Magical teas that promise to boost metabolism, capsules to obliterate tummy fat, a concentrated liquid that will give you the body of your dreams – we all know the saying, if it sounds too good to be true, it probably is.
Case in point: Herbal and dietary supplements promising easy, natural weight loss.
The industry has boomed as our global obesity rates continue to outgrow our daily steps.
Although they’re sold over the counter, these products are not subjected to the same benchmarks as pharmaceutical products.
So, they can be put on the shelf for sale, promising the world – without having to provide clinical evidence to back up those promises.
Getting to the bottom of it
Researchers from the University of Sydney have undertaken the world’s first review of complementary medicines, to try and find out just how effective (or ineffective) these popular supplements are.
Straight up, what they found was an industry running largely unchecked.
Between 1996 and 2006, 1000 weight-loss supplements included on the Australian Register of Therapeutic Goods weren’t tested for efficacy, and just 20 per cent of new listings are checked annually to make sure they measure up, the researchers noted.
Given there’s little to no checks and even less accountability, the researchers’ finding should come as no surprise.
‘‘Our rigorous assessment of the best available evidence finds that there is insufficient evidence to recommend these supplements for weight loss,’’ lead author Erica Bessell said.
‘‘Even though most supplements appear safe for short-term consumption, they are not going to provide weight loss that is clinically meaningful.’’
Ms Bessell further said there’s not enough research to back up the long-term safety of these products.
Teas, powders, liquids
The researchers reviewed 54 randomised trials that pitted herbal supplements against placebos, and compared the weight-loss results.
If an individual recorded a weight loss of 2.5 kilograms or more, that was considered ‘clinically meaningful’.
The supplements involved in the trials included green tea, mangosteen, white kidney bean, the metabolism-boosting ephedra, African mango, licorice root, yerba mate and East Indian globe thistle.
Only the white kidney bean was found to produce a statistically greater weight loss than the placebo.
But, at 1.61 kilograms, the bean doesn’t hit that clinically meaningful benchmark.
The researchers did note African Mango, veld grape and the globe thistle showed some “promising results”, but were part of three or fewer trials, so they need plenty more research before there can be a definitive ruling there.
Again, left wanting
Separately to the herbal market, the researchers took a similar approach to investigating dietary supplements, analysing the data of 67 trials.
Under scrutiny were products or ingredients such as: “Chitosan (a complex sugar from the hard outer layers of crustaceans 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).”
Chitosan, glucomannan and conjugated linoleic acid all recorded weight-loss results (between 1.08 kilograms and 1.84 kilograms), but none breaching that magical 2.5-kilogram measure.
Again, there were some promising contenders (modified cellulose and blood orange juice extract), but they only featured in one trial.
Overall? The data says, these products probably aren’t worth your time, money or hope.
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“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,” Ms 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.”
The research was presented at the European Congress on Obesity last week.