Cognitive deterioration is a normal aspect of growing older, yet a substantial body of research suggests that early dietary and lifestyle modifications can offer significant benefits and preventive support. The onset of cognitive decline typically begins around age 60 and can lead to a loss of both function and independence.^1-3 Approximately two-thirds of older adults will face some degree of cognitive decline in their lives, impacting their autonomy and daily functioning.^1,2 Currently, over 5 million older adults in the US have dementia and this number is expected to double by 2050.⁴ Preventative measures are crucial and should be emphasized by healthcare providers.^3-7

Healthy aging can be negatively affected by cognitive decline and the reasons that it develops are multifactorial.⁶ Estimates show that up to 40% of dementia cases worldwide can be attributed to modifiable factors such as lack of education, hypertension, obesity, diabetes, smoking, excessive alcohol use, lack of physical activity, depression, lack of social connection, hearing loss, traumatic brain injury, and air pollution/environmental toxins.^3,4,6 Non-modifiable factors like genetics and the natural aging process also create challenges for healthcare providers, but the good news is, there’s a lot that can be done to aid in healthy cognitive aging.^2,8

Studies show that the earlier lifestyle changes are introduced, the more effective they may be at slowing decline. Interventions for brain health with aging relate to many lifestyle factors including diet, stress, sleep, mental health, social connection, and even toxin exposure.^3-7 Neurons in the brain need to retain plasticity, or neuronal plasticity, to help meet the dynamic demands needed for proper cognitive function long-term. Physical activity is a proven way to support neuroplasticity including improvements in learning and memory while reducing rates of cognitive decline in older adults. Dietary antioxidant intake has also shown benefits for neuroplasticity which is likely why so many high antioxidant foods have been linked to cognitive benefits with aging.⁹ Health care professionals are uniquely qualified and positioned to intervene before cognitive impairment happens or educate patients at the beginning stages on how to slow the progression. Overarching dietary patterns as well as individual nutrients and foods can be the focus of a healthy aging intervention.

Dietary Patterns for Healthy Cognitive Aging

Though individual foods have shown important relevance to healthy aging, the overall dietary pattern is critical for health care practitioners to assess and educate on because what’s consumed over time in a person’s life plays a role in brain health with aging. The Mediterranean diet has been studied extensively regarding cognitive impairment with aging as has the Nordic Diet, the Dietary Approaches to Stop Hypertension (DASH) diet, and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet.^3,5-7 These diets have some important aspects in common. They are largely plant-based and include antioxidant-rich foods high in polyphenols that offer b-vitamins and both polyunsaturated and monounsaturated fat sources. These diets include foods that likely play a role in neuroprotective benefits such as legumes, fish, vegetables, fruits, whole grains, nuts and seeds.^3,8,10

While no one dietary pattern has been definitively linked to preventing cognitive decline, large epidemiological studies show both cardiovascular benefits as well as cognitive benefits to these types of diets, likely because of anti-inflammatory benefits from antioxidant rich dietary components within the overall pattern.^8-10 Reductions in blood pressure, improved mitochondrial function, preserved white matter microstructure in the brain, proper cerebral brain flow, and lipid lowering properties can all be linked to healthy aging dietary patterns.^8-10 Researchers also acknowledge that other lifestyle aspects such as physical activity, social connection, rest/sleep, and stress management should also be included in health care practitioner education about dietary patterns and lifestyle interventions to support healthy cognitive aging.^6,8-10

Evidence-based dietary patterns for healthy cognitive aging all limit foods that are rich in the Standard American (SAD) or Western Diet such as sugar-sweetened beverages, ultra-processed foods, red meat, and desserts. It’s important for health care providers to know that the SAD dietary pattern is linked to increased risk of Alzheimer’s disease as well as vascular diseases, stroke, type II diabetes, and obesity.^3,8

Foods and Nutrients that Support People with Cognitive Decline

Exciting research has shown that individual foods or food groups show promise when incorporated into evidence-based dietary patterns that could help slow cognitive decline. Many of these foods or nutrients have been independently linked to better cognitive performance in research. Specific compounds like polyphenols in fruits, vegetables, antioxidant-rich beverages like coffee and tea, and macronutrients like protein or unsaturated fatty acids have been the focus of research. Evidence continues to point to the fact that when people eat more of these foods over time as part of an overall healthful dietary pattern, they generally experience less risk of cognitive function loss with age.

Fruit and Vegetables

Large human studies have shown that fruit and vegetable consumption is linked to lower prevalence of cognitive disorders with aging.^6,7,8-11 A large meta-analysis of 16 studies found that the higher the intake of fruit and vegetables were consumed, the lower the prevalence of cognitive disorders were observed.¹¹ Another large cross-sectional study (n=2,460 adults) found that participants with the highest intake of fruit and vegetable had the lowest odds of both memory loss and comorbid heart disease.⁴ Another study (n=139,096) aged 45 and older also saw that participants who had higher fruit and vegetable consumption had lower odds of memory loss over time.¹² This inverse dose-response relationship replicated in large human studies could be related to antioxidant intake, a better regulated immune system, reduced neuroinflammation due to the anti-inflammatory properties of produce, or even better managed serum homocysteine levels (a substance with both cardiovascular damaging and neurotoxic effects) due to the high folate content of fruits and vegetables.^4,6-8,10-12

Tea and Coffee

Antioxidant rich beverages like tea, especially green tea, and coffee have been linked in studies to better cognitive outcomes when it comes to aging.^13,14 A large review (n=389,505) found that generally, coffee and tea consumption is linked to a lower risk of cognitive disorders with aging.¹⁴ Specifically, 2.5 cups of caffeinated ‘regular’ coffee per day minimized the risk of developing Alzheimer’s Disease and 1 cup of tea per day is linked to an 11% reduction in developing cognitive deficits.¹⁴ The researchers hypothesize that green and black teas have more caffeine and catechins than herbal tea which could provide greater cognitive benefits, though more studies are needed on tea subcategories. 

Studies on the subject of beverages and cognitive decline are mixed. A longitudinal study (n=1,305) found that green tea intake but not coffee intake was significantly associated with a reduced risk of cognitive decline in older adults.¹³ Many other studies have found benefits from coffee, and caffeinated vs decaffeinated coffee has also been studied.¹⁵ One large study (n=2513) found cognitive benefits for older adults related to caffeinated coffee, but not decaf coffee.¹⁵ Potential mechanisms that could explain the neuroprotective effects of regular coffee include caffeine’s ability to stimulate some antioxidant and anti-inflammatory pathways in the body, helping to reduce oxidative stress.^14,15 Caffeine interacts with receptors in parts of the brain that play key roles in cognitive health including the hippocampus and cortex.¹⁴ Researchers also hypothesize that polyphenol antioxidants in coffee and tea may help reduce neurogenic inflammation and suppress amyloid-β generation (a peptide that plays a role in plaque formation that can lead to Alzheimer’s disease).^13,14,16

Protein

Protein is an important nutrient for aging adults. Protecting lean body mass can help with long-term independence and function but new evidence supports that protein intake may also play a role in cognitive health as well.⁴ Investigators using National Health and Nutrition Examination Survey (NHANES) results to compare dietary recall data against cognitive testing (n=2,460) found that protein intake was associated with significantly better performance on cognitive tests. These researchers found that protein sources from meat, eggs, and beans were associated with positive cognitive health over time.⁴ Another large meta-analysis (n=4,929) of older adults found that protein was positively correlated with memory, visual spatial processing, verbal fluency, processing speed, and sustained attention.¹⁶  Researchers hypothesize that nutrients such as B12 as well as branch chain amino acids including glutamate which plays a key role in learning and memory functions in the brain may be the reason for these benefits.¹⁷ Studies are still emerging about benefits from different types of protein, quantity of protein, and differences in geographical cohorts and biological sex of participants.^4,17
 

Unsaturated Fatty Acids

Nuts have also been studied in association with healthy aging and brain health. Walnuts, in particular, have gained attention likely related to their naturally occurring omega-3 content which has been studied in conjunction with slowing cognitive decline or even improvements in cognitive health.^21,22  Serum omega-3 status in older adults has been associated with better memory, processing speed, and even brain structure including white matter volume though studies on intake quantity and food vs supplement sources are still mixed.²² The anti-inflammatory properties of omega-3’s in addition to potential antioxidant activity from polyphenols in extra virgin olive oil, and the power of PUFAs and MUFas to reduce oxidative stress in neural tissue are all reasons that foods rich in unsaturated fatty acids omega-3’s may be beneficial.^21-23

Recommendations for Practitioners

Health care providers play a critical role in offering guidance for people at risk of or experiencing cognitive decline with aging to motivate a greater intake of fruits, vegetables, green tea and coffee, healthy fats such as olive oil, nuts, and other omega-3 sources, and ensure that their patients meet their protein needs. Delivering a personalized approach based on each person’s health literacy, cognitive health, and dietary needs is important.²⁴ By taking a multifactorial, interdisciplinary, lifestyle approach that’s proactive, there are many options for nutrition interventions that are evidence-based and could play a role in helping improve cognitive function or slowing the progression to more serious decline.

References:

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