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High Protein ONS

 By Emily Walters RD  @EmilyWaltersRD


We know how difficult it can be for adult patients who are struggling with a poor appetite due to illness to consume adequate protein with symptoms or treatments of their condition often hampering our best efforts to maximise food intake. This is extremely topical right now as we work out how best to nutritionally manage those with COVID-19.

The importance of high protein* medical nutrition including oral nutritional supplements (ONS) and tube feeds is highlighted in recent guidance for patients with COVID-19 across all care settings including the Intensive Care Unit, hospital wards, care homes and patients’ own homes. 

*To qualify as ‘high protein’, legislation states that at least 20% of the energy should be provided from protein.

Much of this guidance is based on existing evidence for high protein ONS and tube feeds in a wide range of non-COVID patient groups.  This transferable evidence comes not only from clinical trials but also from clinicians observations from their own practice. There is also now greater clarity around protein requirements, especially for older people. Therefore many guidelines and pathways now feature high protein products.

Over recent years, we have seen more high protein ONS developed for us to use in our clinical practice including ready to drink, compact style, powders and desserts, with varying energy densities, different serving sizes and a range of micronutrient profiles. The protein source and composition also differ.  

Finding the most appropriate high protein ONS for each individual patient is important. Patient-related factors to consider are many and include clinical condition, age, appetite, nutritional requirements and status, physical ability and social factors. Factors related to the ONS product are also important and include patient preference, energy density, protein source, micronutrient content, volume, ease of use and palatability including flavour, mouthfeel and texture. The availability of reimbursement for community use (ACBS in the UK, GMS in Ireland) and price may also be important.

As health care professionals we also need to ensure our clinical decision-making reflects the evidence for practice. Within the wealth of data that exists for medical nutrition, there are many sources of evidence specifically for high protein ONS. Since the 1980s, trials have been undertaken involving high protein ONS with recent systematic reviews and meta-analyses published. To find out more about the evidence for use of high protein ONS have a look at the High Protein ONS Trials in the MNT evidence database.


The evidence base informs national and international recommendations from experts, professional organisations and societies on the use of ONS, including high protein products. Implementation of these to support practice can be found in many Guidelines and Pathways.


Guidance around protein requirements for older people is presented in the ESPEN Guidelines  on Clinical Nutrition and Hydration in Geriatrics with recommendation that 'ONS should provide at least 400kcal, with 30% of the energy as protein.Evidence for these guidelines includes the systematic review by Cawood et al..  The meta analysis in this review clearly demonstrates a range of positive benefits associated with use of high protein ONS across different patient groups and care settings. These include nutritional benefits, improvements in skeletal muscle strength and better recovery with reduced hospital readmissions and fewer complications. One of the largest placebo-controlled trials of ONS, by Gariballa et al., (2006), was included in this review. This trial in geriatric patients found that use of high protein ONS in addition to diet significantly reduced hospital readmissions, symptoms of depression and improved nutrient status. This seminal piece of work has really helped to inform guidance on the use of ONS in older people.

Most recently, the value of high protein ONS in the support of patients recovering after an admission to intensive care has received a lot of attention, not least because of the COVID-19 pandemic. This quote from Practical guidance for the ICU, post-ICU and long-term convalescence captures the essentiality of this form of medical nutrition:

‘After hospital discharge, probably very high dose protein and calorie feeding for prolonged duration is necessary to optimize the outcome. High protein oral nutritional supplements are likely essential in this period’.

New evidence and recommendations will continue to emerge around the value of high protein ONS but there is already a compelling case supporting their use, to really make a difference to patients in our care.