Yes, that would be nice!

You want to lose weight?

Just take a few pills an Bob’s your uncle!

There is, of course no shortage of such pills – but do they work?

This study aimed at quantifying and ranking the effects of different nutraceuticals on weight loss. PubMed, Scopus, and Web of Science to November 2022 were searched and all randomized trials (RCTs) evaluating the comparative effects of two or more nutraceuticals, or comparing a nutraceutical against a placebo for weight loss in adults with overweight or obesity were included. A random-effects network meta-analysis was conducted with a Frequentist framework to estimate mean difference [MD] and 95% confidence interval [CI] of the effect of nutraceuticals on weight loss.

One hundred and eleven RCTs with 6171 participants that investigated the effects of 18 nutraceuticals on body weight were eligible. In the main analysis incorporating all trials, there was high certainty of evidence for supplementation of spirulina (MD: -1.77 kg, 95% CI: -2.77, -0.78) and moderate certainty of evidence that supplementation of curcumin (MD: -0.82 kg, 95% CI: -1.33, -0.30), psyllium (MD: -3.70 kg, 95% CI: -5.18, -2.22), chitosan (MD: -1.70 kg, 95% CI: -2.62, -0.78), and Nigella sativa (MD: -2.09 kg, 95%CI: -2.92, -1.26) could result in a small improvement in body weight. Supplementations with green tea (MD: -1.25 kg, 95%CI: -1.68, -0.82) and glucomannan (MD: -1.36 kg, 95%CI: -2.17, -0.54) demonstrated small weight loss, also the certainty of evidence was rated low.

The authors concluded that supplementations with nutraceuticals can result in a small weight loss in adults with overweight or obesity.

The authors tell us little about the methodological quality of the studies. All they did report was this:

Among trials with a low risk of bias, only chitosan (mean difference: −1.72 kg, 95%CI: −3.37, −0.06) and green tea (mean difference: −1.61 kg, 95%CI: −3.14, −0.09) were effective for weight loss compared with placebo. There was no significant weight loss following increased consumption of other nutraceuticals in trials with a low risk of bias.

In view of the lack of reliability of the primary studies, I feel that the conclusions drawn by the authors are not justified. Even though far from recent, I much prefer our own conclusion of a similar data set:

The evidence for most dietary supplements as aids in reducing body weight is not convincing. None of the reviewed dietary supplements can be recommended for over-the-counter use.

In other words, if you want to lose weight, don’t rely on dietary supplements!

4 Responses to Nutraceuticals for reducing body weight? A systematic review and network meta-analysis of 111 randomized clinical trials

  • More silly studies that are of no real value to consumers or medical professionals!
    Unfortunately we live in an age of slogans, sound-bites and strap-lines that appeal to those folks who possess a very short attention span.
    ‘Weight Loss’ is guaranteed to gain the attention of those who are ill-informed about how their body works and what they need to do if they want to improve their general health and well-being.
    The phrase ‘weight-loss’ means different things to different people – that is the problem! What we should focus on – in simple terms – is the dangers resulting from an unhealthy balance between excess body fat and lean muscle mass. It is often reported that folks desperate to ‘lose weight’ actually lose the wrong kind of weight via pills, potions or eating less.
    No doubt my opinion will be criticised, but I welcome constructive debate – any takers?

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Subscribe via email

Enter your email address to receive notifications of new blog posts by email.

Recent Comments

Note that comments can be edited for up to five minutes after they are first submitted but you must tick the box: “Save my name, email, and website in this browser for the next time I comment.”

The most recent comments from all posts can be seen here.