What is Malnutrition ?

This follows the pages about What is a Balanced Diet? and Dietary needs at different stages of life.

The literal meaning of 'malnutrition' is 'bad nutrition', i.e. dietary intake that is not entirely appropriate for the organism (although some aspects of the diet might be appropriate, overall something is missing, something is consumed in excessive quanities or the timing and combination 'balance' of the dietary intake is not appropriate in that particular case).

The above is one definition of malnutrition. Different sources e.g. dictionaries, textbooks, and organizations define it slightly differently.

The following is from the international children's organization UNICEF:

" Malnutrition is a broad term commonly used as an alternative to undernutrition but technically it also refers to overnutrition. People are malnourished if their diet does not provide adequate calories and protein for growth and maintenance or they are unable to fully utilize the food they eat due to illness (undernutrition). They are also malnourished if they consume too many calories (overnutrition)."

http://www.unicef.org/progressforchildren/2006n4/malnutritiondefinition.html
(Link still valid as of May 2017 but not present in March 2022.)

Quote from http://www.unicef.org (until 2017, specific page no-longer online in Mar 2022.)

Malnutrition can take several forms.

The most common types are:

• Undernutrition - which can lead to undernutrition diseases details depend on which parts of a healthy diet are lacking.
• Dietary excesses - which can lead to other medical conditions and diseases depending on which components of the diet are being (or have been) consumed to excess and to what extent.

Even an excess of water can have extremely adverse effects, though of course one would have to drink a large volume in a relatively short time. Seek expert advice before following apparently unusual, and especially any extreme, dietary regimes.

What is the difference between malnutrition and undernutrition?

Malnutrition means that the body is showing definite signs of the adverse effects of inappropriate nourishment (normally from dietary intake).

Undernutrition is when the adverse effects are due to a shortage of an essential type of nourishment e.g. energy, protein, or a specific vitamin.

That is, undernutrition applies in situations of dietary deficiency. It can be either:

• General, i.e. due to insufficient amounts of food of any or all types, hence insufficient energy for general activity and resources for the maintenance of the cells, tissues and processes of the body. This leads to starvation.
• Specific, i.e. lack of sufficient amounts of a single nutrient e.g. a single vitamin or mineral. The health consequences of such a deficiency depend on the nutrient that is lacking and the severity of the deficiency. Different medical conditions - hence different symptoms and risks - follow from different deficiencies. There are many examples of medical conditions due to dietary deficiencies. The prevalence and typical severity of cases vary at different locations around the world. See undernutrition diseases.

What about dietary excess(es) ?

The word 'malnutrition' is more commonly used in the context of undernutrition than in the context of overnutrition. Nevertheless, dietary excesses can also result in adverse medical conditions, some of which can be fatal if not treated successfully. In the same way as undernutrition, dietary excess can be either:

• General, i.e. due to excessive amounts of food of any or all types, leading to obesity and the many life-threatening conditions associated with it.
  
• Specific, i.e. excess of of a single nutrient e.g. a single vitamin or mineral. The health consequences of such excess depend on the nutrient and the severity of the excess. Different medical conditions, hence different symptoms and risks, follow from different excesses. See effects of overnutrition.

See also carbohydrates, types of sugar, dietary fibre (roughage), fatty acids, fats and proteins.