Memory decline can be reversed by increasing the consumption of foods such as green tea, apples, and berries, according to new research.
The study is the first to indicate that a diet lacking in flavanols nutrients present in some fruits and vegetables reduces brain function and contributes to memory loss.
Green leafy vegetables, blackcurrants, onions, apples, berries, cherries, peaches, soybeans, citrus foods, tea, chocolate, lettuce, peppers, grapes, and even wine contain flavonols.
The study by US researchers found that over-60s who already ingested enough flavanols got no advantage from adding more, but those with shortfalls had memory gains of up to 16% in a year.
“The improvement among study participants with low-flavanol diets was substantial and raises the possibility of using flavanol-rich diets or supplements to improve cognitive function in older adults,” said Dr. Adam Brickman, professor of neuropsychology at Columbia University.
According to experts, the finding supports the notion that the aging brain requires certain nutrients to operate well, just as the developing brain of youngsters requires specific nutrients for optimum growth.
Previous animal studies have indicated that flavanols promote the growth of neurons and blood vessels in the hippocampus, an area of the brain important for learning and memory development.
Over 3,500 healthy older individuals were randomly randomized to either a daily flavanol supplement tablet or a placebo pill for three years for the study.
The active supplement included 500 mg of flavanols, which is the recommended daily dosage for adults.
Such a dosage might be achieved naturally by drinking one mug of tea and eating six squares of dark chocolate, and a couple of servings of berries or apples.
‘Really important research
At the start of the trial, all participants filled out a survey on the quality of their food and completed a series of web-based exercises in their own homes to test their short-term memory.
The examinations were then repeated after the first, second, and third years.
Participants who reported consuming a poorer diet and having lower baseline levels of flavanols saw their memory scores increase by an average of 10.5 percent compared to those who took the placebo pill, and 16 percent compared to their memory at baseline at the end of the first year of taking the flavanol supplement.
And the improvement continued for at least another two years.
Commenting on the research, Prof Aedin Cassidy, Chair in Nutrition & Preventative Medicine at Queen’s University Belfast (QUB), said: “This is a really important study showing that [a] dose of flavonoids called flavanols, present in tea, cocoa, apples, and berries, is key for improving memory in the aging brain.
“Supplementing with flavanols reversed the lower memory in the participants who had low diet quality after one year of intake and this was sustained throughout the three-year intervention period.
“So when habitual diets are not as healthy as they could be, we now have evidence that simple additions to the diet like flavanols can contribute to maintaining brain health as we age.”
The researchers said that they could not conclusively establish that a low dietary intake of flavanols alone caused poor memory function since they did not run an experiment in which flavanol was eliminated to test if it harmed memory.
To find out for sure, researchers want to undertake a clinical experiment in which they will restore flavanol levels in people with severe flavanol deficits and see if it helps memory.
“Age-related memory decline is thought to occur sooner or later in nearly everyone, though there is a great amount of variability,” said Dr. Scott Small, Professor of Neurology at Columbia University.
“If some of this variance is partly due to differences in dietary consumption of flavonols, then we would see an even more dramatic improvement in memory in people who replenish dietary flavanols when they’re in their 40s and 50s.”