LOS ANGELES, CA (Catholic Online) - Douglas R. Galasko, MD, of the University of California San Diego found that the combination of vitamin E, vitamin C, and alpha-lipoic acid did not lower levels of the amyloid and tau proteins that make up the plaques and tangles seen in the brain of those who suffer from Alzheimer's disease.

However, the combination did reduce CSF levels of the oxidative stress biomarker F2-isoprostane by 19 percent. This raised safety concerns, with a faster decline in cognitive scores.

Oxidative damage is widespread in the brain in Alzheimer's disease and contributes to neuronal damage, Galasko's group explained.

There has been previous observational evidence that pointed out that an antioxidant-rich diet lowered Alzheimer's risk. Prevention trials with supplements have had mixed results, researchers noted.

The study included 78 adults with mild to moderate Alzheimer's randomly assigned to double-blind treatment over 16 weeks with the combination of 800 IU vitamin E, 500 mg vitamin C, and 900 mg of alpha-lipoic acid once a day; CoQ alone at a dose of 400 mg three times a day; or placebo.

Vitamins C and E act as antioxidants by controlling dangerous free radicals produced when oxygen reacts with certain molecules, Alpha-lipoic acid spurs production of many antioxidant enzymes in the body. CoQ is an antioxidant that helps protect mitochondria from oxidation.

However, serial CSF specimens collected from 66 of the participants showed only small changes from baseline.

Beta-amyloid 42, which accumulates to forms plaques in the Alzheimer's brain, declined by 8 pg/mL from a baseline of 190 pg/mL. The antioxidant combination from 15 pg/mL from a baseline of 185 in the CoQ group, but neither was a significant difference from placebo.

Tau protein, which forms neuro-fibrillary tangles in the brain with Alzheimer's, fell by 23 pg/mL with the antioxidant combination from a baseline of 123 and by 9 pg/mL from a baseline of 109 in the CoQ group, but again neither differed from changes with placebo.

The one significant change was in CSF levels of the oxidative marker F2-isoprostane, which is stable oxidized arachidonic acid.

The vitamin C and E plus alpha-lipoic acid group saw a 7 pg/mL reduction in F2-isoprostane from a baseline of 38 over the 16 weeks of treatment (P=0.04). The other groups showed no change.

"It is unclear whether the relatively small reduction in CSF F2-isoprostane level seen in this study may lead to clinical benefits in Alzheimer disease," the group cautioned.

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