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Hoodia gordonii
dietary supplement
is made from 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
dietary supplement 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
dietary supplement, 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
dietary supplement 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
dietary supplement
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.
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