It is not clear whether elevated urinary levels of arabinose detected
in by the Organic Acid Test"
are simply a marker for yeast dysbiosis, or are pathogenic in their own
In some cases, it appears that a metabolic defect in the processing of
pentose sugars such as arabinose may be the cause, since it is reported
that in some children, eating fruits rich in arabinose (apples and pears)
rapidly induces an exacerbation of autistic symptoms [Shaw2008].
It has also been hypothesized that arabinose, being an aldol (reducing)
sugar which contains an aldehyde functional group, may contribute to
pathology by reacting with the terminal ammonia group of the amino acid
lysine, which is found in many proteins of the body, to form a
pentosidine, which may further react with an arginine in an adjoining
protein strand to form a pentosine link [Shaw2008, pg 36].
The pentosidine link alters the structure and function of the affected
proteins, which may be enzymes.
Dr. Weyrich notes that this is similar
to the mechanisms underlying protein glycosylation, which is measured
by the hemoglobulin-A1C test [Sell1989]. Both protein
glycosylation and formation of pentosine links are associated with aging -
once these links are formed, they persist until the cell they are associated
with dies and is replaced. Note that neurons are not replaced when they die.
The concentration of pentosidines has been reported to increase linearly
with age [Sell1989].
Elevated protein-bound arabinose has been found in the serum proteins of
schizophrenics and in children with conduct disorders
Dr. Weyrich notes that it is not clear whether this is a marker for
elevated arabinose, or a cause of the neurological pathology. In any case,
accelerating the aging process is not a good thing.
Elevated urine arabinose has also been found in an autistic child in whom
a brain MRI showed diffuse demyelization [Shaw2008].