The very top analysis though shows: "This review summarizes evidence that DHA synthesis from ALA can provide sufficient DHA for the adult brain by examining wo

The very top analysis though shows: "This review summarizes evidence that DHA synthesis from ALA can provide sufficient DHA for the adult brain by examining work in humans and animals involving estimates of DHA synthesis and brain DHA requirements. Also, an update on methods to measure DHA synthesis in humans is presented highlighting a novel approach involving steady-state infusion of stable isotope-labeled ALA that bypasses several limitations of oral tracer ingestion. It is shown that this method produces estimates of DHA synthesis that are at least 3-fold higher than brain uptake rates in rats." So it seems it's not super efficient, but it's probably far more than sufficient, and we were under estimating how useful ALA is by 3x.