Medicine For People!

April 2006 Supplement: Brain Aging Supplemental Information

Brain Aging Supplemental Info

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Unique susceptibility of the substantia nigra

One reason why the substantia nigra is first to fail is that this area is rich is iron, melanin, dopamine, and enzymes that are unusually prone to oxidation. If the mitochondria aren't able to ramp up energy production, oxidation destroys the mitochondria and the cells they support. People with Parkinson's disease have underperforming mitochondria throughout their body; symptoms appear first in the brain because the metabolic requirements are greater there.

The Blood-Brain Barrier

The blood-brain barrier protects the fragile neurons and their myriad of fine tendrils from the damage that would ensue from a full-fledged battle between microbial invaders and the immune system. To ensure optimal brain function, the blood-brain barrier also prevents hormones and neurotransmitters in the blood stream from entering the brain. Toxins and certain nutrients have difficulty passing this barrier as well.

One of the hazards of high blood pressure is that it weakens the blood-brain barrier, and can impair brain function. We were taught in medical school that people couldn't tell on their own when they had high blood pressure. Many patients have told me over the years that they do feel differently when their blood pressure rises, and this increased permeability of the blood-brain barrier may explain why.

The Acetyl Group

Once acetyl-L-carnitine is within the brain, the acetyl group is removed and can be used to form acetylcholine. Acetylcholine is a major neurotransmitter, and carries the signal from one neuron to another at the synapse. Acetylcholine levels fall in people with Alzheimer's disease. The drug most commonly used to improve memory in people with Alzheimer's disease is donepezil (Aricept®), and it works by increasing levels of acetylcholine.

Acetyl-L-Carnitine Studies

Studies show that older rats, like older humans, have lower levels of carnitine in their brains and, consequently, increased levels of oxidation and cell death. Feed those rats acetyl-L-carnitine, and they perform as well as young rats on tests requiring memory, hearing, and learning. Tests show that the neurons of the treated rats have increased levels of acetylcholine, the neurotransmitter that donepezil (Aricept®) is designed to improve.

An Italian study of 480 patients on 1500 mg of acetyl-L-carnitine daily for 90 days showed significant improvement in memory, mood, and behavior. When these people were retested 30 days after discontinuing acetyl-L-carnitine, they still had improved function.

A 2003 meta-analysis of several studies of acetyl-L-carnitine for Alzheimer's disease concluded that acetyl-L-carnitine improved function within three months at doses of 1500 to 3000 mg per day. That, of course, is the meta-analysis. These are demented people scoring better on tests than other demented people. They are not going back to a professorship at MIT. When you review all the studies in the literature, you see that acetyl-L-carnitine very occasionally doesn't come out ahead of placebo.

What impresses me is a study of young Italians, showing that in comparison to placebo, acetyl-L-carnitine improves reaction time and learning. This shows that even "normal" brain function can be improved by acetyl-L-carnitine.


Glutathione is the central intracellular antioxidant. You don't see it in supplement bottles on the store shelf because it is effective only when given intravenously. I have seen videos of patients with Parkinson's disease shuffling into a neurology clinic, given intravenous glutathione, and then dancing. David Perlmutter, MD, no doubt selected his most successful patients for his video, and the dancing was about what you'd expect from someone 75 years old, but still there was a dramatic response. The problem with the treatment is the expense and the fact that the benefits last only for a day or two.

The exciting thing is now we know that Parkinson's disease is due to mitochondrial failure, and that if we can get those mitochondria going, we can help a great number of people. If intravenous glutathione is not now a practical treatment, at least it proves we are barking up the right tree with alpha-lipoic acid.

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Medicine for People! is published by Douwe Rienstra, MD at Port Townsend, Washington.