The Omega‐6 to Omega‐3 Fatty Acid Ratio Predicts Brain Activity During Planning Tasks in Middle Childhood.
Authors: Sheppard Kelly , Cheatham Carol L. 
Published: November 2023

The dietary omega‐6 (n‐6) to omega‐3 (n‐3) fatty acid (FA) ratio (n‐6/n‐3 ratio) has been shown to predict planning abilities in children 7 to 12 years old. We previously demonstrated that a balanced n‐6/n‐3 ratio and n‐3 intake (e.g., low n‐3 intake with a low n‐6/n‐3 ratio) predicted better performance on difficult planning problems in 7‐ to 9‐year‐olds, and unbalanced intake (e.g., high n‐3 intake with a low n‐6/n‐3 ratio) predicted better performance in 10‐ to 12‐year‐olds. These results imply important developmental considerations for the role of n‐6 and n‐3 FAs in cognitive function. We further explored the role of n‐6 and n‐3 FAs in brain function by collecting brain imaging data from the prefrontal cortex (PFC) using near‐infrared spectroscopy (NIRS) with 57 children (29 children 7 to 9 years old and 28 children 10 to 12 years old) who completed the Stockings of Cambridge (SOC) planning task from the Cambridge Neuropsychological Test Automated Battery (CANTAB). We computed the oxygenated hemoglobin (oxyHb) levels in the left PFC, central PFC, and right PFC (Figure 1) related to children solving simple planning problems (3‐move problems), difficult planning problems (5‐move problems), and the change in brain activity moving from 3‐move to 5‐move problems. The difference in brain activity from 3‐move to 5‐move problems represents both the increased number of moves required and the need to make the counterintuitive moves required of 5‐move problems.Correlations between brain activity and SOC performance (Table 1) indicated that greater activity when solving 3‐move problems and reduced activity when moving from 3‐move to 5‐move problems was related to improved performance (making fewer errors and solving more problems in the minimum number of moves). Increased use of the PFC was important for solving simpler planning problems, and efficiency was important for the ability to make counterintuitive moves and solve more difficult planning problems. Multivariate regressions were run using the n‐6/n‐3 ratio, n‐3 intake, and their interaction to predict brain activity in the PFC related to solving planning problems above and beyond maternal education and physical activity. The interaction between the n‐6/n‐3 ratio and n‐3 intake predicted brain activity in the central PFC when moving from the 3‐move to 5‐move planning problems differently in 7‐ to 9‐year‐olds (t(21) = −2.73, p < 0.05, R2 = 0.14) and 10‐ to 12‐year‐olds (t(19) = 2.53, p < 0.05, R2 = 0.19). In 7‐ to 9‐year‐olds (Figure 2), balanced n‐6/n‐3 ratio and n‐3 intake predicted reduced central PFC activity moving from 3‐move to 5‐move problems, which was associated with improved planning performance. In 10‐ to 12‐year‐olds (Figure 3), unbalanced n‐6/n‐3 ratio and n‐3 intake predicted reduced central PFC activity. These results further support considering the overall balance of n‐6 and n‐3 FAs, and highlight the need to consider developmental changes that affect the brain's nutritional needs. The 10‐ to 12‐year‐olds were likely entering puberty, a time of considerable brain growth that may be best supported by increased n‐3 intake and lower n‐6/n‐3 ratios, whereas younger children may require greater balance of n‐6 and n‐3 FAs to support flexible use of cortical resources as they become more adept at increasingly challenging cognitive tasks.Support or Funding InformationThis work was funded by monies granted to the second author from the University of North Carolina at Chapel Hill (UNC‐CH) Nutrition Research Institute, and to the first author through a Sigma Xi Grants‐in‐aid‐of‐Research (GIAR) grant, a Dashiell Dissertation Start‐Up Grant from the UNC‐CH Psychology & Neuroscience Department, a pre‐doctoral fellowship from the UNC‐CH Center for Developmental Science (NICHD T32‐HD07376), and a Dissertation Completion Fellowship from the UNC‐CH Graduate School.
Pearson correlations between brain activity and SOC planning task performance by age group.

7– to 9‐year‐olds (n = 29)
Central 3‐move
Right Hem 3‐move
Left Hem 3 to 5
Central 3 to 5
Right Hem 3 to 5
Min. Moves Probs.
Total Moves (5‐move)
Mean Initial Thinking Time (5‐move)

Left Hem 3‐move
0.62***
0.82***
−0.36
−0.1
−0.23
0.09
−0.25
−0.12

Central 3‐move

0.75***
−0.35
−0.42*
−0.4*
0.08
−0.25
0.01

Right Hem 3‐move

−0.41*
−0.3
−0.05*
0.27
−0.37*
−0.17

Left Hem 3 to 5

0.75***
0.84***
−0.26
0.36
0.29

Central 3 to 5

0.85***
−0.27
0.24
0.19

Right Hem 3 to 5

−0.33
0.43*
0.37*

Min. Moves Probs.

−0.49**
−0.01

Total Moves (5‐move)

0.04

10‐ to 12‐year‐olds (n=28)'
Central 3‐move
Right Hem 3‐move
Left Hem 3 to 5
Central 3 to 5
Right Hem 3 to 5
Min. Moves Probs.
Total Moves (5‐move)
Mean Initial Thinking Time (5‐move)

Left Hem 3‐move
0.67***
0.81***
−0.63***
−0.33
−0.47*
0.37
0.21
0.18

Central 3‐move

0.73***
−0.52**
−0.69***
−0.53**
0.56**
0.03
0.33

Right Hem 3‐move

−0.61**
−0.44*
−0.6**
0.38*
0.28
0.14

Left Hem 3 to 5

0.71***
0.79***
−0.4*
0.002
0.09

Central 3 to 5

0.8***
−0.55**
0.1
0.03

Right Hem 3 to 5

−0.5*
−0.09
0.15

Min. Moves Probs.

−0.45**
0.29

Total Moves 15‐ move)

−0.27

Note.
p < 0.05,
p < 0.01,
p < 0.001.
Left Hem: Left prefrontal cortex (channels 1 – 6); Central: Central prefrontal cortex (channels 7 –14); Right Hem: Right prefrontal cortex (channels 15 – 20); Min. Moves Probs: Problems solved in the minimum number of moves; Mean Initial Thinking Time (5‐move): Time spent thinking through the problem before beginning to solve it.