11.1 Malnutrition Screening with MUST, Nutritional Support & the Food Pyramid
Key Takeaways
- RCSI lists malnutrition, the MUST tool and the Healthy Food for Life food pyramid in its nutrition reading group, and includes intake including MUST as a current example for the fundamentals of nursing care OSCE station.
- MUST has five steps: score BMI, score unplanned weight loss over three to six months, score acute disease effect, add the three scores, then apply the management guidelines for the resulting risk category.
- BMI of 20 or above scores 0, 18.5 to 20 scores 1 and below 18.5 scores 2; weight loss under 5% scores 0, 5 to 10% scores 1 and over 10% scores 2; acutely ill with no nutritional intake for five days or more scores 2.
- A total score of 0 is low risk and routine care, 1 is medium risk and observe, and 2 or more is high risk requiring treatment including referral to a dietitian or nutrition support team.
- The Healthy Food for Life food pyramid is the Department of Health and safefood national healthy eating guide, with foods high in fat, sugar and salt placed outside the pyramid as not needed for health.
Malnutrition Screening with MUST, Nutritional Support & the Food Pyramid
RCSI names Nutrition/Malnutrition as a reading group - HSE malnutrition material, the BAPEN Malnutrition Universal Screening Tool (MUST) and the Healthy Ireland Healthy Food for Life food pyramid - and separately lists "intake including M.U.S.T." as a current example for the fundamentals of nursing care OSCE station. Assume you may be asked to complete and interpret a MUST score at a station, and to say what you would do with the result.
Why Malnutrition Matters
Malnutrition in hospital is common, under-recognised and expensive in every sense. Its consequences are direct and examinable:
- Impaired wound healing and increased surgical complications
- Pressure injury - it is a scored element on the Waterlow chart
- Immune suppression and more frequent, more severe infection
- Muscle loss, including respiratory muscle, causing weakness, falls and poor cough
- Increased length of stay, readmission and mortality
- Apathy, low mood and reduced engagement with rehabilitation
Malnutrition is not confined to thin people. A patient with obesity who has lost 12% of their body weight over three months is malnourished, and MUST will identify them where a glance will not.
MUST: The Five Steps
MUST is a five-step screening tool for adults, validated across hospital, care home and community settings.
Step 1 - BMI score
| BMI (kg/m²) | Score |
|---|---|
| 20 or above | 0 |
| 18.5 to 20 | 1 |
| Below 18.5 | 2 |
Where height cannot be measured - a patient who cannot stand, or has kyphosis - use a recalled or documented height, or a surrogate measure such as ulna length. Where BMI cannot be obtained at all, MUST provides subjective criteria based on clinical impression of thinness, clothing or jewellery becoming loose, and the patient's own report.
Step 2 - Unplanned weight loss score (over the past 3 to 6 months)
| Weight loss | Score |
|---|---|
| Less than 5% | 0 |
| 5 to 10% | 1 |
| More than 10% | 2 |
Unplanned is the operative word. A patient who has deliberately lost weight through a supervised programme is a different clinical situation from one who has lost the same weight without trying.
Step 3 - Acute disease effect score
| Situation | Score |
|---|---|
| No acute disease, or nutritional intake maintained | 0 |
| Acutely ill and there has been, or is likely to be, no nutritional intake for 5 days or more | 2 |
This step applies mainly in hospital. Both conditions must be met - being acutely unwell alone does not score.
Step 4 - Add the scores
Total the three component scores to get the overall risk.
Step 5 - Apply the management guidelines
| Total score | Risk | Action |
|---|---|---|
| 0 | Low | Routine clinical care. Repeat screening - weekly in hospital, monthly in care homes, annually in the community for vulnerable groups |
| 1 | Medium | Observe. Document dietary intake for 3 days. If intake is adequate, there is little concern and screening is repeated; if inadequate, set goals, start nutritional intervention and monitor |
| 2 or more | High | Treat. Refer to the dietitian or nutrition support team, set goals, improve and increase overall nutritional intake, monitor and review the care plan - monthly in hospital or the community, or more often as clinically indicated |
A score is not an intervention. The commonest failure at this station is calculating MUST correctly and then doing nothing with it. State the risk category and state the action.
Worked example
A 74-year-old woman weighs 48 kg and is 1.62 m tall. She reports weighing 56 kg three months ago. She has been acutely unwell with pneumonia and has eaten almost nothing for six days.
- BMI = 48 / (1.62 x 1.62) = 48 / 2.62 = 18.3 kg/m² → below 18.5 → score 2
- Weight loss = 8 kg from 56 kg = 8 / 56 = 14.3% → more than 10% → score 2
- Acutely ill with no intake for more than 5 days → score 2
- Total = 6. High risk. Refer to dietetics, set nutritional goals, commence a food and fluid chart, and review the care plan.
Nutritional Support in Practice
Accurate recording first. A food chart that says "diet taken" is useless. Record what was offered and what was actually eaten - a proportion or a description. The same applies to fluids: record volumes, not "drinking well".
Protected mealtimes. Non-urgent activity - ward rounds, phlebotomy, cleaning - pauses so patients can eat with assistance available. A meal delivered and removed untouched 20 minutes later while the patient was at X-ray is a missed meal that no chart will show unless someone records it.
Practical measures:
| Barrier | Nursing response |
|---|---|
| Poor appetite | Small, frequent, energy-dense meals; the patient's preferred foods; food from home where permitted |
| Poor dentition or ill-fitting dentures | Modified texture; dental referral; ensure dentures are in and clean |
| Difficulty with cutlery, tremor, weakness | Adapted cutlery, plate guards, occupational therapy referral, assistance with eating |
| Poor positioning | Sit upright at 90 degrees, table at the right height, out of bed into a chair where possible |
| Nausea, pain, constipation | Treat the symptom before the mealtime, not after it |
| Repeated fasting for procedures | Challenge unnecessary fasting; ensure the patient is fed once the procedure is over |
| Dysphagia | Speech and language therapy referral; follow the prescribed texture and fluid consistency exactly |
| Low mood, isolation | Company at mealtimes, dining out of bed, involving family |
Food fortification raises energy and protein without raising volume: full-fat milk, added cream, butter, cheese, milk powder fortification, nourishing drinks between meals. Oral nutritional supplements are prescribed on dietetic advice; they supplement food, they do not replace it, and they should be given between meals rather than immediately before, so they do not displace the meal.
Escalating support. Where oral intake remains inadequate, enteral feeding by nasogastric tube is considered, and parenteral nutrition only where the gut cannot be used.
Refeeding Syndrome
Refeeding syndrome is the potentially fatal shift of fluid and electrolytes that occurs when nutrition is reintroduced to a severely malnourished person. As carbohydrate intake resumes, insulin drives phosphate, potassium and magnesium into cells, causing hypophosphataemia, hypokalaemia and hypomagnesaemia, with thiamine depletion, fluid overload, arrhythmias, respiratory failure, seizures and cardiac arrest.
At risk: very low BMI, substantial unintentional weight loss, little or no intake for an extended period, low baseline potassium, phosphate or magnesium before feeding, and a history of alcohol dependence or of drugs such as insulin, diuretics or antacids.
Nursing role: identify the risk before feeding starts, escalate to medical and dietetic teams, ensure baseline and daily electrolytes are taken, expect thiamine and B vitamins before and during the first days of feeding, feed cautiously at the prescribed rate, and monitor observations, fluid balance and ECG as directed. The danger arrives with the first feed, not with the starvation.
The Food Pyramid: Healthy Food for Life
The Healthy Food for Life food pyramid is Ireland's national healthy eating guide, produced by the Department of Health with safefood and the HSE. It is the tool to use for any healthy-eating teaching station - including the obesity, BMI and waist circumference teaching example and the type 2 diabetes chronic disease example.
From the base upwards:
- Vegetables, salad and fruit - the largest shelf; at least five to seven servings a day.
- Wholemeal cereals and breads, potatoes, pasta and rice - servings vary with age, size and activity level, with wholegrain versions encouraged.
- Milk, yogurt and cheese - around three servings a day, with low-fat options encouraged, and five servings for those aged 9 to 18.
- Meat, poultry, fish, eggs, beans and nuts - around two servings a day, with lean choices, oily fish twice a week and limited processed red meat.
- Fats, spreads and oils - the smallest shelf; use in very small amounts, favouring unsaturated oils.
Outside the pyramid: foods and drinks high in fat, sugar and salt. These are shown deliberately outside the shape because they are not needed for good health; the guidance is a maximum of once or twice a week in small amounts.
Alongside the pyramid, the national guidance covers portion size, reading food labels, limiting salt, drinking 8 to 10 cups of fluid a day, and being physically active - RCSI also lists the HSE weekly low-risk alcohol guidance under chronic disease management, which belongs in the same conversation.
A patient has a BMI of 17.8 kg/m², has lost 6% of her body weight unintentionally over the past four months, and has been eating normally with no acute illness. What is her MUST score and the required action?
A severely malnourished patient with a BMI of 14 and minimal intake for two weeks is about to start nutritional support. Which nursing action is most important?
Where are foods and drinks high in fat, sugar and salt placed on the Healthy Food for Life food pyramid, and what does that placement mean?