Macro partitioning
Increasing dietary alpha-linolenic acid (aLNA) intake results in negligible conversion to long-chain n-3 fatty acids (EPA and DHA) in humans, rendering it significantly less effective than direct EPA/DHA consumption for improving cardiovascular or inflammatory health markers.
Eating flaxseed, walnuts, or canola oil (high in aLNA) is healthy, but it will not significantly raise your levels of EPA and DHA, the long-chain fats critical for brain and heart health. If your goal is to increase EPA/DHA status, you should consume fatty fish or fish oil supplements directly, as your body cannot efficiently convert plant oils into these specific fats.
Overall, the limited capacity for conversion to longer-chain n-3 fatty acids, and the lack of efficacy in ameliorating CVD risk factors and inflammatory markers in man suggests that increased consumption of aLNA may be of little benefit in altering EPA + DHA status or in improving health outcomes compared with other dietary interventions.
Why this rating
Based on a comprehensive review of multiple stable-isotope tracer studies and chronic intervention trials showing consistent low conversion rates (0.05-4%).
Source
Dietary α-linolenic acid and health-related outcomes: a metabolic perspective
Graham C. Burdge et al. · Nutrition Research Reviews · 2006
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