Dietary Supplements for Weight Loss: Buyer Beware!

Author: Darrell Hulisz, RPh, PharmD

The National Institutes of Health estimates that 35% of US adults are obese.1 Obesity ranks second only to smoking as a potentially preventable cause of death. Obesity-related medical conditions, such as hypertension and diabetes mel-litus, contribute to 300,000 deaths annually. Other disorders that are associated with obesity include osteoarthritis and cancer. The cost to the American economy attributable to obesity is staggering if these comorbidities?as well as lost productivity and medical and surgical treatment of obesity?are factored in. Approximately $53.6 million in wages are lost, and $100 billion are spent on treating obesity-related medical disorders.1 The exact etiology of obesity is uncertain, but it is multi-factorial. Factors thought to contribute to its development include genetics, metabolic rate, caloric intake, dietary composition, and activity level.

Treatment for Obesity
Obesity should not be regarded as merely a cosmetic concern, but rather a legitimate medical disorder. Treatment for obesity should be medically supervised, multifaceted, and supported by a team approach. Many patients, however, attempt weight reduction without consulting their physician. Because of the plethora of weight-loss products marketed, pharmacists often find themselves on the receiving end of questions from consumers wishing to purchase diet aids. Most OTC diet aids have been removed from the market?such as those containing phenylpropanolamine?amidst safety concerns. In November 2000, the FDA issued an advisory to manufacturers of phenylpropanolamine to discontinue sales and marketing of these products because they were linked to the development of hemorrhagic stroke.

Ephedra (Ma Huang)
Weight-loss dietary supplements containing ephedra are widely available in some retail outlets. The death of Balti-more Orioles pitcher Steve Bechler in February 2003 brought renewed attention to the dangers of herbal ephedra. Bechler died from multiple organ failure due to heatstroke. A medical examiner concluded, however, that a dietary supplement containing ephedra used by Bechler was a contributing factor in his death. Because of the popularity and wide availability of ephedra-containing products, pharmacists must be well equipped to warn patients appropriately to prevent harmful effects of supplements containing this ingredient. Ephedra is a naturally occurring substance derived from ma huang, a Chinese herb. It has been promoted for weight loss, for enhancing athletic performance, and for relieving asthma.2-4 Ephedra is sold as a dietary supplement, and it is federally regulated under the Dietary Supplement Health and Education Act of 1994. Under this regulation, dietary supplements are exempt from the same FDA scrutiny as OTC and prescription drugs. A manufacturer can market a supplement without proving its safety and efficacy to the FDA, but the manufacturer cannot make any claims that a dietary supplement is intended to prevent, diagnose, mitigate, treat, or cure a disease. Yet, the FDA does have the authority to remove a product from the market if it is proven to be harmful.

The Department of Health and Human Services recently announced a number of actions to address concerns about the safety of ephedra (Table), but the FDA has not removed ephedra from the market.5The American Heart Association (AHA) has issued a statement to the FDA in support of a ban on the substance. Like other critics, the AHA believes that the dangers of the supplement outweigh any possible benefits as a weight-loss aid.

Ephedra has been used in this country since the 1920s as a bronchodilator and decongestant. It is composed of the alkaloids ephedrine and pseudo-ephedrine. The latter is available as an OTC decongestant (eg, Sudafed). Ephedra causes vasoconstriction and cardiac stimulation through its agonistic properties on both alpha- and beta1-adrenergic receptors. By stimulating beta2 receptors, it causes bronchial
smooth muscle relaxation and bron-chodilation?beneficial effects in asthmatic patients.3 Ephedrine is thought to exert its anorexiant effect via adren-ergic pathways to the hypothalamus and possibly by increasing the metabolic rate, although these mechanisms have not been fully elucidated.6

Adverse Effects of Ephedra
Products containing ephedra account for 64% of all adverse reactions to herbs in the United States, yet these products represent less than 1% of herbal product sales.7 The use of ephedra, especially when combined with caffeine, is associated with increased risk of psychiatric, autonomic, gastrointestinal symptoms well as heart palpitations.8 Based on case reports, ephedra appears to be associated with the development of immune-mediated hepatitis and stroke.9-14 It is important to recall that many of these case reports do not prove causality, however.

The use of ephedra and ephedrine-containing products can result in an increase in both systolic and diastolic blood pressure and therefore should be avoided by anyone with cardiovascular disease (hypertension, angina, history of myocardial infarction), as well as thyroid disease, diabetes, and prostate abnormalities. It should not be administered with other sympatho-mimetics, including pseudoephedrine, or caffeine.

The combination of ephedra and St. John?s wort is referred to as "herbal Prozac." The FDA has cautioned consumers not to consume the ephedrine-containing herbal preparations known and marketed as "herbal ecstasy," which manufacturers claim will heighten "sexual awareness."15,16 Furthermore, the efficacy of ephedra in promoting and sustaining weight loss is questionable and modest.8,17 There have been no well-designed, long-term studies to support the unsupervised use of ephedra by consumers.8,17 More than 100 products have been identified in over 800 reports of adverse reactions in which herbal preparations contained, or were thought to contain, ephedra.

Side effects are consistent with those of other sympathomimetic agents and include insomnia, nervousness, tremor, headache, hypertension, seizures, arrhythmias, heart attack, stroke, and even death. Many of the cases were patients under the age of 40, because ephedra preparations have been marketed for weight loss and for enhancing athletic performance. Renal stones also have developed in patients taking ephedra.18 The substance is contraindi-cated for patients taking monoamine oxidase inhibitors.

Pharmacists should discourage the use of ephedra-containing products. Patients with cardiovascular disease, or those at risk for heart disease (eg, from smoking, dyslipidemia, diabetes, family history of premature heart disease) should be warned not to use the supplement. Rather, pharmacists should promote healthy lifestyle habits, such as engaging in a regular exercise routine, reducing consumption of saturated fats, and overall caloric restriction. Pharmacists should encourage patients to seek treatment for obesity that is medically supervised, multifaceted, and supported by a team approach.

For a list of references, send a stamped, self-addressed envelope to: References Department, Attn. D. Ryan, Pharmacy Times, 241 Forsgate Drive, Jamesburg, NJ 08831; or send an e-mail request to: dryan@mwc.com .