The conclusion was based upon a scientific study of 960 participants between the ages of 58 and 99, the results of which were published in the US scientific journal Neurology.
Alzheimers.co.uk reports that the experiment saw the participants divided into five groups based on how often they ate leafy green veg such as spinach and kale.
Researchers found that on average those in the highest group ate just over one serving of these vegetables per day, more than ten times the amount of those in the lowest group.
The study, which involved a series of memory and thinking tests over an average of five years, found that the difference in the rate of decline between the group who ate the most of these vegetables and the group that ate the least was equivalent to 11 years of ageing.
Commenting on the findings, 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.
“It is difficult to drill down to investigate whether a specific food or nutrient could hold particular benefits for memory and thinking skills, and this research doesn’t show that leafy, green vegetables promote brain health any more than other vegetables.
“Observational studies like this are not able to pinpoint cause and effect but can be extremely useful in giving us an idea of lifestyle factors that are associated with good health. Future studies will need to explore how leafy, green vegetables might contribute to brain function or if there is any link to whether people develop dementia.
“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.”