Why we need evidence for alternative medicines for weight loss

19 November 2015

As Australia's fastest growing group of medications, we urgently need to investigate the use of complementary medicines for weight loss, argues Dr Nicholas Fuller.

Proving or disproving the effectiveness of complementary medicines for weight loss could have a fundamental impact in treating obesity
Dr Nicholas Fuller

Household medicine cabinets the world over hold an assortment of complementary medicines. Without being entirely sure whether they work, consumers routinely stock up on alternative medicines. In Australia, they’re used by as many as one in two people, and they’re the fastest growing group of medications.

Weight loss accounts for a growing proportion of the complementary medicines market. While we do have evidence of the benefits of complementary medicines for various health conditions, we are flying blind on weight loss claims.

In fact, despite the fact many complementary medicines have been around for centuries, we have startlingly little evidence across the board for whether or not they work. Complementary medicines have managed to evade the rigorous standards of scientific conduct applied to other pharmaceuticals in well-designed randomised controlled trials.

In the past there has been very little incentive for manufacturers to conduct research because complementary medicines cannot benefit from a protected period of patency as the pharmaceutical industry does with new drugs.

With the obesity epidemic well and truly at crisis point, it’s crucial we test complementary medicines with potential weight loss and associated health benefit claims – notably fibre supplements for the former and ginseng and St. John’s Wort for the latter. No single solution suits all individuals for weight loss success, whether that’s a dietary program, a drug treatment, a medical device or surgery.

One of the biggest challenges with complementary medicines is that the composition of each product varies between manufacturers. Often consumers buy a product based on its name only, failing to realise it may not consist of the same ingredients as the product with proven efficacy and safety. Ginkgo biloba, for example, is touted as a treatment for cognitive function and dementia. While clinical trials have tested some ginkgo leaf extracts – EGb-761 and LI-1370 – the results of these trials cannot be applied to other popular extracts used in other brands.

An analysis of St John’s Wort brands found their hyperforin and hypericin content (the active components required for antidepressant effects) varied from 0.01 per cent to 1.89 per cent and 0.03 per cent to 0.29 per cent respectively. Only two of the eight brands tested contained enough hyperforin for antidepressant effects.

In Australia, we are fortunate the complementary medicines industry is governed by one of the most highly regarded and tightly regulated systems in the world in the TGA.

Proving or disproving the effectiveness of complementary medicines for weight loss could have a fundamental impact in treating obesity. We must investigate whether these increasingly popular products could be a viable treatment option.

Dr Nicholas Fuller is a Research Fellow in Clinical Trials Development and Assessment at the Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders at the Charles Perkins Centre, the University of Sydney. This article was first published in the Medical Observer