Malnutrition may be the result of poor diet or overeating. Both conditions are caused by an imbalance between the need and the body intake of essential nutrients. 


It is a deficiency of essential nutrients and may be the result of an insufficient intake due to poor diet; a bowel malabsorption of ingested food (malabsorption); abnormally high consumption of nutrients by the body; or excessive loss of nutrients through processes such as diarrhea, bleeding (hemorrhage), renal failure. 

Over nutrition 

It is an excess of essential nutrients and may be the result of overeat (excessive intake); or excessive use of vitamins or other supplements. 

Malnutrition develops in stages: changes in the concentration of nutrients in the blood and tissues occurs first, then changes occur in the levels of enzymes, then passes to occur malfunction of organs and tissues of the body and then disease symptoms appear and can occur death. 

The body needs more nutrients during certain stages of life, especially in childhood and adolescence; during pregnancy; and while the mother is breastfeeding. In old age the food needs are smaller, but the ability to absorb nutrients is also often reduced. Thus, the risk of malnutrition is higher in these stages of life, and even more between economically deprived people. 

Nutritional assessment 

To assess the nutritional status of a person, the doctor needs to know the diet and medical problems that may exist, perform a physical exam, and sometimes require laboratory tests - blood levels of nutrients and substances that depend on the levels of these nutrients (such as hemoglobin, thyroid hormones and transferring) can be measured. 

To determine the dietary history of a person, the doctor asks what foods were eaten in the previous 24 hours and what types of foods are usually consumed. It is very common to ask the person to keep a food diary in which he write down everything you eat for a few days. During the physical exam, the doctor observes the overall appearance and behavior of the person and the distribution of body fat and evaluates the functioning of organs and systems. 

Nutritional deficiencies can cause various diseases. For example: 

Gastro-intestinal bleeding can cause iron deficiency anemia. 

A person being treated with high doses of vitamin A for acne may develop headaches and double vision as a result of the concentration of vitamin A. 

Any body system can be affected by a nutritional disorder. For example: 

the nervous system is affected by niacin deficiency (pellagra), thiamine - vitamin B1 (beriberi), deficiency or excess of vitamin B6 (pyridoxine), and vitamin B12 deficiency. 

The taste and smell are affected by zinc deficiency 

The cardiovascular system is affected by beriberi, obesity, a high-fat diet which leads to hypercholesterolemia and coronary heart disease, or a salt diet with excess leading to hypertension.
The gastro-intestinal tract is affected by pellagra, folic acid deficiency and alcoholism. 
The mouth (lips, tongue, gums and mucous membranes) is affected by deficiency of B vitamins and scurvy (vitamin C deficiency). 

Iodine deficiency can result in enlargement of the thyroid gland. 

To an increased bleeding and cutaneous symptoms such as rashes, dryness and swelling from fluid retention (edema) trend may occur in scurvy, deficiency of vitamin K, vitamin A deficiency and beriberi. 

The bones and joints are affected by rickets (vitamin D deficiency), osteoporosis and scurvy. 

Risk Factors 

The children form a population group particularly susceptible to malnutrition because they require a greater amount of calories and nutrients for their growth and development. 

They can also develop deficiencies of iron, folic acid, vitamin C and copper are receiving inadequate diets. 
Insufficient protein, calories and other nutrients intake can lead to protein-energy malnutrition, a particularly severe form of malnutrition that stunts growth and development. 

Insofar as children reach adolescence, their nutritional requirements grow due to the increase in their growth rates. 

Pregnant women or nursing mothers have an increased need for all nutrients to prevent malnutrition in them and their baby. 

The baby of an alcoholic mother may be physically and mentally damaged by fetal alcohol syndrome, as alcohol abuse and resulting malnutrition affect fetal development. 

A child who is breastfed exclusively breastfed may develop vitamin B12 deficiency if the mother is a vegetarian who eats no animal products. 

Who is at risk of malnutrition? 

Children with little appetite. 
Teens who undergo rapid growth spurts 
People who have chronic disease of the gastrointestinal tract, liver, or kidney 
People on strict diets long 
People with alcohol or another drug that does not feed properly 
People who take drugs that interfere with the appetite or absorption of nutrients or exception 
People with anorexia nervosa 
People who have prolonged fever, hyperthyroidism, burns, or cancer 

Elderly people may be malnourished because of loneliness, mental and physical disabilities, chronic illness or immobility. Furthermore, its ability to absorb nutrients is reduced, contributing to problems such as iron deficiency anemia, osteoporosis and osteomalacia disabilities. 

Aging is accompanied by a progressive loss of muscle mass, regardless of illness or dietary deficiency. This loss accounts for the reduction in metabolism that happens, the decreased body weight and increased rate of body fat of about 20 to 30 percent in men and 27 to 40 percent in women. Because of these changes and a reduction in physical activity, older people need fewer calories and less protein than younger people. 

People with a chronic disease that causes malabsorption tend to have difficulty absorbing fat-soluble vitamins (A, D, E, and K), vitamin B12, calcium, and iron. Liver diseases hinder the storage of vitamins A and B12 and interfere with protein metabolism and glucose. 

People who have kidney disease, including those on dialysis are prone to deficiency of protein, iron, and vitamin D. 

Most vegetarians do not eat meat, but eats eggs and dairy products. Iron deficiency is the only risk of this type of diet. 

Vegetarians tend to live longer and develop less chronic disabling conditions than people who eat meat. However, better health of these people may also be a result of abstaining from alcohol and tobacco and the tendency of them exercise regularly. 

Vegetarians who do not consume any animal products are at risk of developing vitamin B12 deficiency, and iron. 

Many fad diets claim to increase well-being to reduce weight; however, highly restrictive diets are nutritionally unhealthy: these diets can result in deficiencies of vitamins, minerals and proteins; in diseases affecting the heart, kidneys and metabolism and even some deaths. People on very low calorie diets (less than 400 calories per day) can not stay healthy for long. 

Between the end of starvation and proper nutrition, there are varying degrees of inadequate nutrition, such as protein-energy malnutrition, a major cause of death in children in developing countries. 

Protein-energy malnutrition 

Protein-energy malnutrition is caused by an inadequate intake of calories, resulting in a deficiency of protein and micro nutrients (nutrients required in small amounts, such as vitamins and some minerals). The rapid growth, an infection or a chronic illness can increase the need for nutrients, particularly in children who are already malnourished. 


There are three types of protein-energy malnutrition: dry (one is thin and dehydrated), wet (the person is swollen because of fluid retention) and an intermediate type. 

The dry type, called marasmus, is the result of almost complete starvation. A child who has doldrums ingests very little food, often because the mother can not breastfeed and is extremely thin due to loss of muscle and body fat. Almost invariably develops an infection. 

The wet type is called kwashiorkor, an African word meaning "first child-second child." Comes from the observation that the first child develops kwashiorkor when the second child is born and replaces the first child in the mother's breast. The first child, weaned, shall be fed a gruel which has low nutritional value compared to mother's milk, so the child does not develop. Protein deficiency in kwashiorkor is usually more significant than the caloric deficiency, resulting in fluid retention (edema), skin disease, and hair discoloration. As children develop kwashiorkor after they are weaned, they are generally older than those having doldrums. 

The intermediate type of protein-energy malnutrition called kwashiorkor - marasmatic. Children with this type retain some fluid and has more body fat than those who have doldrums. 

The kwashiorkor is less common than marasmus and kwashiorkor as usually happens - marasmatic. Tends to be limited to some parts of the world (rural Africa, Caribbean, Pacific Islands, and Southeast Asia) where the foods used to wean babies - such as yam, cassava, rice, sweet potatoes and green bananas - are deficient in protein. 

Protein deficiency impairs the body's growth, immunity, wound healing and production of enzymes and hormones. Both in the doldrums as in kwashiorkor diarrhea is common. 

The behavioral development can be extremely delayed in severely malnourished children and mental retardation may occur. Normally, a child who has marasmus is more severely affected than an older child who has kwashiorkor. 


Up to 40% of children who have protein-energy malnutrition die. Death during the first days of treatment is usually caused by an electrolyte imbalance, infection, hypothermia or cardiac arrest. 

Recovery is faster in kwashiorkor than in marasmus. 

The long-term effects of malnutrition in children are unknown. When children are properly treated, the liver and the immune system recover completely. However, in some children the intestinal absorption of nutrients remains compromised. The degree of mental impairment is related to how long a child was malnourished, how severe was malnutrition and at what age began.