The use of Hoodia in slimming pills has been dealt a blow when a new study found no evidence of weight loss, and recorded some potentially serious side effects. DietDoc responds.
November has been a busy time on the obesity research front. For years, ever since the CSIR started investigating the potential appetite suppressant properties of Hoodia gordonii extract, we have been waiting for studies to clarify if this plant compound actually can suppress the appetite and promote weight loss, and if it has any negative effects on health.
Well, we at last have greater clarity and it seems that Hoodia has failed to come up to expectations.
Negative Hoodia Results
The popular use of Hoodia gordonii extract in slimming pills was dealt a blow early in November, when the results of study conducted by Blom and coworkers (2011) at Unilever Research & Development in the Netherlands were published in the American Journal of Clinical Nutrition and the popular media.
The Unilever study set out to assess the safety and efficacy of Hoodia gordonii extract (HgPE) compared to placebo (dummy treatment) over a period of 15 days in healthy, overweight women. Twenty-five subjects were given 2 doses of 1110 mg HgPE and 24 subjects were given a placebo in servings of a yoghurt drink 1 hour before breakfast and supper (Blom et al, 2011).
Although no serious adverse events were recorded, HgPE was less well tolerated than the placebo. HgPE caused the following significant side-effects:
- nausea, vomiting
- disturbances of skin sensation
- increases in blood pressure, pulse and heart rate
- increases in bilirubin (the breakdown product of red blood cells)
- increases in alkaline phosphatase (an enzyme that increases during tissue injury such as after a heart attack)
(Blom et al, 2011)
In addition Blom and his team (2011) could not find any evidence that Hoodia gordonii extract produced weight loss or a reduction in food intake in the group of women receiving HgPE.
The authors concluded that “In comparison with matched placebo, the consumption of HgPE for 15 days appeared to be associated with significant adverse changes in some vital signs and laboratory parameters. HgPE was less well tolerated than was the placebo and did not show any significant effects on energy intakes or body weights relative to the placebo.” (Blom et al, 2011).
The end of an era
Unilever has to date spent R220m on their research to develop an appetite suppressant based on this plant extract. Reports that Hoodia was used to curb hunger by the San Bushmen when they went on long hunting trips in the Kalahari, were what ostensibly inspired this search for a ‘magic bullet’ weight loss product.
Now the Unilever team cited the results of the above mentioned study as one of the reasons why their company has decided not to continue with this project.
Hoodia research has a long history, which started in 1963 when the CSIR began investigating 400 South African plant species for potential nutritional and medicinal properties. One of these plants was Hoodia gordonii. Experiments conducted with rats, showed that extracts of Hoodia had appetite suppressant properties.
In 1995, the CSIR applied for a patent for the active ingredient P57 obtained from Hoodia. An agreement was reached with the San people that they would receive royalties if a Hoodia-based appetite suppressant could be developed. This patent was eventually filed in January 2005.
Subsequently Phytopharm, a biotechnology company in the UK, purchased the rights to develop the product and then licensed it to Pfizer, a leading, global pharmaceutical company. (Gruenwald, 2005; News24, 2011).
In December 2004, Unilever acquired the rights to develop and market Hoodia as an ingredient for slimming products. But now after 48 years, the latest Unilever study results appear to have put an end to this long saga.
Will this stop sales of Hoodia products?
It will be interesting to see if the findings of the Unilever study will finally put a stop to the manufacture and sale of slimming products containing so-called Hoodia gordonii extract. I have a feeling that manufacturers of over-the-counter slimming pills who add supposed Hoodia to their products, are not going to bat an eyelid and continue to produce, market and sell these bogus products. After all, there are millions of overweight people in the world who will do practically anything to lose weight and will continue to buy these products lured on by the seductive tales of how the San used Hoodia to suppress their appetite in the romantic wastes of the Kalahari. That there appears to be no scientific proof to support this myth, won’t deter the manufacturers or their desperate clients.
It does not seem to matter that it has repeatedly been pointed out that more Hoodia is sold in slimming products worldwide than can possibly be produced, and that many of these weight loss products do not contain any Hoodia but other types of cactus grown in arid areas such as Mexico (Gruenwald, 2005). We tend to sneer at our ancestors who bought snake oil from travelling charlatans to cure all their ills, but people in the 21st century still fall for hype and ads that promise a quick weight loss fix.
The sensible approach
I have in the past repeatedly warned the public not to take over-the-counter slimming products that contain Hoodia gordonii extract because of unproven efficacy and our previous ignorance of what side-effects this extract may have. The Unilever study has now shed light on the potential dangers of using Hoodia products and identified the negative side-effects that they can cause. Seeing that Hoodia has not proven to curb the appetite or cause weight loss, there is no longer any reason to use these products which can harm health.
The sensible approach would be to rather spend your hard-earned money on a gym membership or to buy healthy, low-fat foods. I often hear the complaint that “it’s so expensive to buy food for a slimming diet", but these same people will spend large sums of money on buying potentially harmful slimming products, which don’t promote weight loss. It’s time to stop chasing mirages in the desert!
- (Dr IV van Heerden, DietDoc, November 2011)
(Blom WA et al, 2011. Effects of a 15-d repeated consumption of Hoodia gordonii purified extract on safety, ad libitum energy intake, and body weight in healthy, overweight women: a randomised controlled trial. American Journal of Clinical Nutrition, Vol 54(5):1171-81; Gruenwald J. 2005. Hoodia: Business opportunity or dangerous business? September 2005. www.neutraceuticalsworld.com; News24, 2011. Hoodia doesn’t help weight loss. 2 November 2011. www.news24.com)
Any questions? Ask DietDoc.
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