New York, Mar 11 (IANS): People who eat diets rich in green leafy vegetables as well as other vegetables, fruits, whole grains, olive oil, beans, nuts and fish may have fewer amyloid plaques and tau tangles in their brain -- signs of Alzheimer's disease -- than people who do not consume such diets, according to a study.

These food items are found majorly in the brain-focused MIND -- short for Mediterranean-DASH Diet Intervention for Neurodegenerative Delay -- and plant-based Mediterranean diets.

Although similar, the Mediterranean diet recommends vegetables, fruit, and three or more servings of fish per week while the MIND diet prioritises green leafy vegetables like spinach, kale and collard greens along with other vegetables.

The MIND diet also prioritises berries over other fruit and recommends one or more servings of fish per week. Both the MIND and Mediterranean diet also recommends small amounts of wine.

The study found people who ate the highest amounts of green leafy vegetables, or seven or more servings per week, had plaque amounts in their brains corresponding to being almost 19 years younger than people who ate the fewest, with one or fewer servings per week.

"Our finding that eating more green leafy vegetables is in itself associated with fewer signs of Alzheimer's disease in the brain is intriguing enough for people to consider adding more of these vegetables to their diet," said study author Puja Agarwal, from RUSH University in Chicago.

While this study, published in the journal Neurology, shows an association of regularly consuming these diets with fewer Alzheimer's disease plaques and tangles, it does not establish a cause and effect relationship.

However, "these results are exciting -- improvement in people's diets in just one area -- such as eating more than six servings of green leafy vegetables per week, or not eating fried foods -- was associated with fewer amyloid plaques in the brain similar to being about four years younger," Agarwal said.

"While our research doesn't prove that a healthy diet resulted in fewer brain deposits of amyloid plaques, also known as an indicator of Alzheimer's disease, we know there is a relationship, and following the MIND and Mediterranean diets may be one way that people can improve their brain health and protect cognition as they age," she added.

The study involved 581 people with an average age of 84 at the time of diet assessment who agreed to donate their brains at death to advance research on dementia. The participants died an average of seven years after the start of the study.

Right before death, 39 per cent of participants had been diagnosed with dementia. When examined after death, 66 per cent met the criteria for Alzheimer's disease.

A limitation of the study was that participants were mostly white, non-Hispanic, and older so the results cannot be generalised to other populations.

"Future studies are needed to establish our findings further," Agarwal said.