CARNITINE
Carnitine has been vigorously promoted as a "fat burner" to speed weight loss. At first glance, the claims of carnitine to make sense. The truth is — carnitine is involved in fat metabolism. Carnitine is a vitamin-like substance that functions as a shuttle to transport fatty acids into the muscle which will then be burned for energy. This truth has been turned into claims that carnitine supplements will help you burn more fat.

More than 50 percent of our daily needs for carnitine is normally supplied by the diet. Sources include animal foods such as meat, poultry, fish, and some dairy products. The remainder is synthesized by the body. Deficiencies are unlikely in most people, but may occur in strict vegetarians.

Research on carnitine shows no evidence that carnitine supplementation reduces body fat. It does not increase fat burning. The body of evidence shows that the supplement doesn't deliver on its promises.

CHITOSAN
Chitosan is sold as the Fat Trapper and the Fat Burner. TV infomercials inform that it frees you to eat fried chicken, pizza, cheeseburgers, and even butter without worrying about your weight. Chitosan is a fiber-like material made from shells of lobsters, crabs and shrimp. Manufacturers claim that it causes weight loss by binding to fat in the small intestine, thereby preventing absorption.

Chitosan does bind a little fat, but hardly enough to help you lose weight. Unless you take massive amounts (over 15% of your diet being chitosan), the amount of fat absorption that is blocked by chitosan is minimal and of no significant benefit.

If you're really looking for a fat blocker, ask your physician about the prescription Orlistat (brand name Xenical). Clinical trials involving Orlistat when used in conjunction with diet and exercise have been shown that the average patient will lose about 10% of their initial body weight. The average weight loss that is attributed to the medication averages about 7.5 lb.

CHROMIUM PICOLINATE
"Not everyone needs chromium picolinate - only those who want to lose excess fat and build more muscle." "Melts the fat away!" "Since chromium picolinate is so effective at removing fat, some people can lose weight too fast. Don't allow yourself to become too thin." These are the claims manufacturers make about chromium picolinate. It is not surprising with these claims, that millions of Americans consume $150 million worth of chromium supplements a year. Chromium is the second best-selling mineral supplement in the United States, behind calcium.

Chromium is sold alone and as an ingredient in many weight loss products. It is an essential mineral that in tiny amounts helps burn carbohydrates and fats in the body, and regulates blood sugar levels. A safe and adequate intake of chromium is considered to be 50 to 200 micrograms (mcg) daily. Weight loss supplement labels often suggest taking 200 mcg. Good dietary sources include whole grains, brewer's yeast, wheat germ, seafood, mushrooms, nuts, and cereals. Generally, it is poorly absorbed in our intestinal tract.

In 1982 Dr. Gary Evans, a chemist at the U.S. Department of Agriculture, created chromium picolinate by combining chromium with picolinic acid. Cells absorb the compound more efficiently than they absorb plain chromium. Two small studies done in the late 1980's by Evans found those taking 200 mcg of chromium picolinate added more muscle and took off more body fat than a placebo (sugar pill). But aside from Evan's own research, the results of these studies have never been duplicated. Manufacturers may tout this substance as a "super reducer" but the there is no data from well-controlled experiments to support the use of chromium to help you lose weight.

Safety concerns also exist for chromium picolinate. In 1996 a laboratory study from Dartmouth College showed that chromium could damage the genetic material of hamster cells. This raised the question of whether it might cause cancer in humans. In 1999, a new study from the University of Alabama at Tuscaloosa shows that chromium picolinate reacts with vitamin C which produces a dangerous compound capable of causing mutations in DNA.

The bottom line is that, if you're getting enough chromium in your diet, additional benefits from supplements are unlikely.

MA HUANG (also known as ephedrine)
Most of us would welcome an increase in energy and a little weight loss to boot! Ma Huang, an age-old Chinese herb, promises all these things. Dieters are eagerly consuming this natural supplement which is often combined with caffeine, aspirin or extracts from the guarana fruit (which contains a caffeine-like stimulant), to enhance it's effectiveness.

Also know as ephedra or ephedrine, ma huang has been an active ingredient for decades to treat asthma and allergies. Today, this powerful stimulant is used in diet pills, herbal ecstasy and energy booster products. Such products include Diet Fuel, Metabolife, Herbal Ecstasy, Herbal Trim and Diet Pep. This plant amphetamine suppresses the appetite and speeds up metabolism.

Animal research indicates that the metabolism boosting, appetite suppressing claims are probably true. Most studies show that ephedrine plus caffeine (or guarana) promotes greater weight loss than a placebo. There are side effects. Since 1993, the FDA estimates that there have been reports of 58 deaths and almost 400 adverse effects associated with ephedrine. The adverse effects include seizures, strokes, irregular heartbeat, heart attack, high blood pressure, nervousness, insomnia, and suicidal acts. These effects occur because ephedrine is a stimulant that can overstimulate the heart and nervous system. The FDA advises anyone with high blood pressure, heart conditions, diabetes or neurological disorders to avoid ephedrine.

The expert take on ephedrine is that the bulk of research indicates that it helps people lose weight, but it's not necessarily safe. Safety depends on your health status and your individual reaction to ephedrine.

PYRUVATE
Pyruvate, is claimed by manufacturers to promote fat and weight loss, increase muscle mass, and increase endurance - all without diet or exercise.

Marketers rely heavily on one clinical study that has "proven" pyruvate can induce 37% weight loss and 48% fat loss. While these numbers may sound impressive, the study's protocols and results are questionable. The study involved 14 obese women (over 200 pounds). Seven of these women added 30 grams of pyruvate to a 1,000 calorie liquid diet for 21 days. Subjects using the pyruvate lost an average of only 2.8 pounds more fat than the control subjects. The researchers of this study acknowledged that these small differences in body composition may have been due to measurement error alone. Also, note that 30 grams of pyruvate is much higher than the 1 to 5 gram dose found in most over-the-counter supplements. There is no published evidence that the dosage in the supplements available on store shelves will be effective.

A FINAL WORD
Some nutritional and herbal products may be beneficial for certain individuals. Remain skeptical and carefully review all label and advertising claims, even when the product is billed as "natural." In 1994 the FDA approved the Dietary Supplement Act that allowed dietary supplements to be marketed without mandatory testing for safety and effectiveness. Because supplements are no longer reviewed, manufacturers can make claims that are unproven. People may incorrectly assume that because a product is marketed as "natural" or "herbal" that these products are safe and without negative side effects. Buyer beware - supplements can be marketed without any safety testing. In the end, eating well and exercising regularly are the answer to maintaining weight loss.

Annette Colby, PhD, RD is a nutrition therapist who specializes in weight loss, disordered eating, fitness and women's health. For information and a free weekly email newsletter, log onto http://www.power-nutrition.com/newsletter">www.power-nutrition.com/newsletter www.power-nutrition.com/newsletter. 972.985.8750