Differential metabolic effects of saturated versus polyunsaturated fats in ketogenic diets.
Ketogenic diets (KDs) are used for treatment of refractory epilepsy and metabolic disorders. The classic saturated fatty acid-enriched (SAT) KD has a fat:carbohydrate plus protein ratio of 4:1, in which the predominant fats are saturated. We hypothesized that a polyunsaturated fat-enriched (POLY) KD would induce a similar degree of ketosis with less detrimental effects on carbohydrate and lipid metabolism. Twenty healthy adults were randomized to two different weight-maintaining KDs for 5 d. Diets were 70% fat, 15% carbohydrate, and 15% protein. The fat contents were 60 or 15% saturated, 15 or 60% polyunsaturated, and 25% monounsaturated for SAT and POLY, respectively. Changes in serum beta-hydroxybutyrate, insulin sensitivity (S(I)), and lipid profiles were measured. Mean circulating beta-hydroxybutyrate levels increased 8.4 mg/dl in the POLY group (P = 0.0004), compared with 3.1 mg/dl in the SAT group (P = 0.07). S(I) increased significantly in the POLY group (P = 0.02), whereas total and low-density lipoprotein cholesterol increased significantly in the SAT group (both P = 0.002). These data demonstrate that a short-term POLY KD induces a greater level of ketosis and improves S(I), without adversely affecting total and low-density lipoprotein cholesterol, compared with a traditional SAT KD. Thus, a POLY KD may be superior to a classical SAT KD for chronic administration.
Fuehrlein
Brian S
BS
Department of Medicine, College of Medicine, University of Florida, Gainesville, Florida 32610, USA.
Rutenberg
Michael S
MS
Silver
Jared N
JN
Warren
Matthew W
MW
Theriaque
Douglas W
DW
Duncan
Glen E
GE
Stacpoole
Peter W
PW
Brantly
Mark L
ML
D020155:3-Hydroxybutyric Acid / Q000097:blood; D000328:Adult; D008078:Cholesterol, LDL / Q000097:blood; D004032:Diet; D004041:Dietary Fats / Q000494:pharmacology*; D005227:Fatty Acids / Q000494:pharmacology*; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D007657:Ketone Bodies / Q000096:biosynthesis*; D007662:Ketosis / Q000209:etiology; D008055:Lipids / Q000097:blood; D008297:Male
D008078:Cholesterol, LDL; D004041:Dietary Fats; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D007657:Ketone Bodies; D008055:Lipids; D020155:3-Hydroxybutyric Acid