Malnutrition is a wide spectrum of symptoms caused by an inadequate intake of nutrients.

  • Malnutrition in children (primary malnutrition) is caused by lack of dietary energy, protein and micronutrients (vitamins and minerals); malnutrition in adults (secondary malnutrition) may be caused by diseases or conditions that interfere with nutrient intake or their use by the body, as well as an inadequate diet either due to poverty or lack of food security, or the use of inappropriate diets (slimming, anorexia, orthorexia, etc).
  • Malnutrition may involve stunting of growth, marasmus and kwashiorkor in infants and young children, while adults may exhibit deficiencies of some, or most nutrients, depending on the cause of malnutrition.
  • Treatment is based on providing an adequate and balanced diet to redress any energy, protein, vitamin or mineral deficiencies. In severe cases tube feeds, liquid meal supplements and/or multivitamin and mineral supplements may be prescribed.
  • Poverty alleviation and nutrition education are essential if malnutrition is to be prevented in disadvantaged communities. Patients presenting with malnutrition caused by inappropriate dietary intake may require counseling by a dietitian and a psychiatrist/clinical psychologist.

Alternative names

Primary malnutrition in children is also referred to as marasmus, kwashiorkor or protein-energy deficiency. In secondary malnutrition, the names of specific deficiency diseases are usually linked to the nutrients that are deficient in the diet e.g. iron deficiency, protein deficiency, energy deficiency, etc.

What is malnutrition?

Malnutrition is a wide spectrum of symptoms that occurs when one or more nutrients is lacking in the diet. These symptoms vary according to which nutrients are deficient.

Primary malnutrition is caused by a lack of energy (fats and carbohydrates), protein and micronutrients (vitamins and minerals) in the diets of infants and children. Secondary malnutrition is caused by the lack of one or more nutrients in adult diets, ranging from energy deficiency in anorexics to vitamin deficiencies in older people with poor appetite.

What causes malnutrition?

Human beings need a wide variety of nutrients to supply essential energy, protein, vitamins and minerals to the body. If any one of these nutrients is deficient in a person’s diet, then malnutrition develops.

Generally, the most serious malnutrition occurs when the diet is deficient in energy and protein. In disadvantaged communities, diets are often lacking in energy and protein, which automatically also leads to deficiencies in most of the other essential nutrients: children suffering from energy and protein malnutrition also tend to have deficiencies of vitamin A, iron, zinc, calcium and other vitamins and minerals.

Adults with conditions that interfere with food uptake, such as insufficient stomach acid, a common condition in older individuals, may suffer from iron, calcium or zinc deficiencies, despite the fact that their diet may contain adequate quantities of these nutrients. On the other hand, forced deprivation of essential nutrients due to fad or starvation slimming diets or anorexia and other eating disorders, may result in symptoms of scurvy, protein-depletion, iron-deficiency anaemia, pernicious anaemia (lack of vitamin B12), brittle bone syndrome (calcium), infertility, and many other signs of nutrient deficiencies.

Who gets malnutrition and who is at risk?

Individuals who are dependent on others for their nourishment may be at risk for primary malnutrition, namely infants, children, the elderly, prisoners and persons who are disabled or mentally ill. Primary malnutrition is particularly prevalent in poor communities such as marginalised rural villages, urban squatter camps and refugee camps.

Secondary malnutrition may occur in people whose food intake is disturbed because of poor appetite or faulty digestion, absorption or use of nutrients in the body. Practically all diseases, including tuberculosis, eating disorders, HIV/AIDS, wasting illnesses such as cancer, and many surgical procedures, can interfere with appetite or food uptake and cause malnutrition.

In South Africa, pronounced protein and/or energy malnutrition is often seen in infants and toddlers living in poor, rural areas and squatter camps, which have low levels of food security, education and income. Malnutrition causes stunting and retardation of physical and mental development in older children and teenagers living in poverty-stricken communities. When undernourished teenagers fall pregnant and give birth to underweight infants, the vicious cycle of malnutrition, stunting and sub-optimal physical and mental development may be perpetuated for many generations, with serious economic consequences due to loss of human potential. According to the Barker Hypothesis, children who are exposed to malnutrition before birth and for the first few years of life, have a higher risk of developing degenerative diseases (heart disease, type 2 diabetes, obesity, metabolic syndrome, hypertension), particularly if such children are exposed to a high-fat diet that is also rich in highly processed carbohydrates and sugar.

Anyone living with HIV/AIDS has an increased risk of malnutrition. When people with HIV/AIDS who have depressed appetites, and an increased requirement for certain nutrients, including energy, are also poor and not able to afford a variety of nutritious foods, they can develop multiple-nutrient malnutrition.

Symptoms and signs of malnutrition

Severe primary malnutrition is characterised by the following symptoms:


  • pronounced weight loss with loss of muscle formation, particularly on the shoulders and buttocks
  • absence of fat under the skin
  • thin, papery skin hanging in folds
  • the skin may be darker, as if the child has sunburn
  • hair loss
  • a pinched, starved facial expression, which makes young children look old and wizen
  • infants appear apathetic and may lie still for long periods without moving or crying


  • discoloured, fine, brittle hair that often has a copper sheen
  • skin rash or so-called “crazy-paving dermatitis”, where the skin is darker in patches with pale areas in between
  • oedema or water accumulation, making the infant appear “round and healthy”, but when pressure is applied to the skin it forms dents that take a long time to disappear
  • grossly swollen tummy
  • enlarged liver
  • apathy and listlessness


The child may look normal until his or her weight and height are compared to figures in standard growth charts, or to other children of the same age who are not malnourished. It will be evident that the child is grossly underweight and undersized for his or her age. Some of the other signs and symptoms of marasmus or kwashiorkor may be present, e.g. thinning hair, skin rash, apathy. The South African National Food Consumption Survey conducted with children aged 1-9 years in 1999, found that one in five children suffers from stunting. Younger children (1-3 years) were more severely affected, particularly those living in rural areas and on commercial farms.

In adults suffering from energy malnutrition, gross weight loss is the most common sign, although water retention, skin and hair changes, listlessness and apathy may also occur.

Vitamin and mineral malnutrition is characterised by individual signs and symptoms depending on the vitamin or mineral that is deficient; for example, iron deficiency produces anaemia, tiredness, listlessness, hair loss, etc. (Please refer to individual deficiency diseases in the A-Z of Diseases).

How is malnutrition diagnosed?

The doctor or clinic sister will weigh patients and measure their height and skin fold thickness for comparison with growth charts. Measurement of Mid Upper Arm Circumference (MUAC) is also a simple method of determining is a patient is underweight. If these simple procedures identify a child or adult who is grossly underweight or stunted, a full physical examination should be performed. The doctor or nurse will check for signs of water retention, changes in skin and hair, liver enlargement and abdominal swelling. The doctor will also take a blood sample and request a number of biochemical tests to identify protein, vitamin and mineral deficiencies.

Can malnutrition be prevented?

Protein-energy malnutrition can be prevented if the underlying causes of poverty and lack of food, education and hygiene can be eliminated. Even poor families can prevent malnutrition in their children by making sure that they eat the following regularly:

  • a fortified staple food such as maize meal porridge or brown or wholewheat bread. Mandatory fortification of maize meal and wheaten bread flour with iron, zinc, vitamin A, thiamin (vitamin B1), riboflavin (vitamin B2), niacin, folic acid and pyridoxine (vitamin B6) was introduced as of October 2003. Unrefined or unsifted staple foods (unsifted maize meal, brown rice or crushed wheat), also have a much higher nutritive content than highly processed staples.
  • small quantities of protein-rich foods like eggs, meat or fish (keeping chickens or goats, or fishing, can provide protein-rich foods at low cost)
  • fresh, dried or sour milk (using skim milk powder or keeping goats or a cow)
  • fruits and vegetables (growing your own or bartering from neighbours)
  • some margarine or oil (soft margarine or sunflower oils are best).

Education plays an important role in ensuring that populations do not develop malnutrition. When funds are in short supply, it is essential that caregivers spend money on buying nutritious foods and do not waste it on alcohol, sweets, cold drinks or high-fat, high-salt snack foods. Education should also be used to help poor communities grow their own food and keep livestock.

Food aid programmes, if effectively implemented, can be used to help supply starving populations with essential foods to prevent malnutrition. The food aid that is provided in refugee camps in many parts of Africa and the East, is an example of international attempts to prevent mass malnutrition in displaced persons of all ages.

Anyone who is exposed to the risk of malnutrition because of sociological, medical or surgical conditions should be given supplements as a preventative measure. Elderly people living in frail care centres, for example, often have a combination of poor appetite linked to loss of taste or use of certain medications, difficulty with eating because of lack of teeth or poorly fitting dentures, poor absorption due to lack of stomach acid, and increased nutrient requirements cause by chronic diseases and use of medications. These people should be given liquid food supplements (such as Ensure or Complan or Buildup), plus complete vitamin and mineral supplements (a wide variety of such products are available at your local pharmacy - use liquid preparations, if possible, because they are absorbed more easily), before they develop malnutrition.

It has been suggested that if all persons over the age of 65 would drink one glass of liquid food supplement a day, malnutrition in the elderly could be effectively prevented, thus also preventing many of the illnesses older people suffer from. Unfortunately, this kind of intervention is seldom used.

How is malnutrition treated?

Infants and children suffering from acute malnutrition, kwashiorkor or marasmus are often hospitalised and given intravenous or tube feeding. Once the child has been stabilised, he or she is fed an energy and protein-rich diet together with a vitamin and mineral supplement to try to redress nutritional imbalances.

These infants and children often recover well while in hospital, only to be discharged and returned to their original poverty-stricken environment where they quickly deteriorate and become as malnourished as before. This underlines why poverty alleviation and nutrition education are so essential in preventing malnutrition.

People suffering from malnutrition associated with various medical conditions should receive dietetic counseling and/or food or vitamin and mineral supplements. For example, people who have had part of their duodenum (upper intestine) removed should be counselled by a dietician to ensure that they eat a balanced diet which is easy to absorb and does not cause abdominal distress. They will also need to take a vitamin and mineral supplement and/or an amino acid supplement to provide any essential nutrients they may no longer be able to absorb.

What is the outcome of malnutrition?

If acute severe malnutrition is not treated in infants and children, they may die or be permanently physically and mentally stunted, thus never reaching their full potential. Chronic malnutrition also stunts physical and mental development. Malnutrition involving one or more nutrients can have a variety of effects, most of which delay recovery and may result in additional complications. For example, if a person is not able to absorb fat-soluble vitamins because of removal of part of the intestine, then he or she may develop deficiencies of vitamins A, E, K and D. Prevention is essential and relatively easy to achieve by taking extra fat-soluble vitamin supplements.

When to call the doctor

The warning signs of malnutrition are:

  • loss of appetite
  • pronounced weight loss without dieting
  • pronounced weight loss because of inappropriate dieting
  • failure to grow
  • listlessness and apathy
  • hair and skin changes
  • a swollen abdomen
  • gross water retention

If one or more of these symptoms occur, you or your child may be developing malnutrition and you should consult a doctor or take your child to your local clinic for a check-up. If you notice that a member of your family or one of your friends in losing weight dramatically and showing signs of malnutrition, this could be due to starvation slimming diets, anorexia, bulimia, or other eating disorders. Try to persuade the individual to have a medical checkup to prevent full-blown malnutrition.

Reviewed by Dr I van Heerden, Nutrition Consultant & Scientific Editor, DietDoc,  July 2010.


Barker D J, Osmond C (1986). Infant mortality, childhood nutrition, and ischaemia heart disease in England and Wales. The Lancet, 1986 May 10:1(8489):1077-81.

Black RE, Allen LH, Bhutta Z A, Caulfield LE, et al (2008). Maternal and child undernutrition: global and regional exposures and health consequences. The Lancet, Vol 371:243-60, January 19, 2008.

Labadarios D et al (2008). Executive summary of the National Food Consumption Survey Fortification Baseline (NFCS-FB-I), South Africa, 2005. South African Journal of Clinical Nutrition, Vol 21(3)(Suppl 2):245-300.

Victora C G, Adair L, Fall C, Hallal P C, et al (2008). Maternal and child undernutrition 2. Maternal and child undernutrition: consequences for adult health and human capital. www. thelancet. com Published online January 27,2008 DOI:10.1016.S0140-6736(07)61692.4.

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