Weight Loss Supplements and Manegment of Obesity
If you're one of the two-thirds of American adults who are either overweight or obese, you may be tempted to try one of the many over-the-counter supplements and herbal remedies for weight loss.
But you can't assume that any weight loss supplement is safe and effective simply because it's on the market. Dietary supplements are exempt from FDA regulation. They do not undergo rigorous tests for safety and effectiveness that are required for drugs. And there is no guarantee that what is stated on the label is actually in the product.
The FDA steps in when there is evidence that a weight loss supplement is harmful.
To help safeguard dietary supplements, the United States Pharmacopeial Convention (USP) provides standards and references for determining:
- product and ingredient identity
- strength
- quality
- purity
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| Weight Loss Supplements |
'All-Natural' Supplements ?
In recent years, the FDA tested the contents of many supplements touted as "all natural." The agency found that nearly 70 of those supplements contained ingredients such as:
- controlled substances
- seizure medications
- prescription drugs
- drugs not approved in the U.S.
You should also check with your health care provider to make sure the supplement you're considering will not interact with other medications you are taking.
Few over-the-counter weight loss supplements have been extensively studied. Research suggests that a few of them may be modestly effective. Evidence shows that the most effective way to lose weight and maintain weight loss involves lifestyle changes such as:
- adopting a nutritious, balanced, and calorie-restricted diet
- regular physical activity
Here are some common ingredients found in over-the-counter supplements and herbal remedies for weight loss:
Chitosan
Chitosan is a sugar that comes from the hard outer layers of lobsters, crab, and shrimp. It blocks the absorption of fats and cholesterol to prevent their absorption.Some evidence suggests it helps foster weight loss with or without calorie restriction, while other evidence suggests that it is ineffective.
The Natural Medicines Comprehensive Database says that chitosan is "probably ineffective."
Chromium Picolinate
Chromium is a mineral that enhances the action of insulin, a hormone critical to the metabolism. It's also critical to the storage of carbohydrates, fats, and proteins.There are claims that chromium supplements can:
- decrease appetite
- increase number of calories burned
- reduce body fat
- increase muscle mass
Rarely, chromium supplements can cause side effects such as:
- insomnia
- irritability
- headache
The Natural Medicines Comprehensive Database says that chromium is "probably ineffective."
Conjugated Linoleic Acid (CLA)
CLA is a popular supplement containing chemicals found in the fatty acid linoleic acid. There are claims that it may help reduce body fat. It also seems to be associated with feelings of fullness that reduce hunger.Research suggests that in some people 0.7-4.5 grams of CLA per day may:
- decrease body fat mass (BFM)
- increase lean body mass (LBM)
CLA is associated with side effects such as:
- upset stomach
- nausea
- loose stools
The Natural Medicines Comprehensive Database says that CLA is "possibly safe" and "possibly effective."
Glucomannan
Glucomannan is derived from the konjac plant. Like other dietary fibers, it is supposed to help people lose weight by blocking the absorption of dietary fat.Very preliminary evidence suggests is might be helpful for weight loss. But other evidence shows no effect.
Glucomannan must be taken with at least 8 ounces of water. Taking it without water could lead to choking and/or blockage of the:
- throat
- esophagus
- intestine
Glucomannan also may decrease absorption of other medications. So people should take medications either one hour before or four hours after taking glucomannan or other fibrous products.
The Natural Medicines Comprehensive Database says there is "insufficient evidence" to rate the safety and effectiveness of glucomannan.
Green Tea Extract
Green tea extract supposedly works by:- decreasing appetite
- increasing calorie and fat metabolism
Side effects of green tea extract may include:
- dizziness
- insomnia
- agitation
- nausea and vomiting
- bloating
- gas
- diarrhea
So far there isn't enough evidence to determine if green tea extract can aid in weight loss.
Guar Gum
Guar gum comes from the seed of the guar plant. Like other dietary fibers, it is supposed to work by preventing the absorption of fats by binding them in the gut and increasing feelings of fullness.
Side effects may include:
- abdominal pain
- gas
- diarrhea
Guar gum has been studied more extensively than other fibers for weight loss. Most researchers have concluded that it is ineffective.
The Natural Medicines Comprehensive Database says that guar gum is "possibly ineffective."
Hoodia
Hoodia is a plant that grows in the Kalahari Desert in Africa. According to the National Center for Complementary and Alternative Medicine, the stem of the root was traditionally used by bushmen to reduce hunger and thirst during long hunts. It is marketed for weight loss as an appetite suppressant.
Hoodia contains an extract dubbed P57 that is thought to suppress appetite by increasing feelings of fullness. But there is no credible evidence that hoodia is either safe or effective.
The Natural Medicines Comprehensive Database says there is "insufficient evidence" to rate the effectiveness of hoodia.
So far, no credible human studies of hoodia have been published.
Senna
Senna is an herb that is approved by the FDA as a laxative. But some people use senna for weight loss.
Senna can cause some side effects such as:
- stomach discomfort
- cramps
- diarrhea
It shouldn't be used for more than two weeks because in the long term it can cause the bowels to stop functioning normally and might cause dependence on laxatives.
The Natural Medicines Comprehensive Database says there is "insufficient evidence" to rate senna's effectiveness for weight loss.
Ephedra
Ephedra is also known as ma huang. It is an herb that contains the stimulants:
- ephedrine
- pseudoephedrine
- phenylpropanolamine
Ephedra has been used for more than 5,000 years in China and India to treat conditions such as colds, fever, flu, headaches, asthma, wheezing, and nasal congestion. Dietary supplements containing ephedra have been used for weight loss, increased energy, and enhanced athletic performance. The FDA banned dietary products with ephedra after the herb was linked to serious side effects, including:
- heart attack
- arrhythmia
- stroke
- psychosis
- seizures
- death
The FDA's ban does not apply to traditional Chinese herbal remedies or to products such as herbal teas. So ephedra can still be legally purchased in the U.S.
According to the FDA, there is little evidence for the herb's effectiveness except for short-term weight loss. But the agency says the health risks outweigh any benefits.
The Natural Medicines Comprehensive Database says that ephedra is "likely unsafe."
Bitter Orange
The bitter orange tree is native to Africa and tropical Asia. But it is now also grown in other areas such as the Mediterranean, California, and Florida.
Bitter orange contains synephrine, a stimulant related to ephedrine. It supposedly works by increasing the number of calories burned.
After the FDA banned weight loss products containing ephedra, many manufacturers switched to bitter orange. But there is little evidence that bitter orange is safer.
Like ephedra, there have been reports that bitter orange may be linked to dangerous side effects in people who took bitter orange alone or in combination with other stimulants such as caffeine.
These dangerous side effects include:
- ischemic stroke
- irregular heartbeat
- heart attack
- death
According to the FDA, bitter orange may not be safe to use as a dietary supplement. You should especially avoid taking bitter orange supplements if you have:
- a heart condition
- high blood pressure
You should also avoid bitter orange supplements if you are taking medications (such as MAO inhibitors), caffeine, or other herbs/supplements that speed up the heart rate.
The Natural Medicines Comprehensive Database says that bitter orange is "possibly unsafe" and "probably ineffective."