What is Hoodia ?
Hoodia (hoodia gordonii) also called Kalahari cactus or Xhoba (Masson) — is a flowering, cactus-like plant that grows in the Kalahari Desert indigenous to the arid regions of South Africa, Botswana, and Namibia in Africa 1). Historically, the San Bushmen are said to chew the plant to help stave off hunger or to suppress appetite and thirst during long hunts. However, it may be more accurate to say that Hoodia is a food source and was used mostly to quench thirst. 2). An initial exploratory research with several species of Hoodia showed that H. gordonii contained steroid glycosides have appetite suppressant properties that decreased food intakes and body weights in lab rats 3). The research indicated the efficacy of Hoodia gordonii extract-12 and Hoodia gordonii extract-20, which are 2 major steroid glycosides present in Hoodia gordonii, that pointed to these steroid glycosides as potential lead appetite-suppressing components of H. gordonii. A safety study with a 13-wk repeated administration of Hoodia gordonii extract4 (which contained 79.3% steroid glycosides) also showed that Hoodia gordonii extract induced significant dose-dependent reductions in food intakes and body weights in laboratory rats (SL Nicholson, A Orsi, G Salmon, CW Tam, and CL Ward, unpublished observations, 2007).
From this limited but supportive research evidence and very substantial anecdotal literature, extracts of Hoodia gordonii have become widely promoted as food supplements with putative weight-management properties. This development has arisen despite a lack of published evidence for efficacy and safety from randomized placebo-controlled human clinical trials that used well-characterized material and known dose-exposures to Hoodia gordonii 4).
Today, hoodia dietary supplements are used as an appetite suppressant for weight loss.
Dried extracts of stems and roots of Hoodia are used to make powders, capsules, chewable tablets and liquid preparations for making teas. Some hoodia products also contain other herbs or minerals, such as green tea or chromium. Because it is sold as a dietary supplement, hoodia escapes the level of scrutiny the FDA gives prescription drugs and medications sold over the counter.
Widely sold over the Internet and in health food and discount stores, Hoodia gordonii is typically offered in capsules or tablets, but is also available in milk chocolate chews. A 30-day supply often costs $35 and up.
We know very little about hoodia because only one study of this herb has been done in people. No conclusive evidence to support the claim of appetite suppression.
Little is known about the safety of hoodia. However, the one completed study in people raises concerns 5). In that study, participants taking hoodia had more side effects than those taking placebos, including nausea, vomiting, dizziness, and odd skin sensations; they also had increases in blood pressure and undesirable changes in some blood tests.
Still, some dietary supplement manufacturers market hoodia products as a way to suppress appetite and aid in weight loss. The Federal Trade Commission has warned manufacturers to stop making these unsubstantiated and misleading claims about hoodia and weight loss.
In addition, the quality of hoodia products varies widely. In some cases, hoodia products have been found to contain unidentified ingredients that could be harmful.
Remember, just because an herbal supplement may be natural doesn’t mean it is safe. Steer clear of products that make unproven claims. And always check with your doctor before taking supplements.
Hoodia and Weight Loss
Extracts from Hoodia gordonii have been shown to decrease food intakes and body weights in animals and were proposed as a food supplement or ingredient for weight management 6). The Hoodia species with purported appetite-suppressing properties is Hoodia gordonii. In the 1990s, researchers isolated an extract of the plant called P57, an oxypregnane steroidal glycoside, is the only reported active constituent from this plant as an appetite suppressant, which is thought to stimulate feelings of satiety in the brain 7), 8).
In a very small randomised study involving 49 healthy overweight women aged 18–50 yrs 9). The women were divided into two groups, 25 women were given the Hoodia gordonii extract 2 servings/day of 1110 mg Hoodia gordonii extract in a raspberry-flavored yogurt drink and the other 24 women got placebo formulated in a yogurt drink, to be taken 1 hour before breakfast and dinner for 15 days 10). The women in both groups could eat whatever they like without any restriction. After 15 days there were no difference between the women in terms of the amount of food intakes and body weights. However, the women taking the Hoodia gordonii extract had episodes of nausea, emesis (vomiting) and disturbances of skin sensation 11). Moreover, the consumption of HgPE for 15 d appeared to be associated with significant adverse changes in some vital signs and laboratory parameters – blood pressure, pulse, heart rate, bilirubin, and alkaline phosphatase showed significant increases in the Hoodia gordonii extract group 12).
In a literature review, the reviewer did not find any published, peer-reviewed randomized controlled trials examining efficacy of Hoodia. In addition, the reviewer found literature that suggests some commercial products may not actually contain Hoodia at all 13). It’s not known if this is still a problem for hoodia supplements sold today.
Hoodia Side Effects
We know very little about hoodia because only one study of this herb has been done in people.
In the one small study of hoodia in people, overweight women who took hoodia for 15 days didn’t lose more weight than those who took a placebo 14).
Little is known about the safety of hoodia 15). However, the one completed study in people raises concerns. In that study, participants taking hoodia had more side effects than those taking placebos, including nausea, vomiting, dizziness, and odd skin sensations; they also had increases in blood pressure and undesirable changes in some blood tests.
Hepatotoxicity (Liver Toxicity)
Hoodia has been in use as a weight loss agent for several years and has not been convincingly linked to instances of acute liver injury. In a small controlled trial, serum alkaline phosphatase [8-17 U/L] and bilirubin [0.2-0.6 mg/dL], but not ALT levels, were slightly higher in patients on Hoodia compared to placebo, but no patient developed symptoms or clinically apparent liver injury 16).
Whether hoodia interacts with medicines or other supplements is not known.
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