DHA & Lutein and fMRI Brain Mapping in Healthy Children

Study Design:

A cross-sectional observational study of 62 school-age children in Vancouver, Canada.

Dietary intake assessment:

Children's dietary intake over the previous four weeks was estimated by interview with a parent using a Food Frequency Questionnaire. Three 24h recalls were administered, using the five-pass review technique. The children's dietary intake of DHA was quantified using nutrient analysis software (ESHA Food Processor SQL, version 10.10.0.0; ESHA Research), using Canadian foods, and checking the fatty acid composition of all foods and beverages for accuracy, modifying if necessary based on labels or laboratory analysis of the product.

Blood Markers EDTA venous blood was collected and was centrifuged to collect Red Blood Cells (RBC). RBC fatty acids were extracted and quantified by routine gas liquid chromatography. RBC-DHA to DPA (n-6) ratio was used as an indicator of DHA status.

Cognitive Measures The Kaufman Assessment Battery for Children (KABC)-II (Kaufman, 2004) was administered by one of two individuals trained in child psychometric testing. The KABC consists of several scales: (1) the Sequential Processing Scale measures short-term memory; (2) the Learning Ability Scale measures long-term storage and retrieval; & (3) the Simultaneous Processing Scale measures visual processing. Results of these 3 scales may be combined to give a composite Mental Performance Index (MPI) score. The Delayed Recall subtest was used to evaluate long-term memory.

Statistical Analysis DHA intake and RBC-DHA:DPA were log transformed; transformed data were used in the subsequent analyses. Pearson's correlation tests were conducted to test (1) the associations between DHA intake and RBC-DHA:DPA ratio and (2) the associations between DHA intake and RBC-DHA:DPA with KABC-II domain scores.

Inclusion criteria

• full-term
• single birth (no multiple births)
• no major illness or surgery requiring hospitalization likely to impact the outcomes
• no metabolic, congenital or allergic disease that impact food intakes
• parents have sufficient command of English language to complete the informed consent and study documents

The specific inclusion enrollment criteria for:

Group 1: children consuming <25 mg/day DHA and < 400 μg/day lutein, n=24; Group 2: children consuming >150 mg/day DHA and >1,200 μg/day lutein, n=24; Group 3: children consuming >150 mg/day DHA and <400 μg/day lutein, n=10;

Exclusion criteria

• children of mothers enrolled in studies by our group that involved randomization to supplemental DHA during pregnancy
• children for whom blood, diet records or developmental tests at 5 years and 9 months of age are incomplete
• children consuming 25-150 mg/day DHA or 400-1200 μg/day lutein
• children of mothers who do not sign the informed consent
• any children having a cardiac pacemaker, aneurysm clip, cochlear implant of possible metallic foreign bodies in the eyes or other contraindication as detailed in the C&W MRI Patient Screening Form will be excluded from this study.