For thousands of years the appetite suppressing effects of Hoodia Gordonii were known only to the Bushmen of the Kalahari. Then in 1936 they were noted by a Dutch anthropologist, who went on to write a research paper the following year that quoted Bushmen directly on the subject.
The 1937 research paper inspired South Africa’s Council for Scientific and Industrial Research (CSIR) to study Hoodia and this included animal tests. In the 1960's the first proper clinical trial for Hoodia demonstrated that the weight of laboratory mice went down when Hoodia was administered. It was also noted that the mice suffered no ill effects.
Research into Hoodia at that time was limited by the technology of the day, with the result that it wasn't felt worthwhile to proceed to a human study. In fact it was to be many years before a study was conducted on humans, such a study eventually being performed in England in 2001. In this study a group of morbidly obese men and women were placed in a "phase 1 unit", an environment resembling a prison. All the volunteers could do was read, watch television and of course eat. Half the group were repeatedly given a large quantity of Hoodia and the other half were given a placebo. At the end of 15 days, the group on Hoodia had reduced their food intake by about 1000 calories a day.
Another clinical study was conducted on rats at Brown University in Rhode Island. This study revealed that the action of Hoodia's steroidal glycoside was directly on the hypothalamus, the part of the brain controlling appetite. This was established by injecting the compound into the brains of rats, the injections doubling the level of the chemical ATP in neurons located in the hypothalamus and reducing the rats food intake for the next 24 hours by 40-60%. The study suggests that the increase in ATP in the hypothalamus leads directly to the brain decreasing appetite.
Research is continuing into Hoodia and before long further clinical evidence of its effectiveness should be available.
Tulp OL, Harbi NA, Mihalov J, DerMarderosian A. Effect of Hoodia plant on food intake and body weight in lean and obese LA/Ntul//-cp rats. FASEB J 2001 Mar 7;15(4):A404.
Tulp OL, Harbi NA, DerMarderosian A. Effect of Hoodia plant on weight loss in congenic obese LA/Ntul//-cp rats. FASEB J 2002 Mar 20;16(4):A648
Habeck M. A succulent cure to end obesity. Drug Discovery Today, March 2002, pp 280-281.
Van Heerden FR, Vleggaar R, Horak RM, Learmonth RA, Maharaj V, Whittal RD. Pharmaceutical compositions having appetite suppression activity. United States Patent 6,376,657, issued April 23, 2002.
MacLean DB, Luo L-G. Increased ATP content/production in the hypothalamus may be a signal for energy sensing of satiety: studies of the anorectic mechanism of a plant steroidal glycoside. Brain Res 2004 Sep 10; 1020 (1-2):1-11.