The thesis reviews the previous use of biomarkers of fatty acid intake and concludes that there is a lack of supporting evidence from large randomized controlled trials (RCT) of sufficient duration for their use to be justified. The hypothesis that fatty acid biomarkers are robust indices of the intake certain fatty acids was tested by the analysis of blood samples from three large and long-term RCTs where dietary intake had been well controlled and compared with a control treatment. Erythrocyte lipid fatty acid composition was unable to detect changes in saturated fatty acid (SFA) or oleic acid intake. Plasma total lipids and phospholipids SFA were also poor indicators of SFA intake. The intake of n-3 long-chain polyunsaturated fatty acids (LC-PUFA) could be predicted from the proportions in plasma and erythrocytes. Principal components analysis appeared to be a valid data reduction technique to measure changes in fatty acid patterns. A co-twin study design conducted in 570 female participants enrolled in the St Thomas‟ Twins Study investigated the heritability of fatty acid biomarkers (adipose tissue and plasma). For most fatty acids, environmental factors (dietary intake) were dominant, but in the case of arachidonic acid, 65% of the variance was explained by additive genetic factors. Investigations subsequently explored the effects of variations in single nucleotide polymorphisms (SNP) in the fatty acid desaturase (FADS) genes on the fatty acid composition of the biomarkers. Polymorphism in FADS1 rs174537 explained some of this variation. Carriage of the minor allele of rs174537 SNP also influenced the proportions of n-6 LC-PUFA in an RCT. Further research is suggested to identify what appeared to be a FADS1/FADS2 haplotype predicting lower levels of LC-PUFA, which might be of public health significance. In conclusion, plasma fatty acid composition can be recommended to elucidate the potential relationships between polyunsaturated, trans-unsaturated and branched chain fatty acid intake and non-communicable diseases.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:628211 |
| Date | January 2013 |
| Creators | Alhilal, Maryam |
| Publisher | King's College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://kclpure.kcl.ac.uk/portal/en/theses/biomarkers-of-fat-intake(32ce2b69-77d6-4cc8-93d7-2d9c38b6f9d4).html |
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