Autism Speaks Official Blog

Hi. I’m new to Autism Speaks, though I’ve studied autism several years. I suspect I have Aspergers, though never diagnosed. I’d like to propose a simple ‘food test’ for parents—to clarify an uncertainty about autism biochemistry, and offer a possible remedy. The uncertainty is whether or not these children are depleted of the amino acid L-arginine. The test and the remedy is watermelon or its juice.

The body uses arginine to make nitric oxide—a transmitter in the autonomic nervous system that relaxes blood vessels and smooth muscles throughout the body. Because nitric oxide lasts only seconds, its levels are estimated from its metabolites nitrate and nitrite. High levels of these metabolites in red blood cells of autistic children have led physicians and researchers to suspect their nitric oxide is too high. They also fear high nitric oxide will form the dangerous oxidant peroxynitrite.

Despite these legitimate concerns, there are good reasons to believe the opposite is true—that nitric oxide is actually deficient in these children. Red cells store nitrite and nitrate to deliver nitric oxide elsewhere, so high levels are not conclusive. Peroxynitrite forms when arginine is deficient, not adequate. High levels of arginine vasopressin in autistic boys may deplete arginine over time. And lack of nitric oxide inflames the intestines. But the best reason to suspect insufficient nitric oxide in these children is low blood flow to the brain.

I believe watermelon and its juice (rich in arginine’s precursor citrulline) may be a safe test as well as a remedy for arginine depletion. For further explanation and references, see:
Are the amino acids arginine and taurine depleted in autistic disorders? at:
http://web.me.com/petergood1/AutismStudies/Home.html

Peter Good
Autism Studies
LaPine, OR
petergood1@mac.com