Malnutrition

Anatomy or system affected: Gastrointestinal system, intestines, nails, stomach, all bodily systems

Definition: Impaired health caused by an imbalance, either through deficiency or excess, in nutrients

Causes and Symptoms

Malnutrition literally means “bad nutrition.” It can be used broadly to mean an excess or deficiency of the nutrients that are necessary for good health. In industrialized societies, malnutrition typically represents the excess consumption characterized by a diet containing too much energy (kilocalories) and sodium. Malnutrition is most commonly understood, however, to refer to undernutrition or deficient intake, the consumption of inadequate amounts of nutrients to promote health or to support growth in children. The most severe form of undernutrition is called protein energy malnutrition, or PEM. It commonly affects children, who require nutrients not only to help maintain the body but also to grow. Two types of PEM occur: kwashiorkor and marasmus.

Kwashiorkor is a condition in which a person consumes adequate energy but not enough protein. Kwashiorkor occurs most commonly in areas where there is famine, perhaps due to drought, natural disaster, war, or political unrest, but it can also occur among people with low levels of education.

Diets in many low-income countries are high in bulk, making it nearly impossible for a child to consume a sufficient volume of foods to obtain an adequate amount of protein for growth. The outward signs of kwashiorkor are a potbelly, dry unpigmented skin, coarse reddish hair, low muscle mass, lethargy, failure to grow, and edema in the legs. Edema results from a lack of certain proteins in the blood that help to maintain a normal fluid balance in the body. Other signs requiring further medical testing include fat deposits in the liver and decreased production of digestive enzymes. The mental and physical growth of the child are impaired. Children with kwashiorkor are apathetic, listless, and withdrawn. Ironically, these children lose their appetites. They become very susceptible to upper respiratory infection and diarrhea. Children with kwashiorkor also are deficient in vitamins and minerals that are found in protein-rich foods. There are symptoms caused by these specific nutrient deficiencies as well.

Marasmus literally means “to waste away” and is an acute form of malnutrition. It is caused by a deficiency of both calories and protein in the diet. This is the most severe form of childhood malnutrition. Body fat stores are used up to provide energy, and eventually, muscle tissue is broken down for body fuel. Victims appear as skin and bones, gazing with large eyes from a bald head with an aged, gaunt appearance. Once severe muscle wasting occurs, death is imminent. Body temperature is below normal. The immune system does not operate normally, making these children extremely susceptible to respiratory and gastrointestinal infections.

A vicious cycle develops once the child succumbs to infection. Infection increases the body’s need for protein, yet the child is so protein deficient that recovery from even minor respiratory infections is prolonged. Pneumonia and measles become fatal diseases for PEM victims. Severe diarrhea compounds the problem. The child is often dehydrated, and any nourishment that might be consumed will not be adequately absorbed.

The long-term prognosis for these PEM children is poor. If the child survives infections and is fed, PEM returns once the child goes home to the same environment that caused it. Children with repeated episodes of kwashiorkor have high mortality rates.

Children with PEM are most likely victims of famine. Typically, these children either were not breastfed or were breastfed for only a few months. If a weaning formula is used, it has not been prepared properly; in many cases, it is mixed with unsanitary water or watered down because the parents cannot afford to buy enough to use it at full strength.

It can be difficult to distinguish between the cause of kwashiorkor and that of marasmus. One child ingesting the same diet as another may develop kwashiorkor, while the other may develop marasmus. Some scientists think this may be a result of the different ways in which individuals adapt to nutritional deprivation. Others propose that kwashiorkor is caused by eating moldy grains since it appears in rainy, tropical areas.

Vitamin and Mineral Deficiencies

Another type of malnutrition involves a deficiency of vitamins or minerals. Vitamin A is necessary for the maintenance of healthy skin, and even a mild deficiency causes susceptibility to diarrhea and upper respiratory infection. Diarrhea reinforces the vicious cycle of malnutrition since it prevents nutrients from being absorbed. With a more severe vitamin A deficiency, changes in the eyes and, eventually, blindness result. Night blindness is usually the first detectable symptom of vitamin A deficiency. The blood that bathes the eye cannot regenerate the visual pigments needed to see in the dark. Vitamin A deficiency, the primary cause of childhood blindness, can result from the lack of either vitamin A or the protein that transports it in the blood. If the deficiency of vitamin A occurs during pregnancy or at birth, the skull does not develop normally, and the brain is crowded. An older child deficient in vitamin A will suffer growth impairment.

Diseases resulting from B-vitamin deficiencies are more rare. Vegans, who consume no animal products, are at risk for vitamin B12 deficiency resulting in anemia in which the red blood cells are large and immature. A folic acid or folate deficiency in the diet can cause similar anemia. Beriberi is the deficiency disease of thiamine (vitamin B1) in which the heart and nervous systems are damaged, and muscle wasting occurs. Ariboflavinosis (lack of riboflavin) describes a collection of symptoms such as cracks and redness of the eyes and lips; inflamed, sensitive eyelids; and a purple-red tongue. Pellagra is the deficiency disease of niacin (vitamin B₃). It is characterized by “the Four Ds of pellagra”: dermatitis, diarrhea, dementia, and death. Isolated deficiency of a B vitamin is rare since many B vitamins work in concert. Therefore, a lack of one hinders the function of the rest.

Scurvy is the deficiency disease of vitamin C. Early signs of scurvy are bleeding gums and pinpoint hemorrhages under the skin. As the deficiency becomes more severe, the skin becomes rough, brown, and scaly, eventually resulting in impaired wound healing, soft bones, painful joints, and loose teeth. Finally, hardening of the arteries or massive bleeding results in death.

Rickets is the childhood deficiency disease of vitamin D. Bone formation is impaired, which is reflected in a bowlegged or knock-kneed appearance. In adults, a brittle bone condition called osteomalacia results from vitamin D deficiency. Vitamin D deficiency is common among individuals who do not get enough sunlight and do not take vitamin D supplements. Symptoms of vitamin D deficiency are often subtle and can include tiredness and aches and pains.

Malnutrition of minerals is more prevalent since deficiencies are observed in both industrialized and developing countries. Calcium malnutrition in young children results in stunted growth. Osteoporosis occurs when calcium reserves are drawn upon to supply the other body parts with calcium. This occurs in later adulthood, leaving bones weak and fragile. General loss of stature and fractures of the hip, pelvis, and wrist are common, and a humpback appears. Caucasian and Asian women of small stature are at greatest risk for osteoporosis.

Iron-deficiency anemia is the most common form of malnutrition in developing societies. Lack of consumption of iron-rich foods is common among the poor, and this problem is compounded by iron loss in women who menstruate and who thus lose iron monthly. This deficiency, which is characterized by small, pale red blood cells, causes weakness, fatigue, and sensitivity to cold temperatures. Anemia in children can cause reduced ability to learn and impaired ability to think and concentrate.

Deficiencies of other minerals are less common. Although these deficiencies are usually seen among people in developing nations, they may occur among the poor, pregnant people, children, and the elderly in industrialized societies. Severe growth retardation and arrested sexual maturation are characteristics of zinc deficiency. With iodine deficiency, the cells in the thyroid gland enlarge to try to trap as much iodine as possible. This enlargement of the thyroid gland is called simple or endemic goiter. A more severe iodine deficiency results from a lack of iodine that leads to a deficiency of thyroid hormone during pregnancy. The child of a pregnant person with such a deficiency can be born with severe mental and/or physical disability, a condition known as congenital hypothyroidism (and formerly as cretinism). Proper nutrition during pregnancy is crucial for the health of the baby. For example, a low dietary intake of folic acid in the first trimester of pregnancy was found to be a leading cause of neural tube defects. After this discovery, the US government mandated the fortification of enriched cereal grain products with folic acid in 1998. Subsequently, the birth prevalence of neural tube defects significantly declined in the United States.

The causes of malnutrition can be difficult to isolate because nutrients work together in the body. In addition, the underlying causes of malnutrition (poverty, famine, and war) often are intractable and, therefore, untreatable.

Treatment and Therapy

Treatment for PEM involves refeeding with a diet adequate in protein, calories, and other essential nutrients. Response to treatment is influenced by many factors, such as the person’s age, the stage of development in which the deprivation began, the severity of the deficiency, the duration of the deficiency, and the presence of other illnesses, particularly infections. Total recovery is possible only if the underlying cause that led to PEM can be eliminated.

Prevention of PEM is the preferred therapy. In areas with unsafe water supplies and high rates of poverty, breastfeeding should be encouraged whenever possible. Education about proper weaning foods provides further defense against PEM. Other preventive efforts involve combining plant proteins into a mixture of high-quality protein, adding nutrients to cereal products, and using genetic engineering to produce grains with a better protein mix. The prevention of underlying causes such as famine and drought may not be feasible.

Prekwashiorkor can be identified by regular plotting of the child’s growth. If treatment begins at this stage, the patient response is rapid, and the prognosis is good. Treatment must begin by correcting the body’s fluid imbalance. Low potassium levels must be corrected. Restoration of fluid is followed by adequate provision of calories, with gradual additions of protein that the patient can use to repair damaged immune and digestive systems. Treatment must happen rapidly yet allow the digestive system to recover—thus the term “hurry slowly.” Once edema is corrected and blood potassium levels are restored, a diluted milk with added sugar can be given. Gradually, vegetable oil is added to increase the intake of calories. Vitamin and mineral supplements are given. Final diet therapy includes a diet of milk and other animal protein sources, coupled with the addition of vegetables and fat.

The residual effects of PEM may be great if malnutrition has come at a critical period in development or has been of long duration. In prolonged cases, damage to growth and the digestive system may be irreversible. Mortality is very high in such cases. Normally, the digestive tract undergoes rapid cell replacement; therefore, this system is one of the first to suffer in PEM. Absorptive surfaces shrink, and digestive enzymes and protein carriers that transport nutrients are lacking.

Another critical factor in the treatment of PEM is the stage of development in which the deprivation occurs. Most PEM victims are children. If nutritional deprivation occurs during pregnancy, the consequence is increased risk of infant death. If the child is carried to term, it is of low birth weight, placing it at high risk for death. Malnutrition during lactation decreases the quantity, but not always the nutritional quality, of milk. Thus, fewer calories are consumed by the baby. Growth of the child is slowed. These babies are short for their age and continue to be shorter later in life, even if their diet improves.

During the first two years of life, the brain continues to grow. Nutritional deprivation can impair mental development and cognitive function. For only minimal damage to occur, malnutrition must be treated in early stages. Adults experiencing malnutrition are more adaptive to it since their protein energy needs are not as great. Weight loss, muscle wasting, and impaired immune function occur, and malnourished women stop menstruating (amenorrhea).

Successful treatment of a specific nutrient deficiency depends on the duration of the deficiency and the stage in a person’s development at which it occurs. Vitamin A is a fat-soluble vitamin that is stored in the body. Thus, oral supplements or injections of vitamin A can provide long-term protection from this deficiency. If vitamin A is given early enough, the deficiency can be rapidly reversed. By the time the patient is blind, sight cannot be restored, and frequently the patient dies because of other illnesses. Treatment also is dependent upon adequate protein to provide carriers in the blood to transport these vitamins. Treatment of the B-vitamin deficiencies involves oral and intramuscular injections. The crucial step in treatment is to initiate therapy before irreversible damage has occurred. Scurvy (vitamin C deficiency) can be eliminated in five days by administering the amount of vitamin C found in approximately three cups of orange juice. Treatment of vitamin D deficiency in children and adults involves an oral dose of two to twelve times the recommended daily allowance of the vitamin. Halibut and cod liver oils are frequently given as vitamin D supplements.

Successful treatment of a mineral deficiency depends on the timing and duration of the deficiency. Once the bones are fully grown, restoring calcium to optimal levels will not correct short stature. To prevent osteoporosis, bones must have been filled to the maximum with calcium during early adulthood. Estrogen replacement therapy and weight-bearing exercise retard calcium loss in later years and do more than calcium supplements can.

Iron supplementation is necessary to correct iron-deficiency anemia. Iron supplements are routinely prescribed for pregnant people to prevent anemia during pregnancy. Treatment also includes a diet with adequate meat, fish, and poultry to provide not only iron but also a factor that enhances absorption. Iron absorption is also enhanced by vitamin C. Anemias caused by lack of folate and vitamin B12 will not respond to iron therapy. These anemias must be treated by adding the appropriate vitamin to the diet.

Zinc supplementation can correct arrested sexual maturation and impaired growth if it is begun in time. In areas where the soil does not contain iodine, iodine is added to salt, or injections of iodized oil are given to prevent goiter. Congenital hypothyroidism is easily treated with the hormone thyroxine if caught early enough, and most developed countries screen for the condition in newborns. If untreated for too long, the physical and mental symptoms become permanent.

In general, malnutrition is caused by a diet of limited variety and quantity. The underlying causes of malnutrition—poverty, famine, and war—are often intractable. Overall treatment lies in prevention by providing all people with a diet that is adequate in all nutrients, including vitamins, minerals, and calories. Sharing the world’s wealth and ending political strife and food waste are essential elements of the struggle to end malnutrition.

Perspective and Prospects

Historically, the focus of malnutrition studies was deficiencies in the diet. In the 1930s, classic kwashiorkor was described by Cicely Williams. Not until after World War II was it known that kwashiorkor was caused by a lack of protein in the diet. In 1959, Derrick B. Jelliffe introduced the term protein-calorie malnutrition to describe the nutritional disorders of marasmus, marasmic kwashiorkor, and kwashiorkor.

PEM remains one of the most important public health problems in low-income countries, with comparatively few cases seen in highly developed societies. Historically, the root causes have been urbanization, periods of famine, and the failure to breastfeed or early cessation of breastfeeding. Marasmus is more prevalent in urban areas among infants under one year old, while kwashiorkor is prevalent in rural areas during the second year of life. Severe undernutrition also continues to be linked to societal upheaval, from wars to the restrictions put in place to combat the coronavirus disease 2019 (COVID-19) global pandemic.

Deficiencies of specific nutrients have been documented throughout history. Vitamin A deficiency and its cure were documented by Egyptians and Chinese around 1500 BCE. In occupied Denmark during World War I, vitamin A deficiency caused by dairy product deprivation was common in Danish children. Beriberi, first documented in Asia, was caused by diets of polished rice that were deficient in thiamine. Pellagra was seen in epidemic proportions in the southern United States, where corn was the staple grain, during World War I. Zinc deficiency was first reported in the 1960s. The growth and maturation of boys in the Middle East were studied; their diets were low in zinc and high in substances that prevented zinc absorption. Consequently, the World Health Organization recommended increased zinc intake for populations whose staple is unleavened whole-grain bread. Goiter was documented as far back as Julius Caesar’s reign. Simply adding iodine to salt has virtually eliminated goiter in the United States.

If classic malnutrition is observed in industrialized societies, it usually is secondary to other diseases, such as AIDS and cancer. Hunger and poverty are problems that contribute to malnutrition; however, the malnutrition that results is typically less severe than that found in developing countries. Nevertheless, malnutrition does occur in the United States at a consistently higher rate than it does in many other developed countries; the annual rate of death by malnutrition in the country in 2019 was about 0.89 people in every 100,000, while in the United Kingdom, for instance, it was 0.09 in 100,000. Children and older adults are particularly affected; according to the Centers for Disease Control and Prevention (CDC), killing at least one in 10,000 older individuals in the United States each year. Johns Hopkins Medicine has estimated that 1 percent of children in the United States suffer from chronic malnutrition, which can weaken the immune system and render childhood illnesses more likely to be fatal. According to the nonprofit Feeding America, 34 million people in the United States suffered from food insecurity in the early 2020s due to societal issues, such as the lingering effects of the COVID-19 and economic factors, including inflation and its effect on raising food prices.

Specific nutrients may be lacking in the diets of poor individuals. Iron-deficiency anemia is prevalent among the poor, and this anemia may impair learning ability. Other deficiencies may be subclinical, which means that no detectable signs are observed, yet normal nutrient pools in the body are depleted. Homelessness, poverty, and drug or alcohol abuse are the major contributing factors to these conditions. In addition, malnutrition as a result of poverty is exacerbated by lack of nutritional knowledge and/or poor food choices.

One of the most significant developments in the study of malnutrition is that it has shifted to include the excessive intake of nutrients. While in developing countries, the primary causes of death are infectious diseases, and undernutrition is a risk factor, in industrialized societies, the primary causes of death are chronic diseases, and overnutrition is a key risk factor. In particular, overnutrition in terms of too much fat and calories in the diet leads to overweight and obesity, which have been described as an epidemic in many societies. This kind of malnutrition can also increase rates of high blood pressure, stroke, heart disease, some cancers, liver disease, and type 2 diabetes. The excessive consumption of sugar is also linked to numerous health problems, including diabetes and tooth decay.

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