Diseases resulting from nutrient deficiencies

Nutrient deficiencies are a form of malnutrition, whereby an individual has a lack of nutrients necessary for the body to function normally. This may be a lack of macronutrients (sugars, fats, proteins) or a lack of some more specific nutrients (vitamins, trace elements, essential fatty acids, etc...).

Marasmus
Simple starvation (marasmus) is mainly caused by a lack of energy (energy malnutrition). It occurs due to the long-term insufficient intake of all nutrients and manifests as a typical gradual symmetric weight loss. This leads to a general weakening of the organism: cachexia. There is a breakdown of fat and glycogen stores and ultimately also a breakdown of active muscle mass and body proteins. It affects individuals with anorexia nervosa, elderly people, and otherwise healthy people who have reduced energy intake.

Kwashiorkor
Much more severe stress starvation causes poor intake and rapid protein breakdown (protein malnutrition). Muscle mass is rapidly broken down, fat reserves are preserved, so the affected people do not show signs of malnutrition at first sight. Lack of protein (so-called hypoproteinemia) causes edema. It is protein-energy malnutrition with a predominant lack of protein (unlike marasmus, in which a lack of overall energy intake predominates). Kwashiorkor is a severe form of malnutrition that occurs in young children in developing countries, characterized by, among other things, edema.

However, the authors of a number of studies published since 1968 reject the hypothesis of protein deficiency as the etiology of kwashiorkor because: Several other hypotheses were then postulated on the etiology of kwashiorkor (excess free radicals, aflatoxin, changes in the intestinal microflora, in which malnutrition produces metabolites that damage cell cell membranes, lack of vanadium, a combination of some of these factors), but none of them have been confirmed: its etiology is still unclear. According to the current pathophysiological concept, cell membranes are damaged throughout the body, leading to leakage of potassium and water from cells of all types and dysfunction of all organ systems. Loss of the ability of glycosaminoglycans to bind water is thought to be a potential mechanism for the development of edema.
 * The same diet with insufficient macro and micronutrients led to the development of marasmus in some children in the same area, while in others kwashiorkor developed.
 * Children recovered on a diet with less protein than expected to lead to kwashiorkor, with edema disappearing, but low serum albumin levels (thought to be the cause of the edema) persisting.
 * Kwashiorkor has also been described in exclusively breastfed infants receiving high quality protein from their mothers who did not show any signs of malnutrition..

Protein-energy malnutrition
According to the FAO, 925 million people worldwide suffer from protein-energy malnutrition (PEM), most in Asia Pacific, most often in sub-Saharan Africa (30%). It affects a quarter of children under 5 in the world and is associated with 30% of deaths in children under five in developing countries. Malnutrition is a relatively rare cause of death in children. At the beginning of the malnutrition spiral is an inadequate diet and frequent episodes of common infectious diseases. During the course of the disease, the child's nutritional status deteriorates, which contributes to the increased risk of another episode of the infection, which is more severe and during which the nutritional status deteriorates further. The situation recurs when a malnourished child has a fatal infectious episode.

In more developed countries, malnutrition occurs mainly in the seriously ill, the elderly, and people experiencing anorexia nervosa.

Fat-soluble vitamins

 * Vitamin A deficiency
 * Vitamin A is especially important for sharp eyesight at night. Vitamin A administration in deficiency can significantly improve vision in a few hours. Vitamin A deficiency is a significant problem, especially in developing countries. The major risk groups are young children, and pregnant and lactating women .
 * Manifestations of deficiency include xerophthalmia (dry eyes), age spots, susceptibility to respiratory infections, acne, eczema, loss of appetite, fatigue, and loss of smell. Diseases that occur with a prolonged deficiency of this vitamin are night blindness and conjunctivitis.


 * Vitamin D deficiency
 * If it occurs during childhood (especially in young children) and infancy, it manifests itself as rickets. This occurs due insufficient intake of vitamin D (e.g., it is low in breastmilk, low sun exposure), which is necessary for these periods of rapid growth.
 * Rickets occurs on all continents, but global prevalence is unknown. It occurs mostly in high altitudes (e.g., in Mongolia, 70% of children are affected. This figure is 66% in Tibet.) and in areas where social or religious customs prevent exposure to the sun (the Middle East, some countries in Africa, India): this is more common in the Muslim community when compared to the Hindu community. In temperate zones, there is a higher risk of rickets in dark-skinned populations (African Americans, Asian community in Europe, Australia).
 * In recent years, subclinical vitamin D deficiency - low levels of 25OHD - has attracted attention, especially in relation to possible other roles of vitamin D in the human body. Subclinical vitamin D deficiency is described in a significant percentage of the population in both North America and Europe, but the American Institute of Medicine points to the lack of a general consensus on adequate plasma 25OHD levels and thus the possibility of overestimating the prevalence of the deficiency in the population.

Water soluble vitamins

 * Vitamin B1 deficiency
 * Manifestations of this deficiency include inability to concentrate, fatigue, loss of appetite, heart rhythm disorders, constipation, difficulty breathing, depression, and sleep disorders

Manifestations of this deficiency include red, inflamed tongue, small cracks in the corners of the mouth, burning, reddened, tired eyes, chapped lips, oily hair, flaking of the skin on the nose, mouth, forehead and earlobes, hair loss, and limb tremors. Manifestations of this deficiency include fatigue, persistent nervousness, depression, tingling in the hands and feet, difficulty walking, and inflammation in the mouth. A common consequence of vitamin B12 deficiency is the development of macrocytic anemia.
 * Vitamin B2 deficiency
 * Vitamin B12 deficiency

Iron deficiency
The most common type of malnutrition in the world. The main manifestation is the development of sideropenic anemia. It occurs in both developing and developed countries. In 2002, the WHO identified anemia as one of the most significant contributors to the global disease burden. . The association of severe anemia with increased infant and maternal mortality, and the negative impact of anemia on children's cognitive and physical development and adult productivity have been demonstrated.

According to a WHO assessment in 2008, anemia, measured by hemoglobin level, affects 1.62 billion people, a quarter of the world's population, most often young children (47.4%), and less often men (12.7%), with women representing the greatest percentage of total affected individuals. The highest prevalence of anemia is in Africa (47.5-67.6% of the population), but the majority of affected individuals are in Southeast Asia.

Anemia has a number of causes that can be combined. On a global scale, the most common iron deficiency is due to its insufficient intake, poor absorption of non-heme iron, and increased need for iron (growth, pregnancy). Other causes are blood loss (menstruation, infestation Ankylostoma duodenale, Necator americanus, Ascaris lumbricoides, schistosomiasis, minor bleeding from the GIT). Acute and chronic infections (malaria, cancer, TB and HIV) also reduce hemoglobin levels.

In developing countries, the causes are often compounded by a lack of other micronutrients (vitamin A, folic acid, vitamins B2,  B12, copper) and in some areas also hemoglobinopathies (e.g., sickle cell disease).

Risk groups for the development of iron deficiency anemia are mainly low birth weight infants (insufficient iron supply), children from half a year to two years of age, women of childbearing age, especially pregnant women, and seniors.

Rich sources of iron include meat and offal (heme iron - 20-30% is absorbed), as well as cereals, tuberous and root crops, legumes, nuts, eggs, and leafy vegetables (non-heme iron - less than 5% is absorbed). Breast milk is also an important source of iron - the relative proportion of iron in it is small, but its up to 50% is absorbed. Iron deficiency results in hypochromic microcytic anemia, which leads to a reduction in oxygen delivery to the tissues. Its symptoms include increased fatigue, shortness of breath, pale skin and mucous membranes, hair loss, and koilonychia.

Zinc deficiency
The importance of zinc for the nutritional status of humans has only recently been recognized. Significant zinc deficiency is rare, but a mild deficit is estimated to affect about 20% of the world's population (9% in the US and Canada, 33% in Southeast Asia). The risk of deficiency is highest in infants and young children, and pregnant and lactating women. Globally, it is estimated that 80% of pregnant women and 100% of people in developing countries have a zinc intake lower than is considered necessary.

Mild zinc deficiency is associated with decreased immunity, failure to thrive, and growth retardation. Clinical studies in developing countries show that zinc administration reduces the morbidity and mortality of common childhood infectious diseases (gastroenteritis, pneumonia, malaria) and improves the growth of malnourished children. WHO recommends the administration of zinc as part of the treatment of diarrheal diseases.

''There are generally a number of possibilities in the categorization of pathological conditions, and the choice of one particular method of categorization depends on the purpose for which it is to be used. In the International Classification of Diseases  for epidemiological purposes, diseases caused by a lack or excess of nutrients are classified into different groups:''


 * Diseases of the blood, hematopoietic organs and certain disorders involving the immune system


 * D50-D53 Nutritional anemias


 * Endocrine, nutritional and metabolic diseases


 * E00-E07 Disorders of thyroid gland (iodine deficiency disorders)
 * E40-E46 Malnutrition - malnutrition (kwashiorkor, nutritional marasmus, marasmic kwashiorkor and protein-energy malnutrition)
 * E50-E64 Other nutritional deficiencies (deficiencies of vitamins, minerals, and trace elements)
 * E65-E68 Obesity and other hyperalimentation (obesity, vitamin excess)

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