Overweight and obesity has reached epidemic proportions worldwide, with the global prevalence doubling since 1980 (WHO) and many people turn to supplements in an aim to help maintain and lose weight.
Researchers from the University of Sydney conducted a systematic review and meta-analysis, published in 'Diabetes, Obesity & Metabolism', which analysed the latest international research in this area finding 54 randomised controlled trials comparing the effect of herbal supplements to placebo for weight loss in over 4,000 participants altogether.
The review excluded studies where the herbal medicine did not include the whole plant, was comprised of plant oils or combined with other dietary supplements such as fibres and proteins.
As a single agent, only Phaseolus vulgaris resulted in a statistically significant weight loss compared to placebo, although this was not considered clinically significant (Weight differences of ≥2.5 kg were considered clinically significant).
No effect was seen for Camellia sinensis or Garcinia cambogia.
Statistically, but not clinically, significant differences were observed for combination preparations containing C. sinensis, P. vulgaris or Ephedra sinica.
Of the herbal medicines trialled in ≤3 randomized controlled trials, statistically and clinically significant weight loss compared to placebo was reported for Irvingia gabonensis, Cissus quadrangularis, and Sphaeranthus indicus combined with Garcinia mangostana, among others, but the review authors argue that these findings should be interpreted cautiously because of the 'small number of studies, generally poor methodological quality, and poor reporting of the herbal medicine interventions'.
Senior author Dr Nick Fuller from the University of Sydney's Boden Collaboration for Obesity, Nutrition, Exercise and Eating Disorders based at its Charles Perkins Centre, said: "This finding suggests there is insufficient evidence to recommend any of these herbal medicines for the treatment of weight loss. Furthermore, many studies had poor research methods or reporting and even though most supplements appear safe for short-term consumption, they are expensive and are not going to provide a weight loss that is clinically meaningful."
Source: Diabetes, Obesity and Metabolism
Maunder. A., et al
"Effectiveness of herbal medicines for weight loss: A systematic review and meta‐analysis of randomised controlled trials"