Warning over hoodia ‘diets’

Posted 29 September 2014

This article published in Times, refers to a recent study published in the Journal of Ethnopharmacology, which reports that  consuming extracts of the succulent plant Hoodia may not just shed fat but muscle tissue too. The research was conducted in rats and one cannot necessarily extrapolate to humans. For example, Hoodia has been shown to result in appetite suppression in rats but not in humans.

Cape Town – Consuming extracts of the succulent plant Hoodia gordonii is often punted as a safe way to lose weight but a new study suggests it may not just shed fat but muscle tissue too.

The plant, which grows naturally in South Africa and Namibia, has traditionally been used by the Khoi and San communities to suppress hunger and thirst while on long hunting trips.

Hoodia is available commercially in tea, powder supplements and snack formats and advertised as an appetite suppressant and a “safe” way to lose weight.

Stellenbosch University physiological sciences associate professor, Carine Smith, and her colleague Dr Annadie Krygsman set out to investigate what tissue types accounted for the significant weight loss reported by those who consumed the plant.

Smith, also director of the multidisciplinary stress biology research division, supplemented 12 lean and 12 obese male rats with different doses of the plant extract in a controlled study for two weeks.

She described her results as alarming.

“Similar to popular claims, we saw significant weight loss in rats supplemented with hoodia. However, this weight loss was not only due to fat loss as claimed by suppliers – the rats lost significant amounts of muscle tissue too,” she told Sapa.

She said this would lead to weakness in humans and the increased breakdown of muscle could cause strain on vital organs such as the kidneys.

“We also saw that the rats didn’t empty their stomachs, which were swollen with undigested food. Therefore, the claimed dietary suppression is more likely due to the individual feeling bloated.”

The rats also had cardiac abnormalities.

Smith remained adamant that it was most sensible to not consume the plant extract because the negative effects outweighed any potential benefit.

However, she did not believe indigenous users were wrong in using the plant.

“In my opinion, we see these side-effects when we attempt to apply the indigenous knowledge incorrectly or out of context,” she said.

Hoodia was traditionally used by hunters, who were fit, for short periods of time.

“It is no surprise that we should see side-effects when overweight, unfit, sedentary individuals consume it chronically.”

Smith believed it was up to scientists to contribute to refining the natural product before trying to administer it out of context.

Scientists would have to find out how to isolate the active components for use by the obese population without side-effects.

Despite its use globally, only one human study on hoodia has been published to date.

“While the weight loss effects were not clearly illustrated, subjects in that study did report heart palpitations and bloatedness, so clearly these symptoms are applicable to humans.”

Smith’s study is the first to show the breakdown of muscle.

She believed that because the individual felt ill and bloated, he or she would stop eating and the body would then break down the muscle for energy.

It was her opinion that it was more profitable for companies to invest in advertising than research.

The quality of hoodia products was harder to control because it was a supplement and not medicine.

The results of the study are published in the September issue of the Journal of Ethnopharmacology.


Hoodia gordonii extract targets both adipose and muscle tissue to achieve weight loss in rats
Carine Smith, , Annadie Krygsman
DOI: 10.1016/j.jep.2014.07.018


Ethnopharmacological relevance
Hoodia gordonii (Masson) Sweet ex Decne (family Apocynaceae) is consumed globally as a natural appetite suppressant. While this effect—and its subsequent effect of weight loss—has been reported in the scientific literature, no information is available on the specific tissue types affected that accounts for the significant weight loss reported after consumption of the plant. Furthermore, most studies are performed on lean animals, so that the response of overweight or obese individuals to this plant supplement remains largely unknown.

Materials and methods
Twelve lean and twelve obese male Wistar rats were supplemented with different doses of Hoodia gordonii extract (80 or 160 mg/kg body mass twice daily) in a placebo-controlled study, for a period of 14 days.

All supplemented rats exhibited significant weight loss (P<0.001). This could be ascribed to decrease in both adipose cell size and skeletal muscle fibre size.

We conclude that the weight loss seen after consumption of Hoodia gordonii is due to loss of both adipose and muscle mass.

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