Plenty of debate surrounds the topic of age-related cognitive decline. No one yet knows exactly when this decline begins, although some researchers have shown that changes can begin as early as one’s 20’s or 30’s. Unfortunately, researchers have also shown that—starting in the second decade of life—adults can experience decreases in regional brain volume, cortical thickness, and myelin integrity, as well as the accumulation of neurofibrillary tangles.
“The age at which cognitive decline begins is relevant to the optimum time to implement interventions designed to prevent or reverse age-related declines. Many interventions currently target adults 60 years of age and older. However, if people start to decline when they are in their 20’s and 30’s, a large amount of change will likely have already occurred by the time they are in their 60’s and 70’s. This may affect the likelihood that interventions at that age will be successful because the changes might have accumulated to such an extent that they may be difficult to overcome,” wrote Timothy A. Salthouse, PhD, Department of Psychology, University of Virginia, Charlottesville, VA, in a review article.
In the face of such disquieting news, it may be heartening to know that you can fight age with something as simple as your diet. Many foods may work to prevent or even reverse age-related decline. Here of five foods with proven cognitive benefits—ie, “brain” foods.
Grapes and blueberries
Polyphenols are a hot topic in nutrition, in the hope that they can battle age-related cognitive decline.
In a randomized, double-blind, placebo-controlled trial in 215 elderly participants aged 60 to 70 years, researchers assessed the effects of polyphenol-rich extracts from grapes and blueberries (PEGB) on visuospatial learning, episodic memory, verbal episodic and recognition memory (VRM), and working memory. Participants received 600 mg/d of PEGB (containing 258 mg flavonoids) or placebo for 6 months.
Their results were encouraging. PEGB improved VRM-free recall, compared with placebo. In a subgroup of patients with advanced cognitive decline who responded positively to PEGB, PEGB was associated with a better VRM-delayed recognition, lower polyphenol consumption, and higher metabolite excretion.
“Urinary concentrations of specific flavan-3-ols metabolites were associated, at the end of the intervention, with the memory improvements. Our study demonstrates that PEGB improves age-related episodic memory decline in individuals with the highest cognitive impairments,” they concluded.
In a recent study published in JAMA Neurology, researchers demonstrated that fatty fish may stave off cognitive decline in the elderly. The study sample included 6,158 adults aged 65 years and older drawn from the Chicago Health and Aging Project (CHAP).
Researchers used a food-frequency questionnaire to assess fish intake. Tests of cognition included the East Boston Tests of Immediate and Delayed Recall, the Mini-Mental State Examination, and the Symbol Digit Modalities Test.
The researchers found that, on average, cognitive scores dropped by a rate of 0.04 standardized units per year in all participants. But in those who ate one fish meal each week, they observed a 10% slower decline in cognitive function than those who ate fish less than once a week. Similarly, those who ate two or more fish meals per week experienced a 13% slower rate of cognitive decline.
Importantly, ω-3 fatty acid intake did not have a significant effect on mitigating cognitive decline, but there was a nonsignificant trend toward slower decline.
Encouragingly, fish eaters were 3 to 4 years younger in cognitive terms compared with those who did not eat fish. Of note, the effects of fish on cognitive decline remained even after accounting for age, sex, race, or education.
According to the authors, the results of this study are supported by several other observational studies, as well as studies linking higher fish intake to decreased risk of Alzheimer.
“A major strength of the CHAP study is the use of multiple cognitive tests and multiple periods of assessment that served to reduce bias and random error. The analytic method increased the ability to separate within-person cognitive change from between-person differences in cognitive ability,” they concluded.
Cilantro is an herb that salsa lovers know well. People have been cooking and pickling with cilantro for eons. In fact, cilantro seeds were found in King Tut’s tomb.
In addition to being yummy, cilantro has established anticonvulsant properties, with researchers identifying the molecular underpinnings explaining its anti-seizure activity in a mechanistic study published in FASEB Journal.
"We discovered that cilantro, which has been used as a traditional anticonvulsant medicine, activates a class of potassium channels in the brain to reduce seizure activity," wrote principal investigator, Geoff Abbott, PhD, professor, Physiology and Biophysics, University of California, Irvine, School of Medicine, Irvine, CA. "Specifically, we found one component of cilantro, called dodecenal, binds to a specific part of the potassium channels to open them, reducing cellular excitability. This specific discovery is important as it may lead to more effective use of cilantro as an anticonvulsant, or to modifications of dodecenal to develop safer and more effective anticonvulsant drugs."
Chocolate is a rich source of flavonoids, which burrow into the areas of the brain responsible for memory and learning—in particular, the hippocampus.
The neural effects of flavanoids are hypothesized to occur for two reasons. First, flavanols—a popular group of flavonoids—interact with cellular cascades that form proteins involved in neuroprotection and neuromodulation, and promote neurogenesis, brain connectivity, and neuronal function. Second, they enhance angiogenesis and blood-flow in the central nervous system.
The neuroprotective effects of flavanol consumption on age- and disease-related cognitive decline has been demonstrated in animal models, as well as in a handful of observational studies and trials. Nevertheless, any immediate action of flavanols on cognition is unclear.
Like chocolate, nuts are a rich source of flavonoids and may also promote brain health, in addition to anti-inflammatory, anti-carcinogenic, and cardiovascular benefits. (Anyone thinking dark chocolate almonds?)
In a low-power study published in FASEB Journal, researchers analyzed the effects of nut consumption on brain waves, and found that certain types of nuts stimulated some brain frequencies more than others. For instance, pistachios stimulated gamma waves more than other types of nuts. Gamma waves play a crucial role in information retention, perception, rapid eye movement sleep, and learning.
So, take heart. In the battle against age-related cognitive decline, which may start earlier than any of us suspected, it might never be too early to include these brain-friendly items in your diet.