Hoodia: Lots of Hoopla, Little Science
Few studies support the promise of the South African appetite suppressant, but believers abound.
Goldfarb studied DEX-L10, the 500-milligram hoodia capsules sold by Delmar
Labs. Goldfarb did the study for the manufacturer but says he was not paid for
the research. "I did it as a service to them," he says.
In Goldfarb's study, the seven overweight participants were told to take two
Hoodia gordonii (DEX L-10) capsules a day, eat a balanced breakfast
and take a multivitamin, and keep other eating and exercise habits unchanged. The participants' starting
weights ranged from 193 to 345 pounds. They lost, on average, 3.3% of their
body weight, Goldfarb says. The median loss over the 28-day study was 10 pounds
(half lost more, half less).
Most of the participants reported their caloric intake dropped to less
than half within a few days after starting hoodia, and they didn't report side
effects such as jitteriness or insomnia,
The study was not published in a scientific journal nor presented at a
medical meeting, Goldfarb says, because it was conducted as an
"efficacy" study, trying only to find out if the product actually
Goldfarb is recruiting volunteers for a second, larger study, commissioned
by Delmar Labs, which he hopes to begin by year's end.
"Hoodia gordonii works within the satiety center of the brain
by releasing a chemical compound similar to glucose but up to 100 times
stronger," Goldfarb says in his written report. "The hypothalamus
receives this signal as an indication that enough food has been consumed and
this in turn decreases the appetite."
Phytopharm, a U.K.-based company developing hoodia weight loss products with
Unilever, the giant food and consumer products company, cites a 2001 study on
its web site that it did, in which the plant extract caused a reduction in
average daily calorie intake and in body fat within two weeks. Caloric intake
dropped by about 1,000 a day after about two weeks, according to the study.
(Phytopharm was originally developing P57 with Pfizer, but Pfizer returned
its rights to Phytopharm in 2003.)
None of this is enough science to satisfy experts at the Mayo Clinic. In an
online report on weight loss pills, published in
March, the clinic's bottom line on hoodia was: "No conclusive evidence to
support the claim [of appetite suppression]."
What Doctors Say
Other doctors are skeptical, including Adrienne Youdim, MD, medical director
of the Comprehensive Weight Loss Program at Cedars-Sinai Medical Center, Los
Angeles. When asked by patients about hoodia and whether they should try it,
Youdim tells them: "There is no [published scientific] data to support its
use. But, similarly, there is no data suggesting adverse effects. It's kind of
uncharted territory." She doesn't recommend using the product.
Michael Steelman, MD, chairman of the board of trustees for the American
Society of Bariatric Physicians, treats obese patients in his practice in
Oklahoma City, and many of them ask him about hoodia. "I remain pretty
skeptical," he says. "Some of my patients have tried it, but I haven't
had any who felt like it was helpful to them."