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The Mediterranean diet has been linked to reduced chronic illnesses like cancer and heart disease. A new study suggests it might also aid in preserving cognitive health, too. Photo: Shutterstock

How a Mediterranean diet promotes brain health and lowers dementia risk – new research findings

  • The Mediterranean diet is even better for us than we thought – it helps minimise the build-up of two proteins that can trigger dementia, a study finds
  • How it does so is unclear, but it could be because the diet reduces inflammation and so improves blood flow. Following the diet long-term is key, a doctor says

The Mediterranean diet consistently tops the US News & World Report popular rankings for best overall diet.

The popular plan puts the focus on fruit, vegetables, nuts, whole grains and olive oil while restricting red meat, refined sugars and processed foods. Science backs its link to the reduced incidence of chronic illnesses, including cancer, diabetes and heart disease. Now a new study suggests it might also aid in preserving cognitive health.

Put simply, the Mediterranean diet helps minimise the build-up of the two proteins that can lead to Alzheimer’s and other forms of dementia.

Tommaso Ballarini, a researcher at the German Centre for Neurodegenerative Diseases, says the diet has been associated with several beneficial health outcomes. His team’s study extended previous evidence concerning its potential protective role against neurodegeneration and cognitive deficits.

The Mediterranean diet has been associated with several beneficial health outcomes. Photo: Shutterstock
“The specific mechanisms underlying the association between eating a Mediterranean-like diet and lowering Alzheimer’s disease pathology are largely unknown. Several hypotheses have been proposed. For example, following a Mediterranean diet – rich in vegetables, fruits and healthy fats – could modulate inflammation and oxidative damage, two processes that are thought to influence the progression of neuropathology in the brain,” Ballarini says.

“It is also possible that the beneficial effect of the Mediterranean diet on the cardiovascular system might in turn reduce the risk of cognitive decline and dementia, as brain heath and hearth health are tightly related.”

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Joëlle Touchette Bradford, a naturopathic doctor at Hong Kong’s Integrated Medicine Institute, agrees that a Mediterranean diet may stave off dementia for the same reasons that it does heart disease.

“Less inflammation means less atherosclerosis [build-up of cholesterol in the arteries and veins], meaning better blood flow to the brain (or heart), with less risk of blood clots, strokes or occlusion [blockage] of the arteries to the brain. Better blood flow and reduced inflammation in the long term will lead to less risk for dementia long term.”

The emphasis is on the long term. One has to commit to healthy eating: another study found that indulgence in a typical Western diet – high in processed foods and meat – eroded a Mediterranean diet’s benefits.
Joëlle Touchette Bradford is a naturopathic doctor at Hong Kong’s Integrated Medicine Institute. Photo: Winson Wong

Touchette Bradford adds: “There is also evidence that poor blood sugar regulation could lead to decay of the neurons in the brain which can cause some types of dementia. The Mediterranean diet promotes better blood sugar regulation, as it is low in refined carbohydrates and high in anti-inflammatory foods.”

Interest in this diet was piqued in the 1960s when studies indicated that coronary heart disease was responsible for fewer deaths in countries that bordered the Mediterranean Sea such as Greece, Italy and Spain than in northern Europe and North America.

This diet has a lot less meat and a lot more fish, especially the oily ones such as herring, mackerel and sardines, more vegetables (especially tomatoes), and olive oil.

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Ballarini explains that fish is especially beneficial as it is rich in omega-3 polyunsaturated fatty acids which are important for the brain’s structural and functional integrity. In contrast, the typical Western diet usually has excessive saturated fats and omega-6 fatty acids which are linked to pro-inflammatory effects and detrimental health outcomes.

Touchette Bradford says Britain’s NHS advocates having at least one 140g (50z) portion of oily fish a week, since the omega-3 oil they contain is high in both DHA and EPA, (the long-chain fatty acids docosahexaenoic acid and eicosapentaenoic acid) which are anti-inflammatory omega 3s.

These are able to cross the blood brain barrier and help support brain cell health and even help increase brain size ( dementia often presents with a decreased brain size). They also promote better memory and focus – cognitive health. Supplementing with fish or omega-3s (DHA and EPA) is shown to prevent cognitive decline (that is, loss of memory, focus, attention and concentration).
To cook the Mediterranean way, get a cookbook such as this one.
Those choosing a plant-based lifestyle can find omega-3s in chia, hemp and flax seeds, Brussels sprouts and walnuts, among other seeds, nuts and vegetables.

A person’s mood often deteriorates with dementia, the result of confusion, frustration and anger, Touchette Bradford says. “Omega-3s have been shown to decrease depression and reduce anxiety.”

So the oily fish and extra vegetables, especially tomatoes (which are actually fruit – berries, that are rich in two key antioxidants, lycopene and beta-carotene, which are vital for brain health) make sense. But what about the olive oil? Why not any vegetable oil, or even trendy coconut oil?

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Ballarini says his team found a higher consumption of monounsaturated fats compared to saturated fats is associated with lower levels of markers for Alzheimer’s disease. Monounsaturated fats are found in many foods, including olive oil. Coconut oil is instead rich in saturated fatty acids.

Touchette Bradford agrees. “Olive oil, especially extra virgin, has many monounsaturated fats (like oleic acid) as well as beneficial omega-6 fatty acids. This is significant, since the ratio of omega-3 to omega-6 to omega-9 is important for most body functions.”

She adds: “Inflammatory diets can be up to 20 times higher in omega-6 to -9 than omega-3, when we are looking for 3:1, or even 1:1.”

Monounsaturated fats are found in many foods, including olive oil. Photo: Shutterstock

A variety of oils is key, so you can get a bit of everything, she suggests: fish for the omega-3, olive oil for omega-6s and monounsaturated fats, and coconut oil for the medium chain triglycerides (MCTs). 

Typically, if the oils you are choosing are from nature, as unprocessed as possible and as fresh as possible, then they will typically be beneficial. The more artificially altered they are (for shelf life, preservation or taste), the more unhealthy or inflammatory they tend to be.

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A model Mediterranean diet daily menu

Breakfast: Low-fat Greek yogurt topped with fruit and seeds or a handful of muesli.

Lunch: Tuna salad, with a few olives as garnish, and olive oil and lime juice dressing.

Dinner: Chicken breast roasted with garlic and olive oil, fresh vegetables to your liking – zucchini, beans, spinach – and a quinoa salad.

Snack on unsalted nuts, hummus with vegetable sticks, or fruit.

Cookbooks to help you prepare healthy Mediterranean meals include:

  • Fix-It and Forget-It Mediterranean Diet Cookbook: 7-Ingredient Healthy Instant Pot and Slow Cooker Meals

  • The XXL Mediterranean Diet Cookbook for UK: Delicious and Easy-Going Recipes for Every Day

  • The Complete Mediterranean Diet Cookbook: 550 Quick & Easy Mediterranean Diet Recipes For Beginners