Hoodia gordonii is now famous for its appetite-suppressing properties. Ever
since the BBC and US TV show 60 Minutes reported on Hoodia in the early
2000s, products containing the herb-capsules, tablets, syrups, tinctures and
even lip balms-have been flying off the shelves, all claiming to curb hunger
and promote weight loss. But do these products actually work? WDDTY takes a
look at the evidence so far.
What the science says
In fact, there's little scientific evidence to show that the herb helps
Researchers began studying Hoodia in the early 1960s and, some 20 years
later, isolated an extract called P57, believed to stimulate feelings of
satiety in the brain. But, so far, there are still no published clinical
trials. Yet, web-sites selling Hoodia often cite a trial showing that, after
two weeks, volun-teers taking Hoodia ate 1000 fewer calories a day than
those taking a placebo. However, the study involved only 18 people, was
never peer-reviewed or published, and was sponsored by Phytopharm, a British
biopharmaceuti-cal company licensed to develop P57 on a large scale (Harv
Womens Health Watch, 2008; 15: 8). The results, therefore, need to be viewed
On the upside, there's published evidence in animals that Hoodia may work.
South African researchers tested Hoodia against appetite-suppressing
fenfluramine (now banned due to heart risks) in rats, and found that Hoodia
reduced food intake and also led to weight loss. Fenfluramine, on the other
hand, reduced food intake only slightly and led to weight gain
(Phytochemistry, 2007; 68: 2545-53).
In another rat study, US scientists injected P57 directly into the brain.
Food intake was reduced by 40-60 per cent over 24 hours, and ATP (adenosine
triphosphate) in the hypothalamus-which controls hunger-increased. This ATP
upregulation may lie behind the apparent appetite-suppressing effects of
Hoodia (Brain Res, 2004; 1020: 1-11).
Nevertheless, although this is all very promising, until reliable human
trials are published, we won't know whether Hoodia-and specifically, Hoodia
in pill form-will work in people as it does in rats. Crucially, we're also
completely in the dark as to the herb's safety.
Another problem is that the products currently available aren't regulated,
so it's unclear how much herb-if any-they contain. Experts argue that there
simply aren't enough Hoodia plants in the world to account for all the
alleged Hoodia products now on the market. They may contain little or no H.
gordonii, include the wrong parts of the plant or use questionable plant
sources (Harv Womens Health Watch, 2008; 15:8).
In an investigation by Mike Adams of the health website Natural News, as
much as 80 per cent of the Hoodia purchased by consumers may be either
adulterated (cut with other ingredi-ents) or totally fake
(www.naturalnews.com /020167.html). Indeed, independent labor-atory tests by
Alkemist Pharmaceu-ticals in California revealed that around two-thirds of
the supplements on the US marketplace contained no identifiable H. gordonii
whatsoever (www.naturalnews.com/011425.html). This means that even if Hoodia
does work, there's no guarantee that what you're getting in a supplement is
the real deal.
The bottom line
Although the research is promising, there's a long way to go before Hoodia
is considered safe and effective. Also, given all the counterfeit Hoodia out
there, you're probably better off trying an alternative product for weight
We all know that diet and exercise are the best ways to lose weight, but
it's hard to resist a quick fix, so here are some agents shown to work in
published clinical trials.
- Green-tea extract. Catechins, the active ingredients in green tea,
appear to boost metabolism (Am J Clin Nutr, 1999; 70: 1040-5). Daily
consumption of green-tea extract (containing 690 mg of catechins) for 12
weeks significantly reduced body weight, waist size, body mass index and
body fat (Am J Clin Nutr, 2005; 81: 122-9).
- Conjugated linoleic acid (CLA). In animals, this naturally occurring
fatty acid can increase lean tissue mass while reducing fat storage (J Lipid
Res, 2003; 44: 2234-41), and had similar effects in overweight people (J
Nutr, 2007; 137: 1188-93; Int J Obes [Lond], 2007; 31: 481-7). However,
there are concerns that CLA in such a group of people could increase insulin
resistance and, therefore, the risk of diabetes (Circulation, 2002; 106:
- Hydroxycitric acid (HCA). Although the findings are mixed, HCA-from
Malabar tamarind fruit-may increase weight loss and reduce appetite
(Int J Obes Relat Metab Disord, 2001; 25: 1087-94), decrease calorie intake
(Int J Obes Relat Metab Disord, 2002; 26: 870-2) and increase fat-burning-
at least, in athletes (J Nutr Sci Vitaminol [Tokyo], 2002; 48: 128-33).
Vol 20 07 October 2009