Intra-individual variability of long-chain fatty acids (C12-C24) in plasma and red blood cells.
Level 4 - case-series / case-control
Prospective repeated-measures observational study in a single group without a comparator.
PubMed 30103929 · doi:10.1016/j.plefa.2018.06.006
What was done
Fasting plasma and red blood cell samples were collected from healthy individuals on a regular diet to measure the intra-individual variability of the 22 most abundant long-chain fatty acids (C12–C24).
What was found
Red blood cell measurements of long-chain fatty acids were consistent over time. In plasma, intra-individual variability for omega-3 alpha-linolenic acid and eicosapentaenoic acid was >40% in some participants, whereas docosahexaenoic acid variability was consistently <12.8%. Omega-6 linoleic and arachidonic acids also showed low variability in plasma. Numerical values for the remaining 17 fatty acids were not reported in the abstract.
Why it matters
Single-point plasma measurements of alpha-linolenic and eicosapentaenoic acids have substantial intra-individual noise, making red blood cell measurements or more stable plasma fatty acids like docosahexaenoic acid more reliable biomarkers.
Limits
The abstract does not state the sample size, sampling frequency, duration of observation, or numerical variability for most fatty acids. Findings in healthy fasting individuals may not generalize to non-fasting or diseased populations.
Cited by
- supports Plasma omega-3 percentages fluctuate acutely after meals due to postprandial triglyceride influx, whereas red blood cell membrane omega-3 levels remain stable.