Want To Reduce Your Dementia Risk? Eat These 4 Foods, Says New Study

Updated: Jun. 24, 2024

Plus, here's exactly how many servings per day Harvard researchers found can keep the brain firing young.

If you are what you eat, this might make you hungrier for foods that are bright in every sense. Research has shown that living, vibrant foods can slow down aging at a cellular level; while fruits and vegetables in particular have been associated with lower incidence of cognitive decline as individuals age.

However, research has been relatively lacking on just how much of these brain-healthy foods you really need and which fruits and vegetables are best for the job.

In collaboration with public health experts at Harvard University, medical researchers at China’s Zhejiang University School of Medicine conducted a meta-analysis that’s slated to be published in the June 2024 issue of The Journal of Nutrition, Health, and Aging. They combined data from two large-scale population-representative studies that analyzed the diets and cognitive function of more than 10,000 participants ages 55 and older from China and the U.S.

The data included diet questionnaires that honed in on the average of participants’ total daily intake of several different types of foods, including fruits and vegetables, and also broke them down into sub-types like green leafy vegetables and berries. Over a period of five years, the participants also took part in activities designed to assess their cognitive function and the average rate of cognitive decline.

Baskets of Blackberries, Raspberries and BlueberriesDesiDrew Photography/Getty Images

Overall, participants who included the most fruits and vegetables in their daily diets performed best on the brain tests and maintained those results over time. This suggested that both fruits and vegetables had protective elements that slowed cognitive decline.

Interestingly, certain types of vegetables appeared to be more beneficial than others—say the researchers: “Our findings support the potential beneficial roles of VF, especially cruciferous vegetables, green leafy vegetables, and red and yellow vegetables, in maintaining cognitive function and slowing cognitive decline in middle-aged and older adults.” 

The researchers pointed to several reasons these particular vegetables might have shown a substantial impact, including anti-inflammatory and antioxidation nutrients like flavonoids and various vitamins or even gut improvements that have been shown to help improve or protect cognition.

While beans didn’t figure prominently in both studies, they showed a protective element in the U.S. study, so they are also worth keeping on your plate. (Beans are also thought to be one of the top foods for longevity.)

As for fruits, while some didn’t show as much of a protective effect across the board, berries and apples are two examples of fruits that experts have previously said provide major polyphenol and antioxidant effect.

Participants whose brains maintained performance were shown to have eaten three or more servings of vegetables and two or more servings of fruit per day. This is on par with the two to three cups of vegetables and one to two cups of fruit that are recommended for Americans over the age of 60.