Comparison of Low Fat and Low Carbohydrate Diets on Circulating Fatty Acid Composition and Markers of Inflammation

Abstract

Abnormal distribution of plasma fatty acids and increased inflammation are prominent features of metabolic syndrome. We tested whether these components of metabolic syndrome, like dyslipidemia and glycemia, are responsive to carbohydrate restriction. Overweight men and women with atherogenic dyslipidemia consumed ad libitum diets very low in carbohydrate (VLCKD) (1504 kcal:%CHO:fat:protein = 12:59:28) or low in fat (LFD) (1478 kcal:%CHO:fat:protein = 56:24:20) for 12 weeks. In comparison to the LFD, the VLCKD resulted in an increased proportion of serum total n-6 PUFA, mainly attributed to a marked increase in arachidonate (20:4n-6), while its biosynthetic metabolic intermediates were decreased. The n-6/n-3 and arachidonic/eicosapentaenoic acid ratio also increased sharply. Total saturated fatty acids and 16:1n-7 were consistently decreased following the VLCKD. Both diets significantly decreased the concentration of several serum inflammatory markers, but there was an overall greater anti-inflammatory effect associated with the VLCKD, as evidenced by greater decreases in TNF-alpha, IL-6, IL-8, MCP-1, E-selectin, I-CAM, and PAI-1. Increased 20:4n-6 and the ratios of 20:4n-6/20:5n-3 and n-6/n-3 are commonly viewed as pro-inflammatory, but unexpectedly were consistently inversely associated with responses in inflammatory proteins. In summary, a very low carbohydrate diet resulted in profound alterations in fatty acid composition and reduced inflammation compared to a low fat diet.

Suppression of Long Chain Acyl-CoA Synthetase 3 Decreases Hepatic de Novo Fatty Acid Synthesis through Decreased Transcriptional Activity

“…Isolated free fatty acids were methylated in 3 N methanolic HCl at 100°C for 90 min. The fatty acids methyl esters were extracted with hexane and subjected to gas chromatography analysis (22).…”

Synthesis of specific fatty acids contributes to VLDL-triacylglycerol composition in humans with and without type 2 diabetes

“…Reducing dietary saturated fat is the most common recommendation to reduce CVD risk, even though low-fat/high-carbohydrate diets increase fasting plasma TG concentrations [1], an independent risk factor for CVD [2]. Compared with higherfat intake, low-fat/high-carbohydrate diets change the FA composition of plasma lipoproteins and red cells, which is often attributed to DNL of non-essential FAs [3][4][5]. Synthesis of specific FAs is rarely measured because of limited technological capabilities.…”

“…Quantity of dietary fat has recently been considered with regard to the composition of circulating FAs [3][4][5], particularly saturated FAs. Like dietary fat 'quality', serum FA 'quality' may be important in the longterm development of metabolic disease [8].…”

An Evolutionary and Mechanistic Perspective on Dietary Carbohydrate Restriction in Cancer Prevention

“…Obesity has even surpassed smoking as the greatest behavioral risk factor for cancers in the U.S. Multiple studies have now established CHO restriction as an effective, if not superior, way to treat obesity and type 2 diabetes [32][33][34][35][36][37][38].…”