Rats Fed a Ketogenic Diet Exhibit Significantly Elevated Levels of Long-Chain, Polyunsaturated Fatty Acids.

Abstract number : 3.141
Submission category :
Year : 2001
Submission ID : 3106
Source : www.aesnet.org
Presentation date : 12/1/2001 12:00:00 AM
Published date : Dec 1, 2001, 06:00 AM

Authors :
G.D. Anderson, PhD, Pharmacy, University of Washington, Seattle, WA; J.M. Rho, MD, Pediatrics, University of California - Irvine, Irvine, CA; K.J. Bough, PhD, Neurological Surgery, University of Washington, Seattle, WA; T.W. Storey, BS, Pediatrics, Univer

RATIONALE: The n-3 polyunsaturated fatty acids (PUFAs), specifically eicosapentaenoic acid (EPA, C20:5w3) and docosahexaenoic acid (DHA, C22:6w3), have been shown to reduce neuronal membrane excitability in animals whereas saturated and monounsaturated fatty acids do not (Xiao and Li, Brain Res. 846: 112-121, 1999). The present study was designed to test the hypothesis that rats exhibit elevated levels of EPA and/or DHA after treatment with a ketogenic diet (KD).
METHODS: Male, Sprague-Dawley rats were fed either a KD (n=7) or normal chow (n=7) in equal, calorically-restricted amounts. Blood samples were collected after 30 days and were analyzed quantitatively by gas chromatography/mass spectroscopy (Mayo Medical Laboratories).
RESULTS: Animals fed a KD exhibited alterations in the following saturated fatty acids: lauric (C12:0, P[lt]0.002, incr.), tetracosanoic (C24:0, P[lt]0.05, decr.), hexacosanoic (C26:0, P[lt]0.03, decr.), and pristanic (C15:0[CH3]4, P[lt]0.001, decr.) acids compared to controls; there were no significant changes in octanoic (C8:0), decenoic (C10:0), myristic (C14:0), palmitic (C16:0), stearic (C18:0), arachidic (C20:0), docosanoic (C22:0), tetracosanoic (C24:0), or hexacosanoic (C26:0) saturated fatty acids. KD-fed animals also exhibited marked changes in the PUFAs. Myristoleic (C14:1, P[lt]0.005, incr.), palmitoleic (C16:1w7, P[lt]0.004, decr.), a-linolenic (C18:3w3, P[lt]0.002, decr.), docosapentaenoic (C22:5w6, P[lt]0.001, incr.), docoapentaenoic (C22:5w3, P[lt]0.02, incr.), docosatetraenoic (C22:4w6, P[lt]0.005, incr.), and hexacosenoic (C26:1, P[lt]0.004, decr.) acids were all changed after KD treatment compared to controls; there were no marked changes in levels of decenoic (C10:1), lauroleic (C12:1), tetradecadienoic (C14:2), hexadecadienoic (C16:2), hexadecenoic (C16:1w9), g-linolenic (C18:3w6), linoleic (C18:2w6), oleic (C18:1w9), vaccenic (C18:1w7), arachidonic (C20:4w6), mead (C20:3w9), docosenoic (C22:1), or nervonic (C24:1w9) acids. Notably, there were no observed changes in levels of either DHA or EPA.
CONCLUSIONS: These data show that rats fed a KD exhibit marked alterations in plasma levels of many fatty acids. However, since no changes were observed in either DHA or EPA, we conclude that neither of these PUFAs mediate the anticonvulsant effects of the KD.
Support: This work was supported by the American Epilepsy Society (KJB) and the UW Pediatric Epilepsy Research Center (PERC).