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What is Malnutrition?

Contributors: Esther Ellis, MS, RDN, LDN

Published: August 04, 2021

Reviewed: August 23, 2021

What is Malnutrition?
KatarzynaBialasiewicz/iStock/Getty Images Plus/Getty Images

Malnutrition is a common and detrimental condition that must be addressed quickly and comprehensively. Registered dietitian nutritionists are working hard to improve the speed and accuracy of malnutrition diagnosis and nutrition interventions in health care. Malnutrition is a physical state of unbalanced nutrition. It can mean undernutrition or overnutrition. When most people think of malnutrition, they usually picture undernutrition, which can be caused by a lack of calories, protein or other nutrients. This occurs frequently in areas of the world without adequate access to food and clean drinking water.

Overnutrition comes from eating too many calories. Someone can eat more calories than their body needs and be malnourished at the same time. They may not be eating enough nutritious foods such as fruits, vegetables, whole grains, lean protein, beans, low-fat dairy, nuts and seeds. This can result in vitamin, mineral or protein deficiencies. In the United States, this more commonly occurs in food insecure, impoverished areas.

Malnutrition in children, especially young children, can lead to stunted growth, developmental delays and more sickness due to poor immune function.

Clinical malnutrition is when a hospital patient becomes malnourished. There are many reasons why someone in the hospital may not be getting enough nutrition. For example, their body requires more nutrition than usual, or they are not able to absorb the nutrients they eat. Some hospital patients need to receive nutrition through a tube inserted into their stomach or even intravenous nutrition, where the digestive tract is bypassed altogether.

It is important that malnutrition is diagnosed in a timely manner. When a hospital patient becomes malnourished their medical treatment and recovery are affected. Research shows that malnutrition increases the risk of death, length of stay and health care costs. Hospitals are required to screen for malnutrition within 24 hours of patient admission.

Registered dietitian nutritionists make recommendations and work with the health care team to help patients receive the nutrition they need. RDNs assess malnutrition using weight history, dietary intake, lab values and a physical exam. A nutrition-focused physical exam, also known as an NFPE, involves checking for body fat and muscle loss, fluid accumulation and hand grip strength. The Centers for Medicare and Medicaid Services requires long-term care facilities to employ registered dietitian nutritionists to manage the nutrition care of residents.

Malnutrition also can be the result of an eating disorder, organ failure or severe infection or physical trauma such as a head injury. Malnutrition frequently occurs in the older adult population, especially in those with dementia or Alzheimer’s disease. Tooth loss and other dental issues, loss of appetite and functional decline are contributing factors to malnutrition among older adults.

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