As I am a nutritionist, the aspect of self-care in preventing Alzheimer’s and dementia I am most interested in is diet – and I believe that what you eat can have a huge impact on the health of your brain.

The largest study looking at the association between the Mediterranean diet and memory was published in 2013 in the medical journal Neurology. The research showed that eating a Mediterranean diet is linked to a reduced incidence of cognitive decline. The advice is to increase your consumption of fresh fruit and vegetables, olive oil and eat more oily fish.

Making sure you keep your blood sugar in balance is also important as blood sugar and insulin have been so closely linked with an increased risk of Alzheimer’s that it has been suggested that Alzheimer’s should be called type 3 diabetes.

Your brain function does change as you get older. Age tends to affect your ability to store and retrieve information, and you may find that words and putting faces to names sometimes eludes you.

Dementia risk

The risk of Alzheimer's and other types of dementia also increases with age and is much more common in women. Dementia is now the biggest killer of women causing three times more deaths than breast cancer. There are about 55,000 people living with dementia in Ireland. This number is expected to increase to 68,216 by 2021 and 132,000 by 2041, according to the Alzheimer's Society of Ireland. The financial cost of dementia in Ireland is estimated to be about €1.9 billion per year.

While much of the research into how to treat Alzheimer’s looks at using pharmaceutical drugs to clear the beta-amyloid build-up in the brain, I think it’s more helpful to ask why the beta-amyloid is building up in the first place.

One line of thinking is that your body produces beta-amyloid as a protective response to something else that’s going on physiologically. It could, for example, be a response to inflammation, infection, or it could be a response to exposure to environmental toxins, such as heavy metals, binding to them to help clear them from the body.

Drug therapy

Research from Harvard University suggests that beta-amyloid, often seen as the "baddie", is an immune-system response to something like a bacterial invasion. If that is the case, then a drug therapy focused on getting rid of beta-amyloid could be counterproductive, because it's just treating the symptom and the beta-amyloid will continue to build up while the infection is still present. Stimulating the immune system – treating the cause and ridding the body of infection – would be a far more effective strategy.

The Harvard research team suggests that Alzheimer’s is triggered by a normal immune response that has become overactive in response to an infection. Animal studies have shown them that beta-amyloid proteins surround and cage in bacteria in order to kill them. This tells us that the clumping effect of beta-amyloid proteins that we see in Alzheimer’s is a perfectly appropriate action in response to an infection (more recent research has the same Harvard team calling beta-amyloid “the natural antibiotic” ), but problematic – causing Alzheimer’s – when the infection itself is not treated.

Helpful nutrients

Making sure you are eating well is important and also certain nutrients can be helpful in the fight against dementia and in particular the B vitamins “can slow the atrophy of specific brain regions that are a key component of the Alzheimer’s disease process and that are associated with cognitive decline”. Those people taking specific levels of B vitamins had 90 per cent less brain shrinkage compared with those taking a placebo.

Supplements of omega 3 fish oils can also be beneficial as DHA, one of the major Omega 3 fatty acids in the brain, seems to have the most protective effect against Alzheimer’s. The DHA in omega 3 fatty acids helps to prevent the plaque forming in the brain which is present in Alzheimer’s and they help improve cerebral blood flow and reduce inflammation, making them important in the fight against not only Alzheimer’s but also vascular dementia.

Other nutrients which can be helpful include an amino acid called acetyl-L-carnitine as it increases the brain receptors that would normally deteriorate with age so helpful for memory loss, dementia, Alzheimer’s, depression.

People with Alzheimer’s have been found to have a shortage of the neurotransmitter acetylcholine in the brain and drugs that mimic acetylcholine are often used as a treatment for Alzheimer’s. Acetylcholine is critical for memory and brain function. Choline is a precursor (starting block) for acetylcholine and is contained in high amounts in egg yolks and is also found in soya and nuts. So these are good foods for boosting memory and brain function.

Memory support

Acetyl-L-carnitine works with coenzyme Q10 and alpha lipoic acid to maintain the function of the mitochondria. The mitochondria are the power houses of your cells, they provide the energy for your cells to function and survive. I use a supplement by NHP called Brain and Memory Support in my clinics, available through all good independent health stores.

There has been a great deal of research to show that physical activity can help brain function. One study of a group of women over the age of 65 tracked their level of physical activity over eight years. The researchers found that those women who were the most active had a 30 per cent lower risk of cognitive decline. What was interesting was that it was not the intensity of the exercise that made the difference but the amount. So with walking, the distance the women walked was more important than how fast they walked.

Too little sleep also increases your risk for Alzheimer’s because beta-amyloid protein is cleared away during sleep when your cerebrospinal fluid washes out toxins from your body. The best sleep position for this to happen is on your side.

Just as your body needs regular exercise, your brain needs regular exercise too. Keep it fit by playing cards and chess games, reading books, doing crosswords, learning an instrument or new language or by pursing a new hobby.

Dr Marilyn Glenville PhD is the UK's leading nutritionist specialising in women's health. She is the former president of the Food and Health Forum at the Royal Society of Medicine and the author of a number of books including Fat Around The Middle, Natural Solutions for Dementia and Alzheimer's, and Natural Alternatives to HRT. See glenvillenutrition.ie