High omega-3 blood levels, and especially high DHA levels, lead to better brain function in young children aged 2 to 6, according to a new study published in the Journal of Nutritional Biochemistry.1 The study was specifically conducted with children in Northern Ghana, where people have poor access to foods rich in omega-3s DHA and EPA.
In this cross-sectional study, researchers took dried blood spot samples from 307 children with an average age of 46.5 months, a greater portion of whom were male (51.2%). The average Omega-3 Index, defined as the level of EPA plus DHA fatty acids in red blood cells, for the group was 4.6%, but the levels ranged from 2.3% to 11.7%.
The children were then given a dimensional change card sort (DCCS) task to assess their cognitive function. Subjects were asked to sort a series of bivalent cards based on one of two dimensions such as color and shape. For instance, children were asked to sort a series of eight cards based on color, then asked to switch to sorting by shape, providing researchers an index for executive function because the child must suppress a previously learned set of rules. This kind of task requires attention and flexibility in order to adjust one’s behavioral actions.
The test had four phases, and subjects passed if they could correctly sort six out of the eight cards. If they were unable to correctly sort six, they were considered to have failed and did not move on to the next phase. Also, because previous research has shown that children under 48 months often struggle with the DCCS tasks, subjects were given an initial condition that involved a task similar to DCCS but with monovalent cards to determine if their executive function was developed enough to perform a DSSC task. Subjects who failed the initial condition were considered unable to follow directions.
Half of all subjects were unable to follow directions. Nine passed the initial condition but were unable to pass the subsequent conditions, ten passed the first two conditions, 57 passed three, and 77 passed all four. Results showed that those subjects with the highest omega-3 levels, and especially children with the highest DHA levels, were three to four times more likely, respectively, to pass one or more of the DSSC conditions than children with the lowest DHA levels. Children who passed also had significantly lower levels of saturated fatty acids.
These are promising results, although it’s important to note that they are correlative rather than causative. The population used may also have been at a disadvantage in terms of nutritional deficiencies, disease, and socioeconomic status, though the researchers did account for malaria and low hemoglobin, two factors associated with negative cognitive impact. One of the study’s strengths, however, is that it used an objective biomarker to determine omega-3 status (blood tests and the Omega-3 Index), rather than relying on food frequency questionnaires, for instance.
Bill Harris, PhD, one of the study authors and founder of OmegaQuant (Sioux Falls, SD), the co-inventor of the Omega-3 Index test, said in a press release, “We were happy to see the positive correlation between omega-3 levels and better brain function, especially since an omega-3 deficiency is so easy to correct. All it requires is consuming more of the right omega-3s, especially DHA which in this case was the standout fatty acid here.”
- Adjepong M et al. “Whole blood n-3 fatty acids are associated with executive function in 2–6-year-old Northern Ghanaian children.” Journal of Nutritional Biochemistry, vol. 57 (2018): 287–293