Scientists have found a daily serving of foods such as lettuce and spinach could be linked to a slower rate of brain ageing – the equivalent over a lifetime of keeping the brain 11 years younger.
The study found that people who ate salads each day had a slower rate of decline on tests of memory and thinking skills than people who never or rarely touched such foods.
The team of researchers discovered that eating greens regularly reduced the likelihood of the symptoms of dementia or diseases which cause it such as Alzheimer’s.
In the study the projected difference between the two groups – one regularly eating greens and the other not – over a lifetime was the equivalent of being just over a decade younger in age, according to the American research team.
Study author Professor Martha Clare Morris, of Rush University Medical Center in Chicago, said the findings, published online by the journal Neurology, highlighted the importance of diet.
She explained: “Adding a daily serving of green, leafy vegetables to your diet may be a simple way to foster your brain health.
“Projections show sharp increases in the percentage of people with dementia as the oldest age groups continue to grow in number, so effective strategies to prevent dementia are critical.”
Last night UK research bodies into Alzheimer’s and dementia welcomed the study.
Dr Sara Imarisio, head of research at Alzheimer’s Research UK, said: “Fruits and vegetables are a key component of a nutritionally balanced diet, but figures suggest that many of us struggle to eat our five-a-day. As well as helping to support our overall physical health, this research adds to evidence of a link between a diet rich in vegetables and a healthy brain.
“As well as eating a healthy diet with plenty of vegetables, research points to a number of other lifestyle factors that could help support brain health into old age. These include not smoking, staying mentally and physically active, keeping blood pressure and cholesterol in check and only drinking in moderation.”
Dr James Pickett, head of research at Alzheimer’s Society, said: “It’s no secret that eating vegetables is good for your health. This study found eating food rich in vitamin K – like spinach, kale, asparagus and everyone’s favourite, Brussels sprouts – appears to slow cognitive decline as people age.
“The researchers did not directly look at dementia, so we cannot say that it would delay or prevent the onset of the condition. However, older people who ate one or two servings of vitamin K rich food per day performed better on memory tests than those who didn’t.
“In fact, their scores were similar to those of people 11 years younger, irrespective of other factors such as obesity, high blood pressure and education level.”
He added: “What’s good for the heart is good for the head. A healthy diet rich in essential nutrients, combined with regular exercise and avoiding smoking, can help to reduce your risk of developing dementia. So make sure your Christmas dinner is piled high with greens this year.”
A total of 960 people with an average age of 81 who did not have dementia were followed for an average of 4.7 years.
The participants completed a questionnaire about how often they ate certain foods and had their thinking and memory skills tested yearly during that time.
They were asked how often and how many servings they ate of three green, leafy vegetables – spinach, kale, collards or greens and lettuce.
The participants were divided into five equal groups based on how often they ate the foods.
The people in the top serving group ate an average of about 1.3 servings per day. Those in the lowest serving group ate on average 0.1 helpings per day.
Overall, the participants’ scores on the thinking and memory tests declined over time at a rate of 0.08 standardised units per year.
Over 10 years of follow-up, the rate of decline for those who ate the most leafy greens was slower by 0.05 standardised units per year than the rate for those who ate the least leafy greens.
The difference was found to be equivalent to being 11 years younger in age, according to the researchers.
The study team said the results remained valid after accounting for other factors that could affect brain health such as smoking, high blood pressure, obesity, education level and amount of physical and cognitive activities.