Can a Mediterranean diet reduce the risk of developing dementia?

There are many variations of the Mediterranean diet, but you can consider it as focusing on unprocessed, fibre-rich plant foods (fresh vegetables, fruits, nuts, seeds and legumes), moderate amounts of fish, white meat, dairy and eggs, generous amounts of extra virgin olive oil with less of an emphasis on red meat.

Forms of the Mediterranean diet have been followed by people all around that geographically area since Roman times or earlier. It wasn’t until the 1950s and 60s that scientists started to realise that people following a Mediterranean diet were healthier. Despite there being no universal consensus on a diet for our brains, the bulk of research has been focused on a Mediterranean style diet and cognition.

What research is there on the Mediterranean diet and dementia?

You might have come across the ketogenic diet mentioned in relation to dementia. High fat, very low carbs and adequate protein basically make up this diet that, until recently was used mostly for the treatment of epilepsy. It’s being utilised in dementia research more and more. Results are positive, however bigger and more long term studies are necessary.

In the meantime, a blend of the ketogenic and the Mediterranean Diet (MeDi) may be a helpful and practical way to go. The ketogenic MeDi diet still features a high vegetable and fruit consumption but slightly increases fat and protein and restricts carbohydrates. This is especially beneficial for those living with poor blood sugar control.

What studies have been done on the Mediterranean diet and Alzheimer’s disease?

The most common form of dementia is Alzheimer’s disease. A 2014 meta-analysis and systematic review found that a Mediterranean diet was associated with a reduced risk of developing Mild Cognitive Impairment (MCI) and Alzheimer’s disease. MCI can lead to the development of Alzheimer’s disease and the research found that a Mediterranean diet resulted in a reduced risk of conversion from MCI to Alzheimer’s disease. Indeed, a systematic review carried out the year before revealed that a closer following of a Mediterranean diet was associated with slower cognitive decline and a lower risk of developing Alzheimer’s disease.

When looking at both specific Mediterranean diets and other diets, two alternative diets were found to have advantages. A 2019 review revealed that all three of the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) Diets were associated with less cognitive decline and a lower risk of Alzheimer’s disease. The researchers found that olive oil consumption seemed to be an significant element of all three diets.

Another factor all three diets may have shared is enhanced blood sugar control. A long term study, on over 10,000 people, examined the link between diabetes in middle age and subsequent cognitive decline. It found “Diabetes in midlife was associated with a 19% greater cognitive decline over 20 years.” Fascinatingly, those with HbA1c in the prediabetic range (5.7-6.4%) also had larger declines than those with HbA1c <5.7%. How many people are aware that eating to support their blood sugar is also a effective way to maintain their brain health?

More recently, a systematic review and meta analysis concluded that the Mediterranean diet is recommended to prevent or delay cognitive disorders and improve cognitive function, calling for further long-term studies to strengthen the evidence.

What are the best foods for dementia patients to eat?

The Mediterranean diet contains many foods that are relatively easy to include, such as:

  • Extra virgin olive oil (EVOO). EVOO is a major feature of a Mediterranean diet. How much should we be consuming? In terms of cognitive function, a small study showed that three tablespoons daily for six months had benefits in a group experiencing mild cognitive decline.

  • Dark green leafy vegetables. These are high in magnesium, folate and the antioxidant, lutein, which are all important for brain health. Research shows that eating just over one serving daily may help to slow cognitive decline.

  • Fish (particularly oily fish such as salmon, mackerel, trout, anchovies, herring and sardines) and seafood. These are a good source of omega-3 fatty acids which are important for the brain. Fresh, frozen or tinned are all beneficial. A 2022 meta-analysis of over 30,000 subjects found that people with a high fish consumption (four+ servings fish/seafood a week) had a significantly lower risk of dementia compared to those with low fish consumption.

  • Apples, berries, cocoa, grapes, pomegranates, herbs, green tea and black tea are all high in a type of phytochemical called flavanols. Flavanols are beneficial chemicals found in plant foods. You may hear flavanol rich foods described as “superfoods”. Evolving research suggests that flavanols may support cognitive health and are particularly important for the ageing brain. Aim to consume a wide range of flavanol rich foods and drinks every day.

Can following a Mediterranean diet reverse dementia?

Whilst following a Mediterranean diet reduces the risk of developing cognitive disorders, such as dementia, there’s unfortunately no evidence that any diet can reverse dementia.

Can a poor diet cause dementia?

There’s no current evidence that a poor diet alone can cause dementia. However, there are some aspects of a poor diet, such as ultra-processed foods (UPF), that may increase the risk. A Mediterranean diet is extremely low in UPF. There’s increasing evidence to show that consumption of UPF is associated with a wide range of adverse health outcomes including increasing the risk for dementia. The researchers found that even just “replacing 10% of UPF weight in the diet with an equivalent proportion of unprocessed or minimally processed foods was estimated to be associated with a 19% lower risk of dementia”.

As you can see, there’s a wealth of evidence that the Mediterranean diet can help to protect the brain and reduce the risk of dementia. Whilst we’ve talked a lot about food, but don’t forget that a big part of the Mediterranean lifestyle is about taking time to eat with family and friends. So, think about how you eat as well as what you eat.

For more nutrition tips, head over to the Food section in the Evergreen Life app.

Reviewed by:

Anna Keeble MA BA Wellbeing Expert

Dr Claire Marie Thomas MRCGP DFSRH DTMH DipNLP MBChB BMedSci Medical Expert

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Picture of Ingrid Kitzing

Ingrid Kitzing

Ingrid Kitzing is a nutrition expert here at Evergreen Life. She trained as a Nutritional Therapist at The College of Naturopathic Medicine, and is passionate about helping people bring healthy and nutritious food into their lives.