The human body needs a balance of protein, fat, and carbohydrate to maintain health and vitality.  When the body does not get enough food, undernutrition occurs. When the body does not get enough nutrients, malnutrition occurs. Both undernutrition and overnutrition can cause malnutrition . While deficiency in each macronutrient is problematic, protein deficiency is extremely dangerous and can cause protein-energy malnutrition (PEM) (Maleta K., 2006).

There are two types of protein-energy malnutrition: one is associated with protein deficiency in the absence of sufficient caloric intake, the other presents with both protein and energy deficiency.  The main disorders associated with protein-energy malnutrition are kwashiorkor and marasmus syndrome. Kwashiorkor is caused by protein deficiency while marasmus is caused by energy deficiency. A third condition called marasmic kwashiorkor presents symptoms of both kwashiorkor and marasmus. 

These diseases are prevalent in the developing world, where they affect mostly infants and children. They are also present in economically developed countries, where they affect food-insecure populations and the elderly, especially the hospitalized elderly. PEM can have secondary causes, namely chronic diseases such as chronic kidney disease, cancer cachexia, AIDS, and anorexia (Grover & Ee, 2009) (Merck Manuals, 2021). 

The Dangers of Kwashiorkor & Marasmus

The severity of kwashiorkor and marasmus varies from subclinical deficiency to wasting syndrome to starvation. Adequate nutrition is necessary to combat both diseases, but, unfortunately, it is not enough to undo the metabolic damage done, especially with regards to stunted growth. 

Kwashiorkor is caused by insufficient protein intake in the presence of sufficient calories. Sadly, this severe form of malnutrition is very common in developing countries, where infants and children do not get enough dietary protein. Certain African regions report kwashiorkor rates as high as 15% (WHOs Africa Nutrition Report Highlights an Increase in Malnutrition in Africa., 2021). Kwashiorkor has acute onset, and its main characteristic is edema. Edema usually starts in the legs, but it can spread to the entire body, including the abdomen and the face. Kwashiorkor is also usually accompanied by fatty liver, muscle wasting, loss of hair and decreased hair pigmentation, stunted growth, skin lesions, anemia, diarrhea, apathy and listlessness (NHS website, 2019). 

Malnutrition & Portein Deficiency

Marasmus protein deficiency occurs when a person’s diet is deficient in both protein as well as calories.  Marasmus starts generally immediately after birth.  Infants affected by marasmus are slow to develop and present stunted growth, extremely low body weight, muscle wasting, depletion of adipose tissue, hypotension, and they suffer from repeated infections.

PEM conditions present also with deficiency of micronutrients, especially iron, iodine, zinc and vitamin A.  According to Merk Manual the mortality rate in children affected by PEM varies from 5% to 40%. Severe PEM causes electrolyte imbalance, sepsis, heart failure, and hypothermia, which can lead to shock and death. Patients affected by kwashiorkor recover more rapidly than patients affected by marasmus. 

As mentioned above, PEM therapy includes adequate nutrition; supportive care is considered on a case-to-case basis. Appetite stimulants are generally part of PEM therapy for patients affected by anorexia. Patients with cachexia can often be prescribed anabolic steroids or growth hormone. Refeeding syndrome is a complication of PEM therapy, which can be accompanied by hyperglycemia, diarrhea, fluid imbalance, and arrhythmias (Merck Manuals, 2021). 


December 8th F, 2019. Malnutrition in America [Internet]. Focus for Health. 2019. Available from:

Grover, Z., & Ee, L. C. (2009). Protein energy malnutrition. Pediatric clinics of North America, 56(5), 1055–1068.

Maleta K. (2006). Undernutrition. Malawi medical journal : the journal of Medical Association of Malawi, 18(4), 189–205. 

Merck Manuals. (2021). Protein-Energy Undernutrition (PEU). Merck Manuals Professional Edition.

NHS website. (2019, September 10). Kwashiorkor. Nhs.Uk.

WHOs Africa Nutrition Report highlights an increase in malnutrition in Africa. (2021, September 1). WHO | Regional Office for Africa.

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