: Signs, Symptoms, Diagnosis and Prevention


Written by Esther Diong on 30.3.2021
Medically Reviewed by Dr. K on 1 April 2021

Malnutrition. What is that?

Food is a necessity to live, but how do we know if we are eating enough? The recommended nutrient intake (RNI) are goals set for individuals to ensure that they are meeting their daily nutritional needs. But how many of us can adhere strictly to these guidelines?

Malnutrition happens when an individual does not get sufficient variety and amount of nutrients from their daily diet. Malnutrition could be categorized into:

  • Overnutrition: Overconsumption of certain nutrients. Usually results in overweight or obesity.
  • Undernutrition: Underconsumption of certain nutrients. Usually results in underweight, wasting, and stunted growth.
  • Micronutrient deficiency: Individuals who are deficient in certain vitamins and minerals.

Malnutrition is a common global issue, however, there are some populations with higher risks.

Common Causes of Malnutrition

  • Food insecurity issues (ie: Unable to access affordable food);
  • Inability to obtain and prepare food (ie: Vulnerable population with poor food preparation skills);
  • Digestive problems and conditions that cause malabsorption (ie: Coeliac disease, irritable bowel syndrome, etc.);
  • Excessive alcohol consumption;
  • Mental health disorders.

Signs and Symptoms


A typical result from overconsumption of certain nutrients, usually carbohydrates and fats, which causes an excess intake of calories. Common signs:

  • Overweight
  • Obesity


A typical result from a nutrient-deficient diet can lead to but not limited to:

  • Underweight;
  • Weight loss (ie: Muscle wastage, fat loss, sagging skin, hollow cheeks, sunken eyes)
    Swollen stomach (ie: Kwashiorkor);
  • Dry hair and skin;
  • Delayed wound healing;
  • Weakened immune system;
  • Fatigue and irritability;
  • Difficulty concentrating;
  • Depression and anxiety.

Micronutrient Deficiency

Overnutrition and undernutrition individuals are at high risk of facing micronutrient deficiency issues. An overnutrition individual may have excess consumption of macronutrients (carbohydrates, fats, and protein) while lacking micronutrients. Some common deficiency and their symptoms:

  • Vitamin A – Dry eyes, night blindness, increased risk of infection;
  • Vitamin D – Muscle weakness, bone loss, and an increased risk of fractures. In children, it may cause growth delays and brittle bones (rickets), and weakened immunity;
  • Vitamin C – Scurvy, swollen and bleeding gums, corkscrew hair, spoon-shaped fingernails;
  • Vitamin B –  Common symptoms range from fatigue and confusion to anaemia or a compromised immune system depending on the type of Vitamin B deficiency;
  • Zinc – Loss of appetite, stunted growth, delayed healing of wounds, hair loss, diarrhea;
  • Iron – Anaemia, Impaired brain function, issues with regulating body temperature, stomach problems;
  • Iodine – Enlarged thyroid gland (goitre), increased in heart rate, shortness of breath, weight gain;
  • Magnesium – Abnormal heart rhythm, frequent muscle cramps, restless leg syndrome, fatigue, migraines;
  • Calcium – Brittle bones (rickets) in children and osteoporosis, especially in older adults.

Assessing Malnutrition

Common screening tools that are used by healthcare providers to screen for malnutrition are:

  • Weight Loss/Gain History
  • Body Mass Index (BMI)
  • Blood Tests – To Assess Nutrient Deficiency
  • Physical Examinations – Anthropometry measurements
  • Diet History Taking – To review eating habits

Unresolved long-term malnutrition is detrimental to one’s health and increases the risks of chronic health conditions. Long-term malnutrition increases the risks of obesity, cardiovascular diseases, growth stunting, high blood pressure, diabetes, impaired metabolism, and many more other chronic diseases. For this reason, preventing and treating malnutrition would be protective to the individual in terms of reducing the risks of developing chronic diseases and improving their life quality. Malnutrition can be prevented and treated by addressing its underlying causes.

Every individual is responsible for their own health. You are what you eat. Being aware of eating healthy and being initiative with eating are two separate causes. One can prevent malnutrition by maintaining a healthy diet with a variety of food that includes adequate amounts of carbohydrates, protein, fats, vitamins, minerals, and water.  Malnutrition treatment, on the other hand, would require a more personalized approach with the help of professional healthcare providers.

If you suspect that you or someone you know is malnourished, talk to your healthcare provider as soon as possible.


Referenced on 31.3.2021

  1. https://www.who.int/news-room/q-a-detail/malnutrition
  2. https://www.merckmanuals.com/home/disorders-of-nutrition/undernutrition/undernutrition
  3. Martins, V. J., Toledo Florêncio, T. M., Grillo, L. P., do Carmo P Franco, M., Martins, P. A., Clemente, A. P., Santos, C. D., de Fatima A Vieira, M., & Sawaya, A. L. (2011). Long-lasting effects of undernutrition. International journal of environmental research and public health, 8(6), 1817–1846. https://doi.org/10.3390/ijerph8061817

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