SDA (Stearidonic Acid) (Omega-3) from Echium Oil (Echium plantagineum)
Also known as: Stearidonic Acid, SDA, 18:4n-3, octadecatetraenoic acid, omega-3 fatty acid, Echium Oil
Overview
Stearidonic acid (SDA) is a plant-derived omega-3 fatty acid found in oils such as echium oil, extracted from *Echium plantagineum*. It serves as a metabolic precursor to longer-chain omega-3 fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are associated with various health benefits. Unlike α-linolenic acid (ALA), SDA bypasses the rate-limiting Δ6-desaturase enzyme in the omega-3 biosynthesis pathway, potentially allowing more efficient conversion to EPA. Echium oil is considered a sustainable, plant-based alternative to marine omega-3 sources. Research on SDA is moderately mature, with several controlled trials and systematic reviews evaluating its bioavailability and physiological effects, though fewer large-scale clinical outcome studies exist compared to fish oil-derived omega-3s.
Benefits
SDA supplementation via echium oil significantly increases plasma levels of EPA and downstream omega-3 metabolites, including docosapentaenoic acid (DPA) and DHA, though the increase in DHA is less pronounced. Improved EPA status is linked to anti-inflammatory effects and cardiovascular health benefits, although direct clinical outcomes from SDA supplementation require further validation. SDA intake has been shown to reduce pro-inflammatory arachidonic acid (ARA)-derived eicosanoids and increase EPA-derived eicosanoids, indicating a shift toward an anti-inflammatory profile. Potential benefits in reducing markers of chronic inflammation and supporting cardiovascular health have been suggested but need more robust clinical trials. Healthy young adults show rapid increases in plasma EPA following single-dose echium oil ingestion. Plant-based omega-3 supplementation may be particularly relevant for vegetarians and individuals avoiding marine sources.
How it works
SDA is metabolized in the human body by elongation and desaturation enzymes to produce longer-chain omega-3 fatty acids, primarily EPA. It bypasses the Δ6-desaturase step, which is rate-limiting in the conversion of ALA to EPA, leading to more efficient EPA synthesis. EPA and its metabolites modulate inflammatory pathways by competing with arachidonic acid for enzymatic conversion to eicosanoids, shifting the balance toward less inflammatory mediators. SDA is absorbed in the small intestine and incorporated into plasma lipids, where it can be measured as free fatty acids or esterified forms.
Side effects
SDA from echium oil is generally well tolerated with no significant adverse effects reported in controlled trials. No common or serious side effects (>5%) have been documented in the literature reviewed. No significant drug interactions or contraindications have been identified, but data are limited. Special populations such as pregnant women or those with bleeding disorders should consult healthcare providers, as with all omega-3 supplements.
Dosage
Effective doses in studies range from single doses (providing several grams of echium oil) to daily supplementation over weeks (e.g., 5–10 g echium oil daily). Optimal dosing to achieve plasma EPA increases appears to be in the range of 1–3 g SDA per day, though exact SDA content varies by oil preparation. Timing is flexible; plasma EPA increases are observed within hours and maintained with daily intake. Echium oil is typically consumed in triglyceride form, which supports good bioavailability. No specific cofactors are required, but overall dietary fat intake may influence absorption.
FAQs
Is SDA as effective as fish oil omega-3?
SDA increases EPA levels efficiently but generally results in lower DHA increases compared to direct fish oil supplementation.
How quickly does SDA work?
Plasma EPA rises within hours after a single dose and sustains with continued intake.
Is echium oil safe for vegetarians?
Yes, it is a plant-based omega-3 source suitable for vegetarians and vegans.
Can SDA replace fish oil?
It can be a sustainable alternative for EPA enrichment but may not fully replicate the DHA benefits of fish oil.
Research Sources
- https://www.mdpi.com/2072-6643/11/10/2346 – This RCT with healthy young males found significant increases in plasma EPA, DPA, and DHA within 2 to 72 hours post-dose after single-dose echium oil ingestion. The study demonstrated rapid bioavailability and conversion of SDA to longer-chain omega-3s, but was limited by its short-term, single-dose design.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1359958/full – A controlled intervention over 20 days with ahiflower oil showed significant increases in EPA and EPA-derived oxylipins, with decreased pro-inflammatory ARA metabolites. This provides evidence for anti-inflammatory effects of SDA supplementation, although the oxylipin analysis did not include SDA-derived metabolites due to a lack of standards.
- https://pubmed.ncbi.nlm.nih.gov/32431176/ – This comprehensive review of botanical SDA sources confirmed SDA’s efficient conversion to EPA bypassing Δ6-desaturase and potential benefits in inflammation, cardiovascular disease, and cancer prevention. It highlighted the sustainability and dietary acceptance of SDA-rich oils, but noted the need for larger RCTs due to the prevalence of preclinical and small clinical studies.
- https://pubmed.ncbi.nlm.nih.gov/24553695/ – This RCT with echium oil supplementation showed increased plasma long-chain n-3 PUFAs including EPA, supporting plant-based SDA as a viable omega-3 source. The study was limited by its moderate sample size and focus on biomarker changes rather than clinical outcomes.
- https://www.supplysidesj.com/lipids/vegetarian-omegas-the-importance-of-sda – This article discusses the importance of SDA as a vegetarian omega-3 source. It highlights SDA's ability to convert to EPA more efficiently than ALA, making it a valuable option for those avoiding fish oil.