What was the study?
There is growing evidence to suggest that regular consumption of omega-3 fatty acids, whether from food (e.g. oily fish) or supplements (e.g. fish oil or krill oil), can provide various health benefits.
Previously identified benefits include supporting cardiovascular health, as well as brain structure. There is also some data indicating that consumption of omega-3 fatty acids could benefit cognitive performance.
To date, nearly all human studies that have examined the effects of omega-3 fatty acids had done so after weeks, perhaps even months or years, of supplementation. This is understandable given that omega-3 fatty acid uptake in human body tissue (e.g. red blood cells) is gradual.
However, there was some evidence that a single dose of omega-3 fatty acids could improve blood vessel function within hours of consumption. This raised the question – could omega-3 fatty acids also influence cognitive performance, mood and/or cardiovascular function in the hours following consumption of a single high dose?
The aim of the NuMega trial was to examine whether a single dose (4 grams) of omega-3 fatty acids (specifically docosahexaenoic acid or DHA) incorporated into a meal (in this case a serving of full fat yoghurt) would influence cognitive performance, mood and cardiovascular function in middle-aged (i.e. 40 to 60 years) males.
The NuMega trial was undertaken by the Centre for Human Psychopharmacology located at Swinburne University of Technology in Hawthorn. The trial began in July 2018 with an aim to recruit 15 participants. The trial was then extended in 2019 to recruit a larger number of people.
Unfortunately, due to the COVID-19 pandemic, the trial had to be paused between March 2020 and February 2021. However, eventually we successfully completed the trial with 32 people finishing in late April 2021.
The overview of the trial was:
Potential participants were screened via telephone to ensure they satisfied most major inclusion and exclusion criteria for the trial.
Practice and screening visit
Participants attended our lab at Swinburne University of Technology. During this visit, their eligibility was confirmed. All eligible participants were then familiarised with the trial's computerised tasks.
First and second testing visits
The testing procedure was the same for both testing days, except participants received the opposite treatment at the second visit.
Figure 1. Overview of participant testing
What was the treatment?
The name of the product under investigation was Driphorm HiDHA-360 – a powder consisting of omega-3 fatty acids (from fish or shellfish sources), milk protein, sugars and antioxidants. The total weight of the product was 12 grams with omega-3 fatty acids (i.e. DHA) comprising four grams of the weight. This powder (or identical placebo) was mixed with a single 140-gram serve of full fat vanilla-flavoured yoghurt prior to being served to participants.
Each participant received the real treatment and the placebo, but on different days. The treatments were randomised where some participants received the real treatment first and others received the placebo first.
The trial was double-blinded where neither the participants or researchers knew when participants were given the real treatment or the placebo (though our nurse kept a record).
The context for the dose of omega-3 fatty acids administered
According to Better Health Channel, a serve (150 grams) of:
- canned sardines provide 1.5 grams omega-3 fatty acids
- canned tuna provides 0.3 to 0.5 gram omega-3 fatty acids
- canned salmon provide 0.5 to one gram omega-3 fatty acids
- fresh Atlantic salmon provides a little over 0.5 gram omega-3 fatty acids
However, these comparisons include other omega-3 fatty acids such as EPA. The omega-3 fatty acid DHA is often found in lower concentrations to EPA. The same applies to fish oil capsules – even a single 'high dose' fish oil capsule may only contain 0.24 gram of DHA.
What were the results?
The following is the broad overview of the major findings of the NuMega trial.
Blood omega-3 fatty acid levels
Blood omega-3 and omega-6 fatty acid levels were assessed before cognitive testing in the morning (before treatment) and in the afternoon (after treatment). We compared the change in average blood omega-3 and omega-6 fatty acid concentrations from morning (before treatment) to afternoon (after treatment) following consumption of the real treatment or placebo.
Result: The real treatment was effective in raising the amount of omega-3 fatty acids in participants' blood in the 3.5 to four hours following consumption.
As shown in Figure 1, cognitive performance was assessed in the morning (before treatment) and in the afternoon (after treatment). The primary measure for assessing cognitive performance was the Swinburne University Computerised Cognitive Assessment Battery (SUCCAB).
We compared the change in average performance during morning testing (before treatment) to afternoon (after treatment) testing following consumption of the real treatment or placebo.
Result: There were no differences in the change in cognitive performance (assessed as participants' response speed and response accuracy) from morning testing (before treatment) to afternoon testing (after treatment) when participants consumed the real treatment or placebo.
The participants' mood scores (i.e. alertness, contentedness, calmness, stress, mental and physical fatigue, as well as ability to concentrate) were assessed before and after cognitive testing in the morning (before treatment) and in the afternoon (after treatment).
We compared the change in the participants' average mood scores following cognitive testing before consuming either treatment (morning), after consuming either treatment (afternoon), as well as how mood changed from the start to the end of the testing day.
Results: The real treatment benefited select measures of participants' mood compared to placebo.
- Participants always felt less alert after cognitive testing (morning or afternoon) or at the end of the day than the beginning. However, the decline in alertness was not as large when participants consumed the real treatment compared to the placebo.
- Participants felt more stressed at the end of the testing day than at the beginning. However, the increase in stress was not as large when participants had consumed the real treatment compared to the placebo.
Cardiovascular function was assessed prior to cognitive testing in the morning (before treatment) and the afternoon (after treatment). Whilst other measurements were taken during the study (using the portable blood pressure monitor), these timepoints were the primary assessments of cardiovascular function.
Results: The real treatment influenced select measures of blood pressure. All participants appeared to demonstrate a decline in blood pressure over the testing day (likely a result of time of day and prolonged rest periods before testing). However:
- Peak (systolic) blood pressure within the main artery leaving the heart (the aorta) demonstrated greater decline over the testing day when participants consumed the real treatment compared to the placebo. Similar results were evident for average blood pressure within the aorta.
- More traditional measures of blood pressure (for the artery in the arm – the brachial artery) showed similar results to the aorta, though the effects were not quite as large.
Were there any side effects?
Side effects are unwanted medical events (even a simple as a headache) that happen during the study. While some of these events may be related to the treatments provided in the trial, some may be due to study procedures (e.g. abstaining from caffeine prior to testing), whereas others are completely unrelated to the treatments under investigation (e.g. developing a cold or the flu). However, all events were documented and a report was issued to the sponsor at the completion of the trial.
Overall, there were 26 medical events reported by participants once testing had commenced or treatments were administered. Only one event (mild headache) was classified as a reaction to the treatment as it occurred within half an hour of the real treatment being consumed (though it resolved on its own within 30 minutes of onset). One other participant reported ‘gassiness’ at their first visit, but they had been administered placebo on that day – no similar report was made at the visit where they were administered the real treatment.
What else should I know about this study?
The data collected during the NuMega trial has helped provide insight into the potential benefits of omega-3 fatty acids, notably the fatty acid DHA. As indicated, most studies of omega-3 fatty acids are conducted over long periods of time, often weeks, months or even years!
Though further trials are required, the results outlined here suggest that some benefits to mood and cardiovascular function (primarily blood pressure) can be attained in the hours following consumption of a single high dose of DHA incorporated into a small meal (i.e. yoghurt).
We are working towards publishing data from the NuMega trial in peer-reviewed scientific journals.
In the meantime, if you would like to learn more about the study and its results, please contact a member of the study team.