Malnutrition: Symptoms & Signs

Medically Reviewed on 9/10/2019

Malnutrition is the lack of adequate nutrition, either as a result of imbalances, deficiencies, or excesses in a person's intake of food and nutrients. This can be due to eating too little, eating an improper diet, or having a medical condition that results in the body's being unable to use food and nutrients. Malnutrition can also refer to overnutrition and obesity and is the condition of being poorly nourished.

In cases of undernutrition, children may show slow growth, failure to thrive, developmental delays, behavioral changes (including decreased attention), and muscle wasting. Tiredness, fatigue, slow wound healing, and even loss of appetite may occur.

Causes of malnutrition

Poor nutrition is often caused by a combination of economic and social issues. Those affected by poverty or social isolation are at risk. Certain health problems, like depression, dementia, and chronic illness may reduce an older person's appetite and desire to eat, resulting in compromised nutrition. Alcoholism, drug abuse, and mental illness can all interfere with a person's ability to consume an adequate diet.

Some people with low incomes cannot afford (or access) enough nutritious foods like fresh fruit and vegetables, protein, and milk. Foods and drinks high in fat, sugar, and salt are readily available and inexpensive, so people may turn to these as a substitute for proper nutrition. This practice has led to an increase in overweight and obesity, which are also forms of malnutrition.

Other malnutrition symptoms and signs


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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.