A diagnosis of malnutrition is made based on the following factors:
- your body mass index (BMI), which is your weight in kilograms divided by your height in metres squared
- whether you have unintentionally lost weight in recent months
- your ability to feed yourself
- whether something, such as a health condition, has meant that you are no longer able to absorb nutrients from your diet
You would normally be considered malnourished if:
- you have a BMI of less than 18.5 or you have unintentionally lost more than 10% of your body weight during the last 3-6 months, or
- you have a BMI of less than 20 and you unintentionally lost more than 5% of your body weight during the last 3-6 months
You would normally be considered at high risk of becoming malnourished if:
- you have eaten little or nothing for the last five days or are likely to eat little or nothing for five days or longer
- you do not absorb nutrients from food well, for example you have a condition such as Crohn’s disease that is causing inflammation inside your digestive system
- you have an underlying condition or other factor that means your body is likely to use up nutrients at a higher rate or have an increased need for nutrients
For example, people recovering from serious burns have a higher demand for nutrients as their body requires extra energy to help it repair itself.
A vitamin or mineral deficiency can normally be diagnosed with a blood test.
Diagnosing malnutrition in children
Diagnosing malnutrition in children involves taking a measurement of their weight and height and then comparing it against what would be the expected average height and weight for a child of that age.
Some children will be below average as they are naturally smaller, but a significant drop below the expected level for an individual could be a sign of malnutrition.
Slower than expected growth can also be a sign of malnutrition in children. A child who is growing less than 5cm a year could be malnourished.
Blood tests can also be used to measure levels of protein in the blood. Low levels of protein would suggest that a child is malnourished.
