Although malnutrition is frequently identified in acute settings where nutrition screening is mandatory, 93% of those affected reside in the community (Elia and Russell, 2009), highlighting the need for vigilance and attention to those at risk. Where individuals are identified at risk during a hospital admission, the short length of hospital stays means that the period required to effectively treat and reverse malnutrition extends considerably beyond hospital discharge, necessitating the need for continued nutritional care, including the use of oral nutritional supplements (ONS) in the community.
Financial and clinical consequences of malnutrition
The National Institute for Health and Care Excellence (NICE, 2006) has shown that substantial cost savings can be achieved through identifying and treating malnutrition, subsequently reducing health and care use (Stratton et al, 2018). Failing to identify and treat malnutrition not only increases healthcare costs, but is also associated with poorer quality of life and has a particularly high adverse impact on the older person, impairing function, mobility and independence (Morley et al, 2013; Gossier et al, 2016).
As the impact of malnutrition is so wide-ranging, from an individual to a macro-economic level, every effort should be made to identify those at risk at the earliest opportunity so that suitable interventions can be acted on in a timely manner, to help prevent the adverse effects of malnutrition or slow the rate of deterioration; for example, in long-term conditions and in palliative care.
Identifying those at risk of malnutrition
Malnutrition can develop insidiously over weeks and months in the community, and with two thirds of the population overweight or obese, the risk is often overlooked. Validated screening tools are recommended to identify malnutrition in a timely manner especially among those at risk (NICE, 2006). The most widely used screening tool in the UK, validated for use in acute and community settings, is the Malnutrition Universal Screening tool (MUST) (https://www.bapen.org.uk/pdfs/must/must_full.pdf).
For ease, a self-screening tool has been developed that can be used by patients and health professionals. Knowing current weight, height, weight in the past 3–6 months, the tool automatically calculates malnutrition risk based on body mass index, percentage weight loss over time and includes a score for interrupted food intake (https://www.malnutritionselfscreening.org/self-screening.html). A score of 1 indicates a moderate risk of malnutrition and a score of 2 or more a high risk of malnutrition.
If physical measures are not possible, it is considered acceptable to use patient-reported values of current weight, height, and previous weight or a series of subjective criteria to form a clinical impression of an individual's malnutrition risk category. This includes thinness, unplanned weight loss as noted through fitting of clothing or jewellery, history of reduced food intake, appetite and/or dysphagia (swallowing problems) over 3–6 months and the presence of underlying disease or psycho-social/physical disabilities likely to cause weight loss such as illness, trauma, infections and breathlessness.
Screening for malnutrition is encouraged in the following instances (NICE, 2006; 2012):
| ONS type | Description |
|---|---|
| Chronic disease (consider acute episodes) | Chronic obstructive pulmonary disease (COPD), cancer, gastrointestinal disease, renal or liver disease and inflammatory conditions such as rheumatoid arthritis, inflammatory bowel disease |
| Progressive neurological disease | Dementia, Parkinson's disease, motor neurone disease (MND) |
| Acute illness | Where adequate food is not being consumed for more than 5 days (more commonly seen in a hospital than a community setting) |
| Debility | Frailty (including sarcopenic frail), immobility, old age, depression, recent discharge from hospital, sarcopenic obesity |
| Social issues | Poor support, housebound, difficulty obtaining or preparing food |
| Prehabilitation | Pre-operatively or preparing for cancer treatment |
| Rehabilitation | After stroke, injury, cancer treatment, after hospital admission, after ICU |
| End of life/palliative care | Note in the last few weeks or months, focus may move from achieving requirements to offering comfort foods, comfort eating, good mouth care, a shift to eating snacks and nibbles, replacing food-based activities with other activities if eating is stressful, explaining to family members that the person may not be experiencing hunger |
Adapted with permission from Malnutrition Pathway www.malnutritionpathway.co.uk
Managing malnutrition
Current recommendations from NICE (2006) state that malnutrition should be managed where possible using oral nutrition support. This can include dietary advice, food fortification to provide all nutrients, altered meal patterns, assistance with feeding and ONS to be prescribed until adequate intake from other sources is achieved or anticipated (Box 1).
Options to improve nutritional intake (NICE, 2006)
*Counselling is usually carried out by dietitians. It differs from dietary advice as it includes a thorough assessment of patients medical, social, psychological and physical needs to tailor and personalise nutrition advice
Non-disease-related malnutrition
Malnutrition in the absence of disease, referred to as non-disease-related malnutrition (non-DRM), encompasses socio-economic, psychological and hunger-related malnutrition. The underlying cause is a lack of access to food and/or lack of consumption of food due to factors other than disease and illness. Complex needs arising from issues, such as poverty, poor housing or homelessness, mental health problems or substance abuse often accompany this diagnosis (Holdoway, 2023). Ageing, poor mobility, lack of transport, social isolation and loneliness can make it difficult to access or consume adequate food. Similarly, self-neglect, poor dentition and grief can contribute to non-DRM.
An approach to address the root cause of non-DRM, including improved access to food and support to consume adequate nutrition using a ‘food-first’ or ‘food-based’ approach, is considered an appropriate treatment of choice (British Association for Parenteral and Enteral Nutrition (BAPEN, 2024a). Collaboration with other agencies to ensure that there is support to access or consume adequate food is also often required, e.g. engaging with charities and organisations, social services and community healthcare providers to provide food and meals, shelter, housing. Advice on mealtime environments, feeding or use of specialist cutlery and plates may be required. In non-DRM ONS are not usually used.
Disease-related malnutrition
Managing disease-related malnutrition (DRM) relies on unpicking the factors that are contributing to the reduced dietary intake or recognising the increased nutritional requirements to adjust the diet accordingly. Dietary advice given in the past for prevention of cardiovascular disease or diabetes, for example, may need to be adjusted or put into context when an individual is at risk of malnutrition, as dietary restrictions may hamper an individual's ability to meet nutritional requirements.
Decision-making for managing malnutrition associated with the presence of any disease or medical condition should consider the wide array of physiological processes of ill-health and loss of appetite as these factors can limit the effectiveness of food-based interventions (Cederholm et al, 2019). In these circumstances dietary advice and dietary counselling needs to be carefully tailored to respect symptoms, account for disease physiology and side effects of treatment.
Inflammation associated with many clinical conditions such as cancer, COPD, infection and trauma, creates a cascade of physiological and metabolic effects which in turn can suppress appetite, the desire to eat, induce early satiety (a feeling of fullness), and have adverse effects on the sensation of eating (Cederholm et al, 2019). In those with DRM, the use of food alone may not be sufficient to address the deficit in intake and achieve repletion of nutritional status, or slow or halt deterioration (Cederholm et al, 2019). ONS may therefore be used to complement dietary modifications.
In individuals at high-risk of malnutrition in whom significant amounts of weight and lean tissue have been lost, and where factors hampering food intake or absorption cannot be reversed, a food-based only approach may not be sufficient to treat or reverse malnutrition.
Often, rapid unintentional weight loss and factors hampering food intake or absorption cannot be reversed or treated. Indeed, in some cases, the use of food-based approaches may be limited due to underlying conditions such as malabsorption or gastrointestinal issues limiting the intake of certain foods; for example, advice to eat more food or fortify food may exacerbate disease symptoms or cause unpleasant side effects such as nausea or increase fat malabsorption where diarrhoea is a problem (Holdoway, 2023).
Oral nutritional supplements
ONS are multi-nutrient liquid, semi-solid or powder products that provide macronutrients and micronutrients with the aim of increasing oral nutritional intake. ONS are distinct from dietary supplements (also known as food supplements) which provide only vitamins minerals and trace elements. The nutritional content of ONS varies according to the intended use. ONS typically provide energy and protein intake but also micronutrients (up to a third of micronutrient requirements in one unit of ONS). An individual consuming ≥2 nutritional supplements containing vitamins and minerals, in conjunction with even a limited diet, is likely to meet daily requirements for vitamins and minerals (Public Health England, 2016).
One to three units of ONS are typically used in addition to the diet when diet alone is insufficient to meet daily nutritional requirements. A product that is classed as ‘nutritionally complete‘ can be used as a sole source of nutrition if taken in sufficient quantity. Due to heterogeneity in the studies evaluating oral nutrition support, the dose and duration of ONS derived from clinical trial data alone remains unclear. In clinical practice, product choice, dose and duration should be determined on an individual basis to optimise outcomes (Holdoway et al, 2022).
Clinical benefits are often seen with 300–900 kcal/day (e.g. 1–3 ONS servings per day) (NICE, 2006; Stratton and Elia, 2007). Larger quantities may be necessary dependent on requirements and when ONS is the only source of nutrition, e.g. 5–7 units may be used when the ONS is being administered as a bolus feed for an individual on tube feeding, who has high requirements and intake from normal food and drink is neither possible nor practical.
Practitioners often express concern that ONS interfere with volitional food intake. However, evidence shows that liquid ONS when given in addition to meals tend not to disrupt volitional food intake and so are additive to dietary intake (Stratton and Elia, 2007). Many variants have been developed of varying nutrient content to meet a range of specific nutritional requirements, offering products with different organoleptic properties (taste, mouthfeel and texture) to enable health professionals to tailor the product to an individual's needs and preferences (see Table 2).
| ONS type | Description |
|---|---|
| Milkshake/yogurt style type ready-to-use | Volume ranges from 125–220 ml, energy density ranges from 1–2.4 kcal/ml. Added fibre and high protein versions also available |
| Juice type | Volume ranges from 200–220 ml, energy density ranges from 1.25–1.5 kcal/ml. Fat free/low in fat but high in carbohydrates |
| Soup type | Volume ranges from 200–330 ml. Options include ready mixed and powder to make up with water or milk to give an energy density of 1–1.5 kcal/ml |
| Powdered milkshake or juice style drinks | Volume ranges from 125–350 ml. Ideally made up with full cream milk to give an energy density of 1.5–2.5 kcal/ml |
| Disease specific | Modified to assist in the dietetic management of specific diseases or conditions, e.g. elemental/peptide formulation for the management of malabsorption |
| Semi-solid/dysphagia ranges | Range of presentations from thickened liquids (stage 1 and 2) to smooth pudding styles (stage 3), with an energy density of 1.4–2.5 kcal/ml |
| High protein | Range of presentations; jellies, shots, milkshake style containing 11–20 g of protein in volumes ranging from 30–220 ml |
| Low volume high concentration (shots) | These are fat and protein-based products that are taken in small quantities (shots), typically 30–40 ml as a dose taken 3–4 times daily |
Cost and clinical effectiveness of ONS
For the purpose of randomising participants to the interventions being tested, many trials have evaluated the use of ONS vs dietary advice. In clinical practice, a survey highlighted that an approach combining dietary advice and ONS was commonly used by dietitians (up to 62% of those surveyed) when managing those at nutritional risk (Gibbs et al, 2019). Initiatives to manage the costs of ONS are relatively widespread in the community and are of merit in ensuring costs are managed through appropriate prescribing initiatives combined with recommending products in line with local formulary guidance. Many individuals in hospital will receive ready to drink ONS as this is safe, convenient and reduces the need for staff to be mixing products. In some localities, switches to lower cost ONS including powdered products has been a means of reducing the cost of ONS in the community.
When switches are made, adherence should be checked at the earliest opportunity to ensure the alternative is acceptable as a product not consumed has no nutritional benefit. In addition, if a person has been discharged from hospital on a specific ONS as advised by a dietitian, there may be clinical reasons including nutrient content, determining the specific ONS recommended and hence it is advisable to contact the dietitian or dietetic department before switching products as an adverse consequence may arise from a blanket switch.
A 2022 meta-analysis of 11 studies of malnutrition in frail older people suggested positive effects of oral nutritional supplements compared with standard care for energy intake (kcal) and poor mobility but no evidence of an effect for body weight and body mass index (Thompson et al, 2022). The NIHR is currently calling for further research to determine the effectiveness of ONS (with or without other nutritional support) in older people with frailty (NIHR, 2023). NICE guidance (2006) and evidence from systematic reviews and meta-analysis (Baldwin et al, 2021) demonstrate that ONS in addition to diet can be clinically and cost-effective in managing malnutrition, particularly in people at high risk.
Promoting adherence
Patients may struggle with the volume of products and, as with our food likes and dislikes, taste can be very individual. Optimising adherence to the recommended treatment can be influenced by several factors including:
Dietary intolerances (for example, cow's milk protein), malabsorption (for example, lactose malabsorption), the presence of diabetes, renal function, metabolic status, cost and affordability, palatability, and the individual's ability to reconstitute a powdered product, should all be considered when selecting the most suitable ONS.
For those with diabetes, ONS with the lowest glycaemic index should be chosen where possible and if acceptable to the individual. As the presence of fat and protein in an ONS reduces the glycaemic index, the composition of the ONS will affect glycaemic index hence juice-style ONS with little or no fat, tend to be higher glycaemic index and less suitable for those with diabetes than milk shake style ONS. Advising on taking the ONS in 30–50 ml doses may help avoid peaks in blood glucose levels. As illness can adversely affect blood glucose, adjustment of medication or insulin should be considered rather than defaulting to dietary restrictions which limit intake and worsen malnutrition.
Prescribing of ONS in the community
ONS prescriptions should be clinically appropriate, meet the ‘ACBS’ criteria and be linked to goals (BAPEN, 2024b). Dietitians use comprehensive nutrition assessment to determine the need for ONS but as malnutrition affects so many individuals, other members of the healthcare team may need to decide on the use of ONS if timely access to a dietitian is not possible as delaying appropriate nutrition support may lead to further deterioration.
In the community, ONS are typically indicated when the following criteria are present (Elia, 2003):
There may be local guidance in place on whether over the counter should be or can be tried first, whether the use is managed only by dietitians, or a request needs to go via the GP. Duration of supplementation is hugely variable and can range from weeks to months to years, according to the clinical rationale for use and whether goals are being met. The malnutrition pathway (www.malnutritionpathway.co.uk) guides the appropriate use of ONS, including advice on when to review and stop prescriptions.
Goal-setting
As with the provision of any healthcare, goal-setting with the individual can help with motivation, evaluate adherence, and assess the clinical and cost effectiveness of care. Goals should be co-created with the patient and the family to establish what matters to them. In nutrition, goals can be variable and can include weight gain, muscle gain, feeling stronger, being able to socialise, work, continue with activities of daily living, being able to cope, and alleviating symptoms associated with eating and drinking. Adherence and acceptability should be regularly monitored to enable the amount and type of ONS to be adjusted according to clinical status, level of adherence, effectiveness and ongoing need.
Conclusion
In individuals at high risk of malnutrition and in those who are malnourished secondary to a medical condition or disease, ONS can be a clinical and cost-effective tool (NICE, 2006; Cawood et al, 2012; Stratton et al, 2013). As the role of eating and drinking also holds much meaning in our lives, improving the eating experience is important for quality of life alongside using ONS. Timely individualised interventions can help prevent the carousel of malnutrition that can occur when ONS are discontinued.