It increases the level of Glutathione, an important antioxidant. So forget your 5 a day, just dump the carbs?
The Ketogenic Diet Increases Mitochondrial Glutathione Levels.
The ketogenic diet (KD) is a high-fat, low carbohydrate diet that is used as a therapy for intractable epilepsy. However, the mechanism(s) by which the KD achieves neuroprotection and/or seizure control are not yet known. We sought to determine whether the KD improves mitochondrial redox status. Adolescent Sprague-Dawley rats (P28) were fed a KD or control diet for 3 weeks and ketosis was confirmed by plasma levels of beta-hydroxybutyrate (BHB). KD-fed rats showed a 2-fold increase in hippocampal mitochondrial glutathione (GSH) and GSH/GSSG ratio compared to control diet-fed rats. To determine whether elevated mitochondrial GSH was associated with increased de novo synthesis, the enzymatic activity of glutamate cysteine ligase (GCL) (the rate limiting enzyme in GSH biosynthesis) and protein levels of the catalytic (GCLC) and modulatory (GCLM) subunits of GCL were analyzed. Increased GCL activity, as well as upregulated protein levels of GCL subunits in KD-fed, but not control rats, was observed. Reduced coenzyme A (CoASH), an indicator of mitochondrial redox status, and lipoic acid, a thiol antioxidant, were also significantly increased in the hippocampus of KD-fed rats compared to controls. Since GSH is a major mitochondrial antioxidant that protects mitochondrial DNA (mtDNA) against oxidative damage, we measured mitochondrial hydrogen peroxide (H(2)O(2)) production and H(2)O(2)-induced mtDNA damage. Isolated hippocampal mitochondria from KD-fed rats showed functional consequences consistent with the improvement of mitochondrial redox status i.e. decreased H(2)O(2) production and mtDNA damage. Together, the results demonstrate that the KD upregulates GSH biosynthesis, enhances mitochondrial antioxidant status, and protects mtDNA from oxidant-induced damage.
UPDATE - Emma has written more about a ketogenic diet in the last couple of days here and here