Hoodia gordonii for Weight Control, Stephen Holt* MD, LLD (Hon.), FRCP, MRCP (UK), FACP, FACG, FACN, FACAM and Thomas V. Taylor** MD, ChM, FRCS, FACG *.
To the editor, Lancet: Hoodia gordonii is a succulent plant from South Africa that has putative, appetite-suppressant properties. Hoodia has been used as a dietary supplement, derived by drying the aerial parts of the plant or as a source of extracted steroidal glycosides to induce weight loss in experimental animals and humans. Ethno-botanical studies document the use of whole, fresh, plant material by San Bushmen, as a way of suppressing appetite, thirst and hunger pangs during nomadic hunting expeditions in desert regions of South Africa. Animal and limited human studies have shown that extracts of Hoodia gordonii can reduce body weight in free feeding rats and obese subjects, but full disclosure of this drug development research has not been made in the medical literature.
Much information about the potential of Hoodia gordonii as a non-stimulant, appetite suppressant has been presented in the media. Hoodia has become one of the best-selling weight loss supplements in North America and certain regions of Western Europe, in many different formulations of branded dietary supplements.
Extracts of Hoodia gordonii are being actively researched by major food and pharmaceutical corporations as potential food additive ingredients or as templates for synthetic drug manufacturing. Given the importance of calorie control as a means of impacting the global epidemic of obesity, the commercial market for this new technology is estimated to be tens of billions of dollars. Patents have been and continue to be filed by commercial organizations on specific extracts of Hoodia or the use of Hoodia in combination with other nutrients or botanicals in dietary supplements.
In vitro studies: Sixteen batches of bulk powder alleged to be Hoodia gordonii were examined by infrared spectroscopy, with a view to defining a fingerprint for dried and ground whole Hoodia plant which typically results in a 20 to 1 concentrate. Thirteen samples were received from a bulk supplier of Hoodia powder where the material could be verified to be of South African origin from harvesters of Hoodia gordonii. Three specimens were obtained from three other bulk suppliers of alleged “Hoodia powder” that is sold for use in dietary supplements. These three batches of material were purchased by US suppliers in Eastern Europe, China and Canada, with an unknown initial point of geographic origin. Replicate measurements of infrared absorbance showed much variation in spectroscopic profile of the three latter samples, implying variation in the characteristics of the bulk powder, but the spectroscopic profile of the Hoodia powder of documented South African origin (13 batches) was consistent, implying consistency of the bulk material.
Using simple microscopy the powder from China was found to contain fibers with the general appearance of cellulose. The two specimens of powder from China and Canada appeared to contain unidentified leaves and tiny woodchips, implying adulteration or lack of origin from the plant Hoodia gordonii. In addition, the sample from China contained significant amounts of crystalline material. The purpose of these initial studies was to search for a consistent and reliable bulk supply of Hoodia gordonii for use in the dietary supplement Hoodia Supreme® (Natures Benefit Inc., Little Falls, NJ, USA).
Further testing by standard food analysis showed six of the thirteen batches of Hoodia that had consistent spectroscopic profiles to contain approximate chemical contents of protein 3.7g, carbohydrate 80g, dietary fiber 12g, fat 0.4g, moisture 5.7g, ash 10.5g, calories 335kcl, Vitamin A 85iu, Calcium 800mg, Ion 14mg, Sodium 445mg with negligible fat content per 100g of powder. The tested material was free of significant heavy metal contamination.
Random samples from five of the thirteen batches of Hoodia powder, with a consistent spectroscopic profile, were submitted for chemical analysis of their steroidal glycoside and related chemical content to two independent laboratories for two of six samples and four of the six samples were tested by one independent laboratory.
Both laboratories tested for four marker components, including steroidal glycosides, by extracting compounds with organic solvents. One laboratory tested by HPLC (six samples) and the other by TLC (two samples). The four measured markers included alpha-formyl-pyrrolidone, n-carbamylputracenen, P57-isoberberine alkaloid and steroidal glycosides. All tested samples revealed measurable amounts of the markers, including P57, a steroidal glycoside molecule that has been used as a principle template for drug research.
There was variation in the amounts of measured markers in all samples and samples tested by HPLC and TLC showed variation in content of the markers. These chemical analyses provided a method of further demonstrating the fidelity of the Hoodia bulk powder from South Africa and confirming that it contained chemical compounds that have been described as possessing appetite suppressing and other properties. These results imply differences in amounts of similar marker compounds can be expected to occur with different methods used for laboratory measurement.
In vivo studies: Eight obese individuals (2M.6F, age range 43 to 59 years, average age 49 years) received the dietary supplement Hoodia Supreme® (www.naturesbenefit.com) in an open-labeled, observational study of the ability of Hoodia gordonii, to form an adjunct for weight control. All eight subjects received 400mg of Hoodia Supreme® in a vegetable capsule twice daily. The subjects had their weight measured sequentially and effects on appetite were assessed by direct questioning. All of these subjects lost weight during the study period, with an average weight loss of 9 pounds (range 2-15) over a four week period. All reported a reduction in appetite and a voluntary reduction in calorie intake, estimated at a reduction of approximately 500 to 1000 calories per day (assessed by dietary recall). All subjects reported a reduction in craving for carbohydrate containing foods and 75% admitted to a mild energizing effect that they attributed to the taking of the Hoodia capsules.
Discussion: The folklore history of the use of Hoodia gordonii as an appetite suppressant has been confirmed in several animal and human observations. Our preliminary studies show that it is possible to produce a dietary supplement from whole Hoodia plants which appears to have promising adjunctive properties for weight control in preliminary experiments in humans. These findings contradict claims that it is not possible to source a Hoodia dietary supplement with appetite suppressing properties with a satisfactory content of biologically active substances.
It is alarming that many products labeled as Hoodia gordonii may contain other plant material or may be adulterated. Arguments prevail concerning the acceptance of Hoodia gordonii as a safe dietary supplement, but this plant has been in the food chain of South Africa and other countries for centuries and it is believed to be a grandfathered, dietary supplement ingredient, under the US Dietary Supplement Health and Education Act of 1994 by many commercial enterprises in the US, but industry regulators may disagree. Retailers of dietary supplements and consumers must ask for verification of the authenticity of the Hoodia used in nutritional supplements. We believe that Hoodia gordonii is one of the most important ethnobotanical discoveries of the 20th century and if our earlier observations are confirmed in better constructed, controlled studies, the contents of this plant may revolutionize the management of obesity or overweight status, when used as a drug or dietary supplement.