Malnutrition (Protein-Energy Malnutrition)
What is Malnutrition (Protein-Energy Malnutrition)?
Malnutrition happens when your body does not get enough protein, calories, or essential nutrients to function properly. Protein-energy malnutrition, or PEM, is the most common form of malnutrition worldwide. It affects how your body builds and repairs tissues, fights infections, and maintains energy levels.
PEM can develop gradually over weeks or months. It happens when you eat too little food, cannot absorb nutrients properly, or have increased needs your diet cannot meet. Children in developing countries are especially vulnerable, but adults in wealthy nations can also develop malnutrition. Hospitalized patients, older adults, and people with chronic illnesses face higher risk.
There are two main types of protein-energy malnutrition. Marasmus results from severe calorie deficiency and causes extreme weight loss and muscle wasting. Kwashiorkor develops from inadequate protein intake and causes fluid retention, swelling, and a distended belly. Both conditions require medical attention and careful nutritional rehabilitation.
Symptoms
- Unintentional weight loss and muscle wasting
- Extreme fatigue and weakness
- Dizziness and difficulty concentrating
- Swelling in the legs, feet, or abdomen
- Slow wound healing and frequent infections
- Hair loss or brittle, thinning hair
- Dry, flaky skin or skin discoloration
- Reduced appetite or changes in taste
- Irritability and mood changes
- In children, failure to grow or develop normally
Many people with early malnutrition do not recognize the signs. Symptoms develop slowly and may be mistaken for normal aging or stress. By the time severe symptoms appear, nutritional deficiencies may have already caused significant harm to the body.
Concerned about Malnutrition (Protein-Energy Malnutrition)? Check your levels.
Screen for 1,200+ health conditions
Causes and risk factors
Protein-energy malnutrition develops when calorie and protein intake falls below what your body needs. Inadequate food access is the primary cause in developing countries, but many other factors contribute. Poverty, food insecurity, and lack of nutrition education increase risk. Medical conditions that reduce appetite or increase nutrient needs also play a major role. Cancer, infections, digestive disorders, and chronic diseases can all trigger malnutrition.
Older adults face particular risk due to decreased appetite, dental problems, limited mobility, and medication side effects. Hospitalized patients may develop malnutrition from illness-related stress, inadequate feeding, or prolonged bed rest. Mental health conditions like depression, anxiety, and eating disorders frequently lead to poor nutrition. Alcohol and substance use disorders interfere with nutrient absorption and healthy eating patterns. Even in wealthy countries, millions of people live with hidden hunger and inadequate protein intake.
How it's diagnosed
Healthcare providers diagnose malnutrition through physical examination, medical history, and laboratory testing. Your doctor will check your weight, muscle mass, and look for signs of nutrient deficiencies. They will ask about your diet, recent weight changes, and any conditions that affect eating or digestion. Blood tests help identify specific nutritional deficiencies and assess how malnutrition has affected your body.
Rite Aid offers zinc testing as an add-on to help monitor nutritional status in people with suspected malnutrition. Zinc levels drop in severe malnutrition states and measuring serum zinc guides repletion therapy. Your healthcare provider may also order tests for albumin, prealbumin, complete blood count, and other markers of protein status. Early detection through testing allows for timely intervention before severe complications develop.
Treatment options
- Gradual increase in calorie and protein intake under medical supervision
- High-protein foods like eggs, fish, poultry, beans, and dairy products
- Nutrient-dense foods including whole grains, nuts, seeds, and healthy fats
- Oral nutritional supplements or meal replacement shakes when needed
- Treatment of underlying medical conditions affecting nutrition
- Zinc supplementation and other micronutrient repletion as indicated by testing
- In severe cases, tube feeding or intravenous nutrition in hospital settings
- Working with a registered dietitian to create a personalized eating plan
- Addressing food access barriers through community resources and assistance programs
- Mental health support for eating disorders or conditions affecting appetite
Need testing for Malnutrition (Protein-Energy Malnutrition)? Add it to your panel.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
Malnutrition means your body lacks essential nutrients it needs to function properly. Being underweight simply means weighing less than expected for your height. You can be underweight without being malnourished if you eat a balanced diet. However, many underweight people do have nutrient deficiencies that require medical attention.
The timeline varies based on your starting nutritional status and the severity of inadequate intake. Severe malnutrition can develop in weeks if you consume very little food or have high metabolic demands. Mild to moderate malnutrition typically develops over months of inadequate nutrition. Hospitalized patients and people with acute illness may develop malnutrition more rapidly than healthy individuals.
Yes, most cases of malnutrition can be reversed with proper nutritional rehabilitation and treatment of underlying causes. Recovery requires gradually increasing calorie and protein intake while monitoring for refeeding complications. The process takes weeks to months depending on severity. Some long-term effects, particularly in children, may not be fully reversible if malnutrition occurred during critical growth periods.
Children in low-income countries face the highest risk worldwide. In developed nations, older adults, hospitalized patients, and people with chronic illnesses are most vulnerable. Those with cancer, digestive disorders, eating disorders, or mental health conditions also have increased risk. People experiencing poverty, food insecurity, or social isolation are more likely to develop malnutrition.
Zinc levels help assess nutritional status and are often low in severe malnutrition. Albumin and prealbumin measure protein status in your blood. Complete blood count can reveal anemia from nutrient deficiencies. Your doctor may also test vitamin levels, electrolytes, and other markers depending on your symptoms and risk factors.
Most adults need 0.8 grams of protein per kilogram of body weight daily. A 150-pound person needs about 55 grams of protein per day. Older adults, pregnant women, and people recovering from illness need more protein. Talk to a healthcare provider or registered dietitian about your individual protein needs based on your age, activity level, and health status.
Yes, you can be overweight or obese and still have malnutrition. This condition is called hidden hunger or micronutrient malnutrition. It happens when your diet provides enough calories but lacks essential vitamins, minerals, and protein. Poor diet quality with processed foods high in calories but low in nutrients commonly causes this type of malnutrition.
Prolonged malnutrition weakens your immune system and increases infection risk. It can cause permanent growth stunting in children and delayed development. Adults may experience muscle loss, bone weakness, organ damage, and cognitive impairment. Severe cases can lead to heart problems, liver damage, and life-threatening complications. Early treatment prevents many long-term effects.
Watch for unintended weight loss of more than 5 percent over several months. Notice if clothes fit more loosely or if they seem weaker and more tired. Look for decreased appetite, skipped meals, or eating very small portions. Other signs include confusion, slow healing, frequent illnesses, and social withdrawal. If you notice these signs, schedule a medical evaluation promptly.
Start with small, frequent meals that include protein sources like eggs, chicken, fish, beans, and Greek yogurt. Add calorie-dense foods like nut butters, avocados, olive oil, and whole grains. Include fruits and vegetables for vitamins and minerals. Work with a registered dietitian to create a safe refeeding plan, as eating too much too quickly can cause dangerous complications in severe malnutrition.