Fruit vegetables

A Canadian study involving 45,522 adults (30+) found that higher levels of physical activity, eating more fruits and vegetables, and having a BMI in the normal weight or overweight range were each associated with better cognitive function in both younger and older adults.

Specifically, for those who were normal weight or overweight (but not obese), eating more than 10 servings of fruit and vegetable daily was linked to better cognitive functioning. When moderate exercise was added, those eating less than five servings, reported better cognitive functioning.

Data from the long-running Rush Memory and Aging Project, involving 960 participants who completed a food frequency questionnaire from 2004 to 2013, found that those who ate one daily serving of green, leafy vegetables had a slower rate of cognitive decline than people who rarely or never ate them. Those who ate at least one serving of leafy green vegetables showed an equivalent of being 11 years younger cognitively.

Data from the Canadian Longitudinal Study on Aging, involving 8,574 middle-aged and older adults (aged 45-85), has found that those who ate more vegetables and fruits and more nuts and pulses (such as lentils and beans) scored higher on tests of verbal fluency. Every increase in average daily fruit and vegetable intake was linked to higher verbal fluency scores, but the best outcomes were found among those who consumed at least 6 servings a day.

Additionally, those with stage 2 hypertension had lower verbal fluency scores, as did those with higher levels of body fat.

Analysis of data from the Age-Related Eye Disease Study (AREDS) and AREDS2, involving a total of around 8,000 older adults, has found that those with the greatest adherence to the Mediterranean diet had the lowest risk of cognitive impairment. High fish and vegetable consumption appeared to have the greatest protective effect. At 10 years, AREDS2 participants with the highest fish consumption had the slowest rate of cognitive decline.

A study involving 116 healthy older adults (65-75) has found that higher levels of several key nutrients in the blood were associated with more efficient brain connectivity and better cognitive performance. In fact, the findings suggest that the level of nutrients governs the strength of the association between functional brain network efficiency and cognitive performance.

A study following nearly 28,000 older men for 20 years has found that regular consumption of leafy greens, dark orange and red vegetables and berry fruits, and orange juice, was associated with a lower risk of memory loss.

The study looked at 27,842 male health professionals, who were an average age of 51 in 1986, when the study began. Participants filled out questionnaires about how many servings of fruits, vegetables and other foods they had each day, at the beginning of the study and then every four years.

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A pilot study involving 106 participants of the Rush Memory and Aging Project who had experienced a stroke followed participants for an average of 5.9 years, testing their cognitive function and monitoring their eating habits using food journals. It was found that those whose diets scored highest on the MIND (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay) diet score had substantially slower rates of cognitive decline than those who scored lowest.