Changes in plasma fatty acids and related biomarkers during transition to an exclusively plant- and fish-based diet in healthy adults

Objective: The aim of this study was to examine the time scale of plasma fatty acid changes during transition to an exclusively plant- and fish-based diet in healthy individuals and determine whether there are associated alterations in arachidonic acid (ARA)-derived inflammatory mediators, estimated stearoyl coenzyme A desaturase (SCD) activity, and blood pressure. Methods: In pursuit of a religious fast, 36 adults abstained from eating poultry, meat, dairy products, and eggs, while increasing fish intake for 6 wk. Participants were assessed 1 wk before (W0) and 1 (WI) and 6 (W6) weeks after the diet change. Results: By W6, fasting plasma long-chain omega-3 polyunsaturated fatty acids (omega-3 LC-PUFAs); docosahexaenoic (DHA) and eicosapentaenoic (EPA) had increased (+67% and +73%, respectively; P <= 0.001), with early rise of DHA (+22%), but not EPA at W1.The omega-3 index (sum of DHA and EPA as a percent of total fatty acids) increased from 2.1% to 3.4%. ARA decreased progressively (W1, -9%; W6, -16%; P < 0.001). ARA precursors gamma-linolenic and dihomo-gamma-linolenic acids also decreased, without changes in the ARA-derived mediators prostaglandin-E2 and leukotriene-B4. Myristic acid decreased at W1 (-37%) and W6 (-40%). There was no consistent change in SCD indices. At W6, systolic and diastolic blood pressure had declined by 8 and 5 mm Hg, respectively (P <= 0.013). Conclusions: Shifting to a plant- and fish-based diet produces rapid and sustained increases in omega-3 LC-PUFAs and decreases the omega-6 PUFA ARA and its precursors, consistent with a cardio-protective profile. The rapid response suggests that these biomarkers may be useful for assessment of diet interventions. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

This study found that transitioning to an exclusively plant- and fish-based diet in healthy individuals led to improvements in cardiovascular risk factors through changes in plasma fatty acids. These changes were rapid and sustained, suggesting that biomarkers such as omega-3 polyunsaturated fatty acids could be useful for assessing dietary interventions.