High Protein Diets A Metabolic Poison Essay

When we eat, we consume many different indispensable biomolecules that our organic structure needs to work right. These are things such as saccharides, lipoids and proteins. Proteins are the most of import biomolecule as they mediate every cell in the organic structure and command the procedures and maps that the cell may finish. Most significantly, proteins are the molecular method through which familial information is displayed.

Proteins are of course happening polymers that are made from ironss of amino acid groups. There are 20 different types of amino acids that the organic structure needs to work absolutely ; nevertheless, some are non indispensable. An indispensable amino acid is one that the organic structure can non synthesise itself, such as phenylalanine. Occasionally, there may be a familial upset that means a individual does n’t hold a peculiar enzyme to interrupt down a protein. This means that their organic structure can non utilize these aminic acids to work right farther along the chemical tracts.

An illustration of this is Phenylketonuria ( PKU ) . The faulty cistron that is responsible for cut downing the activity of the enzyme phenylalanine hydroxylase is called PAH. This enzyme is responsible for change overing phenylalanine into tyrosine. With this enzyme either losing or faulty, the procedure can non go on and there is an inordinate physique up of phenylalanine. This elevated degree of phenylalanine is known as hyperphenylalaninemia.

Specifically for people that have PKU, there is a small used tract that comes into drama. This tract allows phenylalanine to be transaminated with pyruvate to make phenylpyruvate. Phenylalanine and phenylpyruvate are so built up in the blood and in bodily tissues and so becomes excreted into the urine giving the upset its name, Phenylketonuria. Phenylpyruvate can be either decarboxylated to phenylacetate, or it can be reduced to phenyllactate. Due to the fact that phenylpyruvate is excreted in the piss, one time it has been decarboxylated into phenylacetate, it produces a peculiar odor in the piss which is used by physicians as portion of the diagnosing of PKU.

Figure 1.

The alternate tract for katabolism of phenylalanine in Phenylketonuria. This shows how phenylacetate and phenyllactate are produced, how they so build up in tissue, blood and piss and are so excreted.

The physique up of phenylalanine and/or its metabolites in babes and immature kids will finally take to unnatural development of the encephalon and this in bend will so take to rational disablement. This is due to the fact of extra phenylalanine viing with other aminic acids to traverse the blood encephalon barrier, which so will ensue in a lack of other necessary metabolites.

Due to the fact that PKU is an congenital mistake of amino acid metamorphosis, if it is detected early plenty, it can be comparatively easy to pull off. It is n’t curable but can be controlled through particular dietetic demands. As people with PKU can non eat anything that contains protein, they can be prescribed particular addendums that there will merely be merely adequate phenylalanine and tyrosine to finish protein synthesis.

The trials that are used to observe PKU in babes and immature kids are comparatively cheap and can take to healthcare establishments salvaging 1000000s in footings of health care costs subsequently on in the sick person ‘s life.

Alternate methods of intervention are presently being tried and tested and one of these is by utilizing the nutritionary addendum BH4. BH4 is besides known as tetrahydrobiopterin. Tetrahydrobiopterin is used in the catalisation of an O2 atom and becomes oxidised itself to organize dihydrobiopterin. Scientists believe that if the BH4 can be given to person with PKU, so their organic structure will go on to work every bit usually as it can.

Figure 2.

This shows the function of tetrahydrobiopterin in the phenylalanine hydroxylase reaction.

Another method is by presenting a wholly man-made, genetically engineered version of the dysfunctional enzyme phenylalanine hydroxylase. This is still undergoing experimentation and is non a preferable method of intervention as of yet.

Another congenital mistake of amino acerb metamorphosis is Alkaptonuria. This is when the faulty cistron is HGD and is used to command the enzyme is homogentisate dioxygenase. Peoples who have Alkaptonuria, excrete big sums of homogentisate in their piss. Equally shortly as the homogentisate is oxygenated it turns black, intending that it is one of the methods that can be used to observe person who has Alkaptonuria.

Archibald Garrod discovered in 1922 that Alkaptonuria is an familial trait, the first of all the congenital mistakes that were known. He managed to follow the cause of the job down to a complete absence of the enzyme homogentisate dioxygenase, and became the first to do the connexion between losing or faulty enzymes and congenital mistakes of metamorphosis.

This metabolic upset besides includes a physique up of dark pigment in tissues such as gristle and tegument which normally occurs in people 30 old ages old and more called Ochronosis. In early maturity, the sick person can besides see arthritis of the spinal column and big articulations around the organic structure. A few other jobs that Alkaptonuria can do include bosom jobs, prostate rocks and kidney rocks.

The cistron that is responsible for this familial malformation is homogentisate 1,2-deoxygenase. This cistron is responsible for commanding the enzyme homogentisate oxidase which is used to interrupt down phenylalanine and tyrosine into maleylacetoacetate. As phenylalanine and tyrosine a broken down, the green goods a substance called homogentisic acid which so builds up in the organic structure. With big extra sums of homogentisic acid, it accumulates in connective tissue which is the ground that gristle and tegument darken. Over a longer period of clip, the inordinate physique up causes the aforesaid arthritis in the affected articulations. Finally, homogentisic acid is excreted with piss, which when it becomes oxygenated, turns dark, about black in coloring material.

Once once more, as with PKU, this status is presently being controlled by the sick person holding either a low protein diet or no consumption at all and utilizing auxiliary medicine to assist the phenylalanine and tyrosine tracts continue every bit usually as possible.

Figure 3.

This shows the tract from phenylalanine to acetoacetyl-CoA. The healthy path and where if there is a faulty or losing enzyme, where it is and the status that this will do.

Finally, a 3rd congenital mistake of amino acerb metamorphosis is Tyrosinemia. There are three types of this status depending upon the phase of the tract that an enzyme is losing, Type I, Type II and Type III. Each has its ain features and symptoms that make them identifiable but are all caused along the same tract, merely in different topographic points due to which enzyme is dysfunctional.

Type I Tyrosinemia is the most terrible of this upset and is caused by the faulty cistron FAH. This cistron is responsible for commanding the enzyme fumarylacetoacetase which breaks fumarylacetoacetate into fumarate and acetoacetate succinyl-CoA. ( See Figure 3. ) Among some of the symptoms of this status are icterus, a chou like smell and an increased inclination to shed blood. More terrible jobs that can happen are liver and kidney failure, jobs related to the nervous system and the sick person is at an increased hazard of undertaking liver malignant neoplastic disease. The jobs to make with the liver are due to the fact that the procedures all happen there and when tyrosine has n’t been broken down wholly to organize acetoacetyl-CoA, these toxic degrees build up in the variety meats and tissues and get down to do harm to these countries.

Type II Tyrosinemia is caused by the faulty cistron TAT. This cistron is responsible for commanding the enzyme tyrosine transaminase. This enzyme is responsible for interrupting down ?-ketoglutarate into glutamate and p-Hydroxyphenylpyruvate. ( See Figure 3. ) This enzymatic lack chiefly affects the eyes and tegument and approximately 50 % of people that suffer from it develop some signifier of rational disablement. This is one time once more due to the high degrees of tyrosine in the blood and tissues which one time built up Begin to do harm to the encephalon.

Type III Tyrosinemia is caused by the faulty cistron HPD which is responsible for commanding the enzyme p-Hydroxyphenylpyruvate dioxygenase. This enzyme is responsible for interrupting down p-Hydroxyphenylpyruvate into homogentisate. ( See Figure 3. ) This is the 2nd most terrible type of Tyrosinemia with symptoms of rational disablement, ictuss and loss of balance and coordination. This is one time once more similar to the old two Tyrosinemia types due to the fact that there is a build up of tyrosine in the blood and tissues doing these jobs.

All three types of Tyrosinemia can be controlled by holding a low protein diet from every bit shortly as it is diagnosed for the remainder of the sick person ‘s life, where merely merely plenty phenylalanine and tyrosine are provided. This ensures that there will non be an inordinate physique up of either doing jobs subsequently on in the patients life. Due to the badness of harm that Tyrosinemia causes to the liver, in some utmost instances, the patient may necessitate to undergo surgery for a liver graft. However, if this status goes undiagnosed for an drawn-out period of clip, about a twelvemonth, so unluckily the patient will go asleep. This is due to the extent of the harm to the liver and the encephalon, intending that their organic structure can no longer map.

Overall, congenital mistakes of amino acid metamorphosis, if detected at a immature plenty age ( babes and babies ) can be easy to name and command. This can be achieved by holding a low protein or zero protein diet and by avoided nutrients with unreal sweetenings such as phenylalanine and aspartame as these contain amino acids that could be potentially deadly to person that has a familial upset that does n’t let for these to be broken down.

Doctors and nurses now understand the importance of observing these conditions early and hence, trials for them tend to be carried out within 6 months of a babe being born in the UK and the US. If an congenital mistake is diagnosed, so it makes managing the status easier and is more cost effectual for infirmaries. This is because the long term cost of medical attention for person that has controlled the upset is a batch less due to the fact that there are non as many jobs in ulterior life for that individual. For person that has an congenital mistake of metamorphosis that is left undiagnosed nevertheless, the costs involved to look after them one time some of the harm has been done is an unbelievable sum more. This includes things from organ grafts to care places if the patient has suffered from rational disablement as an consequence of go forthing their status untreated.