Module 4 - Malnutrition

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Inappropriate nutrient consumption can mean too much or too little of a nutrient. In the US we are primarily concerned about consuming too many calories (obesity), too little of some vitamins and minerals, and too little fiber. The US has some populations that are malnourished, but they are not always obvious. Worldwide, many countries have both populations that are obese and populations that have too few calories to be productive or, in severe cases, to survive. Malnutrition impairs both physical and mental health for individuals. For a community, it can mean low productivity, since malnourished individuals cannot contribute to production of food or development activities.

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PEM is a condition resulting from insufficient consumption of energy and protein. It reduces the body's ability to grow, repair tissue, and develop normally. Severe PEM results in wasting, starvation, and death. In many African languages there are two types of words for hunger. The first is hunger that goes away (mild), even when it is visible. The other is hunger that you cannot survive (severe).

Examples of hunger words that have become part of the international lexicon are:
Kwashiorkor--"the disease that the first child gets when the new child comes"
Marasmus--"to waste away"

Chronic hunger is visible, even when it is relatively mild, because individuals who survive are stunted (below normal height) and underweight (below normal weight for age). Internationally, these terms are applied largely to children under five years of age.

Hidden hungers are vitamin and mineral deficiencies. They are "hidden" because individuals do not necessarily look underweight. Instead, their bodies are unable to function efficiently or their development is impaired. The primary hidden hungers that we will examine are iron deficiency anemia (IDA), vitamin A deficiency (VAD), and iodine deficiency disorders (IDD).

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From this graph, it is easy to see that the majority of the world's undernourished populations are in Sub-Saharan Africa, East and Southeast Asia, and South Asia. There are also substantial numbers of undernourished individuals in Latin American and the Caribbean and the Near East and North Africa. These are aggregated worldwide data. They do not represent percentages of populations in individual countries who are hungry. For example, in Sub-Saharan Africa, which has about one-quarter of the world's chronically undernourished population, about 29% of the population is chronically undernourished. In South Asia, which has about one-third of the world's chronically undernourished population, about 18% of the population is chronically undernourished. [Note: Data for China are not included because the data are unavailable.]

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Stunting is failure to grow to normal height caused by chronic undernutrition during the formative years of childhood. Worldwide there are 215 million stunted children. Children from Asia make up about two-thirds of the stunted children worldwide. When these children emigrate to areas that are food-sufficient or that have food surpluses, they cannot "make up" their lost height, but they frequently have children who are much taller than they are because their children reach their genetic potentials. [Note: Data for China are not included because the data are unavailable.]

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Internationally, underweight is a term used to measure undernutrition in children under five years of age. It means that a child is seriously below normal weight for her/his age. In the US the term is used to describe an individual who is below the normal weight for his/her height, regardless of age.

Underweight is a marker for other nutrition problems, such as delayed development for organ systems and behaviors. Unlike height, individuals can add weight at any age. However, adding weight at a later age will not reverse developmental problems, and adding too much weight (especially as fat) is not healthy for adults.

About half of the underweight children worldwide are in South Asia, and about a quarter are in East Asia and Southeast Asia. [Note: Data for China are not included because the data are unavailable.]

LA & C--Latin America and the Caribbean
SA--South Asia
EA & SEA--East and Southeast Asia
NE & NA-Near East and North Africa
SSA--Sub-Saharan Africa

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Starvation follows wasting. There is not a clear dividing line between wasting and starvation.

All body processes require energy. Typically, energy is replace through the diet every day. The body stores most extra energy as fat, which it can use for muscular activity and to maintain body temperature. The body stores a small amount of energy as carbohydrate (glycogen). Liver glycogen helps to maintain blood glucose levels, and muscle glycogen helps to provide energy for short term use. Glycogen can be made only from carbohydrate or protein "fragments." The brain's primary energy source is carbohydrate, but most body tissues can use fat for energy.

• In starvation, the body depletes all energy reserves.
  • no dietary energy to support muscular activity, brain function, kidney function, immune function, etc.
  • no dietary energy to support tissue repair (or growth)
  • no fat to protect internal organs or to help maintain body temperature
  • blood glucose levels not maintained by short-term stores of carbohydrate (glycogen) in the liver

• Because there is no dietary energy, the body begins to breakdown its own tissue to increase chance of survival
  • heart muscle is compromised
  • diaphragm is compromised

In short, starvation first causes the body to shut down functions that are not required for survival. As starvation progresses, the body's systems shut down one-by-one, until it cannot support life. Also, since the immune system does not function without energy, it is likely that individuals who are starving are at greater risk for dying from infections, such as AIDS. In fact, an individual must have adequate nutrition for AIDS medicines (and many other medicines) to work effectively.

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The child on the left has kwashiorkor. Note the distended stomach, which is an indicator of wasted diaphragm muscle and parasite infestation. Also note the narrow shoulders and weak arms. One of the big needs in international nutrition is appropriate weaning foods so that children who have passed the breastfeeding stage have a high-nutrient food for their development.

The child on the right has marasmus, and died shortly after this picture was taken. Note that the child's arm is no thicker than the adult thumb (left-hand side of picture).

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Even when adequate protein and calories are available, vitamins and minerals are needed to support life. While deficiencies of any of the vitamins and minerals is a problem, there are three vitamin and mineral deficiencies that are critical problems worldwide. These are iodine deficiency disorders (IDD) vitamin A deficiency (VAD), and iron-deficiency anemia (IDA).

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Iodine is required to make thyroid hormones, which help regulate energy use and promote growth and development throughout the body, including the brain. Iodine Deficiency Disorder (IDD) is the world's most prevalent cause of brain damage. WHO estimates that IDD affects over 740 million people worldwide, with actual world incidence of goiter at approximately 200 million persons (US fewer than 500 persons, largely from medical conditions). Even adults who do not have goiter may have IDD symptoms, including fatigue and reduced intelligence (estimated by WHO as a loss of 15 IQ points).

The woman on the left has goiter, an enlargement of the thyroid gland that occurs in an individual if s/he does not have enough dietary iodine.

The child on the right has cretinism, a congenital condition that occurs in the fetus when a woman does not get enough iodine when she is pregnant. Cretinism occurs because development of the fetus is impaired. It is an irreversible syndrome characterized by mental deficiency, deaf mutism, a characteristic shuffling gait, shortened stature and hypothyroidism. Less severe variations of this syndrome may also exist, manifesting moderate retardation in intellectual or neuromotor maturation.

Soil and water contain varying amounts of iodine. Plants grown on iodine-poor soil are low in iodine. Goitrogens, substances occurring naturally in foods, can block absorption or utilization of iodine. Cabbage, turnips, rapeseeds, peanuts, cassava, and soybeans contain goitrogens. While these are not important problems in the US, they are important in international areas that rely on relatively few foods in limited diets. These substances are inactivated by cooking.

IDD is easy to prevent. In the US most salt is iodized to reduce risk of IDD. There are similar worldwide programs to supplement naturally-occurring iodine in foods. Progress in implementation of iodized salt programs worldwide has been impressive over the past decade. In the early 1990s approximately 1 in 5 households (20%) in developing countries had access to iodized salt; that figure is now 2 of every 3 households (67%). This is greater than a three-fold increase during a relatively short time.

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Iron is required for energy production and use. Iron deficiency is the most common cause of anemia worldwide. Iron-deficiency anemia is the most common nutritional disorder in the world. WHO estimates that as many as 2 billion people - over 30% of the world's population - are anemic, mainly due to iron deficiency. In developing countries, iron deficiency is frequently exacerbated by malaria and worm infections. In the US, approximately 3% of children aged 1-2 have iron- deficiency anemia, and approximately 2-5% of women of child-bearing age have iron-deficiency anemia.

The blood cell slide on the left shows iron-deficiency anemia. The blood cell slide on the right shows healthy blood cells. Note that the left-hand slide has fewer blood cells (less hemoglobin). Note also that the cells on the left-hand slide are not bright red. The bright red color is characteristic of healthy red blood cells.

• Iron has many functions in the body.
  • As part of hemoglobin, iron transports oxygen to cells and removes carbon dioxide from cells.
  • As a part of energy-releasing cytochrome, iron helps the body to use energy from carbohydrate, fat, and protein.
  • Iron is required for the synthesis of neurotransmitters that are required for brain function.
  • Iron is required to synthesize DNA, which is required to synthesize new cells.
  • Iron deficiency also impairs immune function.

Since iron is required to use energy, iron deficiency and anemia reduce the work capacity of individuals and entire populations, bringing serious economic consequences and obstacles to national development. WHO estimates that successful treatment of iron deficiency can raise national productivity levels by 20%.

Iron is present in both plant and animal-based foods. Heme iron from animal tissues is better absorbed than iron in plant foods. There is no iron in milk or milk products and very little iron in fruits. Sources of dietary iron vary greatly worldwide. In the US flesh foods contain about 5-10% of dietary iron, but 25% is absorbed. Non-heme plant sources contain 90-95% of dietary iron, but only 2-10% is absorbed. An otherwise adequate US diet usually contains no more than 6 mg iron/1000 kcal, making it difficult for individuals on low-calorie diets to get the iron they need without consuming an iron supplement.

In the US iron is added to grain-based foods as part of a special food fortification program called "enrichment." Worldwide, there are attempts to add iron to many different foods.

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Vitamin A Deficiency (VAD) is the leading cause of preventable blindness in children worldwide. WHO estimates that 100-140 million children have VAD and that 250,000-500,000 children with VAD go blind each year. About half of these children die within a year of going blind. VAD also raises the risk for disease and death from severe infection for all people. Individuals with VAD are more likely to die from measles, diarrheal diseases, and acute respiratory infections.

The individual pictured has xerophthalmia, the type of blindness caused by VAD. This blindness has early symptoms of night blindness, which can be reversed by consuming vitamin A. Later symptoms start with drying of the eye tissues and ulceration of the cornea. This damage is irreversible.

Vitamin A is required for development of specialized cells including those required for development of organ tissues and mucus-forming cells. Vitamin A is also required to support a healthy immune system.

Vitamin A is found in some animal products. It is found as carotenoids (yellow-red pigments) in plants. In the US we frequently fortify milk with vitamin A. Worldwide programs to combat VAD include supplementation, fortification of foods, and diversifying the diet.

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In general, the poor and displaced are the most susceptible to malnutrition. This is because they do not always have access to a healthful diet (or any food).

Individuals who have parasitic infections are at increased risk of malnutrition because the parasites "eat first," i.e., they have access to nutrients before they can be absorbed by the person they infect. Also, the parasites can cause damage to body tissues that must be repaired. This repairs requires extra energy and more vitamins and minerals.

Infants and children are at high risk because their body systems are developing, which requires more protein and energy per kg of body weight than is required by adults. Also, children do not have fully developed immune systems to protect them from illness; recovery from illness requires good nutrition. Appropriate weaning foods are a high priority for international health organizations.

Women of child-bearing years are at increased risk because of pregnancy. Pregnancy is a time of high nutrient need for the fetus and the mother. Many deficiencies present during pregnancy. Multiple pregnancies in a short time increase risk of nutrient deficiency in the mother.