Diet and Aging

This 2021 article focuses on the potential role of anthocyanin supplementation in lowering risk of developing cognitive decline. Anthocyanins are a type of flavonoids mainly found in berries. The aim of this review was to summarize the dietary intervention studies investigating the impact of anthocyanins on cognitive performance in humans. A systematic search on databases yielded a total of 1197 relevant articles, 49 of which reported the effect on cognitive performance, vascular function, or cardiometabolic risk factors. There was evidence of anthocyanins significantly improving memory, while other studies identified changes in attention and psychomotor speed or executive function. Moreover, there were various articles indicating increased endothelial function because of consuming anthocyanins. Blood pressure appeared to improve after supplementation also, but its effects on metabolic risk factors such as carbohydrate and lipid metabolism were less consistent. This review presents proof that eating berry anthocyanins can provide cognitive benefits, indicated by the improvement in memory. The role of anthocyanins in vascular function and blood pressure warrants further investigation. [NPID: cognition, berries, anthocyanins, blood pressure, review, supplements, intervention, cognitive performance, memory]

This retrospective cohort study looked at lifestyle factors and risk for dementia and Alzheimer’s disease over the course of 8 years in almost 200,000 European adults who were age 60 at baseline. Results of this study demonstrate that even if someone had a “high risk genetic profile” for dementia, addressing 4 lifestyle factors significantly reduced the risk of developing dementia. The key lifestyle factors that were determined are smoking status, physical activity, Mediterranean diet, and alcohol consumption.

The main aim of this 2021 study was to identify environmentally sustainable foods that promote health. To do so, many food items were analyzed, classified, and prioritized using both nutritional health-based and environmental indicators. A total of 5853 food items in the U.S. diet were assessed on nutrition based on the Health Nutritional Index. This quantified marginal health effects in minutes of healthy life gained or lost. The results ranged from 74 minutes lost to 80 minutes gained per serving. In terms of environmental impact of the foods, there was a wide variation but a correlation with global warming (except those related to water use) was identified. According to the data, replacing only 10% of your daily caloric intake from beef and processed meat with fruits, vegetables, nuts, legumes and certain seafoods could substantially enhance health (48 minutes gained per person per day) as well as reduce carbon footprint by 33%. [NPID: health, nutrition, meats, vegetables, vegetarian, carnivorous, diet, sustainable foods, US, America, environment, global warming, fruits, nuts, legumes, seafood]

In this study, Yeh et al., (2021) examined the associations between long term dietary flavonoids and subjective cognitive decline in almost 50,000 women and 27,000 men from the Nurses’ Health Study and the Health Professionals Follow Up Study. Results show that higher intake of total flavonoids was associated with lower odds of subjective cognitive decline. The researchers further state that “many flavonoid rich foods such as strawberries, oranges, grapefruits, citrus juices, apples, pears, celery, peppers, and bananas, were significantly associated with lower odds of subjective cognitive decline.” [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, flavonoids, strawberries, oranges, grapefruits, citrus juices, apples, pears, celery, peppers, bananas]

This 2012 trial tested the impact of taking multivitamin supplementation (Swisse Women's 50+ Ultivite ®) for 16 weeks on cognition in elderly women. The 56 participants were community dwelling, elderly women, with subjective complaints of memory loss. Each subject was randomly selected to either consume the multivitamins or a placebo, while neither them nor the experimenters knew which was received. Cognition was then assessed using a battery of memory, while specific biochemical measures (selected nutrients, homocysteine, markers of inflammation, oxidative stress, and blood safety parameters) were also taken at baseline and 16 weeks post-treatment. The multivitamin supplement was found to improve speed of response on a measure of spatial working memory. No other benefits to cognition were detected. The vitamin consumption elevated the levels of vitamin B(6) and B(12), while decreasing plasma concentrations of homocysteine. The safety of taking these vitamins daily was confirmed, as no hepatotoxic effects were reported. In conclusion, 16 weeks of supplementation with a combined multivitamin, mineral and herbal formula may positively influence working memory in elderly women at risk of cognitive impairment. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, older women, homocysteine, inflammation, oxidative stress, and blood safety parameters, multivitamin, working memory]

The aim of this 2017 study was to find associations between dietary patterns and inflammation, and to examine whether these diets are linked to cognitive decline. Ozawa et al. utilized the data on 5083 individuals (28.7% female) from the Whitehall II cohort study. In this study, diet and the inflammatory marker, interleukin-6 (IL-6), were measured twice (in 1991-1993 and 1997-1999). While cognitive tests were conducted in 1997-1999 and again later in 2002-2004 and 2007-2009. The researchers identified an inflammatory dietary pattern (characterized by higher intakes of red meat, processed meat, peas and legumes, and fried food, and lower intakes of whole grains) was associated with elevated interleukin-6 levels in both 1991-1993 and 1997-1999. This dietary habit was also linked with faster cognitive decline after multivariable adjustment. These trends were stronger in those individuals younger than 55 years, which suggests that reverse causation is unlikely. The participants who had diets more adherent to the inflammatory dietary pattern (highest tertile) were seen to experience worse drops in reasoning ability, compared with those who don’t eat as much inflammatory foods (lowest tertile). To summarize, a dietary pattern characterized as higher consumption of red and processed meat, peas, legumes and fried food, and lower consumption of whole grains were related with higher levels of inflammatory markers and accelerated cognitive decline at older ages. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, inflammation, interleukin-6]

Bigford & Del Rossi (2014) reviewed experimental and clinical data on supplemental substances such as curcuminoids, rosmarinic acid, resveratrol, acetyl-L-carnitine, and ω-3 (n-3) polyunsaturated fatty acids that have demonstrated encouraging therapeutic effects on chronic diseases. The many mechanistic parallels discovered between various neurodegenerative diseases suggest that a single therapeutic approach may be used to treat multiple disease conditions. The writers explain that natural compounds and supplemental substances have gained a considerable amount of support in their possible roles in treating neurodegenerative disorders and diseases (NDDs) due to their potential adjunctive therapeutic effects on various neurodegenerative diseases. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, curcuminoids, rosmarinic acid, resveratrol, acetyl-L-carnitine, polyunsaturated fatty acids, neurodegenerative diseases]

The objective of this 2019 study was to examine whether adherence to the Mediterranean-DASH diet intervention for neurodegenerative delay (MIND) was associated with subjective memory complaints (SMC)(as measured by the cognitive difficulties scale) in the NutriNet-Santé cohort. The 6011 study participants were aged 60 and over at baseline and did not have SMCs (defined as a CDS score ≥ 43). The MIND diet score, which is a hybrid of the Mediterranean Diet and the Dietary Approaches to Stop Hypertension (DASH) scores), was not significantly associated with SMC in the sample population as a whole nor among those aged 60-69, whereas a significant inverse association was identified between SMC and adherence to MIND diet among the participants aged 70 and over. This relationship was also strengthened after participants with depressive symptoms were excluded from the equation. Over a mean follow-up of 6 years, the subjects aged ≥ 70 years reported 30% of the SMC cases, while the younger participants between 60-69 only reported 15%. To summarize the findings, the MIND diet could help prevent or delay subjective memory complaints among older adults with depressive symptoms. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, Mediterranean diet, DASH, depression]

In 2019 Cherian and several researchers investigated the Mediterranean-Dash Intervention for Neurodegenerative Delay (MIND) diet and aimed to determine its efficacy in preventing cognitive decline after stroke among 106 people. The participants who had a history of stroke, completed a food frequency questionnaire (FFQ), which was later used to determine the MIND diet score. The components of the MIND diet included whole grains, leafy greens and other vegetables, berries, beans, nuts, lean meats, fish, poultry, and olive oil and reduced consumption of cheese, butter, fried foods, and sweets (the diet is described as a hybrid of the Mediterranean and Dash diets). The results showed a slower rate of global cognitive decline over an average of 5.9 years of follow-up when comparing the top with the bottom tertiles of MIND diet scores after multiple variable adjustments. The study concluded that high adherence to the MIND diet was related to slowing the speed of cognitive decline following stroke. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, Mediterranean diet, DASH, stroke, MIND]

This 2020 article outlines in detail possible mechanisms in which nutritional ketosis may be capable of mitigating changes observed in several neurodegenerative and neuroprogressive disorders. Detrimental effects of oxidative stress, mitochondrial dysfunction and neuroinflammation on neuronal function have been observed in disorders such as cognitive impairment, Parkinson’s disease, schizophrenia, bipolar disorder, autistic spectrum disorder, and all of which can be potentially ameliorated by the use of oral ketogenic compounds, fractionated coconut oil, very low carbohydrate intake, or ketone monoester supplementation. The detailed mechanisms led Morris et. al (2020) to hypothesize that nutritional ketosis may have therapeutic applications in the aforementioned disorders. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, ketosis, neurodegenerative disorders, neuroprogressive disorders, Parkinson’s disease, schizophrenia, bipolar disorder, autistic spectrum disorder, coconut oil, low carb]

Shishtar et al. (2020) examined the prospective relation between dietary flavonoid intake with risk of Alzheimer disease and related dementias (ADRD) and Alzheimer’s disease (AD) using the data from the Framingham Heart Study Offspring Cohort exams 5-9, while also discussing the limitations of the existing prospective observational studies on the flavonoid-ADRD risk association. Flavonoid consumption was updated at each exam using a food frequency questionnaire (FFQ), and was expressed as percentile categories of intake (≤15th, >15th to 30th, >30th to 60th, >60th) to manage their non-linear relation with ADRD and AD. Over an average follow-up of 19.7 years in 2801 participants (mean baseline age = 59.1; 52% females), there were 193 ADRD events, 158 of which were AD. Compared to the subjects with the lowest consumption (≤15th percentile) of flavonols, anthocyanins, and flavonoid polymers, those with the highest intakes (>60th percentile) were less likely to develop ADRDs: hazard ratios (HRs) for flavonols were 0.54; 0.24 for anthocyanins; and 0.58 for flavonoid polymers. Identical trends in associations were found for AD with flavonoids and anthocyanins but not with flavonoid polymers. To summarize the findings, it can be implied that greater long-term intakes of flavonoids are associated with lower risks of both ADRD and AD in adults in the U.S. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, Alzheimer’s disease, Alzheimer’s, flavonoid, anthocyanins, flavonoid polymers]

Hardman et al. (2020) designed this study to investigate the effect of a 6-month intervention program involving the Mediterranean diet (MedDiet), exercise, and a combination of both on cognition, mood, and general health among an older population (aged 60-90) living independently in care communities. This study, named the Lifestyle Intervention in Independent Living Aged Care (LIILAC) Study, recruited 102 older adults and randomly assigned the individuals to 1 of 4 intervention groups. While overall memory performance was the primary outcome of the study, the researchers also investigated changes in cognitive task performance, mood, wellness, cardiovascular function and measured blood biomarkers. Although there was nom significant change in overall memory performance, the subjects in the combined exercise and diet group displayed significant improvements in spatial working memory performance, compared to the control group. Improved emotional state - indicated by the Depression Anxiety Stress scale - was also seen in this combined diet+exercise group and in the exercise-only group. Hartman et al. (2020) provided evidence that diet and exercise programs have potential in improving aspects of cognition and mood in an aging population, while larger randomised controlled trials investigating the diet and exercise programs in a larger sample size of older people would reinforce the validity of this study’s findings. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, Mediterranean diet, memory, performance, depression, anxiety]

This 2020 article summaries the molecular mechanisms involved in the pathology of Alzheimer’s Disease (AD), an incurable neurodegenerative disease), and also discusses the possible positive impacts lifestyle and nutritional interventions (diet, exercise, calorie restriction, bioactive compounds) can have on cognitive decline and dementia. Bhatti et al. (2020) explain that due to the lack of methods of early diagnosis and limited knowledge on the exact pathophysiology of AD, discovering effective therapeutic strategies has been challenging, and the roles of lifestyle interventions and nutraceuticals in the prevention of many metabolic and neurodegenerative diseases have given hope to the scientific community. This article provides insights into the function of non-pharmacological interventions in the modulation of AD pathology, hopefully showing evidence of reduced cognitive decline, incidence of AD, and better quality of life. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, Alzheimer’s, AD, Alzheimer’s disease, neurodegenerative disease, quality of life]

The purpose of this 2018 study was to evaluate the longitudinal associations between haemoglobin (HbA1c) levels, diabetes status and subsequent cognitive decline over a 10 year follow-up period, using data from the English Longitudinal Study of Ageing (ELSA). In total, this study was composed of information on 5189 participants (55.1% women, mean age 65.6 ± 9.4 years). Cognitive function was assessed at baseline and also every 2 years. After adjustment for a multitude of factors, a 1 mmol/mol increment in HbA1c (indicating increase in glucose levels in previous 3 months) was significantly associated with an enhancement in rate of decline in global cognitive z scores, memory z scores, and executive function z scores. Moreover, when those with prediabetes and diabetes were compared to those with normal sugar levels (normoglycemia), the multivariable-adjusted rate of global cognitive decline was increased by -0.012 SD/year and -0.031 SD/year, respectively (p for trend <0.001). In addition, results of memory, executive function and orientation z scores demonstrated a rise in rate of cognitive decline with diabetes. Although future studies are warranted to determine the impacts of maintaining optimal glucose control on rate of cognitive impairment in people with diabetes, Zheng et al. (2018) have exposed significant longitudinal associations between HbA1c levels, diabetes status and long-term cognitive decline. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, memory, executive function, glucose, diabetes]

This 2019 systematic review examined the effects of multiple dietary patterns on cognitive health among older adults, by compiling evidence submitted from randomized controlled trials and cohort studies and following PRISMA guidelines. Chen and the team (2019) assembled all the data on the Mediterranean diet, Dietary Approach to Stop Hypertension (DASH) diet, the Mediterranean-DASH diet Intervention for Neurodegenerative Delay (MIND) diet, Anti-inflammatory diet, Healthy diet recommended by guidelines via dietary index, or Prudent healthy diets generated via statistical approaches, and the cognitive impacts they had. Of the 38 studies included in this review, the Mediterranean diet was the most investigated with evidence supporting protection against cognitive decline among older adults. Other dietary habits such as the MIND, DASH, Anti-inflammatory, and Prudent healthy diets produced positive results especially for those at risk of cardiovascular diseases, however the evidence was more limited. Chen et al. (2019) expressed there was a need for better understanding of the underlying mechanisms in general in order to develop comprehensive and practical dietary recommendations for those fighting against age-related cognitive decline. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, Mediterranean diet, DASH, inflammation]

The aim of this mini review published in 2019 was to provide an updated overview of intracellular oxidative stress and mitochondrial abnormalities in the brain of an individual with insulin resistance (IR). Maciejczyk et al. (2019) reports that indications from the latest studies strongly link systemic IR with higher incidence of neurodegeneration, dementia, and mild cognitive impairment, possibly owing to the hyperglycaemia, hyperinsulinemia, dyslipidaemia, and/or prolonged whole-body inflammation. However, the main role was attributed to the neuronal redox imbalance and oxidative damage. This mini review highlighted important correlations discovered between brain oxidative stress, ceramide generation, β-amyloid accumulation, as well as neuronal apoptosis in the IR conditions. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, oxidative stress, mitochondria, insulin resistance, neurodegeneration, hyperglycaemia, hyperinsulinemia, dyslipidaemia, inflammation, ceramide generation, β-amyloid]

Since there were a few suggestions that a healthy diet is related to lower risk of frailty, Ward and colleagues (2020) set out to measure the diet qualities of male physicians from the U.S. and assess its relationship with frailty. The data was collected from the Physicians’ Health Study, with a total of 9861 participants aged 60 years or older. A cumulative deficit frailty index (FI) was calculated using 33 variables encompassing domains of comorbidity, functional status, mood, general health, social isolation, and change in weight, while the 3 measures of diet quality were the Alternative Healthy Eating Index (aHEI), Mediterranean Diet Score (MDS), and Dietary Approaches to Stop Hypertension (DASH). The FI revealed that 38% of the physicians were non-frail, 44% were pre-frail, while 18% were identified as being frail. In variable-adjusted models, the subjects in the highest quintiles for aHEI possessed significantly lower risk of frailty and pre-frailty when compared with those in the lowest quintiles. Furthermore, similar relationships were found for DASH and MDS quintiles with frailty and pre-frailty, and also restricted cubic splines showed an inverse dose-response relationship of diet quality scores with odds of frailty and pre-frailty. While Ward and her colleagues (2020) have described their findings from cross-sectional data, longitudinal studies are also required in order to investigate whether healthier diet is a modifiable risk factor for frailty. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, frailty, male physicians, doctors, Mediterranean diet, Med diet, DASH]

This 2019 article outlines the objectives of the REACH (Researching Eating, Activity and Cognitive Health) study, which is to investigate associations between dietary patterns, cognitive function and metabolic syndrome, while accounting for a range of covariates since Mumme et al. (2019) believed that previous research had not considered some relevant covariates such as physical activity and the Apolipoprotein E genotype. The REACH study will include covariates and interaction factors such as age, education, socio-economic status, physical activity, Apolipoprotein E ε4 genotype, family history of dementia or cognitive impairment, and lifestyle factors. Older adults (65-74 years old) will be recruited from Auckland, New Zealand, while dietary data will be collected via a 109-item food frequency questionnaire, cognitive function will be examined using the Montreal Cognitive Assessment (paper based) and the Computerised Mental Performance Assessment System (COMPASS). Additionally, biochemical markers including fasting glucose, HbA1c, lipids profile of the participants will be measured, as well as anthropometric measurements (weight, height, waist and hip circumference, body composition using dual X-ray absorptiometry), blood pressure, physical activity, health and demographics. Mumme and her group (2019) believe this study will provide new knowledge on the relationships between dietary patterns and cognitive function and metabolic health in older adults living in New Zealand. This would prove useful for developing nutrition related recommendations to help older adults maintain cognitive function. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, metabolic syndrome, socio-economic status, physical activity, REACH, Apolipoprotein E genotype]

The purpose of this 2019 review was to present the current knowledge of the preventative roles that protein and amino acids play in Alzheimer’s disease and related dementias (ADRD), while also providing future recommendations for this body of research. Glenn et al. (2019) explain that scientists and clinicians have primarily focused on dietary intake to combat the rise in ADRD that has followed the rapid growth in aging populations, and protein/amino acid intake is relevant since its consumption is connected to a number of disease-related risk factors as such low-muscle mass, sleep, stress, depression, and anxiety. It was admitted that the research was still speculative and certain mechanisms need to be proven. In this review, Glenn et al. (2019) discussed the current recommendations for protein consumption and dosing for adults who desire to manage long-term risk for cognitive decline. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, protein, amino acids, Alzheimer’s disease, Alzheimer’s muscle mass, sleep, stress, depression, anxiety]

Kim & Yun (2018) undertook this study investigating the relationship between dietary consumption with cognitive function among an adult population aged over 50 years of age, because the correlation between diet and cognition was uncommon and debated. Of the 324 adults from Gwangju Sun-Han hospital who participated in this study, 276 were examined using the mini-mental state examination (MMSE), while a semi-quantitative food frequency questionnaire (SQ-FFQ) was also utilised for collecting dietary information. The results showed the following food groups either significantly reduced the odds ratio for the risk of mild cognitive impairment (MCI): cooked white rice (< 2 times/day compared with ≥ 3 times/day) (P < 0.05), properly cooked rice with other grains and legumes (P < 0.001), fruits (P < 0.05), milk (low fat and normal) (P = 0.044), liquid-type yogurt (P = 0.019), and curd-type yogurt (P = 0.015). To summarize, a moderate intake of cooked white rice and an adequate intake of whole grains, fruits, milk, and dairy products were associated with reduced risks of MCI among adults aged over 50 years. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, whole grains, fruits, milk, dairy products, dairy]

Hosking et al. (2019) investigated the associations between the Mediterranean-DASH diet Intervention for Neurological Delay (MIND) diet with the incidence of cognitive impairment and incidence of Alzheimer's disease/Vascular dementia (over 12 years) using the Personality and Total Health (PATH) Through Life cohort (n = 1220) set in Canberra, Australia since this relationship had not been evaluated outside the United States. MIND diet and two alternate Mediterranean diet scores were calculated from the baseline food frequency questionnaire responses, with higher dietary scores consequently translating to greater adherence. The results from the adjusted logistic regression models revealed that the MIND diet (OR = 0.47, 95% CI 0.24, 0.91), but not Mediterranean diet, was associated with reduced odds of 12-year cognitive impairment. This study reported preliminary evidence suggesting that the protective effects of the MIND diet are geographically generalizable, while also it exposed the need for more prospective studies with diverse samples that examine the relative effects of the MIND and the Mediterranean diets against cognitive decline. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, Mediterranean diet, Med diet]

Although a number of dietary patterns have been attempted in order to reduce the pathology of Alzheimer’s disease (AD) and to slow cognitive decline, this 2019 review focused on the roles of the Mediterranean diet (MedDi) and Mediterranean-DASH diet Intervention for Neurological Delay (MIND) diet in the battle against Alzheimer’s disease and cognitive impairment. Both diets have been associated with decreasing incidence of AD and slowing cognitive decline, with significant reduction in AD rate observed for the MIND diet. Omar (2019) mentions olives, one of the components of both MedDi and MIND diets, may have potential to improve health due to the presence of its bioactive constituents such as oleic acids and phenolic compounds (biophenols). The author also reported a few trials using medical food showed an optimal result in presymptomatic or early stages of AD. This review reveals the gaps in this research topic and presents future directions for studies. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, Mediterranean diet, Med diet, Alzheimer’s, AD]

The aim of this 2019 study was to explore the relationship between diet quality and vegetable variety with cognition among a population of older adults in Taipei, Taiwan. A food frequency questionnaire completed at baseline was used to attain the Alternative Healthy Eating Index (mAHEI) and consequently the diet quality in the 436 community-dwelling elders (aged 65 and over) who participated. The vegetable variety indicated the number of different vegetable groups, adjusted for vegetable quantity. High diet quality (highest tertile of mAHEI) was linked to lower risk of both global cognitive decline [adjusted odds ratio (AOR) = 0.54] and decline of attention domain (AOR = 0.56) compared with low diet quality. This trend was observed for the elders with high vegetable variety also, with an adjusted odds ratio of 0.49 for those consuming diets high in quality also, relative to those with low quality diets. Chou et al. (2019) concluded that high diet quality along with diverse vegetable intake was associated with a lower risk of cognitive decline in older adults. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, cognition, vegetables, dietary variance, variety, cognitive decline]

Wu & Sun (2017) performed a systematic review and meta-analysis to evaluate the potential association between the Mediterranean diet with incidence of cognitive disorders, and to study the dose-response pattern, since recent articles had presented inconsistent findings. A total of 9 cohort studies were included, allowing data analysis of 34,168 participants. The pooled analysis revealed the highest Mediterrranean diet score was inversely associated with the occurrence of cognitive disorders, with pooled relative risk (RR) of 0.79 compared with the lowest category. It was also observed that the Mediterranean diet score of the median category was not significantly associated with cognitive disorders, also that there was a near-linear relationship of the Mediterranean diet score with the incident risk of cognitive disorders identified. The authors expressed their desire to see more randomized controlled trials to confirm this association in different populations. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, neuroinflammation, Mediterranean diet, cognitive disorders]

McGrattan et al. (2019) examined research studies on healthy dietary patterns and age-related cognition, and in this review discussed the potential neuroinflammatory actions of diet on cognitive function. Recent findings indicated neuroinflammation associated with Alzheimer’s disease (AD) could be inhibited by components consumed in the anti-inflammatory diets, Mediterranean diet (MD) and dietary approaches to stop hypertension (DASH) such as omega-3 fatty acids, antioxidants and polyphenols, and suggest these diets have neuroprotective effects. It was thought these anti-inflammatory diets may also block neuroinflammation through indirect immune pathways from the gut microbiome and systemic circulation. It was also implied that diet may influence cognitive aging via multiple inflammatory pathways, although the mechanism underlying this link is not known and data from human studies are lacking. McGrattan et al. (2019) believe further diet intervention studies focusing on the diet-associated neurological change from the earliest to latest stages of cognitive decline are required, while using neuroimaging measures in these intervention studies would also help with the progress in understanding the mechanisms behind the neuroinflammatory effects of dietary modification in the aging brain. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, neuroinflammation, Alzheimer’s, Alzheimer’s disease, AD, hypertension, DASH, omega-3s, polyphenols, antioxidants, neuroprotective, gut microbiome]

This 2019 review examined plant-based dietary patterns and polyphenol-rich plant foods and their role in preventing age-related cognitive decline (ARCD) and improving cognitive function. Rajaram et al. (2019) came across emerging evidence for brain-health-promoting effects of several plant foods rich in polyphenols, anti-inflammatory dietary patterns, and plant-based dietary patterns such as the Mediterranean diet that include a variety of fruits, vegetables, legumes, nuts, and whole grains. These dietary habits consist of antioxidant vitamins, polyphenols, other phytochemicals, and unsaturated fatty acids, which in animal models, have been shown to enhance neurogenesis, synaptic plasticity, and neuronal survival by reducing oxidative stress and neuroinflammation. Furthermore, this review presents evidence from randomized clinical trials, some of which support the role of plant foods such as citrus fruits, grapes, berries, cocoa, nuts, green tea, and coffee in improving specific domains of cognition, most notably frontal executive function. Gaps in the current knowledge are exposed, while the writers also offer recommendations for future studies aimed at finding the cognitive beneficial effects of plant-exclusive diets compared with plant-centered diets with fish and/or small amounts of animal foods for example. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, polyphenols, anti-inflammatory, plant-based, plant base, Med diet, Mediterranean diet, neurogenesis, synaptic plasticity, oxidative stress, neuroinflammation, executive function]

Davison et al. (2019) used the cohort data from the baseline Canadian Longitudinal Study on Aging (n = 27,162) of adults aged 45-85, to examine depression and socio-economic, health, immigration, and nutrition-related factors in older adults. Depression was assessed using the Center for Epidemiologic Studies Short Depression (CESD-10) rating scale while the sample were also categorized for immigration status as: native-born, recent and mid-term (< 20 years), and long-term immigrants (≥20 years). It was discovered the majority of the respondents were Canadian-born (82.6%), women (50.6%), 56-65 years (58.9%), earning between C$50,000-99,999 (33.2%), and in a relationship (69.4%). Also when compared to Canadian-born residents, recent, mid-term (< 20 years), and longer-term (≥ 20 years) immigrant women were more likely to report depression and this relationship was robust to adjustments for 32 covariates. In women, depression was associated with not completing secondary school (OR = 1.23, p < 0.05), stage 1 hypertension (OR = 1.31, p < 0.001), chronic pain (OR = 1.79, p < 0.001), low fruit/vegetable intakes (OR = 1.33, p < 0.05), and fruit juice (OR = 1.80, p < 0.001), chocolate (ORs = 1.15-1.66, p's < 0.05), or salty snack (OR = 1.19, p < 0.05) consumption. Whereas for men, chronic conditions (ORs = 1.36-3.65, p's < 0.001), chronic pain (OR = 1.86, p < 0.001), smoking (OR = 1.17, p < 0.001), or chocolate consumption (ORs = 1.14-1.72, p's < 0.05) predicted a higher likelihood of depression. Men were less likely to be depressed if they were: in a relationship (OR = 0.62, p < 0.001), completing post-secondary education (OR = 0.82, p < 0.05), consuming higher fat (ORs = 0.67-83, p's < 0.05) and greater amounts of omega-3 egg (OR = 0.86, p < 0.05) as well as eating moderate levels of fruits/vegetables and calcium/high vitamin D sources (ORs = 0.71-0.743, p's < 0.05). For all participants, depression was connected to lower grip strength (OR = 1.25, p < 0.001) and high nutritional risk (OR = 2.24, p < 0.001). The researchers concluded that immigrant women were associated with the highest risk of depression, although depression was linked with socioeconomic, physical, and nutritional factors among middle-aged and older adults, and the relationships varied by sex. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, dementia, depression, socio-economic factors, immigration, hypertension, chocolate, calcium, vitamin D]

Anastasiou et al. (2017) evaluated the association between adherence to an a priori (pre-existing conditions) defined Mediterranean dietary pattern and its components with dementia and certain aspects of cognitive function among a Greek population taken from the Hellenic Longitudinal Investigation of Ageing and Diet (HELIAD) - an on-going population-based study exploring potential associations between diet and cognitive performance. In HELIAD, dementia was diagnosed after full clinical and neuropsychological evaluation, while cognitive performance was assessed according to memory, language, attention-speed, executive functioning, and visuospatial perception (the five cognitive domains) and a composite cognitive score. The adherence to MeDi was evaluated by an a priori score (range 0-55), derived from a detailed food frequency questionnaire. Among the 1,865 individuals (mean age 73±6 years, 41% male), 90 were diagnosed with dementia and 223 with mild cognitive impairment. The analysis indicated a 10% decrease in dementia risk associated with each unit increase in Mediterranean diet score (MedDietScore). Adherence to MeDi was linked to improvements in memory, language, visuospatial perception and the composite cognitive score, with the association most prominent with memory. The researchers also found other associations such as higher consumption of non-refined cereal with enhanced cognitive performance, as well as fish intake’s negative correlation with dementia. Following the results suggesting an association between increased adherence to the MeDi with better cognitive performance and lower dementia rates in Greek elders, it was concluded that the MeDi in its a priori constructed prototype form may improve cognitive function in traditional Mediterranean populations. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, Mediterranean Diet, Med Diet, Greek, dementia, memory, language, attention-speed, executive function, visuospatial perception]

This 2019 review takes a look at nutrients and its role specifically in reducing risk of noncommunicable diseases (NCDs) such as musculoskeletal disorders, dementia, loss of vision and cardiometabolic diseases during aging. Surveys have revealed nutrient intake levels of the aging population were lacking in optimally supporting healthy aging, and these deficiencies have been linked to increased risk of NCDs like fatigue, cardiovascular disease, plus cognitive and neuromuscular function impairments. Bruins et al. (2019) found current knowledge on the protective effects of improving individual nutrient intakes in chronic disease was still emerging with varying effect sizes and degrees of proof. Most pronounced benefits of nutrients were found in participants who had low nutrient intake or status at baseline or who had increased genetic and metabolic needs for that nutrient. The writers felt that authorities should implement ways to optimize essential nutrient intake as an integral part of their strategies to address NCDs. [NPIDs: aging, elderly, cognitive decline, neurodegenerative disorders, noncommunicable diseases, musculoskeletal disorders, dementia, vision, cardiometabolic diseases, fatigue, cardiovascular disease, cognition, neuromuscular function, chronic disease]

This 2020 narrative review aimed to present the existing research on the efficacy of the Mediterranean diet (MedDi) and Ketogenic Diet (KD) against Alzheimer’s Disease (AD)-related cognitive decline and explore the proposed mechanism of action of this protective effect. Vinciguerra et al. (2020) state that there is not a single dietary pattern that has unequivocally been proven to prevent AD although there are several dietary habits that, especially if accompanied with a good lifestyle, could potentially delay the problematic signs of AD. Although the current knowledge on this topic did not allow exhaustive conclusions to be drawn, the review studied the MedDi and KD, both of which have demonstrated a considerable amount of promise in reducing or delaying cognitive decline, and could provide assistance in the mission to better characterize the possible role of MedDi and KD as non-pharmacological therapies in the treatment of AD, and of neurodegenerative disorders. [NPIDs: aging, elderly, cognitive decline, Alzheimer’s, Keto, Med diet, Mediterranean, AD, neurodegenerative disorders]