Food and Behaviour Research

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Effect of Docosahexaenoic Acid and Eicosapentaenoic Acid Supplementation on Sleep Quality in Healthy Subjects: A Randomized, Double-Blinded, Placebo-Controlled Trial

Yokoi-Shimizu K, Yanagimoto K, Hayamizu K (2022) Nutrients Oct 5;14(19):4136 doi: 10.3390/nu14194136 

Web URL: Read this article on PubMed


Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)-omega-3 fatty acids with various functions-influence sleep in children and young adults. However, only limited studies on their effects on sleep in middle- and old-aged adults have been reported. Therefore, we investigated the effects of DHA and EPA on sleep quality in subjects aged ≥ 45 years.

We performed a randomized, placebo-controlled, double-blinded, parallel-grouped study, in which we randomly assigned 66 healthy Japanese males and females. Each individual received six 480 mg capsules containing 576 mg DHA and 284 mg EPA per day (DHA/EPA group, 
n = 33), or corn oil (placebo group, n = 33), for 12 weeks. Before and after the intervention, the Oguri-Shirakawa-Azumi sleep inventory MA version (OSA-MA) and the sleep state test were conducted.

In the DHA/EPA group, factor III (frequent dreaming) scores among the OSA-MA scores were significantly improved compared to the placebo group. Additionally, sleep state tests revealed that sleep efficiency improved in the DHA/EPA group.

To our knowledge, this study is the first to report that DHA/EPA improves sleep quality in middle- and old-aged individuals, even at doses lower than those administered in previous studies.


Previous studies - including human clinical trials in children and younger adults - have shown that sleep may be improved by an increased dietary intake of the special omega-3 fats found in fish and seafood - the long-chain polyunsaturated fatty acds (LC-PUFA) EPA and DHA.

This new clinical trial found improvements in sleep quality in older adults following supplementation with omega-3 EPA and DHA, adding to the evidence than long-chain omega-3 can have benefits for sleep, even in generally healthy populations.

Of particular interest is that this study was carried out in Japan - where baseline dietary intakes of EPA and DHA are significantly higher than they are in the US, UK and most other developed countries. 

This is because fish and seafood still remains a significant part of most Japanese diets - particularly for older adults. By contrast, the modern western-type diets consumed in most developed countries, rich in ultra-processed foods, provide an excess of omega-6 fats, and are very low in omega-3 (particularly the long chain forms, EPA and DHA, which are the biological essential ones).  

These findings add to the evidence that a lack of long-chain omega-3 (and the resulting imbalance between omega-3 to omega-6 LC-PUFA) may impair sleep. 

Sleep problems are extremely common in most countries - and have a major negative impact on health and wellbeing. There are also very strong links between poor sleep and almost all forms of mental and developmental health problems - with which omega-3 deficiency is also associated.

For more information on the links between omega-3 and sleep, please see:

Omega-3 and Sleep - Research