Food, Nutrition and Supplements for Dementia

No food, vitamin or supplement has been proven to prevent, treat or cure dementia. A healthy diet is still important, both for lowering the risk of dementia and for keeping someone who already has dementia as well as possible. This page sets out what the evidence says, and gives practical tips for helping a person with dementia eat and drink well.

Can diet lower the risk of dementia?

A growing body of evidence suggests that a healthy diet may lower the risk of cognitive decline and dementia. The pattern most often studied is the Mediterranean diet: plenty of vegetables, fruit, wholegrains, beans and pulses, nuts and olive oil, fish a couple of times a week, and less red meat, sugar and processed food.

Diet works partly through the heart and blood vessels. What is good for your heart, such as keeping blood pressure, cholesterol and weight in check and reducing the risk of type 2 diabetes, is also good for your brain. For more on lifestyle and brain health, see how to keep your brain healthy as you age.

Eating more fresh fruit and vegetables is recommended for many reasons. But there isn't yet enough evidence to say that a diet rich in antioxidants (such as vitamin C, vitamin E and beta-carotene) by itself reduces dementia risk.

Do supplements help?

At present, no vitamin or supplement is recommended for preventing Alzheimer's disease or cognitive decline. Here is what research has found for the most commonly promoted ones:

• Omega-3 (fish oil). Among dietary factors studied, eating fish has the most consistent positive findings. Some studies link it to lower dementia risk, others find no effect. Omega-3 supplements have not been shown to prevent cognitive decline in healthy older people or to treat Alzheimer's disease.
• Vitamin E. Most human studies have been negative. One study suggested it might slow day-to-day functional decline in Alzheimer's disease, but it does not prevent mild cognitive impairment from progressing to dementia. High-dose supplements can carry risks.
• B vitamins (B6, B12, folic acid). Short-term supplements have not improved thinking in older adults. Some longer-term studies hint at slower decline, especially in people with high homocysteine levels, but this isn't proven. Too much vitamin B6 can cause serious side effects.
• Ginkgo biloba. A large trial of more than 3,000 older adults found ginkgo did not lower the rate of dementia or Alzheimer's disease.
• Turmeric (curcumin). Laboratory findings have not been shown in clinical trials.
• Antioxidant supplements. Trial results are contradictory, and there is no strong evidence they affect dementia risk.

A vitamin B12 deficiency or an underactive thyroid can cause memory problems that improve with treatment. This is one reason to see a GP about memory problems rather than trying supplements first. Always talk to a GP or pharmacist before starting a supplement, as some interact with medicines.

Eating and drinking well with dementia

As dementia progresses, many people have problems with eating and drinking. These can lead to weight loss, dehydration, constipation, infections and more confusion. Common causes include forgetting to eat, changes in taste, difficulty using cutlery, a sore mouth or poorly fitting dentures, and swallowing problems.

Practical tips

• Offer small, frequent meals and snacks rather than three large meals, if appetite is poor.
• Offer foods the person likes. Tastes can change, and many people develop a preference for sweet foods.
• Use finger foods such as sandwiches, cheese cubes or fruit pieces, if cutlery has become difficult.
• Keep mealtimes calm. Turn off the TV, clear the table and allow plenty of time.
• Keep drinks within reach and offer them often. Foods with high water content, such as soup, yoghurt, jelly and fruit, also count.
• Check mouth care. Regular tooth brushing and well-fitting dentures make eating more comfortable.
• If someone is losing weight, a GP or dietitian may suggest a high-energy diet: full-fat milk, butter, cheese and cream added to meals, and nourishing drinks between meals.

Swallowing problems

Coughing or choking when eating or drinking, a "wet" sounding voice after meals or repeated chest infections can be signs of a swallowing problem (dysphagia). Ask the GP for a referral to a speech and language therapist, who can assess swallowing and recommend safer food textures. Make sure the person sits upright while eating and for a while afterwards, and don't feed someone who is drowsy.

In the later stages of dementia, appetite naturally falls. Comfort and enjoyment matter more than calories at this point, and forcing food can cause distress.

Key points

• No diet or supplement can cure or reverse dementia.
• A balanced, Mediterranean-style diet supports heart and brain health and may lower the risk of dementia.
• Supplements such as ginkgo, fish oil and vitamin E have not been shown to prevent dementia. Speak to a GP before taking any.
• For people living with dementia, the priority is getting enough food and fluid, safely and enjoyably.