How Does Hoodia Gordonii work on Appetite Suppression
Hoodia gordonii is a succulent plant from
the botanical family Asclepiadaceae. This plant has a spiny
appearance resembling a cactus, and has been used for centuries by
the San Bushmen of South Africa as a way of controlling hunger and
thirst during hunting expeditions in the Kalahari desert. The
folklore use of hoodia as an appetite suppressant and recent
research on its benefits have piqued worldwide interest among
doctors and scientists engaged in the fight against the global
epidemic of obesity. Likewise, the consistent demonstration of the
appetite-controlling effects of hoodia has led to massive public
interest in the use of this plant as the basis of a dietary
supplement for weight control.
Whole hoodia powder contains variable
amounts of fiber, organic material, antioxidants and biologically
active substances—including steroidal glycosides, which appear to
fool the brain into thinking the stomach is “full.”1
Weight control is all about calorie control.
Recent scientific studies have confirmed the ability of hoodia to
suppress appetite, helping obese people and free-feeding rats
lower dietary calorie intake to a degree that promotes weight
loss, at least in the short term.2,3 Controlled clinical and
laboratory experiments show both animals and humans will restrict
the calorie intake in their diet when hoodia is taken orally. Some
experiments have involved elaborate studies where obese people
have taken hoodia in a controlled metabolic environment; and they
have been able to reduce their calorie intake by 1,000 calories
per day.4
Being overweight is often associated with
high blood pressure, high blood cholesterol, and insulin
resistance. This is the metabolic Syndrome X, which affects 70
million Americans and is a common cause of premature death and or
disability. Hoodia could be an important nutritional factor to
combat Syndrome X, if it fulfills its promise of appetite control
and weight loss.
Some researchers believe they have
pinpointed the active constituent(s) responsible for hoodia’s
appetite-suppressant actions, without much investigation into the
plant’s other potential mechanisms of biological action. However,
hoodia’s active constituent(s) may have only been partially
identified. Government researchers in South Africa have focused
attention on the sterol glycosides. Part of a group of naturally
occurring substances called cardenolides, glycosides are best
known for their effects on cardiac function. However, measurable
effects on Na/KATPase, the target of action of cardiac glycosides,
are not believed to be associated with the administration of
hoodia.
One prevailing hypothesis implies steroidal
glycosides act directly upon the hypothalamus, triggering a
message that blood glucose is high.5 This is an effect related to
the glucostatic mechanism of weight control.6 Animal experiments
found intracerebroventricular injection of hoodia extracts (termed
“P57AS3” by Phytopharm PLC) resulted in increased ATP content or
production in the hypothalamus, which may be a signal for the
energysensing of satiety. Specific receptors for the steroidal
glycoside (P57) have not been identified in the rat brain, but
administration of these compounds into the brain reduces food
intake by a factor of up to 60 percent and increases the content
of ATP hypothalamic neurons of the rat by up to 150 percent. The
sensing of energy input by the hypothalamus may be signaled by
increases in intracellular neuronal energy, in the form of ATP.
These animal experiments suggest one
potential mechanism of action of hoodia components on brain
signals that may regulate appetite, hunger or thirst; but, there
are many complex factors that control feeding behaviors operating
through many messenger molecules.
Any focus on a single system or unitary
mechanism for the control of food intake must be questioned,
because these controls are extremely complex. For example, does
hoodia alter factors that are involved in the “aminostatic” or
“lipostatic” theories of regulation of food intake? The difference
in the many regulatory systems for energy balance in the body is
well documented. In my new book on hoodia, I discuss the ability
of plants to talk to the brain and include examples where actual
receptors for the actions of these plant compounds exist in the
central nervous system.
