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  • eNews - PEN® eNews 15(1) January 2025 - All About Supplements
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PEN® eNews 15(1) January 2025 - All About Supplements

PEN® eNews is a monthly e-newsletter shared with the global PEN Community and created to help dietitians position themselves as leaders in evidence-based nutrition practice. In addition, users of the PEN System will find articles on the new evidence, resources and features available and how to maximize one's use of PEN.


Dietary Supplements for Weight Loss

The Question

First of all, what are dietary supplements? Researchers have often used the terms “nutraceutical”, “dietary supplement” and “herbal supplement” interchangeably. In PEN, we’ve defined these terms as food products (e.g. foods, extracts, supplements) that are sourced from foods that may improve health or prevent disease.

As the new year begins, you may be receiving questions from patients/ clients about dietary supplements for weight loss. Are they safe? Are they effective? Our updated practice question, “Are nutraceuticals/ dietary supplements/ herbal supplements safe and effective in stimulating weight loss in adults?”, has the answers.

The Recommendation

In general, nutraceuticals may have no effect or lead to clinically insignificant weight loss in adults.

Some nutraceuticals have been associated with both minor side-effects (e.g. gastrointestinal complaints) and major safety concerns (e.g. liver failure, organ transplant, death), while others have no reported adverse effects. Dietary supplement use should be individualized and discussed with the individual’s health care practitioner.

Common weight loss supplements that may be associated with liver injury include: GTE epigallocatechin-3-gallate (EGCG; a component of green tea extract); garcinia cambogia; caffeine supplements; yohimbine; Herbalife (saw palmetto and green tea extract); OxyELITE Pro (aegeline); Hydroxycut (ashwagandha, ephedra and green tea extract); and Slimquick (green tea extract and turmeric).

Grade of Evidence: A & B & C & D, depending on the supplement.

To see the full practice question, including the Evidence Statements, Remarks and References, click here.


Dietary Supplements for Attention Deficit Hyperactivity Disorder (ADHD)

The Question

Speaking of dietary supplements, we've updated our practice question, "Is there evidence to support specific dietary supplements (including herbal preparations) for the prevention and treatment of attention deficit hyperactivity disorder (ADHD) in children and adults?". Few studies have examined this question. See our interpretation of the evidence that does exist below.

The Recommendation

Evidence is too sparse and biased to recommend that children and adolescents take herbal supplements or East Asian Herbal Medicine (EAHM) to manage attention deficit hyperactivity disorder (ADHD) symptoms. In addition, the long-term (>6 months) effects of these supplements in this population are unknown.

The effects of herbal supplements on ADHD symptoms in adults have rarely been studied. Saffron may improve the effect of methylphenidate when taken concurrently, while lobeline, cannabinoids and Pycnogenol may not improve ADHD symptoms compared to placebo. All successful studies were very short-term (<6 weeks) and the long-term effects of these products are not known.

Grade of Evidence: C 

To see the full practice question, including the Evidence Statements, Remarks and References, click here.


Melatonin for ADHD

The Question

Melatonin is another dietary supplement that may be used for individuals with ADHD. While prescribing melatonin would not be within the dietitian’s scope of practice, RDs may be asked about melatonin and could give general information on the topic. We take a deep dive into its safety and efficacy in children in our practice question, "Is melatonin safe and effective for the management of sleep problems in children with sleep problems associated with attention deficit hyperactivity disorder (ADHD)?".

The Recommendation

Taking 3 to 6 mg immediate-release supplemental melatonin before bedtime probably improves total sleep time, sleep onset latency (i.e. amount of time spent trying to fall asleep) and sleep efficiency (i.e. time slept divided by time spent lying in bed), but probably does not affect ADHD symptoms, in children with attention deficit hyperactivity disorder (ADHD) and insomnia.

Taking 1 mg extended-release supplemental melatonin before bedtime may improve total sleep time but may not affect sleep onset latency, wake time after sleep onset and sleep efficiency in children with ADHD and insomnia.

Side-effects related to melatonin supplementation may be mild and have not led to discontinuation of the supplement.

Country-Specific Guidelines

The 2020 Canadian ADHD Resource Alliance (CADDRA) practice guidelines do not recommend melatonin as a first-line therapy for improving sleep in children with ADHD, but they recognize that a limited number of studies have shown that melatonin may improve sleep in this population. 

British and Australian guidelines for the management of ADHD in children do not mention melatonin.


Grade of Evidence: B & C, depending on the outcome.

To see the full practice question, including the Evidence Statements, Remarks and References, click here.


ADHD Content Has Been Updated!

The Summary of Recommendations and Evidence allows you to access the most critical content quickly and easily by distilling our Practice Questions into a few key points. If you have limited time to prepare for a patient/ client appointment, the Summary of Recommendations and Evidence is your best place to start.

Learn more about ADHD in our Summary of Recommendations and Evidence - Mental Health - Attention Deficit Hyperactivity Disorder (ADHD).


Tools and Resources: Calculators and Professional Tools


PEN doesn't just have the latest evidence - we also have helpful practice tools such as calculators and conversions. Our Calculators and Professional Tools page gives you access to energy expenditure calculators, BMI calculators, conversion calculators, and nutrition screening and assessment tools. If you think that there’s something we should add, feel free to contact us.

Find these resources here: Calculators and Professional Tools.

Did You Know?


Not only can PEN tell you the latest evidence, but it can tell you what is different between current recommendations and the ones they replaced.

If you see the “updated” flag beside a Practice Question, hover your mouse over the flag. The reason for updating the content will appear. It might say “Reviewed and no new evidence identified that changes current recommendations ”, “New evidence added that supports current recommendations”, “New evidence added that resulted in change to recommendations” or “New evidence added that supports current practice recommendations and has resulted in a change in the grade of evidence”. See the image below for an example.

Happy reading!



PEN eNews
PEN: The Global Resource for Nutrition Practice  
January 2025  Volume 15 (1)


A Publication of the PEN® System Global Partners,
a collaborative partnership between International Dietetic Associations.
Learn more about PEN.
Copyright Dietitians of Canada . All Rights Reserved.
Articles in this issue
  • Dietary Supplements for Weight Loss
  • Dietary Supplements for Attention Deficit Hyperactivity Disorder (ADHD)
  • Melatonin for ADHD
  • ADHD Content Has Been Updated!
  • Tools and Resources: Calculators and Professional Tools
  • Did You Know?
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