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In these pages descriptions only are given. Descriptions may not be interpreted as
instructions. The authors emphasize that none of the descriptions will preserve from
side-effects, injury, harm, damage, if any, resulting from putting into practice.
The correctness of the supplied information is not vouched for.
No guarantee is given that the aimed effect(s) will be achieved.
Before you pass on to self-treatment/ /self-medication, you ought to consult a physician
and your pharmacist. The descriptions presented in these webpages
do not replace the examination by, and consultation of a physician.
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APPETITE Restraining Food ingredients and Medicine
Appetite restraining food ingredients are used to restrict the want for food intake. An example is ground Guar fibre
25 )
, which gives the sensation of a filled stomach by its absorption of fluid.
Another is inulin
as supplied by the tubers of Helianthus tuberosus. It was brought from the American continent to Europe ages ago and is known by its original Indian name Topinambur. It is also known as "sweet potato" though it has nothing to do with the potato plant. This name however indicates its usage: it has a rich content of the sweet carbo- hydrate inulin that is closely related to sucrose. However it has a slightly different chemical structure for which the human body has no enzyme to split it up. So it is sweet but cannot be taken up and leaves the intestinal path.
Its primary function is as ballast like guar. There are indications
32 )
that the
substitution of sugar by inulin also smoothes the swinging of the glucose level between hyperinsulinemi and hypoglykemia in the long run. (Hypoglykemia is a frequent inducement for food intake.)
Xhoba (Hoodia). One more example of
an Appetite Restrainer or Appetite Suppressor is the South African Hoodia or, as it is called by the Bushmen Xhoba. The Hoodia is a cactus, a succulent (plant adapted to store water) of the Asclepiadaceae family 89 ). It has been used by the bushmen to avoid hunger sensation and thirst for millennia. Its way of functioning is not published yet pending submission of patent applications 90 )
. It is undergoing the required pharmacological test phases and is expected to become commercially available in 2004.
Pharmaceutical inhibitors. Appetite restraining can also be induced pharmaco-logically by inhibiting
56 )
nervous signal transmission. Their effect is that the signals of an emptied stomach are
suppressed implying a continued feeling of food saturation.
57 ). A related effect is that the usual decrease in basal metabolism (see our subpage on "Yo-yo effect" ) does not occur.
An example of a pharmaceutical inhibitor is the Meridia pill, in Europe known as Reductil / Zolium / Reduxato, a Sibutramine
58 )
manufactured by BASF/Knoll. The nature of operation of a sibutramine implies potential interaction with other drugs and potential side-effects. Therefore the medication is restricted to physicians.
Another example, still under development, is a so called Insulin mimic. It is known from tests with rats (central intra-cerebro-ventricular administration) that receptors in the brain are sensitive to insulin, with the effect that appetite will be reduced. For an imagined self-medication two options would be either as a pill or as injections like diabetics are accustomed to. However insulin would hardly survive the guts when given as a pill. From diabetics is known that their insulin injections do not reduce appetite and their overweight tends to increase. So the insulin administered this way does not reach the brain receptors. A complication is that insulin also affects metabolism in the usual way.
The idea worked out by Merck Research Laboratories and Un of Cincinnaty College of Medicine is a small molecule they have built, mimicking the effect of insulin on the brain receptors. This insulin-mimic does pass the guts and reaches the brain receptors. As said, the concept is under development, for human use 73 ).
The "APPETITE HORMONE" GHRELin
A recent, exciting discovery is the "Appetite hormon" Ghrelin 74 ). Scientists were researching a Growth-Hormone RELeasing hormone, found one, and coined it correspondingly GHRELin. Ghrelin (a peptide of 28 amino acids) was originally discovered in rats; the human ghrelin is homologous to rat ghrelin apart from two amino acids, according to 74 ). It acts upon receptors of the hypothalamus and pituitary in the brain and seems to regulate Growth hormone secretion.
The ghrelin hormone is produced in the stomach and at some more places 75 ). It is released into the bloodstream and DOES reach the pituitery (for this it needs to attach to a fatty acid as a "dispatch-rider"). Amazingly the ghrelin hormone has more functions, one being to provoke the hunger sensation and also to influence fat metabolism so that more is stored in fat tissue.
A review about the different functions of ghrelin is published in The Scientist 85 ). Important names: K. Kangawa, M. Helman, D.E. Cummings.
What is the relation to the leptin-hormone function ( see the subpage leptin )? There is a competitive interaction between ghrelin and leptin in feeding regulation 76 ). Also inter-meal ghrelin levels displayed a diurnal (~day-time) rhythm that was exactly in phase with that of leptin 77 ).
The challenge now is to develop either a ghrelin-blocker that locks the receptor cells or to block the enzyme that couples ghrelin to its fatty acid carrier. An alternative might be to go through nature with a fine comb to find a blocker similar to the natural carbo-blocker phaseolus described in this page.
The anorectic (="appetiteless") hormone fragment PYY 121 )
In the early eighties the PeptideYY (with amino acids 3-36) was discovered. It is secreted by the Ileocolonic (last part of thin intestine, colon) endocrine cells. PYY reduces appetite. Researchers at the Imperial 122 ) College, London University found that obese subjects had relatively low plasma levels of PYY. PPY is released when a person eats protein-rich foods.
The "Anti-Obesity Vaccine"
A new development (2006) is the idea 120 ) to attach (parts of) a vaccine to the ghrelin molecules. The immune system will react (antibodies) to these so that the pertinent ghrelin hormone-molecule is made inactive. It works with rats. The rats lost weight even with maintained level of food intake. This means reduced metabolism, part of the calorie intake leaves the digestive tract unused. Less ghrelin implies less fat storage, less hunger, less metabolism. Questions to be answered still are: what may happen if and when the levels of ghrelin become (too) low and how to stop the action of the immune system if you want to.
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Appetite restraining is not effective to all individuals. People with overweight do not eat because they are very hungry, except for a rare exception, but because of a social event or stress or habit or (derailed?) conditioning. Some suffer occasionnally from chewing-mania or at least are chewing-happy.
For these people it is effective to chew much low-calorie food: fruit (apples etc.), large quantities of vegetables. At a reception: raw pieces of cucumber, gherkins, cauliflower, etc.
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Blocking the ENZYME lipase
Enzyme blocking according to the "lock & key" principle is
described in the left column.
The enzyme lipase that should split tri- glycerides is neutralized by the
enzyme- blocker. Then the triglycerides remain too big to pass the intestine
lining and again leave the intestinal path unused.
An
example
is Xenical (chemical component: orlistat) supplied by ROCHE
21 ). For Xenical a prescription
is required.
Lipidplex and Chitosan enjoy OTC (=over the counter) -status.
GLUEING TOGETHER SMALL CARBO-HYDRATES
Beside the option to prevent enzymes to split larger poly sac- charides through the
Key & Lock principle exists the option to "glue" (small) poly-saccharides together
to larger ones that cannot pass the intestine wall. That is done by the substance
pectin familiar from stiffening juices
to jellies. Many fruits contain pectin; citrus rinds form the industial source for
pectin production.
A familiar product said to have weight reduction capacity is the family of "apple-slimming"
devices. They are based on the pectin won from pomace a residue from apple-cider presses.
The material of many plants combine pectin with water-absorbing fibre and other
qualities.
An example is the cactus Opuntia ficus -indica,
known in Mexico and South America as Nopal
or Indian fig prickley pear
38 ).
It is also well known in
Northern Africa and Israel. A cultivar without spines is the OFI-cv-Osser. Its pectin
prevents smaller poly sac- charides from being digested, its water absorbing capacity
fills stomach and intestines. It has one of the lowest GI's measured:
7 at the glucose=100 "reference scale".
It is sold in gelatin capsules.
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The blocking of (animal) cholesterol .
A striking blocking mechanism is the clog- ging of cholesterol receptors by phytosterols. Phytosterols are the vegetable variant of animal sterols (=cholesterol). The effect of blocking is again that the uptake of an un- wanted component (in this case cholesterol) is prevented. Phytosterols in turn cannot be digested by humans.86 )
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Supplements to Diets.
.
Many "dieters" know that their nutrition- package requires little fat and few carbo- hydrates.
Not many dieters realize that chan- ging to a reduced package implies a risk of missing essential nutrients: the nutrition- package must contain more than a minimal daily dose of amino-acids (for assembling body-proteins) and a fair amount of vitamins and minerals. Phytotherapeutic diet supplements for that reason often contain additions to cover the essential nutrients.
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Different effects from Gastric-bypass or Diets on Ghrelin-production 103 ).
The active part of a stomach-wall has been limited by a gastric bypass. So production of Ghrelin, and its effect on stimulating appetite, is decreased. Applying an intake restricting diet on the contrary will provoke the Ghrelin production to its full extend. This has been shown by Cummings cs. 83 )
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ScienceDaily |
posted 08/01/2002 |
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