Alternatives Available?” appearing in the May 2002 issue of this Letter, unfortunately contains several errors about potential toxic side effects associated with natural weight loss products. In particular, the inference that people may be hurt due to potential mitogenic, mutagenic, and cytotoxic effects of extracts from the kidney bean Phaseolus vulgaricus (sic), is unnecessarily inflammatory and lacking in evidence.

The author even goes so far as to suggest that in a few years "…it is conceivable that there may be a whole lot of people with gastrointestinal cancer.” And he implies that this is the result of the lack of technically competent people working for commercial companies that produce bean extracts. These alarming generalizations are not substantiated by current research or the history of the use of such products. It is unfortunate that the author fails to provide any citations to support the potential toxicity of commercial bean extract products. In truth, this is because there is no data showing that commercial products present a risk to health.

To the contrary, published reports have established the safety and efficacy of commercial extracts. Furthermore, bean amylase inhibitors have been in use for over 30 years without any reports of the type of health problems mentioned by the author.

The comment that "Legumes, in general, are known to contain large amounts of lectins,” is true. Phytohemagglutinin (PHA), the lectin of kidney beans, is a toxic carbohydrate binding glycoprotein. The toxicity of PHA to both humans and animals is well established. However, the major error of the article is the information that is left out. In particular, the dangers alluded to are connected to raw or undercooked beans. Unfortunately, the author lumps all the seeded classes of Phaseolus vulgaris together — from the large red kidney bean to the small white navy bean — which contain varying amounts of lectins.

Lectins are Readily Deactivated by Cooking

The author acknowledges that cooking destroys lectins in legumes, an effect confirmed by published research.1-4 Phaseolus vulgaris comprises several varieties of beans including kidney beans, navy beans, white beans, northern beans, red beans, black beans, and pinto beans,5 all of which, when cooked, are important food staples throughout the world.

However, to ignore this point and suggest that commercial bean extracts are improperly processed, need "technical people who understand the biology of what they are formulating,” possibly contain significant amounts of lectins, and present a health risk, without analyzing such extracts or interviewing the commercial extractors, is scientifically irresponsible. As previously mentioned, bean extracts have been commercially marketed for more than 30 years without any reports of toxicity.

Lectin content varies among the different types of Phaseolus vulgaris bean types. Mark A. Uebersax, PhD, Professor and Chairperson of the Department of Food Science and Human Nutrition, Michigan State University states that "lectins are most prevalent in large kidney beans and small white beans contain non-detectable levels.”6 Uebersax, who has extensively studied the lectins and phytohemagglutinin activity in these seeded classes, says, "Colored beans, particularly the large seeded kidney, are distinctly noted for high levels of these toxic proteins.” However, he points out that "lectins are readily deactivated during cooking procedures that render them palatable.”

In addition, he says, "The small white navy bean does not possess detectable levels of the active lectin. Neither the raw (uncooked) or cooked (heat treated) seeds will provide the active lectin principle in appreciable quantities to be of health concerns.”

Commercial Extracts

Pharmachem Laboratories, Kearny, New Jersey is one the largest manufacturers of bean extracts. Their product, Phase 2™ (formerly Phaseolamin and Phaseolamin 2250), is manufactured through a proprietary process from a portion of the white kidney bean. Low temperature processing (140-160°F) for several hours removes all lectins from the product.6 Phase 2™ is considered Generally Recognized As Safe (GRAS) under DSHEA. A thorough review of the published literature has reported no toxic effects with ingestion of up to 10 grams and duodenal perfusion of up to 5mg/ml when administered to humans.7

In addition, Pharmachem has sponsored several recent studies demonstrating the efficacy and safety of Phase 2™. A preliminary review of these results has recently been published.8 A brief description of the studies is included here to help your readers understand the science behind the use of bean amylase inhibitors for natural carbohydrate control and weight loss.

Human Studies Show Efficacy, Safety

Two recent double-blind, placebo-controlled, cross-over studies on human subjects showed that starch absorption averaged 66% lower in the group taking Phase 2™, compared to the group on placebo.9,10 No negative side effects were observed.

A double-blind, placebo-controlled study of 60 human subjects, who took a Phase 2™ containing product, lost an average of 6.45 lbs. in 30 days, compared to those on placebo, who lost less than one lb., on average.11 Those participants on Phase 2™ also lost, on average, over 10% of body fat mass, more than 3% in waist circumference, and measurable percentages off their hips and thighs. There was no loss of lean body mass, and researchers said participants showed "good tolerability,” to the product.

Study Shows No Toxicity from White Bean Extract

Ramadasan Kuttan, PhD, Director, Amala Cancer Research Center, Trichur, India and R.C. Srimal, MD, a well-known Pharmacologist and former Director, Industrial Toxicology Research Center, Lucknow, India, who has worked on natural products during the last 30 years, recently completed an LD 50 Acute Toxicity Study of Phase 2™ in rats at a dose of 5 gram/kg body weight. Both Drs. Kuttan and Srimal have published their research in peer-reviewed international scientific journals and are well respected in the field of natural products.

They concluded that there is "absolutely no toxicity in Phase 2™.”

A complete summary of their findings is as follows:
• There was no mortality or adverse reaction in any of the groups after they were given the doses indicated above.
• There was no significant weight change in any of the animals.
• Food consumption in all the groups remained unchanged compared to controls.
• Liver function tests indicated that acute administration of the ingredient at the doses given did not produce any change in the liver function tests such as GOT, GPT, ALP, Bilirubin, total protein and Albumin/Globulin ratio.
• Acute administration of the ingredient did not produce any change in the renal function as indicated by serum urea, creatinine and electrolyte levels.
• Acute administration of the ingredient did not produce any change in the hematological parameters such as total WBC, differential count and platelets.
• The organ weights of the liver, kidney, spleen were unchanged upon treatment with the ingredient.
• There was no change noticed upon necropsy of the animals and histopathology of liver and kidney of the Phase 2™ treated group were normal and similar to controls.

Lastly, a long-term double-blind, placebo-controlled human trial involving 70 obese individuals (BMI=30 kg/m2) is currently underway with the results to be released by the end of the year.

Kidney beans have been an important protein source for centuries. As a result of the data presented here, I hope that your readers will recognize that bean amylase inhibitors are available as safe and effective adjuncts to a sensible weight management program.

While it is true that uncooked, large red kidney beans (Phaseolus vulgaris) contain lectins — a toxic, carbohydrate-binding glycoprotein (PHA) — the lectins are readily removed with cooking. Small, white navy beans of the same class contain such small levels of PHA that they pose no health concern. Finally, recent acute toxicity studies are showing absolutely no toxicity in a standardized, white kidney bean extract, Phase 2™.

It is unfortunate when negative conclusions are made about a product or supplement through insufficient research, or by providing selective information. It is a disservice to your readers if someone relying on inaccurate information is dissuaded from using a product or supplement that may be of benefit to them.

Dennis Meiss, PhD
ProThera, Inc.
4133 Mohr Avenue, Suite I
Pleasanton, California 94566 USA
925-484-5636
Email: dennis.meiss@protherainc.com

(Note: Dr. Meiss serves as a consultant to Pharmachem Laboratories and is involved in the design and interpretation of clinical trial results for Phase 2™. )

References

1. Carvalho MR, Sgarbieri VC. Relative importance of phytohemagglutinin (lectin) and trypsin-chymotrypsin inhibitor on bean (Phaseolus vulgaris L) protein absorption and utilization by the rat. J Nutr Set Vitaminol (Tokyo) 1998 Oct;44(5):685-96.
2. Venter FS, Thiel PG. Red kidney beans — to eat or not to eat? S Afr Med J 1995 Apr; 85(4): 250-2.
3. Toro F, Benshimol AL, Gonzalez Elorriaga M, Soyano A. Spleen and thymus histology and proliferative response of splenic cells in rats fed raw and cooked Phaseolus vulgaris beans. Arch Latinoani Nutr 1992 Dcc;42(4):395-402.
4. Grant G, More LJ, McKenzie NH, Pusztai A. The effect of heating on the haemagglutinating activity and nutritional properties of bean (Phaseolus vulgaris) seeds. J Sci Food Agric 1982 Dec;33(12):1324-6.
5. Duke JA. Handbook of Medicinal Herbs. CRC Press, Boca Raton, Florida, 1985, pp. 362-3.
6. Personal communication.
7. Jensen N, Everone CA, Rosenberg M. A study of the survival, bodyweights, health status, and food consumption of C57BL/6-SIM mice when given varying concentrations of raw bean meal and bean extract which contain Phaseolamin, an inhibitor of the digestive enzyme of carbohydrates, alpha-amylase. 1982, Pharmachem Laboratories, Data on file.
8. Meiss DE. Phaseolamin 2250: New, standardized starch neutralizer evolves from nearly 60 years of research. Health Products Business Dec. 2001, p. 56.
9. Vinson JA. Investigation of the efficacy of Phaseolamin 2250, a purified bean extract from Pharmachem Laboratories. Unpublished results, 2001.
10. Vinson JA, Shuta DM. In vivo effectiveness of a starch absorption blocker in a double-blind placebo-controlled study with normal college-age subjects. Unpublished results, 2001.
11. Ballerini R. Evaluation of the safety and efficacy of a food supplement for weight control through the reduced calories intake from carbohydrates vs placebo (double blind test). Unpublished results, EVIC Italia, 2001.

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