By Dr. Loretta Lanphier, ND, CN, HHP, CH

Certain birth defects can lead to many serious consequences both in childhood and as an adult. Phenylketonuria is one of these, but there is a silver lining in this butt. Unlike some genetic conditions, this disorder can be effectively controlled through the use of a special diet that must be maintained for life. The illness can also be identified soon after birth via the use of a simple blood test that can give parents and health care providers ample time to implement the diet before any damage to the infant occurs. Would that all diseases could be so easily and naturally controlled!
What is Phenylketonuria?
Phenylketonuria (commonly known as PKU) is a genetic disorder that involves a birth defect in a specific gene necessary for metabolizing the amino acid phenylalanine. The defective gene that causes PKU is responsible for manufacturing an enzyme that is required in order to break down phenylalanine. When this amino acid is not metabolized, dangerous levels of it can accumulate in the body, resulting in serious consequences including mental retardation, hyperactivity, and other behavioral disorders.
Statistically speaking, PKU is a quite rare disorder in the overall population, but it favors certain demographic groups. For example, worldwide rates of PKU log in at about one in every 15,000 births. In the US, the incidence is about 1/8000 births amongst Caucasians, and much lower for African Americans (1/50,000 births). The highest incidence of PKU in the world occurs in Ireland, where rates are at 1/4500 births. People of Irish and Scottish descent have the greatest numbers of PKU rates, and it is this factor that leads researchers to the conclusion that this genetic disorder originated in the Celtic population many centuries ago.
One of the factors that keeps most PKU cases from developing is that testing for it at birth is very common throughout the world, with all 50 states in the US requiring PKU testing by law. If the special diet that keeps the disease in check is implemented before four weeks of age, the chances of serious consequences such as mental retardation are greatly reduced.
If there can be such a thing as a “bright side” to a disease, PKU may just have it. For one thing, it can be controlled with diet. No hazardous medications or dangerous vaccinations are needed to control this disease, much to the dismay of Big Pharma. However, in December of 2007 a drug was approved by the FDA for the treatment of PKU, to be used along side of the diet. Not much is known about its safety or efficacy yet, but the diet has been working very well without medication up to this point. However, it is hard to make money off of a diet, so I guess the drug makers felt compelled to get in on the act.
Now, about the diet: That is another piece of good news. The recommended diet for PKU control is generally quite healthy, being low in protein, and high in many fruits, vegetables, and grains. It also eliminates most meat, dairy, and other high fat foods that are so damaging to most Americans. So even though PKU is a very serious disease, it does demand that its victims eat a wholesome diet. This may lead to better overall health for PKU patients than they would have without the illness!
What Are the Signs and Symptoms of PKU?
One of the reasons testing for PKU is so essential is that there are no symptoms at birth. Signs may not show up for several months, and by then damage has most likely already occurred. It is critical that treatment (via the diet ) begin no later than four weeks after birth, preferably sooner.
If testing is not used to discover the presence of the illness, and the diet is not implemented, it can lead to tragic consequences. Symptoms can range from mild to severe, dependent on the amount of phenylalanine in the infant’s system. Each case is different, but general signs of PKU may include the following:
Tremors or tics, especially in the arms and legs
Stunted growth
Microcephaly (unusually small head size)
Eczema and other skin rashes
Mental retardation
Rocking movements
Difficulty socializing and other behavioral problems
Abnormally fair skin and blue eyes (due to difficulties manufacturing melanin, a substance necessary for the formation of hair and skin pigments)
A “musty” odor (caused by abnormal amounts of phenylalanine in the body. Most noticeable on the breath, from the skin, and in the urine.)
There are several different types of PKU, or in some cases closely related conditions, in addition to the classic form described above. The most common ones include:
Maternal PKU: This variation occurs in pregnant woman who have PKU and are not following the diet. Therefore toxic levels of phenylalanine are present in her blood, and damage can occur to the fetus before birth by the mother’s blood passing through the placenta. While the baby cannot get PKU simply from exposure to the mother’s blood (although PKU can be present if the genetic factors are right), effects on the child are very similar, including possible mental retardation, microcephaly, congenital heart disease, low birth weight, and potential behavioral problems later in life. Unfortunately, there is no known treatment for babies born with maternal PKU. In decades past, doctors used to believe that persons with PKU could go off the diet in their teens once they reached full development. However, mainly because of the risk of maternal PKU, it is now recommended that all patients, especially women, stay on the diet for life. It is critical that the diet is maintained so that patients can live a normal life and bear children without the risk of them contracting maternal PKU.
Hyperphenylketonuria: This condition comes in both mild and severe forms. Patients with mild hyperphenylketonuria have a minimal amount of phenylalanine in their blood even when eating a normal diet. The severe form involves higher levels, but typically not as high as individuals with classic PKU. The diagnosis can be made between classic PKU and this variation by testing the blood for the presence of an enzyme called phenylalanine hydroxylase, which is needed to metabolize phenylalanine. Classic PKU patients are completely void of this enzyme, while hyperphenylketonuria patients have a limited amount of enzyme activity, albeit insufficient. The good news is that this related condition can be controlled using the same diet as that for classic PKU patients.
Tyrosinemia: This disorder is similar to PKU in that it involves the presence of too much phenylalanine in the blood, but it also is characterized by excessive amounts of another amino acid called tyrosine. If left untreated, the effects of tyrosinemia are very similar to those of PKU, but it too can be controlled effectively by a diet that is low in both phenylalanine and tyrosinemia.
Tetrahydrobiopterin deficiency disease is a similar malady that produces toxic levels of phenylalanine as well. However, even though levels of this amino acid can be controlled using the same diet as that for PKU, these victims typically suffer from mental retardation due to insufficient amounts of dopamine and serotonin, which are necessary for healthy neurological functions.
How is PKU Contracted?
PKU is referred to as an “autosomal recessive” illness, which simply means that in order for an infant to be born with PKU, he or she must inherit the defective PKU gene from both parents. If only one parent has the PKU gene, there is no risk for having a child with PKU. If a person has the gene but not the disease, he or she is a “carrier,” and can potentially pass the gene or the disease (if the partner has the gene as well) to the next generation. If you are aware that you are a carrier, genetic testing would be advised to determine if your partner is a carrier as well.
What Are the Basics of the Diet?
As I mentioned earlier in this article, the diet is actually quite healthy. Recommended foods to avoid include meat (including beef, pork, poultry, and fish), milk, ice cream, eggs, beans, and nuts-basically all high protein foods of any type. Most vegetables and fruits are allowed and even encouraged, but you have to be aware of some to stay away from r limit. For example, one ear of corn contains about 90 milligrams of phenylalanine, a large chunk of the daily allowance.
Another good feature of the diet is that it recommends eating a variety of foods. Even people with PKU need a small amount of phenylalanine in their diet, so it can be a rather cumbersome thing to manage. Infants are unfortunately not able to breast feed normally, but a special formula including dietary replacements mixed with a certain amount of breast milk is recommended if possible. I suggest working with a naturopath or like-minded nutritionist in order to develop a formula for your PKU positive baby that is composed of natural, and preferably organic, ingredients. There are also quite a few cookbooks designed for PKU patients that can help to simplify the process of sticking to the diet and still eating a variety of healthful foods.
If you have PKU and have gotten off your diet as an adult, even if you have no symptoms of the illness it may benefit you to return to the diet. Studies have shown that adult PKU patients can increase brain function later in life by following the diet. It is also critical that you keep on the diet or return to it if you are a women who is considering having a child.
It is interesting to me that conventional medicine has embraced the idea that a disease such as PKU can be effectively controlled by diet. What if the prevailing mentality changed regarding other diseases such as stroke, cancer, diabetes, and coronary disease? Despite the reluctance of the mainstream medical community to admit it, the truth is that all of the above diseases can be prevented by diet and other lifestyle changes. If Americans would break their awful habits and turn away from living in ways that invite disease, the rate of all debilitating conditions would fall dramatically. If we can only get the AMA and the FDA to focus on that instead of the next “miracle” drug that will only fatten the wallets of Big Pharma…

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