Low blood long chain omega-3 fatty acids in UK children are associated with poor cognitive performance and behavior: a cross-sectional analysis from the DOLAB study

Abstract

Background: Omega-3 long-chain polyunsaturated fatty acids (LC-PUFA), especially DHA (docosahexaenonic acid) are essential for brain development and physical health. Low blood Omega-3 LC-PUFA have been reported in children with ADHD and related behavior/learning difficulties, as have benefits from dietary supplementation. Little is known, however, about blood fatty acid status in the general child population. We therefore investigated this in relation to age-standardized measures of behavior and cognition in a representative sample of children from mainstream schools.

Participants: 493 schoolchildren aged 7-9 years from mainstream Oxfordshire schools, selected for below average reading performance in national assessments at age seven.

Method: Whole blood fatty acids were obtained via fingerstick samples. Reading and working memory were assessed using the British Ability Scales (II). Behaviour (ADHD-type symptoms) was rated using the revised Conners' rating scales (long parent and teacher versions). Associations were examined and adjusted for relevant demographic variables.

Results: DHA and eicosapentaenoic acid (EPA), accounted for only 1.9% and 0.55% respectively of total blood fatty acids, with DHA showing more individual variation. Controlling for sex and socio-economic status, lower DHA concentrations were associated with poorer reading ability (std. OLS coeff. = 0.09, p = <.042) and working memory performance (0.14, p = <.001). Lower DHA was also associated with higher levels of parent rated oppositional behavior and emotional lability (-0.175, p = <.0001 and -0.178, p = <.0001).

Conclusions: In these healthy UK children with below average reading ability, concentrations of DHA and other Omega-3 LC-PUFA were low relative to adult cardiovascular health recommendations, and directly related to measures of cognition and behavior. These findings require confirmation, but suggest that the benefits from dietary supplementation with Omega-3 LC-PUFA found for ADHD, Dyspraxia, Dyslexia, and related conditions might extend to the general school population.

Conflict of interest statement

Competing Interests: The authors have read the journal’s policy and have the following conflicts: Funding for the trial was provided by Martek Biosciences Inc., who also provided product and placebo. JRB, TFS and RPS declare that no other competing interests exist. AJR and PM acts as an occasional paid consultant (lectures and advisory work) for companies and organisations involved in producing, selling, or promoting foods or supplements containing ω-3. None of these issues alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials.

Figures

Figure 1. Flowchart of participants on whom blood data available.

Figure 2. Reading ability in the study sample versus normed sample school children.

Note: Normed distribution based on random draws from a normal distribution (mean = 100, sd = 15).

Figure 3. Distribution of DHA, EPA, and the“EPA+DHA (“Omega-3 Index”)” in school children.

A: Docosahexaenoic acid (22∶6, n-3) B: Eicosapentaenoic acid(20∶5, n-3) C: DHA+EPA% (Omega-3 Index) Data: n = 493.