The NHS definition of malnutrition
According to the NHS, malnutrition is a serious condition that occurs when a person's diet does not contain the right amount of nutrients. Most commonly, this is caused by undernutrition—not eating enough food, or not eating a sufficient variety of the right foods to provide the body with essential calories, protein, vitamins, and minerals. A balanced diet, as promoted by the NHS's Eatwell Guide, is key to preventing malnutrition and maintaining overall health. When intake is insufficient, the body begins to break down its own tissues for energy, leading to a cascade of health issues.
Short-term signs and symptoms of under-eating
Recognising the early signs of under-eating can help prevent the condition from worsening. These symptoms often develop gradually and may be mistaken for general tiredness or stress. The NHS highlights several key indicators:
- Unintentional weight loss: Losing 5% to 10% or more of your body weight over 3 to 6 months without trying is a primary indicator.
- Fatigue and low energy levels: A continuous feeling of tiredness or weakness is common, as the body lacks the fuel to perform essential functions.
- Changes in appetite: A reduced appetite or a general lack of interest in food and drink is often reported.
- Reduced physical and mental function: Individuals may experience a reduced ability to carry out everyday tasks, poor concentration, and low mood, including depression.
- Increased illness: A weakened immune system can lead to getting ill more often and taking longer to recover from infections.
- Feeling cold: Without enough calories, the body struggles to maintain a normal core temperature, causing a persistent feeling of coldness.
Long-term health consequences of malnutrition
If under-eating is prolonged, the effects on the body become more severe and can have lasting impacts on nearly every organ system. The body breaks down muscles and tissues, leading to serious complications.
Impact on organ function
Long-term nutritional deficiency can lead to a reduction in cardiac muscle mass, resulting in a decreased cardiac output, a slower heart rate, and low blood pressure. The respiratory system can also be affected, with a reduction in respiratory muscle function impairing the ability to breathe effectively. Gastrointestinal issues such as reduced pancreatic function, altered gut architecture, and chronic diarrhoea can also develop.
Effects on bone health
Inadequate calorie and nutrient intake can significantly lower hormone levels, including sex hormones like oestrogen, which can accelerate bone loss and increase the risk of developing osteopenia or osteoporosis. This makes bones more fragile and prone to fractures.
Compromised immunity
Malnutrition impairs the immune system, making the body less effective at fighting off infections. This leads to an increased risk of getting sick and can also delay wound healing, making recovery from injuries or surgery more difficult.
Neurological and mental health issues
The brain, which consumes a high percentage of the body's energy, is particularly vulnerable to nutrient deficiency. This can cause poor concentration, memory problems, and changes in mood, such as increased irritability, anxiety, and depression. In severe cases, vitamin deficiencies can lead to neurological problems like tingling sensations, muscle weakness, and even confusion or dementia.
Comparison: Balanced Nutrition vs. Undernutrition
| Aspect | Balanced Nutrition (NHS Eatwell Guide) | Undernutrition (Signs of deficiency) |
|---|---|---|
| Energy Levels | Sustained energy throughout the day for physical and mental activity. | Persistent fatigue, tiredness, and weakness even with rest. |
| Immune System | Strong immune response, recovering quickly from illness. | Weakened immune system, frequent infections, slow recovery time. |
| Body Weight | Maintained at a healthy weight, in proportion to height. | Unintentional weight loss, low BMI, loose clothing/jewellery. |
| Cognitive Function | Good concentration, mental clarity, and memory. | Poor concentration, memory issues, 'brain fog'. |
| Mood | Stable mood, less prone to irritability or anxiety. | Mood swings, irritability, low mood, or depression. |
| Healing | Efficient wound healing and tissue repair. | Slower than normal wound healing and prolonged recovery. |
How to address undernutrition
If you believe you are experiencing under-eating or malnutrition, the NHS advises speaking to a GP or other healthcare professional. They can properly assess your nutritional status, potentially using a screening tool like the Malnutrition Universal Screening Tool (MUST). Depending on the severity, they may recommend a 'food first' approach, dietary fortification, or in more severe cases, referral to a dietitian.
Steps to take based on NHS guidance
- Prioritise balanced meals: Follow the NHS Eatwell Guide, which advocates for a balanced intake of starchy carbohydrates (ideally wholegrain), a variety of fruit and vegetables, protein foods, and dairy or dairy alternatives.
- Increase energy density: If your appetite is small, try fortifying foods with extra energy and protein, such as adding grated cheese to soup or a spoonful of milk powder to a milky drink.
- Eat little and often: For those with a reduced appetite, grazing on smaller, frequent meals and snacks throughout the day can be more manageable than trying to eat large meals.
- Seek professional help: If symptoms persist or you are concerned, consult a GP. They can provide tailored advice or refer you for specialist support.
Conclusion
Ignoring the signs of not eating enough can lead to serious health repercussions, with malnutrition affecting everything from physical strength and mental clarity to long-term organ function. The NHS provides clear guidance on recognising the symptoms and outlines a path to recovery, emphasising the importance of a balanced diet and seeking professional help when needed. Taking a proactive approach to your nutrition is a critical step towards safeguarding your overall health and well-being. For more information on recognising and managing malnutrition, you can refer to the official NHS website.
