- Researchers recently presented the results of the first global analysis in 19 years of clinical trials for weight loss supplements.
- Based on two reviews of the literature, they found insufficient evidence to justify recommending supplements for weight loss.
- The study’s authors drew their conclusions from 121 clinical trials involving nearly 10,000 participants.
The first global review in 19 years of the effectiveness of herbal and dietary supplements for weight loss was recently presented by researchers at the University of Sydney (USYD) in Australia to the European Congress on Obesity (ECO).
The research, which included two reviews of the literature including 121 randomized placebo-controlled trials involving over 10,000 overweight or obese participants, found insufficient evidence that herbal and dietary supplements produce clinically meaningful weight loss.
Erica Bessell, lead author of the study, said:
“Our rigorous evaluation of the best available evidence reveals that there is not enough evidence to recommend these supplements for weight loss. Although most supplements seem safe for short-term consumption, they will not lead to clinically meaningful weight loss.
It is a line of pills, powders, and liquids marketed with the promise that they can help people lose weight. The products can include whole plants or products in which a plant is an active ingredient. They may also contain isolates of substances of animal and plant origin, such as fats, fibers and proteins.
“Over-the-counter dietary and herbal supplements promoted for weight loss are increasingly popular, but unlike pharmaceutical drugs, no clinical evidence of their safety and effectiveness is required before they are put on the market. market, ”Bessell said.
There is often little regulation to protect consumers from unproven claims. For example, while the Food and Drug Administration (FDA) is responsible for the safety of dietary supplements once they are available in the market, prior to that the involvement of the FDA is limited.
The first study included a review of 54 trials comparing the effects of herbal supplements to those of placebos. The research involved 4,331 participants aged 16 or older who were overweight or obese.
Weight loss of at least 5.5 pounds more than that achieved with a placebo was considered clinically significant.
The studies tested:
Only one of the substances, white bean, produced a statistically significant benefit when tested as monotherapy versus placebo, although it was still well below the threshold for clinical benefit.
Other supplements produced statistically significant benefits when given in combination with other supplements, but, again, these benefits were not clinically significant.
In addition, the last four substances in the above list can have shown some promise for clinically significant weight loss. However, the study authors caution that each was tested in up to three trials and that these studies were characterized by inferior methodology and reports.
The second review included 67 randomized trials testing the weight loss value of dietary supplements derived from natural compounds, compared to placebos. There were 5,194 overweight or obese adults who participated in these studies.
Chitosan, glucomannan and conjugate linoleic acid produced statistically significant weight losses compared to placebo, but these were too small to be of clinical significance. Fructans, on the other hand, produced no statistically significant weight loss.
Two substances have given promising results: modified cellulose – which creates a feeling of fullness – and blood orange juice extract. However, each has been tested in a single trial, which is not enough to warrant a recommendation for their use.
“Herbal and diet supplements may seem like a quick fix to weight problems, but people need to be aware of how little we actually know about them. Very few high-quality studies have been done on certain supplements, with little data on long-term effectiveness. Additionally, many trials are small and poorly designed, and some do not reflect the makeup of the supplements under study.
There is also a fundamental problem with weight loss supplements, according to the dietitian of the Cleveland Clinic Kristin kirkpatrick, who said Medical News Today,
“Supplements that can suppress your appetite don’t really teach you how to eat. Eventually you will have to leave […] them, and when you do, you’ve basically learned how to take a pill to control your diet, but you haven’t actually learned which diet is right for you based on genetics, lifestyle, etc.
Learning how to eat well is the key to lasting weight control, Kirkpatrick said, because, “[w]Even though it is not at all easy to lose weight in the first place, it is surely easier to lose it than to keep it.
Despite the lack of rigorous studies, people still buy these diet aids and depend on them to help them with weight problems.
“The phenomenal growth of the industry and the popularity of these products,” Bessell said, “underscores the urgency of conducting larger and more rigorous studies to have reasonable assurance of their safety and efficacy for loss of life. weight.”