Metabolism and Metabolic Disorders
– Part One
Question anyone on the concept of metabolism, and you will surely receive responses supporting that everyone knows about it. Young children learn of its existence at school; science students worldwide study the intricate metabolic reactions of living cells, and the general public speaks this technical term during social banter around food and weight. However, metabolism is a facet of human health involving far more than the breakdown of food or the production of energy.
The Five Pillars of Health
Metabolism and the biomedical understanding of metabolic disorders is one of the five pillars of health, supporting the philosophy behind the MINDD Foundation. Over a series of articles, these five pillars will be presented and discussed to help you understand the importance of each for human health, including the biomedical, nutritional and lifestyle measures to improve your own health, your family's health and safeguarding the health of generations to come.
Research and education into the role of Metabolic Disorders in Pediatric health are fundamental to the work of the MINDD Foundation. This two-part article serves to explain the importance of metabolism to our overall state of health, list the conditions associated with errors in metabolism (including the cause of such errors) and what can be done to prevent the potentially devastating consequences of errors of metabolism.
Metabolism occurs at the cellular and even subcellular level within tiny structures known as organelles. It is usually defined and interpreted in biochemical terms, where all reactions of the metabolic system are considered together. In the most simplistic definition, metabolism is defined as the sum total of all chemical reactions in the body. Metabolism is composed of:
Therefore, every single chemical reaction in your body is part of your metabolism. Every useful chemical substance your body makes for you and every waste product generated is part of your metabolism. These metabolic reactions differ depending on which organ of the body you are looking at. For example, the reactions of thyroid metabolism are completely different from reactions in skeletal muscle; every tissue and organ has a completely different role to play and their metabolic chemical reactions reflect this. Your metabolism represents far more than just weight loss and weight gain.
Errors in Metabolism + Causes
Inborn errors of metabolism are a very large group of rare and congenital disorders of metabolism, where babies are born with a genetic defect involving a specific aspect of their metabolism. These conditions are usually inherited. Most are due to single genetic mutations, where the faulty gene leads to the production of a faulty enzyme. The faulty enzyme produced is unable to catalyse its specific chemical reaction in the body (each enzyme in the human body is highly precise and usually only facilitates one specific chemical reaction). The resulting problems are incredibly varied, depending on the gene and enzyme product involved. Some conditions can be managed well, while others can be lethal errors. Depending on the actual condition inherited, symptoms can range from acute and late-onset acute, through to progressive, generalised and permanent symptoms.
There are hundreds of inherited metabolic disorders, and most are exceedingly rare. As a whole, metabolic disorders usually involve a gene/enzyme product involved in:
Due to the overwhelming number of metabolic disorders, diagnosis in a clinical setting can be difficult. The range of signs and symptoms that could possibly present is enormous. In general, infants and children who present with the following signs/symptoms may be investigated for congenital metabolic disease, depending on their entire clinical picture and medical case history: