In an earlier article, we talked about the importance of following a “rainbow diet” whereby consuming a variety of coloured fruit and vegetables was a healthy way of eating. For more information, please read it here. It would appear that on top of having physical benefits, consuming a variety of coloured fruit and vegetables could yield mental benefits too.

According to Harvard Health Publishing, a diet that includes a vibrant rainbow of fruits and vegetables, like rosy red strawberries, dark green spinach leaves, or sunny yellow peppers may play a vital role in protecting cognition. The colours in these fruits and vegetables often come from flavonoids which are powerful plant chemicals (phytochemicals) that appear to contribute to sustaining, maintaining and boosting memories.

Photo by Trang Doan from Pexels

A study published online in Neurology in July suggests that flavonoids may also play a role in protecting cognition.

Scientists evaluated the health data and self-reported diet information of more than 77,000 middle-aged men and women, collected over two decades. The information included how often participants ate many types of flavonoid-rich foods and whether participants reported cognition changes in their 70s, such as difficulty:

  • remembering recent events or a short list of items
  • remembering things from one second to the next
  • understanding instructions
  • following a group conversation or TV plot
  • finding their way around familiar streets

Researchers then calculated participants’ intake of six classes of flavonoids:

  • flavonols (such as quercetin in onions and kale)
  • flavones (such as luteolin in green chile peppers and celery)
  • flavanones (such as naringenin in grapefruit and oranges)
  • flavan-3-ol monomers (such as catechins in red wine and strawberries)
  • anthocyanins (such as cyanidin in blackberries and red cabbage)
  • polymers (such as theaflavins in black tea).

After taking into account factors that could have affected cognition (such as age, weight, physical activity, alcohol intake, depression, and non-flavonoid nutrient intake), the data revealed that people with the highest daily flavonoid intakes were 19% less likely to report trouble with memory and thinking. This is compared to people with the lowest daily flavonoid intakes.

Photo by Geraud pfeiffer from Pexels

While the study was only observational, relying on what people remembered about their diets and noticed about cognition, and didn’t prove conclusively that flavonoid intake kept people sharp in older age, results do indicate that earlier consumption of flavonoid-rich foods seemed to improve the protective effect on the brain. It also indicated that even participants who began eating more flavonoids later in life saw benefits.

The fruits and vegetables in the study most associated with beneficial cognitive effects, listed from strongest to weakest, were:

  • Brussels sprouts
  • strawberries
  • cauliflower
  • raw spinach
  • yams/sweet potatoes
  • blueberries
  • yellow/orange winter squash
  • cooked spinach
  • cooked carrots
  • peaches/apricots/plums
  • cantaloupe
  • tomato juice
  • applesauce
  • green/red/yellow peppers
  • broccoli
  • cabbage
  • tomato sauce
  • romaine lettuce
  • tomatoes
  • grapefruit
  • celery
  • beets
  • iceberg lettuce
  • baked/boiled/mashed potatoes
  • orange juice
  • raw carrots
  • apples/pears
  • grapefruit juice
  • bananas
  • oranges
  • onions
  • apple juice/cider
  • tea
  • white wine
  • grapes/raisins
  • red wine.

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