Originally published May 15 2009
Cognitive Effects and Dietary Restrictions May Soon Ease for PKU Sufferers
by Barbara L. Minton
(NaturalNews) Natural supplements may be in the works that could help people with phenylketonuria (PKU) live a better life. Children born with PKU are lacking an enzyme necessary to process the amino acid phenylalanine. As a result, they are at risk for depression, anxiety, ADHD, and cognitive problems. One group of scientists is looking for a way to produce this enzyme as a supplement, while other research is delving into the connection between phenylalanine and another amino acid, tyrosine. Both studies may result in supplements that would lessen symptoms of the disorder and strengthen outcomes for its sufferers.
Scientists at Simon Fraser University in British Columbia have identified a plant source of phenylalanine ammonia-lyase (PAL), the enzyme missing in people with PKU. This enzyme breaks down phenylalanine into trans-cinnamic acid and ammonia, making it no longer a threat to people with the disorder. To find a commercial source of PAL, the researchers studied various members of the Poaceae family, a large group of plants that includes wheat, rice, corn, barley, oats, sorghum, and turf grasses.
They identified a corn cultivar, Japanese striped corn, with very high levels of PAL activity in seedling and root tissues. The roots of this cultivar are intensely colored by the presence of high levels of anthocyanins. Due to the coloration from anthocyanins, the scientists characterized the root tissues as "robust". In fact, they were robust enough to retain 90% of their PAL activity even after being freeze-dried and after a 15 week storage period.
It is not unusual for plants to have PAL activity and anthocyanins. However, the high levels of PAL from these cultivars coupled with their ability to remain stable make them a unique and viable option for use in therapeutic supplement form.
Meanwhile, researcher Rachael Sharman, Ph.D. at Queen University of Technology in Ontario is delving into the possibility that low levels of another amino acid, tyrosine, may increase the risk of low dopamine in the brain, and may be associated with some of the effects of PKU such as ADHD and possibly cognitive impairment, anxiety and depression.
If it turns out that low levels of tyrosine combined with high levels of phenylalanine are responsible for the persistent problems associated with PKU, tyrosine therapy may mean that children born with the disease have no greater risk of developing cognitive problems than children born without it.
"This is a link we want to take further, and my study will take a direct inventory of biochemical functions of children with PKU over seven years, to see the differences in the effects of having high levels of phenylalanine in combination with low levels of tyrosine," Dr. Sharman said in a recent press release.
PKU used to cause severe brain damage, and any damage was irreversible. Babies are now screened at birth so that they can immediately be placed on special low phenylalanine diets if they are found to have the disorder. However, research into the condition has stopped short of completely curing the cognitive impairments of suffers.
"It would be the icing on the cake, really, to ensure that people with PKU can reach their full potential," she said.
The diet required by a person with PKU is highly restrictive and often difficult to follow. Because some phenylalanine is needed for normal growth, and too much of it can cause cognitive damage, the diet follows a very narrow road. High protein foods, such as meats, fish, poultry, eggs, cheese, milk, dried beans, and peas must be avoided. Instead, measured amounts of cereals, starches, fruits, and vegetables along with a milk substitute are recommended. Special phenylalanine formulas are available for all age groups.
For children with PKU and their families, following the diet is burdensome and isolating. Children often feel as though they cannot really be a part of a peer group because their dietary restrictions forever separate them.
For women with PKU who are of child bearing age, close adherence to the low phenylalanine diet and phenylalanine monitoring are recommended prior to conception and throughout pregnancy. The risk of spontaneous abortion, mental retardation, microcephaly, and/or congenital heart disease is high if the mother's phenylalanine levels are poorly controlled.
For more information see:
McInnis S et al, The ornamental variety, Japanese striped corn, contains high anthocyanin levels and PAL specific activity: establishing the potential for development of an oral therapeutic, Plant Cell Reports, March, 2009.
http://insciences.org/article.php?article_id...
http://www.medhelp.org/lib/pku.htm
About the author
Barbara is a school psychologist, a published author in the area of personal finance, a breast cancer survivor using "alternative" treatments, a born existentialist, and a student of nature and all things natural.
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