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Limited Effect of Dietary Saturated Fat on Plasma Saturated Fat in the Context of a Low Carbohydrate Diet
Author(s) -
Forsythe Cassandra E.,
Phinney Stephen D.,
Feinman Richard D.,
Volk Brittanie M.,
Freidenreich Daniel,
Quann Erin,
Ballard Kevin,
Puglisi Michael J.,
Maresh Carl M.,
Kraemer William J.,
Bibus Douglas M.,
Fernandez Maria Luz,
Volek Jeff S.
Publication year - 2010
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-010-3467-3
Subject(s) - carbohydrate , saturated fat , chemistry , medicine , endocrinology , context (archaeology) , clinical chemistry , lipidology , lipogenesis , saturated fatty acid , food science , fatty acid , cholesterol , metabolism , biochemistry , biology , paleontology
We recently showed that a hypocaloric carbohydrate restricted diet (CRD) had two striking effects: (1) a reduction in plasma saturated fatty acids (SFA) despite higher intake than a low fat diet, and (2) a decrease in inflammation despite a significant increase in arachidonic acid (ARA). Here we extend these findings in 8 weight stable men who were fed two 6‐week CRD (12%en carbohydrate) varying in quality of fat. One CRD emphasized SFA (CRD‐SFA, 86 g/d SFA) and the other, unsaturated fat (CRD‐UFA, 47 g SFA/d). All foods were provided to subjects. Both CRD decreased serum triacylglycerol (TAG) and insulin, and increased LDL‐C particle size. The CRD‐UFA significantly decreased plasma TAG SFA (27.48 ± 2.89 mol%) compared to baseline (31.06 ± 4.26 mol%). Plasma TAG SFA, however, remained unchanged in the CRD‐SFA (33.14 ± 3.49 mol%) despite a doubling in SFA intake. Both CRD significantly reduced plasma palmitoleic acid (16:1n‐7) indicating decreased de novo lipogenesis. CRD‐SFA significantly increased plasma phospholipid ARA content, while CRD‐UFA significantly increased EPA and DHA. Urine 8‐iso PGF 2α , a free radical‐catalyzed product of ARA, was significantly lower than baseline following CRD‐UFA (−32%). There was a significant inverse correlation between changes in urine 8‐iso PGF 2α and PL ARA on both CRD ( r = −0.82 CRD‐SFA; r = −0.62 CRD‐UFA). These findings are consistent with the concept that dietary saturated fat is efficiently metabolized in the presence of low carbohydrate, and that a CRD results in better preservation of plasma ARA.