Markedly raised intake of saturated and monounsaturated fatty acids in rats on a high-fat ketogenic diet does not inhibit carbon recycling of 13C-alpha-linolenate.

Under various dietary and physiological conditions, carbon from alpha-linolenic acid (ALA) is extensively recycled into saturated and monounsaturated fatty acids. In this study we investigated whether carbon is still recycled from ALA when a dietary source of saturated and monounsaturated fatty acids is provided in excess. 13C-labeled ALA was given to rats consuming a high-fat ketogenic diet and to rats consuming a low-fat control diet. In rats on the ketogenic diet, 13C recycling from alpha-linolenate into several, but not all, saturated and monounsaturated fatty acids matched or exceeded that in the controls (P < 0.05). We conclude that carbon recycling into saturated and monounsaturated fatty acids persists when the main end products of ALA recycling are provided in excess, using a ketogenic diet.