Diet and Aging

In this prospective cohort study by Li et al. (2022), the authors aimed to evaluate the long-term relationship between egg intake and cognitive performance in a population of 9028 seniors. Participants were under the age of 60 and were cognitively healthy. The Mini-Mental State Examination (MMSE) measured cognitive function at baseline and in three waves of follow-up (2015, 2016, and 2019–2020). In the questionnaire's section on nutrition patterns, information on egg intake was gathered from the outset. After six years of follow-up, 3266 (36.18%) individuals had at least one MMSE score that indicated cognitive impairment. Participants who consumed 3.0-5.9 eggs/week and 0.1-2.9 eggs/week had 18% and 9% decreased odds of cognitive impairment, respectively, compared to non-consumers or less-than-weekly consumers. In contrast, those who consumed 6.0 eggs/week or more showed no connection with cognitive impairment. Furthermore, frequent lower-quantity consumption (3 days/week and 0.1-1.9 eggs/day), infrequent higher-quantity consumption (2 days/week and 2.0 eggs/day), and infrequent lower-quantity consumption (1-2 days/week and 0.1-1.9 eggs/day) were all linked to improved cognitive performance, but frequent higher-quantity consumers (3 days/week and 2.0 eggs/day) did not show any association. The results of the sensitivity analyses agreed with those of the primary study. The authors conclude that a reduced risk of cognitive impairment in older people is prospectively associated with reduced egg intake. [NPID: Cognitive impairment, cohort study, eggs consumption, elderly]

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Inadequate dietary intake increases the risk of developing disabilities, chronic diseases, and mortality in the United States. Older adults represent the fastest-growing subpopulation of the United States, thus, a sufficient understanding of the dietary patterns in older adults can help detect opportunities and identify challenges to enhancing their health. In this serial cross-sectional study by Long et al. (2018), the authors aimed to outline the observed patterns of dietary quality, essential food components, and essential nutrients in the older adult population with respect to age, sex, race, ethnicity, income, education and marital status. To do so, data from nine National Health and Nutrition Examination Survey cycles (2001-2002 to 2017-2018) was used, containing 24-hr dietary recall information submitted by 10,837 participants (50% women, 58.5% White participants, mean age = 73.9 ± 0.1 years). Participants were divided into groups (poor, intermediate, or ideal diet groups) according to the American Heart Association (AHA) 2020 Strategic Impact Goals for diet, in addition to having their AHA secondary scores and their Healthy Eating Index (HEI)-2015 scores evaluated. Analysis of the results revealed that older adults exhibited a substantially increasing trend of poor diet quality across the years, with a concomitant decreasing trend in the number of participants classified into the intermediate diet quality group, while the ideal group remained uniformly low. The observed dietary derangements were linked to sociodemographic factors. Furthermore, a substantial decline in dietary scores in both sexes and all age groups surveyed was found, with the exception of the 75-79 years subgroup. The authors conclude that their findings present a consistently deteriorating trend of dietary quality for most dietary components in the diet consumed by older adults in the US between 2001 and 2018, and that despite efforts aimed at enhancing dietary quality, over half of the older adult population still suffers from poor dietary quality. [NPID: Older adult, diet quality, nutrition surveys]

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]