Oral nutrition supplements : Are they an effective intervention in people living with dementia?

Increasing nutritional intake and preventing weight loss by using oral nutrition supplements (ONS) in people living with dementia is not as simple as it sounds. Whether ONS are even indicated as an effective intervention is open to debate.

The link below takes you to an article I wrote for Network Health Digest (NHD) which is the UK’s only independent monthly magazine for nutrition and dietetic professionals. In the article I describe the research evidence and reasons why one must be cautious when using oral nutrition supplements in people with dementia. The full article also follows in this blog post.

Download a pdf. of the article

After you have read the article you can complete a CPD exercise by answering the questions linked here.

Are prescribed oral nutrition supplements (ONS) an effective intervention in people living with dementia?


ONS are still being touted as the saviour of malnutrition by leading UK charities who consistently publish positive research findings when pooling data for all patient groups. But what about sub groups of the population including those living with dementia. What does the evidence suggest about the use of ONS and can ONS improve outcomes such as increased weight and body mass index (BMI) and therefore prevent malnutrition? 

Like most things the answer is not a simple as yes or no and for people with dementia there are some important considerations to take into account which this article will attempt to emphasize. 


Systematic reviews suggest weight gain is variable when using ONS1, while meta-analysis suggest a statistically significant improvement in weight and BMI 2. Despite the gain in weight people with dementia are unlikely to improve in other outcomes 3 perhaps indicating that although statistically significant weight gain is not clinically significant.

The effectiveness of ONS for improving cognition is not clear and there is no evidence that ONS impacts morbidity or mortality or improves function  although studies assessing functional abilities such as levels of mealtime abilities in association with ONS do not exist 1. No evidence exists that ONS increase loose bowel actions although again this is not fully reported 1. Additionally ONS are provided as a source of “complete nutrition” however there is no evidence that ONS improves nutritional status in people with dementia 2. ONS however may have a role in maintaining protein and energy intake 1.  


To be effective prescribed ONS must be consumed. Compliance of ONS in all populations suggests 78% compliance (range 37% – 100%) but is negatively associated with age 4. A Cochrane review of ONS compliance in those >65 years of age found mean compliance of 66% (range 50-85%) 5. While specifically in dementia compliance rates range from 8.5% to 90% with that 8.5% coming from a one year long term follow up study, indicating long term ONS use is unlikely to be effective due to compliance. Finally when looking at compliance one cannot overlook the reporting or lack of reporting of dropouts. For example one study including mainly people with mild dementia had a dropout rate of 54% (65 participants) for a 24 week ONS intervention with ‘distaste’ sighted as the main reason for drop out 6.

Potential reporting bias in ONS research trails has been questioned 3 and considering positive research is more likely to be published and the effectiveness of ONS in dementia is still open for debate there are many factors to consider when deciding on ONS as a treatment option.  

Problems with screening and assessing the use of ONS:

Often the main indicator for offering or prescribing ONS is poor oral intake and weight loss 1. Although poor oral intake can be assessed from food record charts and weight loss or risk of malnutrition can be assessed using the malnutrition universal screening tool (MUST) or similar screening tools, the actual reasons why weight is lost or food is not consumed is not fully evaluated. Rarely is an assessment made on the individuals mealtime abilities or what level of assistance they require to eat their food 7 even though mealtime abilities will affect oral intake and the effectiveness of nutrition interventions 2. If the reason for the individuals’ weight loss is related to their ability to feed themselves then providing additional ONS without supporting their eating and drinking abilities is unlikely to lead to an increased intake. The MUST and all literature associated with its use strongly advocate the use of ONS based on BMI and weight loss however an assessment of the individuals eating abilities and a clear idea of what assistance the individual requires would surely help target assistance and screen those individuals who would gain most from ONS as an effective intervention. For further information on assessing mealtime abilities in people with dementia please refer to my previous NHD article for additional information 8.

A further drawback with using weight loss and BMI as the main indicator for prescribing ONS is evidence suggesting people with dementia and with a low BMI (<20kg/m2) are found to decrease their oral intake when prescribed ONS. Additionally these individuals continue to have decreased habitual intake even when ONS are ceased 7,9. Furthermore weight loss in these individuals with a low BMI and later stage dementia can be seen despite consuming all prescribed ONS (Faxen-Irving et al. 2002). Disappointingly this can be commonly seen in dementia care 9 and was something I witnessed many times in nursing home residents whose needs were not fully supported at mealtimes. Careful prescription of ONS in people with dementia and a low BMI (<20kg/m2) is warranted. If ONS affects oral intake at subsequent meals then this may indicate the individual is less likely to return to pre-ONS oral intake levels once ONS is removed therefore overall intake will decrease. Recent guidelines published by ESPEN recommend the use of the Mini Nutritional Assessment (MNA) either in its full or short form (MNA-SF) to assess malnutrition in older people 10. While a previous ESPEN consensus statement recommend BMI <20 kg/m2 for subjects <70 years of age, and BMI <22 kg/m2 for subjects 70 years and older 11. When working with the older people with dementia population one should strongly consider the most appropriate assessment methods used.  It is worth noting people with dementia who have a low BMI are more likely to have later stage dementia and are also more likely to have reduced mealtime abilities 12.

Increasing the consumption and effectiveness of ONS in dementia:

Some potential ways to increase the efficacy of ONS is provided in table 1 although as with all general advice there are some important points to consider for individuals.

In general people with dementia are less likely to suffer a decrease in appetite if ONS are provided in small regular intervals 1 however a reduction in intake may still be observed. Offering ONS between meals is often used and recommended but what the most desirable and effective between meal times are is debatable. If lunch is the main meal of the day, as it often is in care settings, close monitoring of lunch intake is required to ensure oral food intake is not decreased from ONS use prior to this 9.  Importantly when comparing meal intakes for both ONS and oral snacks as between meal interventions (twice daily), a decrease in intake at meals was seen however this was only significant in those receiving ONS 7. Similarly the percentage of a meal eaten decreased when both a 200ml ONS was provided between meals and when a 60ml ONS was provided four times per day however the decreased intake was significantly more when the 200ml volume was provided 2.

Providing assistance with eating and drinking is seen as a labour intensive caring task and in instances of inadequate staffing levels ONS can become a meal replacement rather than a supplement to the diet 1. Be wary of settings where staff time and staffing levels are reduced as people with dementia need increased assistance at mealtimes due to reduced mealtime abilities 7

Table 1 highlights two potential monitoring techniques to determine in whom the ONS intervention will be most effective in regards to ONS impacting on oral food intake. One monitoring intervention involves a two day trail of ONS and detailed recording of oral food intake 7. Secondly in those whom require ongoing use of ONS then a 3 week on and 3 week off rotation system can be employed to effect 9.

There are many things that can be done to improve the effectiveness of ONS as highlighted in the table below.

Non dementia specific ONS practical tips

Considering the effectiveness and compliance of ONS in all patient groups rather than only dementia one can see some similar themes emerging as highlighted in table 2. Interestingly the review from which table 2 was compiled found no significant differences in set time delivery, medication rounds or providing ONS ab-libitum on consumption of ONS or mean energy intake when looking at all patient groups 4. Looking at mean results obtained from groups are not always generalizable to subgroups or individuals. Some research focused on dementia does highlight the impact of timing on compliance and effect on oral nutrition intake 7,9,13, although conflicted results are still seen 2. Many of these tips for increasing effectiveness rely on the staff providing additional assistance in some form and probably the benefits from this type of administration of ONS in the research is due to increased staff assistance at this time.

Table 2: Potential ways to increase the compliance and effectiveness of ONS in dementia and non-dementia


The research discussed indicates more staff availability to provide assistance and monitoring of ONS can increase the effectiveness of ONS consumption and weight gain. In the cash strapped world of older people’s care however more staff availability is often not a viable choice. Certainly if the correct level of assistance is provided then providing snacks or oral food may be just as or more effective and cost less than ONS 7. So are ONS an effective intervention in people living with dementia?

Temporary use of ONS can be both beneficial and detrimental to short term nutritional intake and body weight but are unlikely to improve long term weight or functional outcomes 14. There are several practical ways to increase compliance and consumption of ONS (tables 1 & 2) however they all require additional staff resources. Additionally current screening tools (e.g. MUST) used in the assessment for administration or prescription of ONS may not be specific enough to assess the nutritional complexities in people with dementia. Those identified as at risk of malnutrition by low BMI (<20kg/m2) and/or with later stage dementia may not respond to ONS as an effective intervention 3. ONS may cause a decrease in oral intake which is not recovered when ONS is stopped but why ONS creates such dependence is unknown. For someone living with dementia where mealtimes will be one of their few opportunities for social interactions a decrease in meal intake is unwanted from both a nutritional and quality of life aspect. Certainly research suggests the psychosocial impact of mealtimes is a key factor in improving nutritional intake in people with dementia 15. Finally there is a need to assess the pre-cursors to decreased nutritional intake and weight loss, such as reduced mealtime abilities and intervene at this stage 2. Nutrition and dietetic interventions for people with dementia have been suggested to focus on strategies to improve mealtime abilities and eating environments to promote oral intake 14. The family members of people with dementia prefer oral food being offered 1 and although research has failed to ask people living with dementia what they think one would imagine they would agree.  


1.          Hines, S., Wilson, J., McCrow, J., Abbey, J. & Sacre, S. Oral liquid nutritional supplements for people with dementia in residential aged care facilities. Int. J. Evid. Based. Healthc. 8, 248–251 (2010).

2.          Allen, V. J., Methven, L. & Gosney, M. A. Use of nutritional complete supplements in older adults with dementia: Systematic review and meta-analysis of clinical outcomes. Clin. Nutr. 32, 950–957 (2013).

3.          Hanson, L. C., Ersek, M., Gilliam, R. & Carey, T. S. Oral feeding options for people with dementia: A systematic review. J. Am. Geriatr. Soc. 59, 463–472 (2011).

4.          Hubbard, G. P., Elia, M., Holdoway, A. & Stratton, R. J. A systematic review of compliance to oral nutritional supplements. Clin. Nutr. 31, 293–312 (2012).

5.          Milne, A. et al. Protein and energy supplementation in elderly people at risk from malnutrition ( Review ) Protein and energy supplementation in elderly people at risk from malnutrition. Cochrane Libr. 2–4 (2009).

6.          Manders, M. et al. The effect of a nutrient dense drink on mental and physical function in institutionalized elderly people. J. Nutr. Heal. Aging 13, 760–767 (2009).

7.          Simmons, S., Zhuo, X. & Keeler, E. Cost-effectiveness of nutrition interventions in nursing home residents: A pilot intervention. J. Nutr. Health Aging 14, 367–372 (2010).

8.          Martin, L. Innovation in the nutritional care of dementia. NHD 114, 53–57 (2016). https://issuu.com/nhpublishingltd/docs/issue_115_nhd_extra

9.          Parrott, M. D., Young, K. W. H. & Greenwood, C. E. Energy-containing nutritional supplements can affect usual energy intake postsupplementation in institutionalized seniors with probable Alzheimer’s disease. J. Am. Geriatr. Soc. 54, 1382–1387 (2006).

10.        Cederholm, T. et al. ESPEN guidelines on definitions and terminology of clinical nutrition. Clin. Nutr. 36, 49–64 (2017).

11.        Cederholm, T. et al. Diagnostic criteria for malnutrition – An ESPEN Consensus Statement. Clin. Nutr. 34, 335–340 (2015).

12.        Lin, L.-C., Watson, R. & Wu, S.-C. What is associated with low food intake in older people with dementia? J. Clin. Nurs. 19, 53–59 (2010).

13.        Faxen-Irving, G. et al. The effect of nutritional intervention in elderly subjects residing in group-living for the demented. Eur. J. Clin. Nutr. 56, 221–227 (2002).

14.        Jansen, S. et al. Nutrition and dementia care: Informing dietetic practice. Nutr. Diet. 72, 36–46 (2015).

15.        Keller, H. H. Improving food intake in persons living with dementia. Ann. N. Y. Acad. Sci. 1367, 3–11 (2016).

Online article link:
Oral nutritional supplements : Are they an effective intervention in people living with dementia? (NHD, 2017, pages 19-24), by Lee Martin MSc RD