You may be aware of foods that protect our hearts and bones and even keep our weight in check as we age. But which foods keep our brains in top shape? Below is an evidence-based list of brain foods that may help pre-empt senior moments and more.
Berries may do more than add sweetness and color to a morning bowl of cereal or yogurt. In fact, they may help to keep our brains sharp as we age.
In a study that looked at the diet habits of more than 16,000 older women over a 15-year period, researchers found that those who consumed at least one half-cup of blueberries or at least one cup of strawberries each week had slower rates of cognitive decline. Specifically, when women were given various tests, including the ability to recall words or retell a story, the berries appeared to slow memory decline by up to 2½ years, according to lead author Elizabeth Devore, associate epidemiologist at Brigham and Women's Hospital and an instructor in medicine at Harvard Medical School.
The fact that diet intake was followed for such a long time is meaningful, as it's long enough to also potentially impact the pathology of diseases that may begin in midlife, such as Alzheimer's, explained Devore.
Berries contain natural compounds known as anthocyanidins, which, in addition to contributing color to fruit, may help keep our brains in top shape through their antioxidant and anti-inflammatory effects.
"Inflammation and oxidative stress have been implicated in cognitive decline," Devore said. Additionally, animal research has revealed that anthocyanidins cross the blood-brain barrier, which may directly impact neurons involved with learning and memory, she explained.
Green and leafy cruciferous vegetables
Stick with the salad for lunch and broccoli at dinner: These veggies are not only helpful in boosting vitamins and fiber, they may keep our brains young.
A recent study from Rush University involving close to 1,000 adults found that those who ate just one serving of leafy greens per day (think spinach, kale, collard greens and arugula) appeared 11 years younger in terms of their cognitive health compared with those who rarely or never consumed green leafy vegetables.
"When we looked at memory, the speed at which you can think and being able to understand visual spatial relationships -- for every single one of these domains, leafy greens slowed decline," said study author Dr. Martha Clare Morris, a professor of internal medicine and the director of the Rush Institute for Health Aging and the MIND Center for Brain Health.
Morris, who is also the creator of the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet, said the protective nutrients in leafy greens include vitamin E, folate, lutein, beta-carotene and vitamin K.
"Leafy greens have so many nutrients that are protective of the brain," she said. "Each one is doing something a little different, but together, they protect the brain in many different ways."
The findings are consistent with research from Brigham and Women's Hospital, which found that women who munched on eight servings of green leafy vegetables and five servings of cruciferous vegetables (such as broccoli and cauliflower) each week did better on memory tests, appearing one to two years younger in terms of their cognitive age as they entered their 70s, compared with those who consumed only three servings of green leafy vegetables and two servings of cruciferous vegetables per week. (One serving was equivalent to half a cup of vegetables.)
"The aging brain, particularly the areas involved in memory, is susceptible to oxidative stress and inadequate blood flow. Both cruciferous and green leafy vegetables are high in antioxidants, B vitamins, fiber and other nutrients that are directly neuroprotective or may lower the risk of cardiovascular risk factors or conditions, such as high blood pressure and diabetes, which are associated with cognitive decline," said lead study author Jae H. Kang, assistant professor of medicine at Harvard Medical School.
Fish and oil
If you've been pregnant, you might remember taking a prenatal vitamin with DHA in it. That's because DHA, an omega-3 fatty acid that is found in fish (and also plant foods like algae), plays a role in brain development, starting before birth. The important role of this omega-3 fat continues into adulthood: One meta-analysis linked consumption of DHA to improved memory function in older adults with mild memory complaints.
The study is consistent with Morris' previous research, which found that consuming omega-3 rich fish just once a week was associated with a 10% per year slower rate of cognitive decline among older adults.
In another study that Morris co-authored, people who consumed fish at least once per week had a 60% lower risk of Alzheimer's disease.
"There is a very solid literature, from human trials and animal models, demonstrating the importance of DHA and omega-3s to the developing brain, and the aging brain," Morris said.
In Morris' most recent study, which examined participants' autopsied brains, fish consumption was associated with less evidence of Alzheimer's disease in the brain. What's more, the higher levels of mercury from increased seafood consumption appeared irrelevant.
"We had their fish intake during life and looked at their brains when they died and found that higher fish consumers had higher mercury in their brains, but the mercury was not associated with any of the brain neuropathologies," Morris said.
Oily fish such as salmon, tuna, mackerel, herring, trout and sardines are rich in DHA. Aim to eat at least 8 ounces per week (that's about three decks of playing cards big).
The composition of fat in general in the diet may play a role in brain health. Specifically, consuming more vegetable oils and fewer saturated and trans fats may reduce cognitive decline and lower the risk of dementia, according to Morris.
Eggs are rich in choline, an important brain nutrient. In one study involving about 1,400 men and women, those with high choline intakes performed better on tests of verbal and visual memory compared to those with lower intakes. Additionally, those who consumed high amounts of choline over time appeared to have healthier MRI scans of their brains, suggesting that choline intake during midlife may protect against dementia.
"There is that possibility that maintaining recommended intakes of choline is potentially neuroprotective," said study author Dr. Rhoda Au, professor of anatomy and neurobiology, neurology and epidemiology at the Boston University Schools of Medicine and Public Health. "It may help you maintain your memory and may help you keep your brain healthier."
Choline helps create the brain chemical acetylcholine, which is crucial to normal brain function and cognition. Yet surveys show that most of us don't consume enough of this important nutrient. If you don't eat eggs, then peanuts, fish, poultry, lean beef, broccoli, Brussels sprouts and dairy are other good sources of choline.
Coffee and alcohol
And while caffeinated beverages such as coffee and tea may improve your focus at work, other research suggests that the caffeine may also have longer-term benefits. Research has shown that compared with those who avoid caffeine, consuming it can give you the edge on forming memories. In another study, caffeine appeared to reduce cognitive decline in older women without dementia when studied over a four-year period.
A glass of wine each day may help too -- that is, as long as you stick to one. "Alcohol consumption is potentially protective (of the brain) as well," Morris said, though she added that benefits have been seen among "people who consume more than rarely, but no more than seven alcoholic beverages per week."
Lisa Drayer is a nutritionist, an author and a CNN health and nutrition contributor.