Red blood cell fatty acid patterns from 7 countries: Focus on the Omega-3 index.
Level 4 - case-series / case-control
Cross-sectional pooled analysis of heterogeneous convenience cohorts and clinical laboratory data
PubMed 35366625 · doi:10.1016/j.plefa.2022.102418
What was done
Analyzed red blood cell (RBC) fatty acid patterns, specifically the Omega-3 Index (EPA + DHA as a percentage of total RBC fatty acids), across 167,347 individuals from seven countries (USA, Canada, Italy, Spain, Germany, South Korea, and Japan). Fatty acid data were measured using a uniform analytical methodology, pooled from clinical laboratories and various observational and interventional studies collected across different years. Only the Canadian cohort was a formal, representative population-based survey. Mean Omega-3 Index values per country or region were categorized as desirable (>8%), moderate (>6% to 8%), low (>4% to 6%), or very low (≤4%).
What was found
A desirable Omega-3 Index (>8%) was observed only in cohorts from Alaska (evaluated separately from the US), South Korea, and Japan. The cohort from Spain showed a moderate Omega-3 Index (>6% to 8%). Cohorts from the contiguous US, Canada, Italy, and Germany were all classified as low (>4% to 6%). Exact numerical mean values for each country were not reported in the abstract.
Why it matters
Using a standardized analytical method, this study highlights substantial international disparities in RBC omega-3 status, demonstrating that Western nations generally have lower tissue omega-3 levels than East Asian populations and Alaska.
Limits
The dataset is heavily skewed, with 93% of all samples originating from the United States. Except for Canada, cohorts were convenience samples that varied substantially in sample size, demographics, health status, and year of collection, limiting generalizability to national populations.
Cited by
- supports The average omega-3 index in Japan is 10%, while in the United States it is about 5%.