Health Topic

Malnutrition

People suffer from hunger if they don't get enough food. Over time this can cause malnutrition. Some diseases can also cause malnutrition. Read more.

Reviewed Reviewed by a registered pharmacistGeneral information

Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.

About Malnutrition

Malnutrition means that your body isn't getting enough calories or the right balance of nutrients to stay healthy. This can happen if you don't get enough protein, carbohydrates, and fats, eat too much unhealthy food, or don't get the vitamins and minerals your body needs.

Malnutrition can affect people of all ages, but children, older adults, and people with chronic (long-term) health problems have a higher risk.

Most people think of undernutrition with malnutrition. But malnutrition can refer to undernutrition, overnutrition, or an imbalance of nutrients.

Types of malnutrition include:

  • Protein-energy undernutrition, also called macronutrient undernutrition, happens when your body doesn't get enough protein or calories from food. Two serious forms of this are kwashiorkor and marasmus.
  • An imbalanced nutritional status occurs when you are not getting the right mix of nutrients. You may get enough calories, but not enough vitamins or minerals.
  • Vitamin deficiency diseases happen when your body doesn't get enough of certain vitamins. Without the right vitamins, your body cannot stay healthy and may develop specific diseases. For example, scurvy can develop from too little vitamin C, rickets from too little vitamin D, and anemia from too little iron or vitamin B12.
  • Failure to thrive occurs when children don't gain weight or grow as expected. This may be due to not getting enough food, trouble absorbing nutrients, or other health problems.
  • Overnutrition can occur when your body gets too many calories or nutrients. This may lead to obesity or other health issues.

Malnutrition may occur for many reasons, including:

  • An unbalanced diet that lacks variety or specific nutrients.
  • Some medical issues, which could include malabsorption syndromes, dementia, eating disorders, depression, alcohol use disorder (AUD), or cancer.
  • Problems with swallowing, digestion, or dental issues.
  • Certain medicines that affect how food tastes and smells.
  • Not being able to get food or cook due to things such as chronic illness, mobility issues, or low income.

Malnutrition can affect anyone, but some people have a higher risk than others. This includes people who:

  • Don't have enough knowledge about nutrition
  • Don't have access to a variety of food
  • Are older adults or children
  • Have a low income
  • Have a chronic (long-term) illness

The symptoms of malnutrition can vary. You may have no symptoms, but if you do, they may include:

  • Fatigue and weakness
  • Dizziness
  • Losing weight without trying
  • Low body weight
  • Slow growth or development in children
  • Frequent infections or slow healing
  • Dry skin or brittle hair and nails
  • Swelling in the legs, feet, or belly

To check for malnutrition, your provider may:

  • Do a nutritional screening, which may include questions about weight loss, changes in your appetite, and your ability to eat.
  • Do a physical exam and order blood tests to check for signs that you don't have enough nutrients.
  • Refer you to other providers that specialize in nutrition, such as a dietician.

Treatment for malnutrition may include improving your diet, replacing missing nutrients, and treating the underlying cause.

To help prevent malnutrition, eat a healthy diet with many different foods. Talk with your provider if you are worried about your diet, weight loss, or your child's growth.

It sits within Food and Nutrition.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Malnutrition

2,929 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.

Start Here

Symptoms

Diagnosis and Tests

Treatments and Therapies

Prevention and Risk Factors

Related Issues

Clinical Trials

Medical subject headings

Clinicians and researchers index this subject under Malnutrition. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Malnutrition, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.