In the wake of concerns over one ingredient, this spring Cytodyne Technologies introduced Xenadrine EFX with an “ephedrine-free” formula.

During the past 20 years there has been a dramatic increase in obesity in the U.S. A CDC report states: "Currently, more than half of all U.S. adults are considered overweight (defined as BMI 25 to 29.9) or obese (BMI 30 or higher)."

The most sensible advice for weight reduction "a healthful diet along with adequate exercise" is beyond the ability of millions of Americans. And, concerns over serious side effects such as changes in heart rate, blood pressure and/or elevated cholesterol of prescription medications such as Wyeth-Ayerst Laboratories' Pondiminit or fen-phen (fenfluramine and phentermine ) has cast a shadow on the ability of these products to provide an answer to those wishing to lose weight.

As one result, many are turning to natural weight loss products in an effort to find the "magic pill."? Nutrition Business Journal reports that the sports/weight loss segment was the fastest growing category in the U.S. nutritional market in 2001.

Natural product companies are developing "anti-appetite," "satiety- inducing" or weight loss pills. However, despite the potentially huge, receptive market, consumers have learned that just finding a single pill that is easily absorbable and that does not result in gas, flatulence, or other digestive problems is difficult.

Krebs (Citric Acid) Cycle

The Contenders

What are the some of the leading compounds that may benefit weight loss?

Stimulants such as caffeine and mahuang or ephedra; minerals (chromium); plant components such as fenugreek seed, green tea extract of HCA (hydroxycitrate acid) isolated from the fruit of the Malabar tamarind (Garcinia cambogia); certain dietary fibers (particularly chitosan, see NutraSolutions, July 2002, p. NS11); and even fatty acid lipids themselves (CLA or conjugated linoleic acid) have been studied extensively.

For example, a June press release from Marshall Blum Herbal Research Clinic, Bangor, Maine, announced that in a double-blind, placebo-controlled study, the 36 participants given Fat Cutter, from Health and Nutrition Systems, West Palm Beach, Fla., containing ephedra/caffeine and chitosan, lost almost 2% body weight. This was compared to an insignificant weight loss in the 36 participants in the control group.

In another example, a recent study that was published in the American Journal of Clinical Nutrition found that green tea extract increased 24-hour energy expenditure and fat oxidation beyond what could be explained by its caffeine content.[1]

Cytodyne Technologies, Wall, N.J., was quick to react to interest in ingredients from green tea as well as to concerns over ephedrine when it introduced ephedrine-free Xenadrine EFX. The product contains vitamins C, B6, panothenic acid, magnesium and extracts of green tea, cocoa, bitter orange and grape seed, as well as standardized ginger root and yerba mate, among other compounds.

Minding Metabolic Processes

The mechanisms behind weight control are extremely complex and involve both psychological and physiological factors. A look at one compound, HCA, exemplifies the use of a particular molecule for weight control.

It is believed that a feeling of fullness (satiety) occurs when excess glucose is stored as glycogen in the liver. HCA suppresses hunger by increasing the production of glycogen. However, if blood glucose levels drop too low, hunger results, which may lead to overeating.

The Krebs or Citric Acid Cycle is a fundamental pathway in cellular metabolism. HCA is thought to suppress appetite and inhibit fat production. It is a competitive inhibitor of the ATP-citrate lyase, an enzyme critical in the synthesis and storage of fat in the body. ATP-citrate lyase catalyses the cleavage of citrate to oxaloacetate and acetyl-CoA.[2] HCA's actions lead to a satiety signal being sent to the brain. The recommended dose for this is about 750mg of hydroxycitric acid. HCA is not thought to be a stimulant or to generate any side effects.

Chromium is thought to increase insulin sensitivity leading to better utilization of glucose into muscle tissue, rather than converting the excess glucose into fat.[3] Many researchers believe that chromium reduces appetite. However, high doses of chromium are reported to be toxic. Safe amounts according to the National Academy of Sciences for chromium are known to be between 50mcg to 200mcg per day. There are generally two forms of chromium sold in the marketplace for weight loss, chromium nicotinate and chromium picolinate.

In addition to these, there is a long list of other compounds that have gained a reputation for potential benefits in weight loss. For example, fenugreek seed is also thought to improve the insulin response. One theory is that it normalizes the activity of glucose and lipid-metabolizing enzymes.[4]

CLAs, or conjugated linoleic fatty acids, exist in a number of isomeric forms, of which just a few have biological activity. Recently, it has been studied more extensively for its ability to reduce the risk of cancer. However, particularly in animal studies, CLA has been observed to burn fat or promote fat loss (by blocking the storage of fat) and to build muscle tissue.[5] Other compounds holding the attention of the natural product industry include extract from the root of Coleus forskohlii[6], HMB (beta-hydroxy-beta-methylbutyrate, pyruvate, plantain or psyllium (Plantago) and, more recently, in glycomacropeptides derived from milk.

Obese consumers are a "growing" market. When all is said and done, the choice in regards to how they will address their weight concerns remains in their control. For some consumers, the draw of these compounds go beyond the simple appeal of a "magic pill,"? to the desire to reconnect their physical manifestation with nature from where they originated.