The study found that eating approximately a serving a day of leafy green vegetables and foods rich in certain vitamins, such as vitamin K, may have some protective effect against age-related memory loss and declining cognitive or thinking skills.
This new research into whether eating a diet high in leafy green vegetables protects against age-related memory loss and decline in thinking skills had its participants followed-up for two years, with an average follow-up time of 4.7 years.
This was a prospective cohort study of 960 people from the Memory and Ageing Project (MAP) published in the journal Neurology. The researchers began collecting data in 1997.
They were old people with an average age of 81. They were mostly of white ethnicity and 74 per cent of them were women from only one city in the United States of America.
The participants completed a questionnaire about how often they ate certain foods and had their thinking and memory skills tested yearly during that time.
The researchers divided the participants into five groups based on their intake of leafy green vegetables. It ranged from 0.07 portions a day to 1.14 portions a day (highest).
They also looked at the nutrients in green leafy vegetables separately to determine if any specific foods could be targeted for preventing memory decline as well as took into consideration a number of factors that might have influenced these results such as age, education, physical activity, obesity and smoking history.
In comparison with those with the lowest intake of leafy greens, those with the highest intake, they found were more likely to be higher educated, male, take part in more cognitive and physical activities, and have fewer cardiovascular and depressive symptoms, which could in theory have additional protective effects on memory.
The Rush University researchers found eating approximately a serving a day of leafy green vegetables was linked to slower loss of memory with ageing.
Also, people in the highest quintile of leafy green vegetable that take an average of 1.3 servings a day had a slower rate of cognitive decline over the 10-year period.
They estimated also that participants who ate the most leafy greens have a memory age around 11 years younger compared with those eating the least.
According to them, eating approximately a serving of leafy green vegetables may help slow the decline of cognitive abilities in older age, perhaps because of the protective effects chemical substances like lutein, folate, beta-carotene and phylloquinone that vegetables have on the brain.
But, Dr Martha Morris of Rush University Medical Centre in Chicago, who led the study noted that the study does not prove that eating green, leafy vegetables slows brain ageing, it only shows an association.
She also warned that the study cannot rule out other possible reasons for the link.
“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,” she said.
Previously, researchers have said that marriage, having close friends and education may help protect against dementia, which causes an age-related memory loss and a decline in cognitive or thinking skills.
The researchers found people who were not married and those with higher loneliness scores had a higher risk of developing dementia. It was published in the peer-reviewed Journals of Gerontology.
But this cannot prove that being married will protect against dementia. A combination of many biological, health, lifestyle and environmental factors is likely to influence the risk of developing dementia.
Also, they said in the study published in the peer-reviewed British Medical Journal that Alzheimer’s risk reduces by 11 per cent for every year spent in education.
The study that looked at the genetic make-up and modifiable risks of around 17,000 people with Alzheimer’s disease, the most common form of dementia. It found that education showed the strongest association with the risk of Alzheimer’s disease.
Currently, the causes of some types of dementia – particularly Alzheimer’s disease – remain poorly understood. But factors linked to the development of dementia included heart and vascular disease, impaired mobility, and lower educational levels.
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