We North Americans are not as svelte as we once were. With two-thirds of the U.S. adult population overweight, and one-third obese, weight control is now an obsession. And the dietary supplement industry has risen to the occasion, with more than 50 individual supplements and 125 proprietary products proffered for weight loss, the majority of which have yet to receive rigorous clinical testing. In fact, some products may be relieving us of more dollars than pounds.
Recently, the U.S. Food and Drug Administration (FDA) served notice to nine supplement manufacturers. Products promising weight loss of several pounds a week without dieting and exercise, or those claiming to reduce fat absorption or to trim fat on certain parts of the body, now have to prove those claims. That has tapped the brakes on this $2 billion-plus industry, and it prompts the question: What really does work for weight loss?
Supplements may help to curb appetite or stimulate the body to burn energy, reduce fat, restrain carbohydrates or expel water. Here’s what we know about some of the popular ones.
Most appetite suppressors are soluble fiber foods such as glucomannan, psyllium and guar gum, which help us to feel full. Preliminary studies indicate only glucomannan, a polysaccharide from the plant Amorphophallus konjac, may trigger modest weight loss at dosages of 3 to 4 grams per day, but larger trials are needed.
Psyllium from seed husks of Plantago psyllium, and guar gum, a fiber derived from Cyamopsis tetragonoloba, don’t work for weight loss. And guar gum may intensify insulin action (thus driving down blood sugar to possibly dangerous levels), decrease the effectiveness of oral contraceptives and cause gastrointestinal upset.
Hoodia (Hoodia gordonii), a much-talked-about, cactus-like plant used by Kalahari bushmen to cut appetite during frequent food shortages, is, ironically, now sought after because of the dietary overconsumption of Westerners. According to an animal study published in Brain Research in 2004, hoodia may fool the hypothalamus into thinking the body has enough energy, so less food is desired. Appropriate dosage and possible side effects in humans are not yet known.
Ephedra (Ephedra spp.) is known to promote weight loss by stimulating the central nervous system much like adrenaline (curbing appetite and boosting metabolism). Hundreds of adverse incidences have been reported to the FDA by people using ephedra products, and at least 50 clinical trials support serious adverse events such as psychiatric, cardiovascular and gastrointestinal problems. Ephedra products are now banned by the FDA.
Ephedra-free supplements abound, including herbals such as yerba maté (Ilex paraguariensis), bitter orange (Citrus ¥aurantium), guarana (Paullinia cupana) and yohimbe (Pausinystalia johimbe). None has generated clear proof that it works, and only yerba maté appears relatively free of adverse effects; it has a long history of traditional use in South America as a hot drink. Side effects with the others include high blood pressure and anxiety (yohimbe), heart palpitations (guarana) or other cardiovascular problems (bitter orange). Further, some ephedra-free formulations contain substances chemically similar to those in ephedra; an example is Xenadrine EFX, which contains phenylephrine, implicated in irregular heartbeat and fainting during exercise. Even yerba maté should be taken with caution, since it is often combined with guarana, caffeine or other ingredients.
Products claiming to stimulate fat breakdown or to reduce fat uptake or synthesis may contain extracts from green tea (Camellia sinensis), garcinia (Garcinia cambogia), licorice (Glycyrrhiza glabra) or cocoa (Theobroma cacao), or the nutrients pyruvate and conjugated linoleic acid (CLA).
Green tea may assist fat metabolism for marginal weight loss. In one study, published in Phytomedicine in 2002, moderately obese individuals taking the commercial extract Exolise — containing 25 percent catechins, mainly epigallocatechin gallate (EGCG) — lost 4.6 percent of their body weight after three months. However, cases of hepatitis have been reported with this extract; whether this is because its alcohol extraction method liberates toxins, or because the catechin concentration is too high or because of some other factor, is unknown. A questionable approach is to put green tea EGCG into multivitamins, as some manufacturers are doing. Although green tea has many benefits, it can impede absorption of plant-derived iron, thus reducing the effectiveness of certain multivitamin products as well as your body’s absorption of iron if supplements are taken with meals.
CLA may trim body fat. A Scandinavian study reported individuals taking 3.4 grams of CLA daily for two years had a 9 percent reduction in body fat in the first year and kept it off during the second year without adverse effects, but weight was unaffected.
Contradictory or weak evidence exists for other supplements, such as pyruvate, licorice or hydroxycitric acid from garcinia. Licorice is not recommended if you have hypertension or glaucoma. Cocoa, which may help activate genes that decrease the body’s production of fat and increase its breakdown, has been studied only in animals.
Our bodies need carbohydrates, which are our main source of energy. It is therefore worrisome to see products that decrease their absorption into the body. For example, a proprietary product with white kidney bean (Phaseolus vulgaris) — an otherwise healthy food — is being studied as an inhibitor of complex carbohydrate digestion and absorption. Results from the first small study with obese adults were inconclusive.
Chromium, an essential trace mineral obtained from our diet that increases the action of insulin in controlling blood sugar levels, has been lauded as a way to help metabolize fats formed from carbohydrates. In a review of 10 randomized, double-blind human trials, chromium supplementation, given in the form of chromium picolinate, was found to reduce body weight by 1.5 pounds or less per month, but animal studies suggest that chromium picolinate (unlike other forms, such as chromium chloride) also may produce damaging free radicals.
Asian ginseng (Panax ginseng) is marketed as a weight-loss aid because it may improve glucose tolerance, but no random controlled trials with humans support its effectiveness.
Diuretic and laxative herbs, such as dandelion (Taraxacum officinale) and cascara sagrada (Rhamnus purshiana), can help eliminate excess water and waste. These may trim pounds in the very short term, but continued usage can cause dehydration and electrolyte abnormalities. It is best to avoid these herbs (and their pharmaceutical counterparts) for weight-loss purposes.
While research indicates that glucomannan, green tea and some other natural products may support weight loss and management, they should not be your primary tools for weight control.
There is no shortage of expert advice on how to lose weight — for example, get eight hours of sleep, eat breakfast, eat six small meals a day and develop a custom weight-loss program tailored to your unique reasons for being overweight. Certainly one has to be aware of possible behavioral, metabolic, hormonal or genetic factors underlying weight problems. But in general, there is really only one successful formula for weight loss that works across the widest swath of individuals: Increase physical activity and cut calories while emphasizing wholesome, nutritious foods.
That is the simple secret of most people who have lost weight and kept it off for years, according to the National Weight Control Registry, an ongoing research study that has grown to include 4,000 individuals who have lost 30 pounds or more and kept it off for at least one year. Nearly every success story in the study has been accomplished through a combination of a low-calorie, low-fat diet and exercise (usually walking).
Herbs can complement healthy eating habits and activity while alleviating hunger pangs or perhaps supplying a little extra metabolic boost. Occasional detoxification with bitter herbs, such as dandelion root and endive, can help keep digestive organs functioning at their peak and aid nutrient absorption and elimination of toxins that might contribute to unhealthy weight gain. Or, if you overeat when anxious or depressed, a cup of calming chamomile (Matricaria recutita) tea might soothe frazzled nerves. If you’re feeling sluggish, how about a mug of your favorite green tea for an energy lift — then head out the door for a walk!
Weight control is a byproduct of a healthy, productive and balanced lifestyle. For myself, to do the work and activities that are important to me, I need to be well rested and eat a nutritious diet — otherwise, my brain and body go on strike. I enjoy walking because it clears my head and inspires me with new ideas from nature. I take a green tea break in the afternoon because it smoothes my transition from one project to another. I’m happy that these things also help my weight, but it’s not why I do them. Food is a blessing, to be enjoyed in good measure and in its most wholesome form — not just from a pill.
Gina Mohammed, Ph.D., is a plant physiologist in Sault Ste. Marie, Ontario, Canada. She is the author of Catnip and Kerosene Grass: What Plants Teach Us About Life (www.Candle nutBooks.com).
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