Dementia strikes every three seconds. In the time it takes you to read this sentence, someone will have developed memory loss, confusion and behavioural changes, according to the Alzheimer’s Society’s calculations.
It is a frightening thought, but recent months have finally brought signs of a breakthrough in the global battle against Alzheimer’s disease, the most common form of dementia.
The good news is that a new drug, Donanemab, has been shown to slow the progression of the disease by up to 35 per cent, while another large new study, published in the journal BMC Medicine, points to another potential treatment path.
Sticking to a Mediterranean diet may lower your risk of developing all forms of dementia by a quarter, as data from 60,000 people suggests a plant-rich diet may help, regardless of a person’s genetic risk factors.
“A Mediterranean diet, composed of wholegrain cereals, fish rich in omega-3 fatty acids, vegetables and other healthy foods, is excellent for reducing the risk of Alzheimer’s disease,” says Barbara Sahakian, professor of clinical neuropsychology at the University of Cambridge.
Scientists believe it may come down to neurotransmitters, important chemical messengers in the brain. “Acetylcholine, dopamine and serotonin, for example, have roles in cognition, including attention and learning, motivation and mood,” says Sahakian. And they are built from the foods we eat.
Sahakian’s early research showed that taking a drug that boosts acetylcholine had a positive effect on the attention spans of Alzheimer’s sufferers. The NHS now uses this same mechanism to treat patients through drugs like donepezil, which raise this crucial brain chemical. But, Sahakian points out, acetylcholine levels also increase when people eat lecithin – a substance that occurs naturally in many foods that take pride of place in the Mediterranean diet, including seafood and vegetables. There may, however, be an even more potent diet for the prevention of Alzheimer’s and other forms of dementia.
The MIND diet (Mediterranean-DASH intervention for neurodegenerative delay) is a hybrid of the Mediterranean and DASH (dietary approaches to stop hypertension) diets. Both are linked with a reduced risk of cardiovascular conditions like high blood pressure, heart attack, and stroke, as well as slower cognitive decline.
“The MIND diet is partially based on the Mediterranean Diet,” explains Sahakian. Alongside whole grains, poultry, fish and olive oil, it also emphasises the regular consumption of leafy green veg and berries, while placing limits on foods like pastries and sweets, red meats, fried foods and butter.
A 2015 study published in the journal Alzheimer’s & Dementia suggested that adhering closely to the diet could reduce your likelihood of developing the disease by as much as 53 per cent.
What more do we know about the foods that protect our little grey cells?
Go full Popeye on the spinach
“It really is best to eat dark-green leafy vegetables,” says Sahakian. Take spinach: “Rich in vitamins and iron, it also has antioxidant activity. While a high-fat diet increases oxidative stress in a variety of tissues, which may contribute to a number of degenerative diseases, foods that are very high in antioxidants prevent oxidative damage to cells,” says Sahakian. A 2018 study found that simply eating a daily serving of spinach or kale was associated with slower cognitive decline among those in later life.
A study found blueberry extract improved ability to plan and focus along with working memory and learning. Photo / 123RF
Boost your blueberries
“Recent clinical research has demonstrated that berry fruits can reduce the risk of age-related neurodegenerative diseases and improve motor and cognitive functions,” says James Goodwin, director of Science and Research Impact at the Brain Health Network and author of Supercharge Your Brain. He points to a 2022 study that found blueberry extract improved ability to plan and focus along with working memory and learning.
“Higher intake of flavonoids, particularly from berries, appears to reduce rates of cognitive decline in older adults,” explains Goodwin. “Berry fruits are also capable of modulating, or controlling, the intracellular signalling pathways that are involved in inflammation, cell survival, neurotransmission and enhancing neuroplasticity.”
These powers are down to the phytochemicals contained within berries. “Many of the chemical compounds in berries have powerful effects on our neurons but equally, they provide nutrients for our gut microflora whose health is essential for normal brain function,” says Goodwin. “Berries should be consumed daily as part of a brain healthy diet,” advises Goodwin.
Eat the rainbow
Don’t squeeze other fruit and vegetables out, however.
“In hunter gatherer times, we ate over 300 types of plants but according to the Food and Agriculture Organisation of the United Nations (FAO), 75 per cent of all prepared food in retail outlets comes from only 12 plants and five animal species,” warns Goodwin. “We have lost all of this diversity, and it’s no wonder we are now susceptible to many life-threatening chronic long-term illness, including dementia.”
A 2021 study showed that consuming just half a serving of colourful plants a day helped to reduce cognitive decline by 20 per cent, because it boosts our consumption of a class of micronutrients called flavonoids. So eat the rainbow.
Wholegrain foods use the entire grain seed – germ, bran and endosperm – while refined ones have had the germ and bran removed to produce a whiter product. Goodwin points to a recent study suggesting that people who eat the most whole grain foods have a lower risk of dementia broadly and Alzheimer’s specifically.
“One of the principal reasons is their high fibre and polyphenol content,” explains Goodwin. “Both are highly nutritious to our gut microflora, which have an intimate connection to brain function.”
Kimchi. Photo / 123RF
A daily dose of kefir, kimchi or kombucha
Wondering how the health of your gut might affect that of your brain? Scientists are exploring links between diseases such as dementia and the microbes in our gut and making exciting new discoveries.
“The evidence on the gut-brain axis and its potential implications for mental health, including cognitive decline and Alzheimer’s disease, is rapidly growing,” says Professor Tim Spector, co-founder of ZOE, the personalised nutrition company. “The gut microbiome (namely the community of microbes that live in our guts) plays a pivotal role in creating metabolites, also known as postbiotic chemicals, such as bile acids and vitamin B, that directly influence brain function and brain health.”
Recent studies have found that the gut microbes of patients with Alzheimer’s are significantly different and less diverse, suggesting that changes in gut microbes might be involved in the developments of the disease, says Spector:
“We also know that gut microbes are important in how we process sugars and type 2 diabetes and an increased risk of diabetes strongly increases your risk of Alzheimer’s.”
Spector agrees that colourful plants and whole unprocessed foods are key. But: “Introducing new beneficial strains through regular probiotic fermented foods is also likely to be really beneficial as these foods are rich in plant chemicals called polyphenols.” So add a daily dose of kefir (fermented milk), kimchi (fermented cabbage) or kombucha (fermented tea).
Chicken or beans?
In 2021, a Japanese study shed light on the link between protein-rich diets and the reduced risk of Alzheimer’s.
“In older individuals, low-protein diets are linked to poor maintenance of brain function,” explained lead scientist Dr Makoto Higuchi. His results suggest that a diet of essential amino-acids (the building blocks of proteins) reduces inflammation and inhibits brain cell death, in mice at least.
Beware processed meats like bacon, which research suggests can increase your risk of developing dementia. Instead, eat high-quality protein, including chicken breast and fatty fish, as well as beans and legumes like lentils and chickpeas.
Fish
Fish may have the edge, however. A 2012 study concluded that adding just one extra gram of omega-3 to your diet a day (or half a fillet of salmon per week) was associated with 20 to 30 per cent lower blood levels of beta-amyloid (a protein related to Alzheimer’s disease and memory problems), compared to people who included the average quantity of omega-3 in theirs.
Olive oil is rich in powerful antioxidant polyphenols. Photo / 123RF
Olive oil
Olive oil is rich in powerful antioxidant polyphenols. Last year, a Yale University study found that the extra-virgin variety enhanced brain connectivity and reduced blood-brain barrier permeability, both of which are markers of mild cognitive impairment and early Alzheimer’s disease.
Meanwhile, research from Harvard suggests that eating olive oil every day reduces your risk of death from neurodegenerative disorders like Alzheimer’s by 29 per cent. Study author Marta Guasch-Ferré recommended consuming three to four tablespoons daily.
Go nuts for walnuts
“Walnuts have strong antioxidant properties and are thought to have beneficial effects on oxidative stress,” says Sahakian. “However, in 2021, a study published in the journal Annals of Medicine reviewed a number of studies on walnuts and their effects on cognition and stated that they could not reach a definitive conclusion as to whether walnut consumption improved cognition or not.”
A small glass of wine
To drink or not to drink? That is the question.
A study published in 2020, in the journal Nutrition, concluded that: “Excessive wine consumption increases the risk of dementia by direct neurotoxic effects; however, light to moderate wine consumption seems to reduce the risk of dementia and cognitive decline in an age-dependent manner”.
Goodwin points to two possible reasons for this positive impact: “Alcohol in moderate amounts helps to reduce stress and is commonly consumed for this purpose. Plus, wine, particularly red wine, contains molecules that are antioxidant, anti-inflammatory, neuroprotective and anti-ageing; for example polyphenols such as resveratrol, flavonoids. It pays to be conservative with alcohol of all types but to my mind, readers would be justified in taking a small daily glass of wine to reduce their dementia risk”.
“If you have a poor diet, for example one high in fat and salt, and you drink excessive alcohol, then you increase the risk of obesity, diabetes and also other illnesses, such as Alzheimer’s disease,” summarises Sahakian.
“If, on the other hand, you have a healthy diet, with whole grain cereals, fish rich in omega-3 fatty acids, dark-green vegetables, blueberries, walnuts, then you decrease your risk.”
The old cliché, in other words, is right when it comes to our brains. We are indeed what we eat.
