An Overview of Malnutrition

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Malnutrition means your body isn't getting enough of the nutrients it needs. You can be deficient in calories, carbohydrates, protein, fats, vitamins, and/or minerals. If you are lacking in any of these, you can experience symptoms such as weight loss, infections, low energy, diminished wound healing, and more. There are several potential causes of malnutrition, including an inadequate or unbalanced diet, gastrointestinal (GI) problems, and medical conditions such as kidney disease.

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Your healthcare provider may order diagnostic tests to determine if and why you are malnourished. You might be advised to eat or drink nutritional supplements. And if you can't eat or drink, you may need intravenous (IV, in a vein) support and/or a feeding tube to replenish your nutrition.


Symptoms of malnutrition can vary from mild to very severe. You can experience gradual effects that worsen over time, especially if you have developed malnutrition due to a chronic issue like heart failure or alcoholism.

If your malnutrition is caused by a rapidly progressive illness, such as acute pancreatitis, you can experience consequences of malnutrition along with symptoms of your underlying condition.

Common symptoms of malnutrition include:

  • Fatigue
  • Moodiness, depression, irritability
  • Dizziness
  • Weight loss
  • Decreased muscle tone and strength
  • Weakened immune system (frequent infections)
  • Trouble concentrating
  • Disruption or cessation of the menstrual cycle
  • Slow wound healing
  • Prolonged bleeding from wounds
  • Glossitis (inflammation of the tongue) and/or stomatitis (inflammation of the mouth)
  • Constipation and/or diarrhea
  • Fainting
  • Brittle hair or hair loss
  • Bone fractures

You can be malnourished with normal weight or even be overweight and lacking in nutrients.

Children and Malnutrition

Malnutrition can also affect children's growth and development, potentially causing irreversible health issues. Children who are malnourished might not grow to their expected height. They can also have thin hair, skin breakouts, spotty skin discoloration, fragile bones, learning difficulties, personality issues, and/or mood problems.

Children who are malnourished may have a predisposition to serious health effects that could develop years later, such as heart failure, asthma, allergies, chronic respiratory disease, GI disease, diabetes, and kidney failure.

Depending on the cause of your malnutrition, you can have other symptoms that stem from the issue as well. For example, gastrointestinal issues that lead to malnutrition can also cause diarrhea; anemia that leaves your iron levels low can result in tachycardia (rapid heart rate).

If you experience any effects of malnutrition or associated symptoms, be sure to talk to your healthcare provider.


When many think of malnutrition, their mind immediately goes to an outright lack of food. That is just one potential cause. Malnutrition can also occur if you eat an unhealthy diet or have certain health issues that make eating difficult or affect your body's ability to fully benefit from the foods that you eat.


What you eat may be by choice, but it may also be dictated by access to healthy foods, financial concerns, personal limitations, or other concerns. Processed and fast foods, for example, are not good sources of nutrition. While quick and generally inexpensive, making them a large component of your overall diet can, among other things, cause you to miss out on important nutrients.

Diet may also be influenced by symptoms of health issues you have. For example, if you have chronic constipation, anxiety, hyperosmia (an enhanced sense of smell, common during pregnancy), or are undergoing chemotherapy, you may experience severe nausea, which may prompt you to stay away from certain foods that make you feel like vomiting—or avoid eating altogether.

Other medical conditions interfere with eating because of neuromuscular problems that affect chewing and swallowing. This can happen after a stroke or due to a disease like amyotrophic lateral sclerosis (ALS), and it limits what can be eaten safely.

Eating disorders such as anorexia nervosa or bulimia are driven by pathological anxiety about weight. Extremely low caloric intake with these disorders results in malnutrition.

The result of dietary deficiency is that you can be low in calories, and you might also be disproportionately low in certain vitamins, minerals, and proteins.


A number of GI conditions lead to inefficient nutrient absorption. Even if you eat enough healthy food, your body might not be able to use it properly.

This can happen with conditions such as:

If you have had a bowel or stomach resection due to disease or for weight loss, you might also absorb fewer nutrients from the food you eat.

Increased Nutritional Needs

Most medical illnesses consume your body's energy. In doing so, nutrient levels can also become depleted. Pregnancy requires extra calories and nutrients, and a lack of nutrients can have consequences for the mother and baby.

Some conditions, like chronic obstructive pulmonary disease (COPD) or cancer alter your metabolism as your body works extra hard to cope with the disease.

A major infection, trauma, or recovery after surgery can also cause your body to consume a lot of calories as you heal. You might notice substantial weight loss lasting for weeks or even months after a major health event.

Most of the time, you will feel extra hungry during and after recovery from a brief illness. Your care team may advise that you follow a certain diet knowing that your body is drawing on particular nutrients to help you get well. For example, wound healing heavily relies on protein.

You can usually eat enough healthy food once you recover to avoid any lasting effects of malnutrition.

Chronic diseases, such as heart failure, emphysema, kidney failure, diabetes, liver disease, and cancer may result in long term malnutrition due to high caloric demands on your body.


Identifying malnutrition isn't always clear-cut. In addition to your physical examination, your healthcare provider might run blood tests to help identify nutritional deficiencies. You may also need further evaluation to determine the cause of your malnutrition.

Physical Examination

Your weight is the most obvious indicator of malnutrition. If you have lost weight, your current weight will be compared to your previous weights. Your body mass index (BMI) will also be determined and compared to the normal BMI range for a person of your height and age.

Your healthcare provider will look for physical signs of malnutrition. A bony appearance, such as hollow cheeks, can indicate related weight loss. Your muscle bulk, tone, and strength will be tested, and your heart rate, blood pressure, and skin will all be examined for signs of malnutrition. For example, skin discoloration, especially white patches, can develop due to nutritional deficiencies.

Other signs, such as sunken eyes, can indicate dehydration—which often goes hand-in-hand with malnutrition. A swollen abdomen can indicate ascites, a sign of related late-stage liver failure. Severe fluid retention associated with abdominal swelling can develop with Kwashiorkor, a rare consequence of severe protein deficiency.

Labs and Tests

You might also need tests to look for and confirm the extent of specific nutritional deficiencies. Other diagnostic tests can help pinpoint the actual cause of your malnutrition (such as heart disease, lung disease, or cancer).

  • Complete blood test (CBC): Vitamin B12 anemia and iron deficiency anemia are common types of nutritional anemia, and a CBC will show abnormalities in red blood cells (RBCs) reflective of these deficiencies. A CBC can also help identify certain types of blood cancer, such as lymphoma and leukemia.
  • Specialized blood tests: Liver function tests (LFTs) can identify liver disease, and abnormalities in electrolytes may point to kidney disease or other systemic diseases. A lead level may also be ordered because lead toxicity can contribute to malnutrition, especially in young children.
  • Urinalysis: Dehydration, which is suboptimal body fluid concentration, is often associated with malnutrition. A urine test can determine if you are dehydrated, and it can also be used to check for signs of diabetes mellitus (high glucose and/or protein) or kidney disease.
  • Stool sample: Lack of nutrient absorption is often associated with blood in the stool or with fat in the stool. Your stool may be sent to a laboratory for testing to assess the cause of your malnutrition.
  • Tests of cardiovascular function: Because heart failure can lead to malnutrition, your healthcare provider may check your heart with an electrocardiogram (EKG) or echocardiogram, non-invasive tests that can detect heart failure and heart rhythm issues.
  • Oxygen concentration: Severe infections, lung disease, or heart disease can impair your ability to breathe or absorb oxygen, resulting in low blood oxygen levels. This can be detected with non-invasive pulse oximetry, or with an arterial blood gas (ABG) test.


In some cases, the addition of imaging may also be helpful.

  • Chest X-ray or chest CT: A lung disease or lung cancer that causes malnutrition may show changes in chest imaging. Metastasis from cancer that spread from elsewhere in the body (such as breast or prostate) can also appear on chest imaging tests.
  • Abdominal imaging: If there is concern about cancer or disease in the abdomen, you may need an abdominal ultrasound, computerized tomography (CT), or magnetic resonance imaging (MRI).
  • Bone X-ray or bone scan: Malnutrition can lead to thinning bones in adults or deficient bone development in children. Diagnostic imaging tests can help identify these issues.

You are unlikely to need all of these diagnostic tests, but you may need some of them if you are malnourished or suspected to be.


Malnutrition needs to be treated. Eating a healthier diet is one approach, but that may be impossible for some people (e.g., those with swallowing issues).

Eating or drinking nutritional supplements may help you gain weight and get your essential nutrients because they are generally calorie-dense and packed with protein, vitamins, and minerals.

Dietary Program

Your healthcare provider may recommend certain changes in your diet, such as adding calories, protein, or certain vitamins and minerals. Decreasing or completely avoiding certain foods may be part of your strategy as well. For example, reducing junk food or eliminating foods that cause diarrhea can be effective solutions.

You may be advised to meet with a nutritionist or a dietitian to craft a dietary plan that will provide you with the nutritional components that you need. This plan would include foods that are safe and easy for you to chew and swallow.

If you have restrictions due to liver disease (such as diminished fat absorption), your nutritional program may include spacing out your fat intake for optimal absorption. Or, if you have an intolerance of dairy products, your program can incorporate other sources of vitamin D and calcium.


If you have severe GI issues or a major illness, you might need other approaches for treating malnutrition. Injections such as vitamin B12 and vitamin D can be used to get these vitamins directly into your system if you can't take them by mouth or if your absorption is impaired.

Intravenous (IV, by vein) fluids containing essential minerals can supplement fluid and electrolytes directly into your system if you are severely ill.


If you are pregnant, undergoing chemotherapy, or have another issue that makes you feel repulsed by food, your healthcare provider may also prescribe anti-nausea medication or medication to increase your appetite.

Medications like Megace (megestrol acetate)Reglan (metoclopramide), and Marinol (dronabinol) can improve these concerns and help make it easier for you to eat a balanced diet.

Some prescription medications used to increase appetite or decrease nausea can have side effects and may not be safe during pregnancy.

Feeding Tubes

Though more drastic, for some people, a feeding tube placed in the nose, stomach, or intestines can be the most effective route for nutrients to be directly delivered into the GI system for absorption.

A nasogastric tube is a flexible tube placed in the nose and advanced into the stomach. This is typically kept in place with tape that is placed around the nostrils and the tube. It is usually temporary and can be used for nutritional feeding as well as medication.

A gastric tube can be surgically placed in the stomach, and a jejunostomy tube is surgically placed in the small intestine.

You may need to have a feeding tube surgically placed if you need long-term nutritional support.

Treating the Underlying Cause

In addition to nutritional "catching up," the cause of your malnutrition needs to be addressed as well. If you have an infection, anxiety, digestive issues, liver disease, cancer, or any other illness contributing to your malnutrition, you need to have the cause taken care of in addition to your nutritional recovery.

A Word From Verywell

Malnutrition is a serious problem that affects people worldwide for a variety of reasons. If you do not have healthy food available, it's important that you seek assistance for yourself and your family. And if a medical condition is at the root of your malnutrition, talk to your healthcare provider so you can get treatment as soon as possible.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Deborah Leader, RN
 Deborah Leader RN, PHN, is a registered nurse and medical writer who focuses on COPD.