Scientists at the Harvard T.H. Chan School of Public Health in Boston looked at data from a study that followed nearly 28,000 men over a 26 year period.
The men had recorded what they ate and drank at the start of the study in 1986 (when they were 51), and then every four years until 2002. A follow up 2012 involved doing a series of tests looking into their ability to think and recall facts.
More vegan, more memory
All the men had been in professions that involved years of training and high levels of concentration, such as dentistry and veterinary work.
And the experts found that those who ate higher amounts of fruit and veg had a much lower risk of memory decline and thinking ability.
The foods they found to be most effective were leafy greens, red and dark orange veg, berries and orange juice.
The men were split into five groups, according to their fruit and veg intake. The group who ate the most veg ate around six portions a day, while the group who consumed the least had around two. Fruit consumption ranged from around three portions a day to just half a portion.
A comparison of subjective cognitive test (SCT) results found that the men who ate the most veg were up to 34 percent less likely to report having experienced a reduction in memory function. Only 6.6 percent of them scored poorly, compared to 7.9 percent of those who ate the least.
The results also showed a 47 percent less chance of having a poor SCF score among the men who drank orange juice every day compared with those who only drank it once per month. The link was most relevant for older men who drank orange juice every day. And those men who ate the most fruit were the least likely to score poorly on the tests.
Dietary choices and brain health
The study’s lead author, Dr. Changzheng Yuan, said: "Our studies provide further evidence [that] dietary choices can be important to maintain your brain health."
Of course, that doesn’t mean that drinking OJ every day is going to necessarily stop you from developing dementia but the study does reveal an interesting link. And it provides us with yet more ideas of how potentially protective plants can be to our health.
The test relied on self-analysis which is also a bit tricky. Typical questions in SCF included: "Do you have more trouble than usual remembering a short list of items, such as a shopping list?"
Another question was: "Do you have more trouble than usual following a group conversation or a plot in a TV program due to your memory?". Was every man completely accurate in his reply? This can be a limitation of these kinds of studies.
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.