What is malnutrition?

Malnutrition remains one of the most pressing health challenges worldwide, affecting millions of people across all age groups, genders, and socio-economic statuses. This blog explores what malnutrition is, who is at risk, how to identify it, its consequences, and strategies for prevention and treatment.

What is malnutrition?

Malnutrition is a condition that occurs when an individual's diet does not provide adequate nutrients for proper functioning or when the body cannot effectively utilise the nutrients it receives.¹ It encompasses both undernutrition (e.g., deficiencies in calories, protein, or micronutrients) and overnutrition (e.g., excess consumption of calories, leading to obesity and associated health risks).¹

Types of malnutrition

Undernutrition

Stunting: Low height for age
Wasting: Low weight for height
Micronutrient deficiency: Lack of essential vitamins and minerals like iron, iodine, vitamin A, and zinc.

Overnutrition

Overweight and obesity: Excess body weight due to an imbalance between energy intake and expenditure.
Micronutrient excess: Overconsumption of certain nutrients, sometimes leading to toxicity (e.g., excessive vitamin A or iron).

Who is at risk of malnutrition?

Certain populations are more vulnerable to malnutrition due to various socio-economic, health, and demographic factors²:

The elderly

People over the aged of 65 are more at risk, particularly if they are living in a nursing home or have been admitted to hospital. Malnutrition can make older people more susceptible to disease, making their nutritional status worse and impairing recovery.

People with long-term conditions

Conditions like cancer, diabetes, kidney disease and chronic lung disease increase the body’s energy demands while impairing nutrient absorption.

People who abuse drugs or alcohol

Limited access to nutritious foods can lead to diets that are nutrient-poor.

In addition, physical factors can increase the risk of malnutrition²:

Eating can be challenging due to mouth or tooth pain
Difficulty chewing may arise from poor dental health or the absence of dentures
Swallowing might be painful or impaired, such as after a stroke
A reduced sense of smell or taste can diminish appetite
Inability to cook independently may lead to lower food consumption
Limited mobility or lack of transportation can hinder access to food
Dependence on others for assistance with eating and drinking

How to spot malnutrition

Recognising malnutrition early is crucial for effective intervention^1,3. While signs vary depending on the type and severity of malnutrition, here are common indicators:

Physical signs include:

Undernutrition:

Low body weight and muscle wasting
Stunted growth in children
Getting ill more often ad taking a long time to recover
Wounds taking longer to heal
Feeling cold most of the time

Behavioural and developmental signs include:

Irritability, lethargy, or low energy levels
Difficulty concentrating
Delayed physical or cognitive development in infants and toddlers
Lack of interest in food and drink

What are the consequences of malnutrition?

Malnutrition impacts every system in the body, increasing susceptibility to illness, complications, and, in severe cases, even death⁴:

Immune system

Reduced capacity to fight infections

Muscles

Decreased mobility, leading to difficulty with tasks like working, shopping, cooking, and self-care
Inactivity can contribute to pressure ulcers and blood clots

Respiratory system

Reduced ability to cough, increasing the risk of chest infections and pneumonia

Cardiovascular system

Heart failure

Wound healing

Delayed or impaired healing processes

Kidneys

Difficulty regulating salt and fluid balance, potentially causing over-hydration or dehydration

Brain and mental health

Apathy, depression, social withdrawal, self-neglect, and reduced social engagement

Reproductive health

Lower fertility
During pregnancy, malnutrition may lead to long-term health issues for the baby, such as diabetes, heart disease, or stroke later in life

Temperature regulation

Impaired ability to regulate body temperature, increasing the risk of hypothermia

Effects of malnutrition in children and adolescents

Growth failure and stunting
Delayed sexual maturation
Reduced muscle mass and strength
Cognitive impairment and delayed intellectual development
Increased risk of rickets and long-term osteoporosis

Consequences of specific micronutrient deficiencies

Iron deficiency: Causes anaemia.
Zinc deficiency: Leads to skin rashes and weakened immunity.
Vitamin B12 deficiency: Can result in anaemia and nerve damage.
Vitamin D deficiency: Causes rickets in children and osteomalacia in adults.
Vitamin C deficiency: Leads to scurvy.
Vitamin A deficiency: Results in night blindness.

What is the scale of the problem when it comes to malnutrition?

BAPEN’s Malnutrition and Nutritional Care Survey in Adults 2022 highlighted that nearly half (45%) of adults screened across UK health and care settings were at risk of disease-related malnutrition—the highest percentage recorded since the survey began in 2019.⁵

Conducted in October 2022, the survey found malnutrition prevalence was particularly high among individuals with:

Cancer: 62%
Gastrointestinal conditions: 50%
Respiratory conditions: 48%
Frailty: 45%
Neurological diseases: 43%

Malnutrition prevalence by setting was as follows:

Own homes: 56%
Care homes: 55%
Hospitals: 44%

The survey utilised the Malnutrition Universal Screening Tool (MUST), the UK’s most widely used screening method, to assess adults of all ages across diverse settings and conditions. Participants included individuals with a range of primary diagnoses such as neurological diseases (20%), gastrointestinal conditions (16%), frailty (12%), cancer (9%), and others (respiratory conditions, COVID-19, falls and fractures, and cardiovascular issues). Key findings revealed:

24% of patients were underweight
17% were obese
26% experienced unplanned weight loss

How can malnutrition be identified, prevented and treated?

Recognising those at risk of malnutrition is a critical first step. Once individuals and their caregivers are aware of the issue, simple strategies to increase food intake may often be sufficient to break the cycle of decline.⁶

The easiest and quickest way to detect those at risk of malnutrition is by the use of malnutrition screening tools, such as the ‘Malnutrition Universal Screening Tool’ (‘MUST’).⁷ This tool consists of three parts:

Measuring Body Mass Index (BMI) – this is calculated from an individual’s weight and height. A BMI of less than 18.5kg/m2 suggests a significant risk of malnutrition.
Considering any history of recent weight loss that has occurred without any intention to lose weight. The unintentional loss of more than 10% of normal body weight in the last 3 -6 months suggests a significant risk of malnutrition.
Identifying an “acute disease effect” associated with being acutely ill and being unable to eat adequate amounts for more than five days.

‘MUST’ identifies patients as being at low, medium or high risk of malnutrition and guides the user to develop individualised care plans for management or further monitoring.

After identifying the risk of malnutrition, a detailed assessment is necessary to identify any contributing factors. Care should be personalised to the individual’s needs. If the person can eat and drink normally, a “Food First” approach is typically recommended. This involves providing guidance on meals, snacks, nourishing drinks, and food fortification. It is important to set treatment goals and establish a monitoring plan to ensure these goals are met.

When food-based measures are insufficient, or the individual has a reduced appetite, a dietitian’s support may be required. Oral nutritional supplements (ONS) might be prescribed to complement food intake. These are generally used under the supervision of a dietitian or doctor. Research indicates that ONS can reduce complications related to malnutrition—such as infections, pressure ulcers, and delayed wound or fracture healing—by approximately 30%.⁸

Nutritional support for patients unable to eat or drink normally

When oral intake is not possible, nutrition may need to be delivered via tube feeding or intravenously. The specific method depends on the individual’s condition.

Enteral nutrition (tube feeding)

Nasogastric tube (NGT): A tube passed through the nose into the stomach, typically used for short-term feeding during recovery but may be extended as needed.
Percutaneous endoscopic gastrostomy (PEG): A tube inserted directly into the stomach through the abdominal wall for long-term feeding.
Jejunal tube: For conditions where stomach feeding is not viable, a tube may be placed in the jejunum (the small intestine) either through the nose (nasojejunal) or the abdominal wall (jejunostomy).

Parenteral nutrition (PN)

If the gut cannot be used for nutrition, parenteral nutrition (PN) may be necessary. This involves delivering sterile nutrients through a venous catheter, often inserted into a central vein.

Short-term PN: Usually administered in a hospital setting for a few weeks as the patient recovers.
Home parenteral nutrition (HPN): For patients with long-term conditions where PN is the only source of nutrition and hydration, care may continue at home.

Conclusion

Malnutrition is a complex issue, but it is preventable and treatable. By prioritising access to good nutrition, we have the opportunity to help those at risk thrive. We hope this blog helped you learn more about how to protect you and your loved ones against malnutrition.

References:

BAPEN, n.d. Introduction to Malnutrition. Available at: https://www.bapen.org.uk/malnutrition/introduction-to-malnutrition/ Accessed December 2024
BAPEN, n.d. Who is at Risk of Malnutrition?. Available at: https://www.bapen.org.uk/malnutrition/introduction-to-malnutrition/who-is-at-risk-of-malnutrition/ Accessed December 2024
NHS, n.d. Symptoms of Malnutrition. Available at: https://www.nhs.uk/conditions/malnutrition/symptoms/ Accessed December 2024
BAPEN, n.d. What are the Consequences of Malnutrition?. Available at: https://www.bapen.org.uk/malnutrition/introduction-to-malnutrition/what-are-the-consequences-of-malnutrition/ Accessed December 2024
BAPEN, n.d. What is the Scale of Malnutrition in the UK?. Available at: https://www.bapen.org.uk/malnutrition/introduction-to-malnutrition/what-is-the-scale-of-malnutrition-in-the-uk/ Accessed December 2024
BAPEN, n.d. How is Malnutrition Prevented and Treated?. Available at: https://www.bapen.org.uk/malnutrition/introduction-to-malnutrition/how-is-malnutrition-prevented-and-treated/ Accessed December 2024
BAPEN, n.d. How is Malnutrition Recognised?. Available at: https://www.bapen.org.uk/malnutrition/introduction-to-malnutrition/how-is-malnutrition-recognised/ Accessed December 2024
Clinical Nutrition Journal, 2018. Abstract. Clinical Nutrition, [online] Available at: https://www.clinicalnutritionjournal.com/article/S0261-5614(18)32343-4/abstract Accessed December 2024

What is malnutrition?