A deficiency in medical terms is a situation where a vital nutrient or bodily enzyme or compound is found to be lacking or even nonexistent.  Due to this, the body's internal processes, which maintain the stability of the system becomes greatly diminished, which can cause disorders and conditions called "deficiency diseases."  Deficiency diseases vary in their morbidity and remedy, and are the most unrecognized contributors to disease across the globe. 

Deficiency Background

A deficiency disease is one that is generated due to a body becoming deficient in one, or several, key nutrients.  An individual can become nutrient deficient due to a number of causes, most of them related to nutritional problems, and most commonly malnutrition.  Malnutrition is widely regarded as one of the greatest threats to public health, and a large part of that threat are diseases that are generated by nutrient deficiencies. 

Iron Deficiency Background

Iron deficiency is the most common nutritional deficiency in the world.  Generally caused by a loss of blood due to digestive bleeding or sustained malnutrition, a lack of iron impedes the multitude of bodily processes which are supported by iron metabolization.  Iron deficiency, and especially the more severe iron deficiency anemia, thus has a pronounced effect on the the human body, altering one's appearance and significantly impairing the immune system. 

Magnesium Deficiency

Though sometimes better known in plant life, magnesium deficiency can often occur in humans who lack the essential mineral nutrient magnesium.  Symptoms of magnesium deficiency can vary tremendously based upon the severity of the condition; if left untreated, the condition can cause death.  Magnesium deficiency symptoms are sometimes easily attributed to other diseases, as a result, the condition often goes undiagnosed and even when diagnosed, can be difficult to treat.

Potassium Deficiency

Potassium deficiency, or hypokalemia, is a nutritional disorder where potassium levels required for effective bodily function are not adequately maintained.  Potassium itself is a natural diuretic, and reestablishing levels of it in the system can be tricky once potassium deficiency symptoms begin to emerge.  Symptoms of potassium deficiency vary in severity based on the lack of the nutrient, but in advanced cases can be extremely severe, both mentally and physically. 


G6PD Deficiency

Glucose-6-phospate dehydrogenase deficiency is a hereditary condition that effects about 10% of the world's population, to varying degrees, making it the world's most common enzymatic deficiency.  G6PD deficiency exists when a body does not produce enough of the G6PD enzyme, which metabolizes the sugar in red blood cells for energy.  Though often asymptomatic, some manifestations of the disease lead to very severe forms of anemia and other potentially fatal conditions. 

Calcium Deficiency

Calcium deficiency, or hypocalcemia, is a condition that can lead to the weakening of bones and the impairment of many different bodily processes.  Since calcium is one of the most abundant minerals in nature, calcium deficiency symptoms commonly occur due to imbalances in other substances in the system.  Calcium deficiency can be very severe to the course of human development, leading to osteoporosis and many diseases of the nervous system.

Zinc Deficiency

Hypozincemia, or zinc deficiency, occurs when the system is not able to perform many crucial enzymatic functions due to a lack of the nutrient zinc.  Zinc deficiency can result from many different condtions, such as malnutrition and disease, and its symptoms can be extremely severe.  It is one of the leading risk factors of disease in the developing world, where it is sometimes not a consistent component of people's diet. 

Iodine Deficiency

Iodine deficiency is perhaps the world's most serious common nutritional disorder.  Utilized by the body to produce necessary hormones, iodine intake is often provided through diets high in marine life or iodized salt.  Populations who have diets low in iodine due to poverty or geographical restrictions on diet are prone to many serious physical defects, and the deficiency is often related to poor mental development, up to an including retardation. 

Alpha 1-Antitrypsin Deficiency

Alpha 1-Antirypsin deficiency is an autosomal disorder, meaning it can effect either sex, which effects the ability of the body to create the eponymous inhibitor enzyme.  A1AT is responsible for protecting the elastic fibers in the lungs and elsewhere from being destroyed.  When there is a lack of the enzyme, it can lead to serious pulmonary and respiratory diseases, as well as cirhhosis of the liver. 

Folic Acid Deficiency

Folic acid deficiency, or folate deficiency, is defined by a lack of dietary nutrients that are considered "folates," such as viatmin B9 or folacin.  On the whole, folic acid deficiency is not considered among the most serious deficiency diseases, but if left untreated, it can significantly impair quality of life, as it is sometimes likned with depression and other behavioral disorders, as well as anemia and other medical condtions. 

Dopamine Deficiency

Dopamine deficiency, as well as serotonin deficiency, is a condition where it is believed that the brain is lacking crucial neurotransmitters, which directly influence human behavior.  Dopamine and serotonin deficiency are disorders linked to the chemical imbalance theory of mental illnesses, which speculates here that the amount of neurotranstmitters in the brain regulate action, emotion, and response.  The concept has still not been proven, and both conditions remain highly theoretical.

Protein Deficiency

A protein deficiency can potentially be one of the most potentially devastating types of deficiency disease as proteins are used by the system to synthesize the necessary amino acids used in bodily functions.  While most forms of protein deficiency are linked to malnutrition, protein C deficiency and protein S deficiency are genetic, and relate to the body's inability to produce either protein, each of which are used as blood anticoagulents.

Growth Hormone Deficiency

Growth hormone deficiency results when the body is unable to to produce enough of the human growth hormone somatotropin to support the body's needs.  Deficiency of somatotropin varies by age, and thus growth hormone deficiency is often differentiated by age between childhood manifestation, which is often congenital and permament, and adult onset, which is commonly acquired and in some cases is possible to treat and even cure.  


Beriberi

Beriberi is the name given to diseases caused by thiamine deficiency.  The different types of beriberi are classified by pathological effect on the body; wet beriberi, for instance, effects the circulatory system.  In all of its forms, however, beriberi is extremely debilitating due to its effect on the nervous system and can easily be fatal.  It has historically been common in populations with diets that are high in white rice.  

Deficiency Diseases

Deficiency diseases generally emerge due to the body being deficient in a crucial enzyme, compound, or substance.  The most common of these are vitamin deficiency diseases, or nutritional disorders, which cause health issues due deficient intakes of essential nutrients, which are required for the biochemical processes that allow our bodies to function.  Without these nutrients, our bodies stop functioning correctly, leading to sometimes severe illnesses. 

Tocopherol

Tocopherol is a compound classified under Vitamin E.  In humans, tocopherols are used to protect the lipid in cell membranes from oxidizing agents that can kill them.  When a body lacks tocopherols, it is said to have a Vitamin E deficiency, of which there are many types, all of which are severe.  Unlike some other nutritional disorders, however, this condition is not related to malnutrition, but usually to genetics.

Immune Deficiency

Immune deficiency is a condition where the immune system is prevented from being able to function appropriately, leaving the body susceptible to disease.  The best known immune deficiency is acquired immune deficiency syndrome, or AIDS, which is a global pandemic effecting 30 million people worldwide.  Auto immune deficiency is another common type, where the immune system malfunctions and actually attacks the body, thinking that it is, instead, a foreign infection.

IgA Deficiency

Selective immunoglobulin A deficiency, or IgA deficiency, is caused when the body is unable to produce the serum form of the eponymous antibody.  Immunoglobulin A is used by the immune system to attack outside pathogens, especially bacterial.  The condition varies in severity based upon the extent of the deficiency, which can effect the severity of outside infection.  It is currently the worlds most common genetic immunodeficiency. 

Cortisol Deficiency

Cortisol deficiency occurs when the body's adrenal gland is unable to produce suitable quantities of the hormone cortisol.  Cortisol is vitally important to the functioning of the body, as it responsible for regulating blood pressure and controlling blood sugar; individuals lacking this vital adrenal hormone are usually unable to convert fats and proteins into energy, leading to many serious medical conditions and even behavioral problems. 

Mineral Deficiency

A mineral deficiency is a form of nutritional disorder where one or many essential nutrients are found to be lacking, and can thus severely impair the function of the body and even cause disease.  Commonly, one mineral deficiency can lead to other mineral deficiencies, since minerals often serve correlative bodily functions with one another.  About half of the Earth's population is believed to be experiencing some form of mineral deficiency.

Selenium Deficiency

Though largely regarded as a poison, selenium is actually a nutrient vital in forming antioxidants in the body.  Selenium deficiency is quite rare, as it is almost impossible to become deficient in the substance while maintaining a regular diet.  Generally, the main cause of the deficiency is an extended period of parenteral nutrition, where the lack of needed selenium can lead to a negative imbalance that can cause serious illness.

Carnitine Deficiency

Primary carnitine deficiency is an autosomal disorder where the body lacks compounds of carnitine, which are used by the body to derive usuable energy from fats.  Carnitine deficiency usually emerges when the sufferer is young and the symptoms are fairly severe, as the disease can significantly impact mental and physical development.  Fortunately, carnitine deficiency is extremely rare and usually treatable with replacement therapy when diagnosed correctly and early.

Biotin Deficiency

An extremely rare nutritional disease, biotin deficiency can severely impair the metabolism of fatty acids and cellular respiration.  Biotin is a common vitamin readily available in most food, and even produced by bacteria in the intestines.  Therefore, biotin deficiency generally occurs only in very rare circumstances such as in athletes who have a diet high in raw egg whites, which contain a material that renders biotin in the body unusable.

Vitamin B6 Deficiency

Vitamin B6 deficiency, or pyridoxine deficiency, is deficiency disorder that generally appears in neglected infants.  Pyridoxine is a substance used to maintain chemical balances in the blood, and also helps in the creation of neurotransmitters, which are necessary for mental and nervous system function.  The condition is fairly rare, as pyridoxine is fairly common and easily available in most consummable foods.  Symptoms are generally serious, but it is rarely fatal. 

Pellagra

Pellagra is a recognizable disease caused predominantly by niacin deficiency.  Pellagra is extremely sevre, with its main symptoms popularly known as the four Ds: dermatitis, dementia, diarrhea, and death.  The disease has historically been associated with untreated corn.  Untreated corn has always been a cheap and common food source, but it does not provide adequate supplies of niacin unless treated with lime, which makes the nutrient accessible when ingested. 

Copper Deficiency

Copper deficiency is a disorder caused due to copper depletion from the body.  It is a fairly rare condition often caused by other nutrient imbalances, such as iron deficiency or an overuse of zinc, as opposed to malnutrition.  The symptoms of copper deficiency can be numerous and severe, and it is often linked to conditions such as anemia and pancytopenia, which is an overall decrease in blood cells and platelets.

Congenital Hypothyroidism

Congenital hypothyoridism is the most common, and most treatable, cause of mental retardation in the world.  The condition is a thryoid deficiency, commonly caused by genetics or iodine deficiency, where the thyroid does not produce enough of the hormone thyroxine.  Congenital hypothyroidism used to be a serious disorder, but it is easily caught by most prenatal screenings, and it can be easily treated after birth by inexpensive hormone treatment. 

Estrogen Deficiency

"Estrogen deficiency" can generally refer to two different conditions.  General estrogen deficiency occurs in premenopausal women due to a variety of causes, and can be the cause of a number of symptoms which can severely impair a woman's quality of life. Congenital estrogen deficiency is a rare type of genetic conditions that can effect men or women, and is noted by a body's inability to either recognize or produce estrogen. 

Scurvy

Scurvy is a disease infamous throughout human history, especially among sea travelers and soldiers, for its legacy of death.  Caused by a dietary deficiency of vitamin C, scurvy is actually quite rare today due to the relative abundance of vitamin C in the diet of most of the world's population.  It is also easily treatable, which is especially fortunate when considering scurvy's extremely severe symptoms and notoriously deadly reputation.