Obesity is caused by eating too many calories compared to the amount of exercise the individual is performing, causing a distorted energy balance. It can lead to diseases such as cardiovascular disease and diabetes. Obesity is a condition in which the natural energy reserve, stored in the fatty tissue of humans and other mammals, is increased to a point where it is associated with certain health conditions or increased mortality.

The low-cost food that is generally affordable to the poor in affluent nations is low in nutritional value and high in fats, sugars and additives. In rich countries, therefore, obesity is often a sign of poverty and malnutrition while in poorer countries obesity is more associated with wealth and good nutrition. Other non-nutritional causes for obesity included: sleep deprivation, stress, lack of exercise, and heredity.

Acute overeating can also be a symptom of an eating disorder.

Goitrogenic foods can cause goitres by interfering with iodine uptake.

List of types of malnutrition or list of nutritional disorders include diseases that results from excessive or inadequate intake of food and nutrients. They come in two broad categories: undernutrition and overnutrition.

There are three commonly used measures for detecting malnutrition in children:

- stunting (extremely low height for age),

- underweight (extremely low weight for age), and

- wasting (extremely low weight for height).

These measures of malnutrition are interrelated, but studies for the World Bank found that only 9 percent of children exhibit stunting, underweight, and wasting.

Children with severe acute malnutrition are very thin, but they often also have swollen hands and feet, making the internal problems more evident to health workers.

Children with severe malnutrition are very susceptible to infection.

Protein–energy malnutrition (PEM) refers to a form of malnutrition which is defined as a range of pathological conditions arising from coincident lack of protein and/or energy in varying proportions.The condition vary in forms ranging from mild through moderate to severe degrees.

Types include:

- Kwashiorkor (protein malnutrition predominant)

- Marasmus (deficiency in calorie intake)

- Marasmic Kwashiorkor (marked protein deficiency and marked calorie insufficiency signs present, sometimes referred to as the most severe form of malnutrition)

PEM is fairly common worldwide in both children and adults and accounts for 6 million deaths annually. In the industrialized world, PEM is predominantly seen in hospitals, is associated with disease, or is often found in the elderly.

Note that PEM may be secondary to other conditions such as chronic renal disease or cancer cachexia in which protein energy wasting may occur.

Protein–energy malnutrition affects children the most because they have less protein intake. The few rare cases found in the developed world are almost entirely found in small children as a result of fad diets, or ignorance of the nutritional needs of children, particularly in cases of milk allergy.

Malnutrition in children – here understood as undernutrition – is common globally and results in both short and long term irreversible negative health outcomes including stunted growth which may also be linked to cognitive development deficits, underweight and wasting. The World Health Organization (WHO) estimates that malnutrition accounts for 54 percent of child mortality worldwide, about 1 million children. Another estimate also by WHO states that childhood underweight is the cause for about 35% of all deaths of children under the age of five years worldwide.

The main causes are unsafe water, inadequate sanitation or insufficient hygiene, factors related to society and poverty, diseases, maternal factors, gender issues and – overall – poverty.

Overnutrition or hyperalimentation is a form of malnutrition in which the intake of nutrients is oversupplied. The amount of nutrients exceeds the amount required for normal growth, development, and metabolism.

The term can also refer to:

- Obesity, which "usually" occurs by overeating, as well as:

- Oversupplying a "specific" nutrient, such as dietary minerals or vitamin poisoning. This is due to an excessive intake or a nutritional imbalance caused by fad diets.

For mineral excess, see:

- Iron poisoning, and

- Low sodium diet (a response to excess sodium).

Overnutrition may also refers to greater food consumption than appropriate, as well as other feeding procedures such as parenteral nutrition.

Wet beriberi affects the heart and circulatory system. It is sometimes fatal, as it causes a combination of heart failure and weakening of the capillary walls, which causes the peripheral tissues to become edematous. Wet beriberi is characterized by:

- Increased heart rate

- Vasodilation leading to decreased systemic vascular resistance, and high output cardiac failure

- Elevated jugular venous pressure

- Dyspnea (shortness of breath) on exertion

- Paroxysmal nocturnal dyspnea

- Peripheral edema (swelling of lower legs)

Dry beriberi causes wasting and partial paralysis resulting from damaged peripheral nerves. It is also referred to as endemic neuritis. It is characterized by:

- Difficulty in walking

- Tingling or loss of sensation (numbness) in hands and feet

- Loss of tendon reflexes

- Loss of muscle function or paralysis of the lower legs

- Mental confusion/speech difficulties

- Pain

- Involuntary eye movements (nystagmus)

- Vomiting.

A selective impairment of the large proprioceptive sensory fibers without motor impairment can occur and present as a prominent sensory ataxia, which is a loss of balance and coordination due to loss of the proprioceptive inputs from the periphery and loss of position sense.

Protein malnutrition is detrimental at any point in life, but protein malnutrition prenatally has been shown to have significant lifelong effects. During pregnancy, one should aim for a diet that consists of at least 20% protein for the health of the fetus. Diets that consist of less than 6% protein "in utero" have been linked with many deficits, including decreased brain weight, increased obesity, and impaired communication within the brain in some animals. Even diets of mild protein malnutrition (7.2%) have been shown to have lasting and significant effects in rats. The following are some studies in which prenatal protein deficiency has been shown to have unfavorable consequences.

- Decreased brain size: Protein deficiency has been shown to affect the size and composition of brains in rhesus monkeys. Monkeys whose mother had eaten a diet with an adequate amount of protein were shown to have no deficit in brain size or composition, even when their body weight amounted to less than one-half of that of the controls, whereas monkeys whose mothers had eaten low-protein diets were shown to have smaller brains regardless of the diet given after birth.

- Impaired neocortical long-term potentiation: Mild protein deficiency (in which 7.2% of the diet consists of protein) in rats has been shown to impair entorhinal cortex plasticity (visuospatial memory), noradrenergic function in the neocortex, and neocortical long-term potentiation.

- Altered fat distribution: Protein undernutrition can have varying effects depending on the period of fetal life during which the malnutrition occurred. Although there were not significant differences in the food intake, there were increased amounts of perirenal fat in rats that were protein-deprived during early (gestation days 0–7) and mid (gestation days 8–14) pregnancy, and throughout pregnancy, whereas rats that were protein-deprived only late in gestation (gestation days 15–22) were shown to have increased gonadal fat.

- Increased obesity: Mice exposed to a low-protein diet prenatally weighed 40% less than the control group at birth (intrauterine growth retardation). When fed a high-fat diet after birth, the prenatally undernourished mice were shown to have increased body weight and adiposity (body fat), while those who were adequately nourished prenatally did not show an increase in body weight or adiposity when fed the same high-fat diet after birth.

- Decreased birth weight, and gestation duration: Supplementation of protein and energy can lead to increased duration of gestation and higher birth weight. When fed a supplement containing protein, energy, and micronutrients, pregnant women showed more successful results during birth, including high birth weights, longer gestations, and fewer pre-term births, than women who had consumed a supplement with micronutrients and low energy but no protein (although this finding may be due to the increase of energy in the supplements, not the increase of protein).

- Increased stress sensitivity: Male offspring of pregnant rats fed low-protein diets have been shown to exhibit blood pressure that is hyperresponsive to stress and salt.

- Decreased sperm quality: A low-protein diet during gestation in rats has been shown to affect the sperm quality of the male offspring in adulthood. The protein deficiency appeared to reduce sertoli cell number, sperm motility, and sperm count.

- Altered cardiac energy metabolism: Prenatal nutrition, specifically protein nutrition, may affect the regulation of cardiac energy metabolism through changes in specific genes.

- Increased passive stiffness: Intrauterine undernutrition was shown to increase passive stiffness in skeletal muscles in rats.

From these studies it is possible to conclude that prenatal protein nutrition is vital to the development of the fetus, especially the brain, the susceptibility to diseases in adulthood, and even gene expression. When pregnant females of various species were given low-protein diets, the offspring were shown to have many deficits. These findings highlight the great significance of adequate protein in the prenatal diet.

Disease-related malnutrition can be considered in four categories:

Weight loss issues related to specific diseases include:

- As chronic obstructive pulmonary disease (COPD) advances, about 35% of patients experience severe weight loss called pulmonary cachexia, including diminished muscle mass. Around 25% experience moderate to severe weight loss, and most others have some weight loss. Greater weight loss is associated with poorer prognosis. Theories about contributing factors include appetite loss related to reduced activity, additional energy required for breathing, and the difficulty of eating with dyspnea (labored breathing).

- Cancer, a very common and sometimes fatal cause of unexplained (idiopathic) weight loss. About one-third of unintentional weight loss cases are secondary to malignancy. Cancers to suspect in patients with unexplained weight loss include gastrointestinal, prostate, hepatobilary (hepatocellular carcinoma, pancreatic cancer), ovarian, hematologic or lung malignancies.

- People with HIV often experience weight loss, and it is associated with poorer outcomes. Wasting syndrome is an AIDS-defining condition.

- Gastrointestinal disorders are another common cause of unexplained weight loss – in fact they are the most common non-cancerous cause of idiopathic weight loss. Possible gastrointestinal etiologies of unexplained weight loss include: celiac disease, peptic ulcer disease, inflammatory bowel disease (crohn's disease and ulcerative colitis), pancreatitis, gastritis, diarrhea and many other GI conditions.

- Infection. Some infectious diseases can cause weight loss. Fungal illnesses, endocarditis, many parasitic diseases, AIDS, and some other subacute or occult infections may cause weight loss.

- Renal disease. Patients who have uremia often have poor or absent appetite, vomiting and nausea. This can cause weight loss.

- Cardiac disease. Cardiovascular disease, especially congestive heart failure, may cause unexplained weight loss.

- Connective tissue disease

- Neurologic disease, including dementia

- Oral, taste or dental problems (including infections) can reduce nutrient intake leading to weight loss.

FTT may be evaluated through a multifaceted process, beginning with a patient history that notably includes diet history, which is a key element for identifying potential causes of FTT. Next, a complete physical examination may be done, with special attention being paid to identifying possible organic sources of FTT. This could include looking for dysmorphic features, abnormal breathing sounds, and signs of specific vitamin and mineral deficiencies. The physical exam may also reveal signs of possible child neglect or abuse. Based on the information gained from the history and physical examination, a workup can then be conducted, in which possible sources of FTT can be further probed, through blood work, X-rays, or other tests.

Unintentional weight loss may result from loss of body fats, loss of body fluids, muscle atrophy, or even a combination of these. It is generally regarded as a medical problem when at least 10% of a person's body weight has been lost in six months or 5% in the last month. Another criterion used for assessing weight that is too low is the body mass index (BMI). However, even lesser amounts of weight loss can be a cause for serious concern in a frail elderly person.

Unintentional weight loss can occur because of an inadequately nutritious diet relative to a person's energy needs (generally called malnutrition). Disease processes, changes in metabolism, hormonal changes, medications or other treatments, disease- or treatment-related dietary changes, or reduced appetite associated with a disease or treatment can also cause unintentional weight loss. Poor nutrient utilization can lead to weight loss, and can be caused by fistulae in the gastrointestinal tract, diarrhea, drug-nutrient interaction, enzyme depletion and muscle atrophy.

Continuing weight loss may deteriorate into wasting, a vaguely defined condition called cachexia. Cachexia differs from starvation in part because it involves a systemic inflammatory response. It is associated with poorer outcomes. In the advanced stages of progressive disease, metabolism can change so that they lose weight even when they are getting what is normally regarded as adequate nutrition and the body cannot compensate. This leads to a condition called anorexia cachexia syndrome (ACS) and additional nutrition or supplementation is unlikely to help. Symptoms of weight loss from ACS include severe weight loss from muscle rather than body fat, loss of appetite and feeling full after eating small amounts, nausea, anemia, weakness and fatigue.

Serious weight loss may reduce quality of life, impair treatment effectiveness or recovery, worsen disease processes and be a risk factor for high mortality rates. Malnutrition can affect every function of the human body, from the cells to the most complex body functions, including:

- immune response;

- wound healing;

- muscle strength (including respiratory muscles);

- renal capacity and depletion leading to water and electrolyte disturbances;

- thermoregulation; and

- menstruation.

In addition, malnutrition can lead to vitamin and other deficiencies and to inactivity, which in turn may pre-dispose to other problems, such as pressure sores.

Unintentional weight loss can be the characteristic leading to diagnosis of diseases such as cancer and type 1 diabetes.

In the UK, up to 5% of the general population is underweight, but more than 10% of those with lung or gastrointestinal diseases and who have recently had surgery. According to data in the UK using the Malnutrition Universal Screening Tool ('MUST'), which incorporates unintentional weight loss, more than 10% of the population over the age of 65 is at risk of malnutrition. A high proportion (10-60%) of hospital patients are also at risk, along with a similar proportion in care homes.

Failure to thrive (FTT), more recently known as faltering weight or weight faltering, is a term used in pediatric medicine, as well as veterinary medicine (where it is also referred to as ill-thrift), to indicate insufficient weight gain or inappropriate weight loss. When not more precisely defined, the term refers to pediatric patients. In children, it is usually defined in terms of weight, and can be evaluated either by a low weight for the child's age, or by a low rate of increase in the weight.

The term ‘failure to thrive’ has been used vaguely and in different contexts to refer to different issues in pediatric growth. It is most commonly used to describe a failure to gain weight, but some providers have also used it to describe a failure to grow, or a failure to grow and to gain weight. As used by pediatricians, it covers poor physical growth of any cause and does not itself imply abnormal intellectual, social, or emotional development, although it can subsequently be a cause of such pathologies. The term has been used in different ways, and different objective standards have been defined. FTT is suggested by a fall in one or more weight centile spaces on a WHO growth chart depending on birth weight or when weight is below the 2nd percentile of weight for age irrespective of birth weight. In children whose birth weight was between the 9th and 91st percentile FTT is indicated by a drop across 2 or more centile spaces. Weight loss after birth is normal and most babies return to their birth weight by 3 weeks of age. Clinical assessment for FTT is recommended for babies who lose more than 10% of their birth weight or do not return to their birth weight after 3 weeks.

Obesity in pets occurs when excessive adipose tissue accumulates in the body, and is generally defined as occurring when an animal's body weight is at least 20% greater than its optimal body weight. Obesity is associated with metabolic and hormonal changes.

Stunted growth, also known as stunting and nutritional stunting, is a reduced growth rate in human development. It is a primary manifestation of malnutrition (or more precisely undernutrition) and recurrent infections, such as diarrhea and helminthiasis, in early childhood and even before birth, due to malnutrition during fetal development brought on by a malnourished mother. The definition of stunting according to the World Health Organisation (WHO) is for the "height for age" value to be less than two standard deviations of the WHO Child Growth Standards median.

As of 2012 an estimated 162 million children under 5 years of age, or 25%, were stunted in 2012. More than 90% of the world's stunted children live in Africa and Asia, where respectively 36% and 56% of children are affected. Once established, stunting and its effects typically become permanent. Stunted children may never regain the height lost as a result of stunting, and most children will never gain the corresponding body weight. Living in an environment where many people defecate in the open due to lack of sanitation, is an important cause of stunted growth in children, for example in India.

Stunted growth in children has the following public health impacts apart from the obvious impact of shorter stature of the person affected:

- greater risk for illness and premature death

- may result in delayed mental development and therefore poorer school performance and later on reduced productivity in the work force

- reduced cognitive capacity

- Women of shorter stature have a greater risk for complications during child birth due to their smaller pelvis, and are at risk of delivering a baby with low birth weight

- Stunted growth can even be passed on to the next generation (this is called the "intergenerational cycle of malnutrition")

The impact of stunting on child development has been established in multiple studies. If a child is stunted at age 2 they will have higher risk of poor cognitive and educational achievement in life, with subsequent socio-economic and inter-generational consequences. Multi-country studies have also suggested that stunting is associated with reductions in schooling, decreased economic productivity and poverty. Stunted children also display higher risk of developing chronic non-communicable conditions such as diabetes and obesity as adults. If a stunted child undergoes substantial weight gain after age 2, there is a higher chance of becoming obese. This is believed to be caused by metabolic changes produced by chronic malnutrition, that can produce metabolic imbalances if the individual is exposed to excessive or poor quality diets as an adult. This can lead to higher risk of developing other related non-communicable diseases such as hypertension, coronary heart disease, metabolic syndrome and stroke.

At societal level, stunted individuals do not fulfill their physical and cognitive developmental potential and will not be able to contribute maximally to society. Stunting can therefore limit economic development and productivity, and it has been estimated that it can affect a country's GDP up to 3%.

Selenium deficiency in combination with Coxsackievirus infection can lead to Keshan disease, which is potentially fatal. Selenium deficiency also contributes (along with iodine deficiency) to Kashin-Beck disease. The primary symptom of Keshan disease is myocardial necrosis, leading to weakening of the heart. Kashin-Beck disease results in atrophy, degeneration and necrosis of cartilage tissue. Keshan disease also makes the body more susceptible to illness caused by other nutritional, biochemical, or infectious diseases.

Selenium is also necessary for the conversion of the thyroid hormone thyroxine (T4) into its more active counterpart, triiodothyronine, and as such a deficiency can cause symptoms of hypothyroidism, including extreme fatigue, mental slowing, goiter, cretinism, and recurrent miscarriage.

Weight gain will occur when an animal is in a positive energy balance, meaning energy provided as calories in the diet exceed calories expended. Evidence suggests that middle-aged cats and dogs, especially those between the ages of 5 and 10, may be at an increased risk of obesity. This is supported by studies showing that as cats age from 2 years to approximately 11.5 years of age their energy requirements decreased. Weight gain will occur if calories from the diet do not decrease with the animal’s energy requirements.

Obesity in pets is usually due to excessive food intake or lack of physical exercise. Owners may view food as a way to reward and treat their pets, which contributes to overfeeding. Pets confined to a house or small yard which are not regularly exercised are more prone to obesity.

The risk of obesity in dogs (but not in cats) is related to whether or not their owners are obese.

In cats, neutering increases the risk of obesity, partly because the alteration in sex hormones after neutering lowers the basal metabolic rate, and partly because neutered cats have a reduced inclination to roam compared to non-neutered cats.

In the months following birth, signs and symptoms will appear. Some symptoms will manifest gradually during childhood.

- Failure to gain weight

- Failure to thrive

- Diarrhea

- Foul-smelling feces, steatorrhea

- Impaired nervous system functions

- Decreased reflexes, hyporeflexia

Some prefer to classify malabsorption clinically into three basic categories:

1. selective, as seen in lactose malabsorption.

2. partial, as observed in abetalipoproteinaemia.

3. total, as in exceptional cases of coeliac disease.

Selenium deficiency is relatively rare in healthy well-nourished individuals. Few cases in humans have been reported.

Nutritional anemia refers to the low concentration of hemoglobin due to poor diet. According to the World Health Organization, a hemoglobin concentration below 7.5 mmol/L and 8. mmol/L for women and men, respectively, is considered to be anemic. Thus, anemia can be diagnosed with blood tests. Hemoglobin is used to transport and deliver oxygen in the body. Without oxygen, the human body cannot undergo respiration and create ATP, thereby depriving cells of energy.

Nutritional anemia is caused by a lack of iron, protein, B12, and other vitamins and minerals that needed for the formation of hemoglobin. Folic acid deficiency is a common association of nutritional anemia and iron deficiency anemia is the most common nutritional disorder.

Signs of anemia include cyanosis, jaundice, and easy bruising. In addition, anemic patients may experience difficulties with memory and concentration, fatigue, lightheadedness, sensitivity to temperature, low energy levels, shortness of breath, and pale skin. Symptoms of severe or rapid-onset anemia are very dangerous as the body is unable to adjust to the lack of hemoglobin. This may result in shock and death. Mild and moderate anemia have symptoms that develop slowly over time.[5] If patients believe that they are at risk for or experience symptoms of anemia, they should contact their doctor.

Treatments for nutritional anemia includes replacement therapy is used to elevate the low levels of nutrients.[1] Diet improvement is a way to combat nutritional anemia and this can be done by taking dietary supplements such as iron, folate, and Vitamin B12.[2] These supplements are available over-the-counter however, a doctor may prescribe prescription medicine as needed, depending on the patient’s health needs.

Internationally, anemia caused by iron deficiencies is the most common nutritional disorder. It is the only significantly prevalent nutritional deficiency disorder in industrialized countries. In poorer areas, anemia is worsened by infectious diseases such as HIV/AIDS, tuberculosis, hookworm infestation, and Malaria. In developing countries, about 40% of preschool children and 50% of pregnant women are estimated to be anemic. 20% of maternal deaths can be contributed to anemia. Health consequences of anemia include low pregnancy outcome, impaired cognitive and physical development, increased rate of morbidity, and reduced rate of work in adults.

'

Nutritional Anemia has many different causes, each either nutritional or non-nutritional. Nutritional causes are vitamin and mineral deficiencies and non-nutritional causes can be infections. The number one cause of this type of anemia however is iron deficiency.

An insufficient intake of iron, Vitamin B12, and folic acid impairs the bone marrow function.

The lack of iron within a person’s body can also stem from ulcer bacteria. These microbes live in the digestive track and after many years cause ulcer’s in the lining of your stomach or small intestine. Therefore, a high percentage of patients with nutritional anemia may have potential gastrointestinal disorder that causes chronic blood loss. This is common in immunocompromised, elderly, and diabetic people. High blood loss can also come from increases loss of blood during menstruation, childbirth, cancers of the intestines, and a disorder that hinders blood’s ability to coagulate.

Medications can have adverse effects and cause nutritional anemia as well. Medications that stop the absorption of iron in the gut and cause bleeding from the gut (NSAIDs and Aspirin) can be culprits in the development of this condition. Hydrocortisones and valproic acid are also two drugs that cause moderate bleeding from the gut. Amoxicillin and phenytoin are the ability to cause a vitamin B12 deficiency.

Other common causes are thyroid disorders, lead toxcities, infectious diseases (e.g Malaria), Alcoholism, and Vitamin E deficiency.

Symptoms

Symptoms of nutritional anemia can include fatigue and lack of energy. However if symptoms progress, one may experience shortness of breath, rapid pulse, paleness --especially in the hands, eyelids and fingernails---, swelling of ankles, hair loss, lightheadedness, compulsive and atypical cravings, constipation, depression, muscle twitching, numbness, or burning and chest pain.

Those who have nutritional anemia often show little to no symptoms. Often, symptoms can go undetected as mild forms of the anemia have only minor symptoms.

----[1] “Micronutrient deficiencies” World Health Organization. Accessed March 31, 2017. http://www.who.int/nutrition/topics/ida/en/

[2] "Ibid."

[3] "Ibid."

[4] "Ibid"

[5] "Ibid"

[6] "Ibid"

----[1] "Ibid".

[2] “Treatments for Nutritional anemia.” Right Diagnosis. Assessed March 31, 2017. http://www.rightdiagnosis.com/n/nutritional_anemia/treatments.htm

----[1] "Ibid".

[2] “What are the symptoms of anemia?” Health Grades, INC. Accessed March 31, 2017. https://www.healthgrades.com/conditions/anemia--symptoms.

[3] "Ibid."

[4] "Ibid."

[5] "Ibid."

[6] "Ibid"

----[1] "Ibid".

[2] "Ibid".

----[1] "Nutritional Anemia." The Free Dictionary. Accessed March 31, 2017. http://medical-dictionary.thefreedictionary.com/nutritionalanemia.

[2] "Ibid".

[3] "Ibid".

[4] "Ibid".

Nutritional anemia refers to types of anemia that can be directly attributed to nutritional disorders.

Examples include Iron deficiency anemia and pernicious anemia.

It is often discussed in a pediatric context.

Substantial numbers of patients with intestinal malabsorption present initially with symptoms or laboratory abnormalities that point to other organ systems in the absence of or overshadowing symptoms referable to the gastrointestinal tract. For example, there is increasing epidemiologic evidence that more patients with coeliac disease present with anemia and osteopenia in the absence of significant classic gastrointestinal symptoms. Microcytic, macrocytic, or dimorphic anemia may reflect impaired iron, folate, or vitamin B12 absorption. Purpura, subconjunctival hemorrhage, or even frank bleeding may reflect hypoprothrombinemia secondary to vitamin K malabsorption. Osteopenia is common, especially in the presence of steatorrhea. Impaired calcium and vitamin D absorption and chelation of calcium by unabsorbed fatty acids resulting in fecal loss of calcium may all contribute. If calcium deficiency is prolonged, secondary hyperparathyroidism may develop. Prolonged malnutrition may induce amenorrhea, infertility, and impotence. Edema and even ascites may reflect hypoproteinemia associated with protein losing enteropathy caused by lymphatic obstruction or extensive mucosal inflammation. Dermatitis and peripheral neuropathy may be caused by malabsorption of specific vitamins or micronutrients and essential fatty acids.

Pagophagia is the compulsive consumption of ice or iced drinks.

It is a form of the disorder pica. It has been associated with iron deficiency anemia, and shown to respond to iron supplementation,

leading some investigators to postulate that some forms of pica may be the result of nutritional deficiency. Chewing ice may lessen pain in glossitis related to iron deficiency anemia. However, the American Dental Association recommends not chewing ice because it can crack teeth; instead ice should be allowed to melt in the mouth.

Folk wisdom (and some early investigators) maintained that pica reflected an appetite to compensate for nutritional deficiencies, such as low iron or zinc. Some forms of pica (as in pregnant women who are iron deficient) can be treated by supplementing the nutrient.

Later research has demonstrated that the substances ingested generally do not provide the mineral or nutrient in which patients are deficient. As the people start eating nonfoods, pica can also cause the nutritional deficiencies with which it is associated. In one case study, pagophagia was reported to "cause" iron deficiency anemia. At the same time, however, the researchers suggested that chewing ice may benefit stomatitis and glossitis. The nutrients obtained from nonfoods such as soil or ice will vary widely depending on geographic location. For example, ice made from hard water will contain more minerals, especially calcium and magnesium, but simply drinking the water will provide the same minerals.

The word derives from Greek: pagos, frost, + phagō, to eat.

In equids, it is most common in the first twelve months of life. Neonatal foals born to dams that are selenium-deficient often develop the condition. There are two forms: peracute, and subacute. The peracute form is characterized by recumbency, tachypnea, dyspnea, myalgia, cardiac arrhythmias, and rapid death. The subacute form causes weakness, fasciculations, cramping, and stiffness of muscles, which can lead to recumbency, as well as a stilted gait, dysphagia, ptyalism, and a weak suckle. It may be treated with selenium supplementation, but there is a 30–45% mortality rate. Other sequelea include aspiration pneumonia, failure of passive transfer, and stunting of growth.

Clinical laboratory changes include evidence of rhabdomyolysis (elevated CK and AST, myoglobinuria) and low blood selenium levels. On necropsy, muscles are pale with areas of necrosis and edema evidenced as white streaks.