Omega-3 and cognitive performance during adolescence
The area of the brain that develops most during adolescence is the prefrontal cortex (an area especially rich in docosahexaenoic acid (DHA)). This area is crucial to higher cognitive processes (inhibition and interference, working memory and cognitive flexibility), which are essential for reasoning and problem solving. Therefore, these processes are considered important for academic success, although clearly school performance also depends on other factors, such as time spent on homework and personality.
Observational studies in teenagers have found a beneficial association between fish consumption (principle source of the long-chain polyunsaturated fatty acids EPA and DHA), cognitive performance and average academic marks. Recently, the association between the omega-3 index (percentage EPA + DHA out of total fatty acids in the red blood cell membrane), a more objective and precise measure of ‘consumption’, and cognitive performance in typically developing adolescents was assessed (n=266; age ≤13 to ≥15). The results show that a higher omega-3 index is associated with faster information processing speeds and fewer mistakes of omission in an attention test (as a result of greater attention and less impulsiveness).
The mean omega-3 index in the sample of teenagers was found to be much lower (3.83%) than the recommended range (8-11%); not surprisingly, as 13.9% stated they never ate fish while 77% said they ate it only rarely.
Numerous studies have shown the benefits of omega-3 long-chain polyunsaturated fatty acids. For this reason, institutions such as The American Heart Association and the Dietary Guidelines Advisory Committee recommend at least two portions of fish a week, especially fatty fish, rich in EPA and DHA (this represents at least 250 mg a day of EPA and DHA). However, in the USA less than 10% of the population follow this recommendation. As a result, in 98% of the population, the blood concentration of these omega-3 fatty acids is below the level of dietary recommendations. It is estimated that in 2030, 40.5% of the US population will have some form of cardiovascular disease (CVD) and the real indirect cost of total CVD will rise by 61% from 2010 to 2030. However, it is also estimated that increasing omega-3 consumption (and, consequently, its blood levels) could significantly reduce the costs of the US health system.
Yet, by contrast, a survey carried out by the Global Health and Nutrition Alliance in the United States, Germany and the United Kingdom showed that 52% of the population believe they consume all the key nutrients needed for optimum nutrition in their diet alone. Most adults, regardless of country, think they have an optimal diet with an adequate omega-3 fatty acid intake, yet CVD continues to be the main cause of mortality in the three countries in the survey.
The need to increase omega-3 fatty acid consumption is evident, yet consuming fish at the recommended levels to obtain the right concentrations of omega-3 can be expensive, while concerns over mercury may limit fish consumption among groups such as children and pregnant and breast-feeding women. For this reason, omega-3 supplementation represents a good alternative.
- Bailey RL, Denby N, Haycock B et al. Perceptions of a Healthy Diet: Insights From a 3-Country Survey. Nutr Today. 2015 Nov;50(6):282-287. Epub 2015 Nov 23.
- Murphy RA, Yu EA, Ciappio ED et al. Suboptimal Plasma Long Chain n-3 Concentrations are Common among Adults in the United States, NHANES 2003–2004. Nutrients 2015, 7(12), 10282-10289; doi:10.3390/nu7125534
- van der Wurff IS, von Schacky C, Berge K et al. Association between Blood Omega-3 Index and Cognition in Typically Developing Dutch Adolescents. Nutrients. 2016 Jan 2;8(1). pii: E13. doi: 10.3390/nu8010013.