Now you just need to remember to eat them!

By Lauren Wicks
Updated: December 03, 2018
Photo: Iain Bagwell

One in nine Americans over the age of 45 have reported experiencing “cognitive decline,” such as confusion or memory loss. Christopher Taylor, a CDC epidemiologist, said symptoms of confusion and memory loss are not a normal part of aging, which can be shocking to many, as they seem like usual—albeit unwanted—part of growing older in the U.S. However, a 20-year study conducted by Harvard University points to promising signs for prevention. The researchers noted orange juice, leafy greens, and berries as possible ties to preventing memory loss over time in men.

"One of the most important factors in this study is that we were able to research and track such a large group of men over a 20-year period of time, allowing for very telling results," said study author Changzheng Yuan, ScD, of Harvard T.H. Chan School of Public Health in Boston. "Our studies provide further evidence dietary choices can be important to maintain your brain health."

This study researched almost 23,000 male health professionals with an average starting age of 51. Participants initially tracked their daily intake of fruits and vegetables, and then tracked them again every four years. One serving of fruit was considered to be one cup of whole fruit, or one-half cup of fruit juice. One serving of vegetables was considered to be one cup of raw vegetables, or two cups of leafy greens.

The participants were also required to take subjective thinking and memory skills tests. The tests served to detect any changes in memory, and any changes would be considered precursors to mild cognitive impairment. 55 percent of participants ended the study with good thinking and memory skills after 20 years, while 38 percent had moderate skills, and 7 percent had poor skills.

The participants were divided into five groups, based on their fruit and vegetable intake. The group with the highest consumption of vegetables ate six servings per day, while the group with the lowest only ate two. The group with the highest level of fruit consumption ate three servings per day, while the lowest group only ate half a serving each day.

Looking for tasty ways to eat more produce?

Those who consumed the most vegetables were 34 percent less likely to develop poor thinking skills than the men with the lowest recorded vegetable intake. The men who routinely ate the most fruit showed to also have a lower risk of developing poor thinking skills, but the association was weakened after researchers adjusted for other dietary factors in the study. Interestingly enough, the participants who drank a glass of orange juice every day were 47 percent less likely to develop poor thinking skills than infrequent orange juice drinkers (those who drank one or fewer glasses per month).

Researchers also discovered that those who ate more fruits and vegetables when the study began were less likely to develop thinking and memory problems over the 20-year period. While the study did not test participants for cognitive ability before conducting research, they believe all participants began the study with relatively high cognitive function, as each participant experienced professional training to become medical doctors.

Besides leafy greens, berries, and orange juice, researchers also included dark orange and red vegetables as part of potential cognition defenders. It’s easy to incorporate these foods daily through making salads or smoothies, adding berries to your morning oatmeal, or placing your lunch or dinner on a bed of greens.