Limited effect of dietary saturated fat on plasma saturated fat in the context of a low carbohydrate diet.

Abstract

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.

• Authors: Cassandra E Forsythe, Stephen D Phinney, Richard D Feinman, Brittanie M Volk, Daniel Freidenreich, Erin Quann, Kevin Ballard, Michael J Puglisi, Carl M Maresh, William J Kraemer, Douglas M Bibus, Maria Luz Fernandez, Jeff S Volek
• Journal: Lipids (Lipids) Vol. 45 Issue 10 Pg. 947-62 (Oct 2010) ISSN: 1558-9307 [Electronic] United States
• PMID: 20820932 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Dietary Carbohydrates
• Dietary Fats
• Fatty Acids
• Arachidonic Acid

Topics

• Adult
• Arachidonic Acid (blood)
• Body Weight
• Diet
• Diet, Carbohydrate-Restricted
• Dietary Carbohydrates (administration & dosage, blood, urine)
• Dietary Fats (administration & dosage, blood, metabolism)
• Fatty Acids (administration & dosage, blood, pharmacology)
• Humans
• Male
• Middle Aged