Orange
juice, leafy greens and berries may be tied to decreased memory loss in men
American Academy of Neurology
Eating leafy greens, dark orange and
red vegetables and berry fruits, and drinking orange juice may be associated
with a lower risk of memory loss over time in men, according to a study
published in the November 21, 2018, online issue of Neurology®, the
medical journal of the American Academy of Neurology.
"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."
The study looked at 27,842 men with
an average age of 51 who were all health professionals.
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 for 20 years.
A serving of fruit is considered one cup of fruit or ½ cup of fruit juice. A serving of vegetables is considered one cup of raw vegetables or two cups of leafy greens.
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 for 20 years.
A serving of fruit is considered one cup of fruit or ½ cup of fruit juice. A serving of vegetables is considered one cup of raw vegetables or two cups of leafy greens.
Participants also took subjective
tests of their thinking and memory skills at least four years before the end of
the study, when they were an average age of 73.
The test is designed to detect changes that people can notice in how well they are remembering things before those changes would be detected by objective cognitive tests.
Changes in memory reported by the participants would be considered precursors to mild cognitive impairment. The six questions include "Do you have more trouble than usual remembering a short list of items, such as a shopping list?" and "Do you have more trouble than usual following a group conversation or a plot in a TV program due to your memory?"
The test is designed to detect changes that people can notice in how well they are remembering things before those changes would be detected by objective cognitive tests.
Changes in memory reported by the participants would be considered precursors to mild cognitive impairment. The six questions include "Do you have more trouble than usual remembering a short list of items, such as a shopping list?" and "Do you have more trouble than usual following a group conversation or a plot in a TV program due to your memory?"
A total of 55 percent of the
participants had good thinking and memory skills, 38 percent had moderate
skills, and 7 percent had poor thinking and memory skills.
The participants were divided into
five groups based on their fruit and vegetable consumption. For vegetables, the
highest group ate about six servings per day, compared to about two servings
for the lowest group. For fruits, the top group ate about three servings per
day, compared to half a serving for the bottom group.
The men who consumed the most
vegetables were 34 percent less likely to develop poor thinking skills than the
men who consumed the least amount of vegetables. A total of 6.6 percent of men
in the top group developed poor cognitive function, compared to 7.9 percent of
men in the bottom group.
The men who drank orange juice every
day were 47 percent less likely to develop poor thinking skills than the men
who drank less than one serving per month. This association was mainly observed
for regular consumption of orange juice among the oldest men.
A total of 6.9 percent of men who drank orange juice every day developed poor cognitive function, compared to 8.4 percent of men who drank orange juice less than once a month. This difference in risk was adjusted for age but not adjusted for other factors related to reported changes in memory.
A total of 6.9 percent of men who drank orange juice every day developed poor cognitive function, compared to 8.4 percent of men who drank orange juice less than once a month. This difference in risk was adjusted for age but not adjusted for other factors related to reported changes in memory.
The men who ate the most fruit each
day were less likely to develop poor thinking skills, but that association was
weakened after researchers adjusted for other dietary factors that could affect
the results, such as consumption of vegetables, fruit juice, refined grains,
legumes and dairy products.
The researchers also found that
people who ate larger amounts of fruits and vegetables 20 years earlier were
less likely to develop thinking and memory problems, whether or not they kept
eating larger amounts of fruits and vegetables about six years before the
memory test.
The study does not show that eating
fruits and vegetables and drinking orange juice reduces memory loss; it only
shows a relationship between them.
A limitation of the study was that
participants' memory and thinking skills were not tested at the beginning of
the study to see how they changed over the course of the study. However,
because all participants completed professional training, they can be assumed
to have started with relatively high cognitive function in early adult life.
In addition, the study participants were all male health professionals such as dentists, optometrists, and veterinarians. Thus, the results may not apply to women and other groups of men.
In addition, the study participants were all male health professionals such as dentists, optometrists, and veterinarians. Thus, the results may not apply to women and other groups of men.
The study was supported by a grant
from the National Institutes of Health and an anonymous gift to the Harvard
T.H. Chan School of Public Health.