Can diet prevent or slow down dementia?
We hear so much from the media about what we should or should not eat. One day blueberries are the new so-called ‘superfood’ that will reduce our risk of developing dementia, the next it is the humble plum.
But what information can we rely on to be accurate? Can the food we eat really reduce our risk of developing dementia? If a person has dementia, can their diet or use of supplements influence how they experience dementia or its progression?
Knowing what and what not to eat is so confusing, the messages seem to change daily!Person with dementia
The brain requires a regular supply of nutrients in our diet to function and remain healthy. There is growing recognition that what we eat affects the way our brains work and our mental health, as well as our physical health.
Traditionally research undertaken to investigate the connection between diet, cognitive function and risk of dementia has primarily focused on the impact of individual nutrients on brain health. Those nutrients commonly researched include: vitamins B6, B12, C, E and folic acid, as well as omega 3 essential fatty acids. The outcome of such research has been inconclusive and thus guidelines to advise on specific nutrient intakes have not been developed. In this feature we’ll explore some of the ongoing research on this topic.
Healthy hearts mean healthy brains
We know that certain medical conditions such as high blood pressure, high cholesterol, diabetes and obesity can increase our risk of dementia. For some time these risk factors were commonly associated with vascular dementia. We now know that they are also associated with the development of Alzheimer’s disease.
Much of what we know now to be healthy for our heart is also healthy for our brain, so many of the dietary messages we have been encouraged to follow for a healthy heart will also apply to the health of our brains.
It is advisable to reduce our salt intake regardless of the type of dementia we are considering. A salt-rich diet can contribute to the risk of increasing our blood pressure, which in turn can increase the risk of stroke and vascular dementia (Skoog et al, 1996).
About three-quarters of the salt we eat comes from processed foods such as bread, breakfast cereals, soup and sauces. So it is not just what you add yourself that makes the difference, but how the food itself is manufactured.
The Food Standards Agency recommends that we should aim to have no more than 6 grams of salt daily, which is approximately one level teaspoon.
Fats and oils
The significance of too much fat in the diet has been the topic of much conversation with regards to a healthy heart and vascular system. In particular saturated fat, commonly derived from animal fat (for example fat on meat, lard, butter or ghee) or trans fats (fats created during the hydrogenation of vegetable oils and often found in processed foods such as pastry or vegetable shortening) can elevate cholesterol levels in the body if eaten in significant quantities. A high saturated fat intake has also been implicated, along with other dietary factors, as increasing the risk of dementia.
Omega 3 and oily fish
Omega 3’s essential fatty acids have an important part to play in the structure of our brain cells, helping to maintain the health and functioning of our brain. Research undertaken as part of the Older People And n-3 Long-chain polyunsaturated fatty acid (OPAL) study supported the view that eating oily fish (or omega 3) is associated with better cognitive function in later life, but recommended further work to clarify the impact of these essential omega 3 oils on the brain (see Dangour et al, 2010).
We need omega 3 oils from food as they cannot be made efficiently by the body. Oily fish is a rich source of omega 3’s essential vitamins and minerals and it is recommended that we have at least one portion of oily fish a week. Guidelines vary though according to the individual – see the Food Standards Agency website, www.eatwell.gov.uk/healthydiet/fss/fats/ for further information. Omega 3 oils may also be found in vegetarian sources such as linseeds, rapeseed oil, walnuts and soya beans.
The European Commission-funded LipiDiDiet project is researching the impact of omega 3 and other key nutrients on the risk of developing Alzheimer’s disease and vascular dementia. Results should be available in 2015. For more information go to www.lipididiet.eu
Vitamins C and E, commonly found in fruit and vegetables, are examples of antioxidants – that is, substances that work against the negative effects of oxidation that occurs naturally in the body.
Vitamin E has been the subject of much research in relation to reducing the risk of dementia, with conflicting results. There are many other sources of antioxidants other than vitamins, for example in green tea, red wine and cocoa. Each of these has been the subject of studies and considered as a potential ‘superfood’ in protecting mind and body.
Research appears to demonstrate a link between antioxidants activity and dementia, but is not conclusive about which foods are guaranteed to help reduce the risk of dementia and how much we need.
It is generally considered that a diet rich in fruit and vegetables will provide us with a valuable source of antioxidants and be more beneficial than taking supplements alone. The Food Standards Agency recommends at least five portions of fruit and vegetables daily to help maintain a good intake of vital vitamins and antioxidants.
Folic acid, vitamin B6 and B12
Deficiencies in folic acid, vitamin B6 and vitamin B12 can cause an amino acid in our body, called homocysteine, to rise. Higher than normal levels are considered to be a risk factor for a number of disease states including cardiovascular disease and dementia, and are thought to contribute to poor cognition.
However, there are no guidelines to consuming supplements of B6, B12, or folic acid individually merely to reduce the risk of dementia (although these nutrients may be prescribed for actual deficiencies such as anaemia). Again the advice is to ensure that foods rich in B6, B12, and folate are present in the diet.
Can a Mediterranean-style diet help?
In recent years, research in the field of nutrition, cognitive function and dementia has built on what we know about the key nutrients involved in brain health. Subsequently this research has begun to focus more on dietary patterns or how combinations of specific nutrients can impact on cognitive function or reduce the risk of developing dementia, such as Alzheimer’s disease (Gu et al, 2010), and the process involved in developing this dementia (Laus et al, 2013).
The ‘Mediterranean-style diet’ has been popular for many years for helping to maintain a healthy heart and body. This style of eating is traditional to people living in the countries bordering the Mediterranean Sea. Generally such a diet is considered to be rich in fruits and vegetables, olive oil, cereals, legumes and fish, with small amounts of lean meat and moderate amounts of dairy foods. Overall this style of eating provides a diet rich in vitamins and antioxidants and low in saturated fats. This diet has been associated with reducing the risk of developing Alzheimer’s disease (Scarmeas et al, 2006).
The impact of good nutrition on the health of our brains cannot be dismissed. We know that malnutrition affects physical and mental wellbeing: our brains need nutrients to work and remain healthy.
Diet and what we eat has an important role to play in adopting a healthy lifestyle which can help keep both our bodies and brains healthy. Eating a nutrient-rich diet, particularly one that has lots of fruits and vegetables, omega 3 oils, and low amounts of salt and saturated fats, will help to maintain the health of both our heart and brain.
Research in this field is ongoing and the hope is that that this will provide us with more knowledge and understanding of how diet and nutrition impact on cognitive health and the risk of developing dementia.
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- Activity: Can diet prevent or slow down dementia
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Further reading Open
Alzheimer’s Society (2011) Food for thought: A guide to healthy eating for people with dementia. London: Alzheimer’s Society.
Alzheimer’s Society, ‘Food for thought: food and health’, online information.
Broersen, L.M., Kuipers, A.A.M., Balvers, M., van Wijk, N., Savelkoul, P.J.M., de Wilde, M.C., van der Beek, E.M., Sijben, J.W.C., Hageman, R.J.J., Kamphuis, P.J.G.H. and Kiliaan, A.J. (2013) ‘A specific multi-nutrient diet reduces Alzheimer like pathology in young adult mice’, Journal of Alzheimer’s Disease, vol 33, no 1, pp 177–190.
Coleman, G. (2009). Alzheimer’s Society’s guide to catering for people with dementia, York: Alzheimer’s Society.
Dangour, A.D. Allen, E., Elbourne, D., Fasey, N., Fletcher A.E., Hardy, P., Holder, G.E., Knight, R., Letley, L., Richard, M. and Uauy, R. (2010) ‘Effect of 2-y n3 long-chain polyunsaturated fatty acid supplementation on cognitive function in older people: a randomized, double-blind, controlled trial.’ American Journal of Clinical Nutrition, vol 91, no 6, pp 1725–1732, doi: 10.3945/ajcn.2009.29121.
Doyle, P. and Deane, A. (2009) Top 100 omega 3 recipes: Reduce your risk of heart disease, keep your brain active and agile, London: Duncan Baird Publishers.
Gu, Y., Nieves J.W., Stern. Y., Luchinser, J.A. and Scarmeas, N. (2010) ‘Food combination and Alzheimer disease risk: a protective diet’, Archives of Neurology, vol 67, no 6, pp 699–706, doi: 10.1001/archneurol.2010.84
Heart Protection Study Collaborative Group (HPSCG) (2002) ‘MRC/BHF Heart Protection Study of antioxidant vitamin supplementation in 20,536 high risk individuals: a randomised placebo-controlled trial’, The Lancet, vol 360, no 9326, pp 23–33.
Mental Health Foundation (2006) Feeding minds: The impact of food on mental health, London: MHF.
NHS Choices website, ‘Healthy eating’, online information.
Scarmeas, N., Stern, Y., Tang, M-X., Mayerux, R. and Luchsinger, J.A. (2006) ‘Mediterranean diet and risk for Alzheimer’s disease’, Annals of Neurology, vol 59, no 6, pp 912-921, doi: 10.1002/ana.20854
Skoog, I., Nilsson, L., Persson, G., Lernfelt, B., Landahl, S., Palmertz, B. Andreasson, L-A., Oden, A. and Svanborg, A. (1996) ‘15-year longitudinal study of blood pressure and dementia’, The Lancet, vol 347, no 9009, pp 1141–1145, doi:10.1016/S0140-6736(96)90608-X
Useful links Open
The Alzheimer’s Society website has a section entitled Eating and drinking, which covers a wide range of issues to do with helping people with dementia to eat well: difficulties with eating and drinking, preparing meals, the eating environment and finger foods. The Society also produces a factsheet on Eating and drinking (511).
Eating and drinking well: supporting people living with dementia
A team from Bournemouth University has developed a 26-minute training film aimed at nurses and care home staff, based on findings from a major study in this area. A workbook to accompany the film is also available from the research team.
Eating well for older people and older people with dementia: Practical guide
This 2011 guide from the Caroline Walker Trust explains why eating good food matters for older people with dementia, suggests types and amounts of food that might be appropriate to meet nutritional needs, and includes sample menus.
Eating well for people with dementia: a guide for carers
This 24-page booklet has been produced by the Northern Health and Social Care Trust in Northern Ireland. It covers topics such as ‘Encouraging eating’, ‘Common problems with eating and drinking’, ‘Dealing with diabetes’, as well as explaining the role of occupational therapists and speech therapists in this area, and the importance of mouth and dental care.
Nutrition and dementia
This 2014 report from Alzheimer’s Disease International investigates the links between diet and dementia and looks in detail at a range of ways in which nutrition can be improved for people who live with dementia.
Prevention and early intervention of malnutrition in later life: best practice principles and implementation guide
The Malnutrition Task Force have produced a range of guides, each bearing this main title and then focusing on a particular area (such as hospitals, care homes or community). The guides each include detailed attention to the particular needs of people with dementia.
Related pages from this section Open