Vitamin supplements guide   Vitamins & health supplements guide

 
Weight loss supplements
Ma Huang (ephedra)
Green tea extract
Chromium polynicotinate
St. John's Wort
Glucosamine
Growth hormone (GH)
5-Hydroxytryptophan (5-HTP)
Hydroxycitric acid (HCA)
Chitosan
 

Weight loss dietary supplements


Obesity is the number one nutritional problem in the U.S. An estimated one third of Americans are overweight, with an additional 25 percent being classified as obese. Globally, there are more than 1 billion overweight adults, at least 300 million of them obese. Overweight and obesity is a condition characterized by the excessive accumulation of fat in the body as a consequence of an energy intake which is greater than energy expenditure. Overweight is present if the body weight exceeds a "desirable weight", whereas obesity represents a condition where the weight is 20% or more above the desirable weight. The prevalence of overweight and obesity is commonly assessed by using body mass index (BMI), defined as the weight in kilograms divided by the square of the height in metres (kg/m2 ). A BMI over 25 kg/m2 is defined as overweight, and a BMI of over 30 kg/m2 as obese. The American Institute for Cancer Research considers a BMI between 18.5 and 25 to be an ideal target for a healthy individual (although several sources consider a person with a BMI of less than 20 to be underweight).
 

Causes of overweight and obesity


Overweight occurs as a result of an imbalance between energy intake as food and energy expenditure through physical activity.
Most importantly, the trend to increased consumption of sugar and refined carbohydrate in excess of energy needs results in a metabolic and hormonal status favoring the formation and storage of fat. The basic nutritional needs of most people are approximately 2,000 calories a day for women and 2,500 for men. However, people who are very active, such as professional athletes or manual laborers, may need 4,000 or more. Pregnant women and nursing mothers require about 300-500 more calories/day than women who are neither pregnant nor nursing. The body cannot store protein or carbohydrates, so excess protein or carbohydrate intake is converted to fat for storage. One pound of fat represents about 3,500 excess calories.

Increased carbohydrate consumption in modern society is the result of the introduction of refined sugar and processed carbohydrate in various forms. The presence of sugar and other "high glycemic" processed carbohydrates found in bread and pasta, increases blood insulin levels, inhibits lipolysis, and promotes new fat synthesis. This raises serum triglycerides, serum cholesterol, and increases the risk of atherosclerosis and coronary heart disease. When an imbalance occurs and there is a greater intake of calories than required for the amount of energy expended in the average day, an increase in weight occurs. Maintaining a reasonable balance between the caloric intake and the energy expended during the day is necessary in order to lose weight and maintain a constant weight.

 

Complications of overweight and obesity


Obesity is a devastating disease. Obesity is associated with physical, psychological, and social problems. Being overweight significantly increases a person's risk of developing diabetes mellitus, hypertension, hyperlipoproteinemia, cardiac diseases (atherosclerotic disease, congestive heart failure), pulmonary diseases (sleep apnea, restrictive lung disease), cerebrovascular accidents, cancers (breast, uterus, colon, prostate), gall bladder disease (stones, infection), toxemia during pregnancy, risks during surgery (pneumonia, wound infection, thrombo-phlebitis), gout, decreased fertility, degenerative arthritis, and early mortality. In addition to harming physical health, obesity can wreak havoc on mental health because obesity affects self-esteem, which ultimately can affect a person's ability to interact socially with others. While being severely obese has many health ramifications, those who are somewhat overweight face little increased mortality or morbidity.
 

Mechanism of weight loss therapy


While the causes of excess body weight and obesity are complex, a common denominator in the overweight person's diet is a
caloric intake which exceeds his body's expenditure. Weight loss is achieved either by reducing the caloric intake (eat less food or healthier food) or by increasing the energy expenditure (exercise more).

To combat excess weight and the associated conditions, many search for ways to lose weight. Most weight reduction treatment regimens involve caloric restriction, which is based on the principle that if intake of food is less than energy expenditure, stored calories, will be consumed, mainly in the form of fat. Other treatment regimens are based on the principle of increasing metabolism. By increasing metabolism, calories are burned thereby decreasing body weight. Interventions to decrease appetite have focused on supporting brain levels of the neurotransmitter serotonin which is derived from the amino acid tryptophan. However, simply providing increased dietary sources of tryptophan have in themselves not proven successful at reducing appetite. Use of drugs such as fluoxetine and fenfluramine, which raise brain serotonin levels, have proven effective in promoting weight loss. Unfortunately, this pharmacologic approach has been recently associated with serious cardiovascular side effects.

Much of modern obesity research has concerned methods for maintaining a hormonal balance which favors .beta. over .alpha. receptor activity to promote more efficient and active lipolysis. When fat stored in adipose tissue is going to be used as an energy source, lipase enzymes hydrolyze triglycerides into glycerol and free fatty acids in a process called lipolysis (the breakdown of fat). Weight loss depends on mobilization and metabolism of fat at the cellular level. This requires the metabolic process of lipolysis and encompasses the release of stored fat from fat cells. In all mammals the process and rate of lipolysis are highly regulated by the system of catecholamine hormones. Strategies to decrease our daily intake of processed carbohydrate and increase the release and metabolism of stored fat are clearly needed. The process of lipolysis is regulated primarily by the system of catecholamine hormone receptors present on the surface of fat cells. These catecholamine receptors consist of a family of membrane bound proteins with differerent structure and activity known as the .alpha. and .beta. receptors. The .alpha. and .beta. receptors have opposing action on the rate of lipolysis. Predominance of activity from the .beta. receptors favors active lipolysis and translates into weight loss. Predominance of .alpha. receptor activity inhibits lipolysis and favors continued fat storage.

 

Weight loss supplements


To achieve healthy weight loss, most experts recommend a combination of healthy eating patterns and regular physical exercise. Among the many possible solutions for treating obesity are formulations of weight loss products that work with some of the basic biochemical processes involved in fat metabolism.

Ma Huang, or ephedra, contains ephedrine, an alkaloid that stimulates the production of catecholamines such as norepinephrine. Norepinephrine or noradrenaline is presumed to start the thermogenic process by stimulating metabolism in fat cells via the neurocrine axis that involves beta-adrenergic receptors. This in turn results in lipolysis. Ma huang increases basal metabolic rate (BMR), and help body burn calories faster. Ephedra sinica, the primary species of ma huang, is used as a weight-loss aid in people because of its stimulant effect and as a decongestant because of its vasoconstrictive effect.

Standardized green tea extract (standardized for 20% polyphenols) (leaf) inhibits the enzyme that causes the breakdown of norepinephrine, thus causing an increase in metabolic rate. It has also been shown to increase the rate of brown fat metabolism. Green tea extract is effective in stimulating thermogenesis by relieving inhibition at different control points along the NA-cAMP axis. Epigallocatechin gallate from green tea polyphenols significantly reduced food intake, body weight, blood cholesterol and triglyceride, as well as growth of the prostate, uterus, and ovary.

Chromium polynicotinate has been shown to possess greater biological activity and is safer than other chromium supplements. Chromium picolinate helps insulin to metabolize fat, turns protein into muscle, and converts sugar into energy. It potentiates the effects of insulin and helps overcome insulin resistance in overweight people. Chromium also seems to stimulate thermogenesis, the burning of fat, without any physical exertion.

St. John's Wort is a herb of the hypericaceae family which contains the therapeutically active ingredient hypercin. St. John's Wort functions to reduce weight and also acts as an appetite suppressant, most likely by controlling serotonin levels.

Glucosamine also contributes to weight loss. The effect of insulin on lipogenesis, the formation of fatty acids in the body, is blocked by glucosamine, indicating that glucosamine plays a role as a messenger for this insulin effect. Insulin is secreted when there is high sugar content, insulin secretion allows for fat storage. Glucose triggers a rise in insulin. Insulin acts to lower blood glucose levels, regulating those levels through several actions, including lipogenesis (conversion of carbohydrate and protein into fat). High insulin levels trigger the hypothalamus to send hunger signals, which sets off a craving for carbohydrates; this leads one to eat more, which leads to more insulin. Excess carbohydrates are converted into glucose, and then stored as fat.

Growth hormone (GH) has been implicated in a number of metabolic effects. Administration of exogenous growth hormone by injection has been shown to accelerate body fat loss. Obese people have a blunted or suppressed HGH release. Insulin levels are elevated in obesity, and high insulin levels also suppress human growth hormone production.

5-hydroxytryptophan is an effective nutrient that promotes weight loss. 5-Hydroxytryptophan (5-HTP) is the intermediate metabolite of the essential amino acid L-tryptophan (LT) in the biosynthesis of serotonin. 5-HTP is used by the human body to make serotonin The component gives the feeling of satiation and a calming effect. 5-HTP administration causes a significant increase in the hormone leptin. Leptin plays an imporant role in the regulation of appetite and other physiological processes, and various factors can alter leptin secretion. 5-HTP administration results in significant increases in insulin, corticosterone, and prolactin levels, and all of these hormones can increase leptin levels.

Hydroxycitric acid (HCA), a rare organic acid, reduces appetite and helps prevent excess carbohydrates from being stored as body fat. Hydroxycitric acid is derived from the Malabar tamarind tropical fruit (Garcinia cambogia) native to India. HCA has been found to inhibit mitochondrial citrate lyase, leading to decreased acetyl coenzyme A production and decreased fatty acid synthesis.

Chitosan supplements are promoted as weight-loss agents that act by preventing the absorption of dietary fats from the intestines. Chitosan is a special fiber which is able to "soak up" or absorb anywhere from six to ten times its weight in fat and oils. chitosan is able to significantly bind with fat molecules and convert them into a form which the human body does not absorb. Like some plant fibers, chitosan is not digestible, therefore it has no caloric value.

In addition to above weight loss products, other weight loss supplements also contribute weight loss effects, they include bitter orange, guarana, caffeine, country mallow, ginseng, glucomannan, psyllium , l-carnitine, vitamin B5, licorice, conjugated linoleic acid, pyruvate, dandelion, cascara, DHEA, and laminaria.