A very uncommon genetic disorder that is always inherited is phenylketonuria-or PKU in short. An individual affected by this condition suffers from an excessive accumulation of the phenylalanine, amino acid within the blood and this is accompanied by a deficiency in the blood levels of L-tyrosine, another amino acid.
Individuals affected with this condition often sustain some form of brain or nerve damage especially if the condition is not detected and treated at an early stage itself. The reason for such problems is that high levels of the phenylalanine amino acid can cause severe behavioral disturbances and mental retardation, which are common in such individuals.
As a result of this condition the biochemical basis of the body is disturbed and results in these complications. In this day and age however, the incidence of such complications has been largely addressed as most countries and the United States all newborn children take part in screening programs that recognize nearly all cases of phenylketonuria at an early stage.
This is very important as the reduction of the symptoms or the prevention of the symptoms associated with PKU can only be done at an early stage and the only treatment feasible for the condition is early treatment. One possible cure could be the use of gene therapy; this is presently being researched but it is likely to bear fruit only far in the future.
The reduction of the levels of amino acid-phenylalanine in the blood throughout the use of certain classes of enzymes and different amino acids is also being researched on groups of patients.
Some of the typical symptoms seen in newborns with PKU are very lethargic movements, they tend to eat very little and in addition the sweat and urine of such children possessed a "mousy" smell from the excreted phenylalanine. Other physical symptoms that are common in kids with PKU are light skin colors and conditions such as eczema, the children are also very sensitive to sunlight. Seizures, hyperactivity and an appreciable reduction in the mental capacities are other symptoms possessed by kids with untreated phenylketonuria.
The treatment methodology of individuals suffering from PKU is mostly done through the use of a diet absent or low in phenylalanine, this is in fact the only treatment methodology known. Even though treatments started at a later stage of life bring about substantial benefits and lead to significant reduction in the severity of the PKU related symptoms, it is known that greatest benefits can only be achieved when this special diet is begun in the very first days of life, provided that the child has been positively identified as suffering from PKU.
This diet control is very important, as all parameters of symptomatic action such as intellectual function, behavior and muscular control significantly improve when a diet low in is maintained throughout; the phenylalanine levels must be kept low throughout life by careful dietary monitoring.
In newborns and in young kids the effects of high phenylalanine in the blood causes severe disorders because of the fact that their nervous system is still developing; the same elevation of the amino acid in older kids and in adults appears to be less severe and does not create complications to the same degree as it does in smaller children.
For this reason, researchers have been looking at the possibility of relaxing the strict dietary regimen as the affected individual ages; an older individual copes much better physically with the complications of PKU, the problem is compounded by the fact that most individuals find it difficult to adhere to a strict lifetime diet.
This is questioned by other researchers who suggest on the basis of other studies that the relaxation of dietary measures could complicate things further, all other studies have not necessarily borne out this contention and a relaxed dietary regimen may not necessarily lead to complications.
This issue will only be resolved in the future as more controlled studies are undertaken on people with PKU. Conventional wisdom still holds true however, and 87% of respondents in a study of 111 phenylketonuria treatment centers, held to the old viewpoint and favored a lifetime dietary restriction of amino acid-phenylalanine in the diet of patients with PKU.
The supervisory role of a physician and a nutritionist must be available at all times in the management of the PKU diet; the diet is a very tough regimen and requires effort and consistency.
In children who did not start receiving treatment for PKU until they were 20 to 40 days old, the benefits of breast-feeding, over formula feeding, was apparent and breast milk appeared to confer some extra benefits to such children born.
This is demonstrated easily through higher IQ scores of PKU children who had been breast fed during a preliminary study, the other kids with phenylketonuria who had been formula fed scored lower; these test were of course carried out before these children started on similar restricted diets.
Anther interesting fact is that the accumulation of the trace molybdenum mineral is often observed in infants with PKU; this abnormal accumulation of molybdenum is universal in kids with PKU. This is another reason breast feeding is initially important, many of the formulas are reinforced with molybdenum far exceeding levels found in breast milk and hence newborns with phenylketonuria who are fed formula milk run the very real risk of accumulating too much molybdenum in their bodies.
A restricted diet for PKU patients provides only very little phenylalanine and for this reason all PKU diets are protein low, the reason is that this amino acid-phenylalanine is a constituent of most proteins. Therefore the diet must eliminate all protein rich foods including high-protein foods, for example dairy products, poultry and eggs, fish and meats, all nuts and legumes, and any other food groups that may contain proteins in high amounts.
The foods used are specially prepared to contain extremely low phenylalanine or no phenylalanine at all, additionally the diet is also rich in low protein foods, these can include items such as some fruits and vegetables and several grain products, and these are of course allowed only in controlled and measured amounts.
Also, without the addition of phenylalanine, supplements of an amino acid formula is also usually included to increase the vital protein intake which is nutritionally required; the diet is strictly monitored and screened for the level of permissible phenylalanine form all sources in combination.
Changes in the diet, natural growth and overall health of an individual also lead to fluctuations in the level of the phenylalanine within the body of the individual-these levels has to be monitored and the individual must be regularly checked to see that the levels are kept low. For people with PKU, the best source of information on diet will be given by a nutrition specialist; this professional will have all the necessary details on homemade foods, specially prepared that can be used, recipes for infant formulas, and how to prepare pastas low in protein.
This is important because variety in the diet is essential to relieve monotony and advice on all kinds of low phenylalanine crackers, breads, and other foods will usually be given by such nutrition specialists.
A water soluble vitamin of the B complex group called biotin is often deficient in individuals with phenylketonuria who may not be strictly following the phenylketonuria diet. Biotin metabolism is one of the first things that phenylalanine blocks-hence the rising levels of phenylalanine in the body of a PKU affected person is almost always manifested in deficient levels of biotin.
For example the development of seborrheic dermatitis which is caused by the deficiency of biotin was observed during a preliminary trial on kids with PKU, a return to the phenylalanine-restricted diet corrected this disorder. The long term implications can be severe and thus this stage must never be reached; the diet should be maintained at all times.
A low calorie sweetener aspartame that is often used nowadays contains about 50% phenylalanine in its composition and there is question about whether aspartame is safe for individuals with phenylketonuria to consume it; the answer should be relatively straightforward. However; it is complicated by the results of one study that showed the blood levels of phenylalanine in an individual with PKU who ingested a twelve ounce soft drink sweetened with aspartame increased only slightly during the trail.
What is lacking is that the long term affects of continual aspartame consumption by people with phenylketonuria was not addressed and there is a very good possibility that phenylalanine may be accumulated in the body in the long term. Therefore it is advisable for people suffering from PKU to stay away from all aspartame-containing beverages and foods at least at lest concrete results are reported in regard to aspartame consumption by phenylketoneurics.
It is important to remember that the use of any and all kinds of food supplements must be done under the supervision of a specialist; this is more so because of the significance of strict dietary control, that must be maintained at all times.
Many essential fatty acids are vital for proper brain functioning and this is a major concern because the phenylketonuria diet is low in some of these vital fatty acids. The deficiency in these fatty acids was investigated during one controlled study on a group of children with phenylketonuria, they underwent supplementation with fish oil-excluding black currant seed oil, and this was carried out for 6 months and resulted in the deficiencies being corrected. For a period of six months, these children received 500 milligrams of oil per 8.8 lb of body weight as part of the study.
Every day each child was usually given a capsule though the amount varied from 5-8 capsules (500 mg each) per child during the duration of the study.
Because of the controlled diet that is low both in fat and protein content, many of the individuals suffering from PKU may be deficient in several essential nutrients. Some of these nutrients deficiencies can include low levels of the compounds like the long-chain polyunsaturated fatty acids-or LC-PUFAs, low level of essential minerals like selenium, low vitamin B12 levels, and deficiencies in the levels of vitamin K.
For the normal antioxidant functioning within the body, the availability of sufficient levels of the mineral selenium within the body is very important. The nervous disorder and brain related damages in individuals afflicted with PKU can probably be worsened by deficiency of selenium and furthermore research suggest that reduced antioxidant activity due to the selenium deficiency can substantially contribute to such disorders.
The deficiency of selenium was corrected successfully during two studies involving selenium-deficient individuals with PKU, who were given supplements of selenium in the form of sodium selenite; however; supplements of selenomethionine did not lead to the correction of the deficient selenium levels in the body in all test subjects.
All animal sourced foods are restricted in the diet for individuals with PKU; however, nutrients like the B12 vitamin is found exclusively in animal origin foods, and thus made of protein. This vitamin is often found to be deficient in inconsistent users of a B12 vitamin supplement along with the PKU dietary regimen.
This is further borne out by the results of a survey involving young individuals with PKU, where at least 32% of the participants were found to have deficient levels of the vitamin B 12, the vitamin was low or at below-normal blood levels in these children. It is important to have regular supplement of the vitamin B12; complications like nerve problems and anemia are some of the things that can occur because of a deficiency of the vitamin.
The intake of fat is also reduced in the diet of PKU sufferers indirectly as a result of the PKU diet being low in all animal products. A possible deficiency in the levels of the vitamin K can occur in such individuals because of this low fat content in the diet; this was suggested by a preliminary study carried out on kids with PKU, thus it is suggested based on these results that low fat reserves into the body may impair the body's ability in retaining the fat soluble vitamin.
This theory is further borne out by additional observations done during the study where it was found that the children on the strict diet possessed low levels of certain vitamin K-dependent proteins; all of which are vital for the normal clotting of blood.
Improvements in the ability of the child to adhere to the complex dietary restrictions can occur if access to PKU resource and support groups is made available to the PKU afflicted individual and members of his or her family. The involvement of family members must in these groups must be encouraged for their own education about the condition, these measure will aid the individual to adjust to the daily life long restrictions he or she must face.
Another particular some expectant mothers is maternal PKU or more correctly the care of PKU child during pregnancy. The fetus may already be determined to be phenylketoneuric while still in the womb; this can complicate things as it is known those excessive fluctuations or high and low levels of phenylalanine may often occur during pregnancy, these fluctuations can adversely affect the child.
Some of the problems inherent in the situation are that these complications can cause disorders in the child at birth; thus the maternal PKU can lead to malformation of the fetus, the child may have a very small head size-microcephaly, the child may develop several abnormalities of the heart, there may also be a failure to grow properly within the uterus-called intrauterine growth retardation, and lastly mental retardation can often develop in the womb itself.
Therefore during the pregnancy term itself, the mother will have to enter into a restricted diet program to avoid the adverse effects on the offspring; such a controlled diet on the part of the mother can stop all deterioration of the baby and will greatly aid in the reduction or elimination of the more severe complications.
Effective guidance in dietary matters and monitoring including regular consultation and follow-up visits with medical and nutritional specialists is always necessary for the pregnant mother; the aim being to minimize the damage to the baby that can occur because of fluctuating levels of phenylalanine in the womb.