Do they really work? New research targets popular weight-loss supplements

May 10, 2021
Weight loss supplements have boosted in popularity over the last few years. Source: Getty

Weight loss supplements are having a moment in the health world, with consumers eager to find easy solutions to their weight loss woes. However, new research has found that these ‘fast and easy’ solutions aren’t all they’re cracked up to be.

According to Aussie research being presented at the European Congress on Obesity, there isn’t enough evidence to prove herbal and dietary supplements help with weight loss.

“Over-the-counter herbal and dietary supplements promoted for weight loss are increasingly popular, but unlike pharmaceutical drugs, clinical evidence for their safety and effectiveness is not required before they hit the market,” lead author, Erica Bessell, from the University of Sydney in Australia, said.

“Our rigorous assessment of the best available evidence finds that there is insufficient evidence to recommend these supplements for weight loss. Even though most supplements appear safe for short term consumption, they are not going to provide weight loss that is clinically meaningful.”

Despite their increasing popularity, between 1996 and 2006, 1,000 dietary supplements for weight loss listed on the Australian Register of Therapeutic Goods weren’t evaluated for efficacy. The researchers also discovered that supplements can be sold and marketed to the public without providing sufficient evidence backing their claims. Not only that, but just 20 per cent of new listings are audited annually to make sure they meet the standard requirements. And in some countries, the only requirement for a supplement to make a health claim is that it contain acceptable levels of non-medicinal products.

To provide more evidence, the researchers did a systematic review of all randomised trials comparing the effects of herbal supplements (containing whole plants or combinations of plants) to placebos on weight loss. Data were analysed for 54 studies involving 4,331 healthy overweight or obese adults aged 16 years or older. Weight loss of at least 2.5 kilograms was considered clinically meaningful.

Herbal supplements included in the analysis were: green tea, Garcinia cambogia and mangosteen (tropical fruits); white kidney bean; ephedra (a stimulant the increases metabolism); African mango; yerba mate (herbal tea made from the leaves and twigs of the Ilex paraguariensis plant); veld grape (commonly used in Indian traditional medicine); licorice root; and East Indian Globe Thistle (used in Ayurvedic medicine).

The analysis found that only one single agent, white kidney bean, resulted in a statistically, but not clinically, greater weight loss than placebo (-1.61kg). Other herbal supplements such as African Mango, veld grape, East Indian Globe Thistle and mangosteen showed promising results, however the researchers cautioned they were investigated in three or fewer trials, often with poor methodology or reporting.

The researchers also did a systematic review of 67 randomised trials comparing the effect of dietary supplements containing naturally occurring isolated compounds to placebo for weight loss in 5,194 healthy overweight or obese adults aged 16 years or older.

Dietary supplements included in the analysis were: chitosan (a complex sugar from the hard outer layers of lobsters, crabs and shrimp that claims to block absorption of fat or carbohydrates); glucomannan (a soluble fibre found in the roots of the elephant yam, or konjac, that promotes a feeling of fullness); fructans (a carbohydrate composed of chains of fructose) and conjugated linoleic acid (that claims to change the body composition by decreasing fat).

The analysis found that chitosan (-1.84kg), glucomannan (-1.27kg), and conjugated linoleic acid (-1.08kg) showed promising results statistically, but not clinically.

The findings were published in the International Journal of Obesity.

“Herbal and dietary supplements might seem like a quick-fix solution to weight problems, but people need to be aware of how little we actually know about them,” Bessell concluded.

“Very few high-quality studies have been done on some supplements with little data on long-term effectiveness. What’s more, many trials are small and poorly designed, and some don’t report on the composition of the supplements being investigated. The tremendous growth in the industry and popularity of these products underscores the urgency for conducting larger more rigorous studies to have reasonable assurance of their safety and effectiveness for weight loss.”

IMPORTANT LEGAL INFO This article is of a general nature and FYI only, because it doesn’t take into account your personal health requirements or existing medical conditions. That means it’s not personalised health advice and shouldn’t be relied upon as if it is. Before making a health-related decision, you should work out if the info is appropriate for your situation and get professional medical advice.

What are your thoughts on this research? Have you tried weight loss supplements before? Did they work?

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