A metabolic disorder is a disorder that negatively alters the body's processing and distribution of

macronutrients A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

, such as

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers specif ...

s, and

carbohydrate A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...

s. Metabolic disorders can happen when abnormal chemical reactions in the body alter the normal metabolic process. It can also be defined as inherited single gene anomaly, most of which are

autosomal recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the Phenotype, effect of a different variant of the same gene on Homologous chromosome, the other copy of the chromosome. The firs ...

Signs and symptoms

Some of the symptoms that can occur with metabolic disorders are

lethargy Lethargy is a state of tiredness, sleepiness, weariness, fatigue, sluggishness, or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overw ...

weight loss Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat (adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other conn ...

jaundice Jaundice, also known as icterus, is a yellowish or, less frequently, greenish pigmentation of the skin and sclera due to high bilirubin levels. Jaundice in adults is typically a sign indicating the presence of underlying diseases involving ...

and

seizure A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...

s. The symptoms expressed would vary with the type of metabolic disorder. There are four categories of symptoms: acute symptoms, late-onset acute symptoms, progressive general symptoms and permanent symptoms.

Causes

Inherited metabolic disorders are one cause of metabolic disorders, and occur when a defective gene causes an

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

deficiency. These diseases, of which there are many subtypes, are known as inborn errors of metabolism. Metabolic diseases can also occur when the

liver The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of var ...

pancreas The pancreas (plural pancreases, or pancreata) is an Organ (anatomy), organ of the Digestion, digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity, abdomen behind the stomach and functions as a ...

do not function properly.

Types

The principal classes of metabolic disorders are:

Diagnosis

Metabolic disorders can be present at birth, and many can be identified by routine screening. If a metabolic disorder is not identified early, then it may be diagnosed later in life, when symptoms appear. Specific blood and DNA tests can be done to diagnose genetic metabolic disorders. The

gut microbiota Gut microbiota, gut microbiome, or gut flora are the microorganisms, including bacteria, archaea, fungi, and viruses, that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the g ...

, which is a population of

microbes A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in ...

that live in the

human digestive system The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (the tongue, salivary glands, pancreas, liver, and gallbladder). Digestion involves the breakdown of food into smaller and smaller compone ...

, also has an important part in metabolism and generally has a positive function for its host. In terms of pathophysiological/mechanism interactions, an abnormal gut microbiota can play a role in metabolic disorder related

obesity Obesity is a medical condition, considered by multiple organizations to be a disease, in which excess Adipose tissue, body fat has accumulated to such an extent that it can potentially have negative effects on health. People are classifi ...

. A 2023 meta-analysis of six cohort studies involving 484,994 participants found no significant overall association between metabolic syndrome (MetS) and Alzheimer's disease (AD) risk. However, individual components of MetS, such as hypertension and hyperglycemia, were linked to an increased risk of AD, highlighting the complex interplay between metabolic dysfunction and neurodegeneration.

Screening

Metabolic disorder screening can be done in newborns via

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

, or

hearing test A hearing test provides an evaluation of the sensitivity of a person's sense of hearing and is most often performed by an audiologist using an audiometer. An audiometer is used to determine a person's hearing sensitivity at different frequencie ...

Management

Metabolic disorders can be treatable by nutrition management, especially if detected early. It is important for dieticians to have knowledge of the genotype to create a treatment that will be more effective for the individual. Recent systematic reviews and meta-analyses have highlighted the effectiveness of medical nutrition therapy (MNT) in managing metabolic disorders, especially when tailored to individual genotypes. For instance, a 2023 study demonstrated that MNT provided by dietitians significantly improved glycemic control, anthropometric measures, lipid profiles, and blood pressure in adults with prediabetes. These findings underscore the importance of personalized nutrition interventions in the effective management of metabolic disorders.

References

External links

* {{Authority control * Metabolism Endocrinology Medical genetics