Avocado on whole-wheat toast isn’t just a staple at trendy brunch spots—it could also be part of a diet to combat Alzheimer’s and dementia.
Scientists who examined the diet and cognitive abilities of more than 3,000 Britons over 70 years say they have discovered which foods eaten in childhood and early adulthood help brain function later in life.
They found that diets consisting of unprocessed or less processed green leafy vegetables, beans, whole fruits, and whole grains were the most protective.
Experts linked this to the high levels of antioxidants and monounsaturated and polyunsaturated fats in these foods, which improve circulation to the brain and fight harmful substances in it.
They found that only seven percent of people who ate such diets early in life reported poor cognitive ability, which can be a precursor to dementia, over the course of the study.
Experts found that diets consisting of unprocessed or less processed green leafy vegetables, legumes, whole fruits and whole grains were the most protective of our cognitive health.
Around 900,000 Britons are currently thought to have the memory-impairing disorder. But scientists at University College London estimate this figure will rise to 1.7 million within two decades as people live longer. This is a 40% increase on the previous forecast in 2017.
In dramatic contrast, 92 percent of those who ate diets high in salt, added sugars and refined grains like white bread suffered from poor cognitive ability in old age.
The scientists based their findings on a long-running British study that began in 1946 and followed the diet and health of 3,059 Britons from age four to 75.
Participants’ diets were examined at five time points throughout the study and their cognitive ability was assessed seven times.
Cognitive ability is a term that reflects the strength of a person’s memory and speed of thinking.
While some cognitive decline occurs naturally as we age, it can also be a sign of diseases such as dementia: a quarter of people with low cognitive ability in the study also showed signs of the disease.
The authors of the new research, who presented their findings at the American Society for Nutrition’s annual meeting in Chicago, acknowledged that advice to eat more fruits and vegetables is not new.
However, they added that this research suggests that eating these foods early in life has a more sustained protective effect on the brain than previously believed.
Researcher Kelly Cara, a nutrition expert at Tufts University in Boston, said: “These initial findings generally support current public health guidance that it is important to establish healthy dietary patterns early in life to support and maintain health throughout life.”
‘Our findings also provide new evidence suggesting that improvements in dietary patterns up to midlife may influence cognitive performance and help mitigate or slow cognitive decline in later years.’
He added that while the findings have not yet been peer-reviewed, they suggest a clear pattern in which foods appear to help protect the brain.
“Dietary patterns rich in whole or less processed plant food groups, such as green leafy vegetables, legumes, whole fruits and whole grains, may be the most protective,” she said.
‘Adjusting dietary intake at any age to incorporate more of these foods and align it more closely with current dietary recommendations will likely improve our health in many ways, including our cognitive health.’
What’s more, the researchers found that eating patterns appeared to be established in childhood and then continue into later life, for better or worse.
Fruits and vegetables, in general, are considered to be high in antioxidants that fight unstable atoms called “free radicals,” which are believed to damage cells.
Foods rich in monounsaturated fats help reduce bad cholesterol in the blood and include avocados, peanut butter and nuts such as almonds.
Polyunsaturated fats have similar benefits and also provide omega-6 and omega-3 fatty acids, essential fats that the body needs. Some examples of foods rich in polyunsaturated fats are oily fish, such as salmon, some nuts and tofu.
Researchers assessed the diets of the British people who participated in the study as high or low quality according to the US government’s dietary guidelines.
They recommend that adults generally eat at least two and a half cups (one American kitchen measure) of vegetables, two cups of fruit, 170 g of grains, about 155 g of lean or plant-based protein such as beans, and 27 g (two tablespoons) of oils each day.
An example of what this might look like is an adult eating 88g of broccoli, two medium carrots, 33.5g of kale, 210g of apples, about four slices of wholemeal bread and a chicken or fish fillet, as well as 27g of oil for cooking or salad dressing in one day.
However, exact amounts vary depending on the specific food and the caloric intake requirements of the adult in question, which vary between men and women.
The NHS guidelines for a healthy diet are broadly similar, encouraging adults to eat five portions of a variety of fruit and vegetables each day, starchy carbohydrates such as bread or pasta, ideally wholegrain, 30g of fibre a day, some low-fat dairy products for protein, some pulses, fish, eggs, leaner meat (including 2 portions of fish each week, one of which should be fatty) and small amounts of unsaturated oils and spreads.
Adults are also advised to consume less than 6 g of salt and 20 g of saturated fat for women or 30 g for men each day.
Authors of the new research He noted that the lengthy nature of the study meant there were some gaps and inconsistencies in data collection.
It is estimated that around 944,000 people in the UK are living with dementia, while the figure is estimated at around seven million in the US.
Alzheimer’s is the leading cause of dementia, affecting approximately six out of ten people with the disease.
It is thought to be caused by a buildup of amyloid and tau in the brain, which clump together to form plaques and tangles that make it difficult for the brain to function properly.
But they can also be a sign of dementia, the memory-destroying disease that affects nearly one million Britons and seven million Americans.
Over time, the brain struggles to cope with this damage and symptoms of dementia develop.
The second most common form of dementia is vascular, which is when there is reduced blood flow to the brain, such as in a stroke.
Memory problems, thinking and reasoning difficulties, and language problems are common early symptoms of the disease, which then worsen over time.
An analysis by Alzheimer’s Research UK found that 74,261 people died from dementia in 2022, compared with 69,178 a year earlier, making it the country’s biggest killer.
WHAT SHOULD A BALANCED DIET LOOK LIKE?
Meals should be based on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally wholegrain, according to the NHS.
• Eat at least 5 servings of a variety of fruits and vegetables every day. Fresh, frozen, dried and canned fruits and vegetables all count.
• Base meals on potatoes, bread, rice, pasta or other starchy carbohydrates, ideally whole grains.
• 30 grams of fiber per day: This is the same as eating all of the following: 5 servings of fruits and vegetables, 2 whole grain crackers, 2 thick slices of whole wheat bread, and one large baked potato with skin.
• Eat some dairy products or dairy alternatives (such as soy drinks) and choose lower-fat and lower-sugar options.
• Eat some legumes, fish, eggs, meat and other proteins (including 2 portions of fish per week, one of which should be fatty)
• Choose unsaturated oils and creams and consume in small quantities.
• Drink 6 to 8 cups/glasses of water a day.
• Adults should consume less than 6 g of salt and 20 g of saturated fat for women or 30 g for men per day.
Source: NHS Eatwell Guide