Impact of 8-week linoleic acid intake in soy oil on Lp-PLA(2) activity in healthy adults

BACKGROUND: No intervention follow-up study has examined the association between plasma n-6 polyunsaturated fatty acids (PUFAs) and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), which is a risk factor for cardiovascular disease (CVD). We aimed to determine whether the administration of linoleic acid (LA, 18:2n-6) in soy oil affected Lp-PLA(2) activity in healthy adults. METHODS: Self-reported healthy participants (n = 150) were randomly assigned to three groups: a low LA group, in which 10 mL soy oil was replaced with one apple; a medium LA group, in which the typical food intake was maintained; and a high LA group, in which 1/3 cup of cooked refined rice was replaced with 9.9 g of soy oil capsules daily. Plasma fatty acids and Lp-PLA(2) activity were measured along with other CVD risk factors. RESULTS: After 8 weeks of treatment, plasma LA levels decreased in the low LA group and increased in the high LA group. The high LA group showed greater increases in apolipoprotein B (apoB) and oxidized low-density lipoprotein (ox-LDL) than those in the low LA group. Plasma LA levels and Lp-PLA(2) activities demonstrated greater increases in the high LA group than those in the medium and low LA groups. Changes in plasma LA positively and independently correlated with changes in Lp-PLA(2) activity, which was negatively correlated with changes in collagen-epinephrine closure time (CEPI-CT). CONCLUSIONS: An increase in plasma LA following intake of soy oil was independently associated with Lp-PLA(2) activity, which was also related to apoB, ox-LDL and CEPI-CT. TRIAL REGISTRATION: ClinicalTrail.gov Identifier: NCT02753907, registered 25 April 2016 (retrospectively registered). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12986-017-0186-2) contains supplementary material, which is available to authorized users.