Spicy foods are often touted as defenders against dementia, while berries are praised for enhancing cognitive abilities, and supplements are said to bolster memory. These intriguing claims about so-called ‘brain foods’ frequently appear online and across social media platforms.

But do certain foods or diets actually have the power to prevent dementia?

Dementia is the leading cause of death in the UK, yet research indicates that up to 40% of cases could be avoided through straightforward lifestyle adjustments.

Although no specific anti-Alzheimer’s diet exists, studies suggest that dietary modifications may lower the risk of developing dementia.

This is particularly relevant for individuals with conditions like heart disease, high blood pressure, obesity, and diabetes. These conditions, affecting over two million people in Britain, are linked to a greater likelihood of experiencing cognitive decline as one ages.

That’s because those with certain conditions like heart disease, high blood pressure, obesity and diabetes — which affect at least 2million Brits — are more likely than those without such conditions to experience age-related cognitive decline. 

You don’t need to overhaul your diet overnight, diet and ageing experts say.

But such changes can involve limiting the consumption of certain unhealthy foods. Here are the foods they want us to cut back on — and why.

Up to four in 10 dementia cases could be prevented with simple lifestyle changes, research suggests

Fizzy drinks

Cans of fizzy or sweetened drinks have long been blamed for weight gain and tooth decay. 

But a growing body of research also suggests the sweetened beverages, like Coca-Cola or Sprite, are associated with a greater risk of developing dementia. 

‘This might be due to effects on blood glucose and insulin levels, or indirectly by increasing the risk of obesity — a known dementia risk factor,’ Dr Oliver Shannon, a lecturer in nutrition and ageing at Newcastle University, says. 

‘One study showed that individuals who have two or more sugary drinks per day had a 34 per cent increased risk of dementia than those who drank none.’

Sweetened drinks often include fizzy drinks, squash and cordial. But studies suggest tea and coffee could also fall into this category, if sugar is added.

In September, Brazilian researchers who tracked the dietary habits of almost 13,000 adults, also discovered that higher consumption of ‘added sugars’ — which they defined as just one can of diet fizzy drink each day — was linked to a 62 per cent higher risk of brain ageing.

This was equivalent to roughly 1.6 years of ageing. 

But a growing body of research also suggests the sweetened beverage, like Coca-Cola or Sprite, is associated with a greater risk of developing dementia 

The risk was particularly heightened in those with diabetes, who are more likely to use artificial sweeteners as sugar substitutes, the researchers also found. 

Brain ageing can affect cognitive functions such as memory, attention, and multitasking, increasing susceptibility to neurodegenerative diseases such as dementia. 

The NHS also says more than 20 per cent of the added sugar in adult diets comes from soft drinks and fruit juice — and as much as a third for children aged between 11 and 18.

And while the sugar in fruit and dairy products comes with beneficial nutrients such as vitamins, minerals and fibre, the sugar in soft drinks is simply empty calories.

Processed meat and ‘fake’ meat 

According to Dr Shannon, it may also be worth bidding goodbye to your classic fry-ups and charcuterie boards if you want to minimise your dementia risk.

Sausages, bacon, salami, chorizo, ham, hot dogs, canned meat and patés are all examples of processed meats.

Processed meat is any animal flesh that has been treated to increase its shelf life or taste better. This is often done by adding chemical preservatives such as nitrates.

Sausages, bacon, salami, chorizo, ham, hot dogs, canned meat and patés are all examples of processed meats

When eaten, nitrates can undergo a reaction that turns them into a substance called N-nitroso chemicals (NOCs). 

‘Eating processed meat like sausages, ham and bacon has been linked with a higher risk of dementia and a greater drop in cognitive functions with age,’ Dr Shannon says.

‘These associations may be due to negative effects on blood pressure, cholesterol levels and the formation of potentially harmful N-nitroso compounds.’

He adds: ‘Most of the evidence we have on the negative impact of these foods comes from observational studies, so can’t prove cause and effect.

‘But there are biologically plausible mechanisms which link their consumption with greater dementia risk. Try replacing these processed meats with pulses, white meat or fish.’

Fuelled by a deluge of alarming reports into the dangers of eating too much red or processed meat, supermarket shelves are now littered with vegan sausages, bacon and burgers.

But vegan burgers are, by their very nature, highly processed too, containing a concoction of emulsifiers, stabilisers, flavour enhancers and artificial colourings designed to help them feel and taste and look like the real thing.

They can also be packed with higher levels of salt, sugar and fat, diet experts warn — all substances Britons have been advised to cut down on. 

Sugary sweets, pastries and chocolate are all rich in free sugars — those that are added to food, as opposed to those that occur naturally

Sweets and high sugar treats  

Experts have long advised that junk food isn’t good for us.

So, it should come as little surprise that sugary sweet treats are on the list of foods they suggest you avoid.

Sugary sweets, pastries and chocolate are all rich in free sugars — those that are added to food, as opposed to those that occur naturally.

Eating too much of these treats over time will lead to weight gain and continuous spikes in blood sugar levels — two dementia risk factors, says Kim Pearson, a London based author and nutrition expert.

‘Although they’re tempting, do keep high sugar processed foods to a minimum. 

‘Over time, repeated fluctuations in blood sugar levels can drive inflammation and damage the blood vessels that supply the brain. 

‘Poorly controlled blood sugar is strongly linked with cognitive decline, and some researchers now refer to Alzheimer’s as type 3 diabetes.’

While the term isn’t formally recognised by medical organisations and isn’t used in official diagnoses, scientists often refer to type 3 diabetes, to acknowledge the association between uncontrolled blood sugar and Alzheimer’s disease. 

‘Research from Johns Hopkins Bloomberg School of Public Health has also shown that people diagnosed with diabetes in midlife are more likely to experience significant memory and cognitive problems over the following twenty years than those with healthy blood sugar levels,’ Ms Pearson adds. 

It’s recommended that adults limit their intake to a maximum of six teaspoons of sugar per day. 

To put this into context, that’s the amount found in just nine chocolate Mini Eggs.