The nutritional and cardiovascular health benefits of rapeseed oil-fed farmed salmon in humans are not decreased compared with those of traditionally farmed salmon: a randomized controlled trial

Purpose: Farmed fish are increasingly raised on feeds containing vegetable oils, which affects their composition and possibly health properties. We investigated the effects of consuming farmed salmon, raised on different feeding regimes, on nutrient status and health outcomes in healthy subjects. Methods: Salmon were grown on feeds containing mainly fish oil (FO) or rapeseed oil (RO), resulting in an eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) content of fillets of 2.1 or 0.9 g/100g, respectively. In a randomized parallel controlled trial, 51 healthy subjects were allocated to consume 2 portions/wk of FO salmon (n=17), RO salmon (n=17) or no additional salmon (Control, n=17) as part of their habitual diet, for 18 wk. We collected blood at 0, 9 and 18 wk to measure omega-3 index (O3I) in red blood cells, plasma markers of cardiovascular risk, serum 25(OH)- vitamin D3 (25(OH)D3) and plasma trace elements. Results: After 18 wk, O3I was similarly increased in subjects consuming 2 portions/wk of FO or RO salmon compared to control (both p<0.05). Serum 25(OH)D3 was significantly higher, whereas plasma triacylglycerols were significantly lower in subjects consuming RO salmon compared to control (both p<0.05). Heart rate was significantly lower in subjects consuming FO salmon after 9 wk, compared to control (p<0.01). Salmon consumption did not affect other markers. Conclusion: Consuming two portions/wk of salmon raised on rapeseed oil rather than fish oil increased the O3I and vitamin D status, and decreased plasma triacylglycerols. These outcomes endorse opportunities for developing more sustainable feeds within aquaculture food systems.