Eating less than a handful of walnuts daily as a snack or as a part of a meal can sharpen your memory, says a study.

The first-ever large representative analysis of walnut intake and cognitive function found that eating just 13 grams walnuts a day improved memory performance on cognitive function tests, including those for memory, concentration and information processing speed.

In this study, participants included adults aged 20-59 as well as 60 and over.

Lenore Arab, a doctor from David Geffen School of Medicine at University of California, Los Angeles, and co-researcher Alfonso Ang, also a doctor, found that participants with higher walnut consumption performed significantly better on a series of six cognitive tests.

Cognitive function was consistently greater in adult participants that consumed walnuts, regardless of age, gender or ethnicity.

“The analysis supports previous results of animal studies that have shown the neuroprotective benefit from eating walnuts and it is a realistic amount – 13 grams,” Arab said.

There are numerous possible active ingredients in walnuts that may be contributing factors in protecting cognitive functions.

This includes the high antioxidant content of walnuts and the combination of numerous vitamins and minerals.

Walnuts also contain a significant source of alpha-linolenic acid (ALA), a plant-based omega-3 fatty acid with heart and brain-health benefits.

It includes the possible beneficial effects of slowing or preventing the progression of Alzheimer’s disease.

According to a 2012 World Health Organisation (WHO) article, the estimated number of new cases of dementia each year worldwide is nearly 7.7 million and the number of people living with dementia worldwide is estimated at 35.6 million.

This number is predicted to double by 2030 and more than triple by 2050.