Nutrition and dementia

A review of available research

About the report

The ‘Nutrition and dementia’ report investigates how the right nutrition can help make life better for people affected by dementia.

The report reviews dietary factors across the life course that might increase or decrease the risk of onset of dementia in later life. While obesity in mid-life may be a risk factor for developing dementia in late life, weight loss tends to become a more significant issue in the decade leading up to the onset of dementia symptoms and accelerates after that. The report finds that 20-45% of those with dementia in the community experience clinically significant weight loss over one year.

The report details actions that could improve the nutrition of people with dementia through diet and external factors such as modifying the mealtime environment, and supporting and training carers.

Given the evidence for effective interventions, there is much potential to improve the food intake and nutrition of people with dementia. We believe that a focus on diet, nutrition and wellbeing is an important aspect of supporting people affected by dementia, as well as reducing the population risk of developing dementia.

ADI, supported by a grant from Compass Group, commissioned researchers Prof Martin Prince, Prof Emiliano Albanese, Dr Maëlenn Guerchet and Dr Matthew Prina from the Global Observatory for Ageing and Dementia Care at King’s College London to produce the report.

Key findings

  1. Undernutrition is common among older people generally, particularly in low and middle income countries. For this age group it is, arguably, a larger public health problem than obesity.
    The consequences include increased frailty, skin fragility, falls, hospitalisation and mortality.
  2. Undernutrition is particularly common among people with dementia in all world regions. It tends to be progressive, with weight loss often preceding the onset of dementia and then
    increasing in pace across the disease course.
  3. Obesity in mid-life may be a risk factor for developing dementia in late-life. If so, this is an important modifiable risk factor, and a matter of concern given rising levels of obesity worldwide.
    However, careful examination of the existing evidence casts some doubt upon the validity and robustness of this finding, which requires more research.
  4. There are many dietary factors that might plausibly increase or decrease risk for the onset of dementia. However, we could find no clear or consistent evidence to support a causal protective role for vitamins B6, B12, C or E, folate or omega-3 PUFA (polyunsaturated fatty acids). There is quite consistent evidence from epidemiological cohort studies that adherence to a Mediterranean diet (with a high proportionate intake of cereals, fruits, fish and vegetables) may lower the risk of cognitive decline and dementia. However, to date, only one trial has been carried out, with encouraging findings.
  5. The mechanisms underlying weight loss and undernutrition in dementia are complex, multifactorial, and only partly understood. Reduced appetite, increased activity, and, in the more advanced stages of the illness, the disruption of eating and feeding behaviours by cognitive and behavioural problems all play a part. For some forms of dementia, it may be that central regulation of appetite and metabolism is disturbed as an inherent feature of the disease.
  6. A key finding in this report is that while weight loss is a common problem for people with dementia, undernutrition can and should be avoided. Proof of concept comes from a new review of the use of oral nutritional supplements, indicating that it is possible to stabilise or even increase the weight of people with dementia over relatively long periods. The nutritional benefits of education and training for caregivers was less apparent, although such interventions were popular and there are likely to be other benefits.
  7. In care homes, attention to staff training and mealtime environment can lead to significant enhancement in calorie intake among residents. Eating is a social activity, and more thought should be given to how this can be optimised, normalised and made a core aspect of person-centred care. Sensitive and inclusive design of dining rooms, kitchens, furniture and tableware can all make important contributions.
  8. There is no current evidence that nutritional supplementation whether with micronutrients or macronutrients can modify the course of dementia (cognitive and functional decline). There
    is currently insufficient evidence to recommend the use of any medical food. However, data are emerging indicating some potential for therapeutic benefit (e.g. Souvenaid), and trials are
    ongoing. Vitamin E shows some promise, but at doses that may lead to harmful side effects.
  9. Much more attention needs to be focused upon the problem of undernutrition in dementia. This has been grossly neglected in research and practice. Studies reviewed in this report indicate
    that 20-45% of those with dementia in the community experience clinically significant weight loss over one year, and that up to half of people with dementia in care homes have an inadequate food intake.


  1. More research needs to be conducted into:
    • The possibility that nutritional supplementation of dietary components with high mechanistic plausibility may be effective in reducing the incidence of dementia if targeted upon those with evidence of deficiency (for example vitamin B12 and folate).
    • The effective components of a Mediterranean diet with respect to the prevention of dementia and progression of Mild Cognitive Impairment, and the feasibility of sustained implementation of such dietary modification.
    • The possibility that some forms of micronutrient supplementation may yet be effective in altering the course of dementia, if targeted upon those who are deficient.
    • The minimum effective dose of vitamin E as a treatment for clinical progression in dementia, and the balance of associated risks and benefits.
    • The relative efficacy of food fortification and oral nutritional supplementation in maintaining weight among people with dementia at risk for undernutrition.
    • The feasibility and effectiveness of long-term fortification or oral nutritional supplementation strategies, including the wider health and quality of life benefits.
  2. It is important that clear, consistent and independent evidence based advice is provided to support decision-making on nutritional supplements by those at risk of, or already living with, dementia.
  3. Nutritional standards of care for people with dementia should be introduced throughout the health and social care sectors, and monitored for compliance.
    • All people with dementia should have their weight monitored and nutritional status assessed regularly.
    • All people with dementia, and their family carers, should receive dietary advice from a dietician as a part of post-diagnostic care,updated, as appropriate, as their condition evolves, particularly with the onset of weight loss, aversive feeding behaviours, and need for feeding assistance.
    • Undernutrition, once established, is a serious health concern requiring medical attention and input from a dietician and occupational therapy as appropriate. Those at risk of
      undernutrition require a detailed assessment of diet, feeding behaviours and need for feeding assistance. This should inform an immediate and intensive nutritional intervention to restore and maintain normal nutrition.
    • Nutritional advice and natural food fortification should be tried first, but the use of oral nutritional supplements should not be delayed for those with undernutrition and those at risk who fail to respond.
    • All care homes and hospitals that care for people with dementia need to develop and implement plans to optimise and monitor their nutritional status. This should include staff training; attention to the nutritional content and variety of the food provided, and its suitability for people with different eating and feeding difficulties; the way in which food is prepared and delivered; and dining room design and mealtime environment.
    • Staff training in care homes and hospitals should be part of a comprehensive programme of workforce development linking managers, nursing staff, care assistants and caterers all of
      whom need to understand the challenges involved in maintaining adequate nutrition for people with dementia, and the part that they have to play. This should address gaps in knowledge (the nutritional content of food, the impact of dementia on diet and nutrition) and skills (in monitoring nutritional status, providing feeding assistance, managing aversive feeding behaviours).

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