Development and effect of an N-3 fatty acid-rich spread on the nutritional and cognitive status of school children
Date
2006-03
Authors
Dalton, Annalien
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch: University of Stellenbosch
Abstract
Long-chain polyunsaturated fatty acids (LCPUFA), especially the n-3 LCPUFA metabolic
products eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) play an important
role as regulators in many biological processes. To date hake (Merluccius capensis) heads, a
rich source of EPA and DHA, have been discarded at sea. The South African Fisheries Policy
Development Committee concerned with the environmental impact of this practice has
rendered it undesirable. The high prevalence of under-nutrition amongst children in South
Africa can be addressed by the supplementation of their diet with this unexploited fish source.
The aim of the current study was to develop a microbiologically safe and sensory acceptable
sandwich spread using fish flour prepared from fish heads, as a prime ingredient. The
intervention trial aimed to compare the effects of an increased dietary intake of n-3 LCPUFA,
specifically DHA, on the blood fatty acid levels and absenteeism (as indicator of immune
function), as well as the cognitive status, of the subjects. The microbiological content of the
sandwich spread was determined after storage for 20 d at 5°C and 15 d at 25°C. Sensory
evaluation was performed by consumers (n = 95; M:F = 44:51; 6 – 9 yr) to determine
acceptance of the five different flavours individually incorporated into the sandwich spread to
mask the fishy note and to provide different flavour options. For the intervention trial
subjects (n = 351) were stratified within class group (A - E) and gender and randomly
assigned to two treatment categories, an experimental group (EG; n = 174) receiving 25 g
sandwich spread.d-1 (191.66 mg DHA. d-1) and a control group (CG; n = 177) receiving an
analogous placebo. On school days (104 d), each subject received two sandwiches consisting
of two slices of bread (ca. 60 g), spread with 25 g of either the placebo or the experimental
spread. Blood samples were drawn at baseline and post intervention. Plasma fatty acid and
red blood cell (RBC) membrane status, C-reactive protein levels, as well as vitamin and
micronutrient status, were determined. Trained test administrators conducted a battery of
cognitive tests. According to South African Government health standards, the sandwich
spread remained microbiologically safe after storage. Male and female consumer respondents
revealed a significant difference between gender preferences of the five different spread
flavours (p <0.05). Significant treatment effects (p <0.05) were observed in n-3 LCPUFA
status of the EG, as well as for their absenteeism from school. The two subtests of the
Hopkins Verbal Learning test, Recognition and Discrimination Index, showed significant
differences between the EG and CG (p <0.05) post intervention in the Grade 2 subjects. The
Spelling tests also showed a significant difference between the two groups (p <0.05). In the
current study a microbiologically safe and sensory acceptable sandwich spread was developed
and tested during an intervention trial, and could possibly in future, provide a healthier option in the School Nutritional Programme. This study proved that supplementation of children (6 -
9 yr) with n-3 LCPUFA, with specific reference to EPA and DHA from a marine source,
could have a beneficial effect on their fatty acid status and absenteeism from school. Based
on the outcomes of the Hopkins Verbal Learning test and Spelling test, the current study
proved that an n-3 fatty acid-rich spread improved the learning ability and memory of
children.
Description
Thesis (PhD (Food Science))--University of Stellenbosch, 2006.
Keywords
Theses -- Food science, Dissertations -- Food science