Taiwanese Vegetarians Are Associated with Lower Dementia Risk: A Prospective Cohort Study

Impact of vegetarianism on cognition and neuropsychological status among urban community-dwelling adults in Telangana, South India: a cross-sectional study

PURPOSE

The potential benefits of vegetarian diets in reducing cognitive impairment have garnered attention due to existing mixed results; hence, our study aims to examine the impact of vegetarianism on cognitive function and neuropsychological status among urban community-dwelling adults from Telangana.

METHODS

The dietary patterns were self-reported and dietary data collected using a Food Frequency Questionnaire while cognitive function was assessed using Mini-Mental State Examination (MMSE) and depression, anxiety, and stress (DASS-21) questionnaire for psychological measures. Adults (N = 304) aged 40 years and above, who followed either a vegetarian or non-vegetarian diet for at least 6 months prior to data collection, scored MMSE ≥ 19 indicating mild cognitive impairment, and were recruited using convenience sampling.

RESULTS

Among the participants, vegetarians (n = 155) exhibited significantly better mood states compared to non-vegetarians (n = 149), as indicated by lower scores on the DASS subscales for depression (10.0 ± 0.06 vs. 17.0 ± 0.07, p =  < 0.001), anxiety (4.0 ± 0.05 vs. 6.0 ± 0.07, p = 0.005), and stress (8.0 ± 0.02 vs. 10.0 ± 0.05, p = 0.007). Vegetarians also demonstrated superior cognitive functioning compared to non-vegetarians, as indicated by higher MMSE scores (26.0 ± 0.04 vs. 24.0 ± 0.03, p =  < 0.001). MMSE scores were inversely correlated with depression, anxiety, and stress for vegetarians (ρ = - 0.371, p = 0.000; ρ = - 0.027, p = 0.734; and ρ = - 0.105, p = 0.914), respectively. Similar to the vegetarians group, MMSE scores were negatively correlated with depression (ρ = - 0.059), but the correlation is not significant.

CONCLUSION

Vegetarianism exerted a positive influence on the cognitive and neuropsychological status of the investigated population. Nevertheless, additional research is required to comprehend the underlying mechanisms that elucidate the long-term effects of vegetarianism and plant-based nutritional interventions on brain health.

Can the gut microbiome inform the effects of omega-3 fatty acid supplementation trials on cognition?

PURPOSE OF REVIEW

Most omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation clinical trials report inconsistent or null findings on measures of cognition or Alzheimer's disease (AD) with a relatively large variability in the response to n-3 PUFA supplementation. The purpose of this review is to identify whether the gut microbiome together with the metabolome can provide critical insights to understand this heterogeneity in the response to n-3 PUFA supplementation.

RECENT FINDINGS

A Western diet with high saturated fat and omega-6 fatty acid content, obesity, and lack of exercise puts strain on the gut microbiome resulting in imbalance, dysbiosis, reduced bacterial diversity, and increased abundance of the pro-inflammatory taxa. A plant-based diet has beneficial effects on the gut microbiota even when deficient in n-3 PUFAs. Human and animal studies show that increased intake of the n-3 PUFAs correlates with increased beneficial intestinal bacteria when compared to a Western diet.

SUMMARY

The composition of the gut microbiota can help define the effects of n-3 PUFA supplementation on the brain and lead to more personalized nutritional interventions.

Plant-based dietary patterns and risk of insomnia: a prospective study

BACKGROUND

Accumulating evidence suggests that dietary factors may affect sleep, but the associations between dietary patterns and insomnia risk have been poorly explored. The aim of this study was to investigate if plant-based diets are associated with reduced insomnia risks in a cohort study design.

METHODS

Tzu Chi Health Study participants (N = 5821) recruited from 2007 to 2009 without insomnia were followed until 2018. A traditional classification method (vegetarians vs. non-vegetarians) and a healthful plant-based index (hPDI) were used to define adherence to plant-based dietary patterns. Incident cases of insomnia were ascertained by linking with the National Health Insurance Research Database (NHIRD). Associations between plant-based diets and insomnia were estimated using Cox proportional hazard models.

RESULTS

A total of 464 incident cases of insomnia were identified in the 55,562 person-years of follow up. Insomnia risk was lower in vegetarians when compared to non-vegetarians, hazard ratios (HR) 0.47 (95% CI: 0.27, 0.81) and 0.71 (95% CI: 0.55, 0.91) for males and females respectively. Male participants with the highest hPDI were associated with a significant lower risk of insomnia (HR 0.50 [95% CI: 0.30, 0.85]) when compared to those in the lowest quintile. No association between adherence to hPDI and insomnia in female participants was observed.

CONCLUSIONS

Our study showed that vegetarians are associated with a lower risk of insomnia, but there may be sex-specific associations between adherence to hPDI and insomnia risk. These favorable associations are important when considering plant-based diets for their potential additional sleep benefits.

Vegetarian and vegan diets: benefits and drawbacks

Plant-based diets have become increasingly popular thanks to their purported health benefits and more recently for their positive environmental impact. Prospective studies suggest that consuming vegetarian diets is associated with a reduced risk of developing cardiovascular disease (CVD), diabetes, hypertension, dementia, and cancer. Data from randomized clinical trials have confirmed a protective effect of vegetarian diets for the prevention of diabetes and reductions in weight, blood pressure, glycosylated haemoglobin and low-density lipoprotein cholesterol, but to date, no data are available for cardiovascular event rates and cognitive impairment, and there are very limited data for cancer. Moreover, not all plant-based foods are equally healthy. Unhealthy vegetarian diets poor in specific nutrients (vitamin B12, iron, zinc, and calcium) and/or rich in highly processed and refined foods increase morbidity and mortality. Further mechanistic studies are desirable to understand whether the advantages of healthy, minimally processed vegetarian diets represent an all-or-nothing phenomenon and whether consuming primarily plant-based diets containing small quantities of animal products (e.g. pesco-vegetarian or Mediterranean diets) has beneficial, detrimental, or neutral effects on cardiometabolic health outcomes. Further, mechanistic studies are warranted to enhance our understanding about healthy plant-based food patterns and the biological mechanisms linking dietary factors, CVD, and other metabolic diseases.

Plant-based dietary patterns and the risk of dementia: a population-based study

BACKGROUND

Plant-based dietary patterns are increasingly popular in western countries and are supported by many governments and health organisations for their potential beneficial role in the prevention of chronic diseases. Yet, the potential role of plant-based dietary patterns in the development of dementia remains unclear.

OBJECTIVE

To evaluate the association between plant-based dietary patterns and the risk of dementia.

METHODS

Dietary intake was measured at baseline in 9,543 dementia-free participants (mean age 64 years, birth years 1897-1960, 58% women) of the prospective population-based Rotterdam Study, using food frequency questionnaires. Based on these questionnaires, we calculated an overall plant-based dietary index (PDI), healthy PDI (hPDI) and unhealthy PDI (uPDI), with higher scores reflecting higher consumption of (any, healthy and unhealthy, respectively) plant-based foods and lower consumption of animal-based foods. We analysed the association of the PDIs with incident dementia using Cox proportional hazard models.

RESULTS

During a mean follow-up of 14.5 years, 1,472 participants developed dementia. Overall, the PDIs were not associated with the risk of dementia (hazard ratio [95% confidence interval] per 10-point increase: 0.99 [0.91-1.08] for PDI, 0.93 [0.86-1.01] for hPDI, 1.02 [0.94-1.10] for uPDI). However, among men and APOE ε4 carriers, a higher hPDI was linearly associated with a lower risk of dementia (0.86 [0.75-0.99] and 0.83 [0.73-0.95], respectively), while this association was U-shaped among APOE ε4 non-carriers (P value for non-linearity = 0.01).

CONCLUSIONS

We found no strong evidence for an overall association between plant-based eating and the risk of dementia. Our findings in stratified analyses warranted further investigation.

Dietary Patterns and Alzheimer's Disease: An Updated Review Linking Nutrition to Neuroscience

Alzheimer's disease (AD) is a growing concern for the aging population worldwide. With no current cure or reliable treatments available for AD, prevention is an important and growing area of research. A range of lifestyle and dietary patterns have been studied to identify the most effective preventive lifestyle changes against AD and related dementia (ADRD) pathology. Of these, the most studied dietary patterns are the Mediterranean, DASH, MIND, ketogenic, and modified Mediterranean-ketogenic diets. However, there are discrepancies in the reported benefits among studies examining these dietary patterns. We herein compile a narrative/literature review of existing clinical evidence on the association of these patterns with ADRD symptomology and contemplate their preventive/ameliorative effects on ADRD neuropathology in various clinical milieus. By and large, plant-based dietary patterns have been found to be relatively consistently and positively correlated with preventing and reducing the odds of ADRD. These impacts stem not only from the direct impact of specific dietary components within these patterns on the brain but also from indirect effects through decreasing the deleterious effects of ADRD risk factors, such as diabetes, obesity, and cardiovascular diseases. Importantly, other psychosocial factors influence dietary intake, such as the social connection, which may directly influence diet and lifestyle, thereby also impacting ADRD risk. To this end, prospective research on ADRD should include a holistic approach, including psychosocial considerations.

Quality of plant-based diet and the risk of dementia and depression among middle-aged and older population

BACKGROUND

several previous studies have shown the importance of the plant-based diets. However, not all plant-based foods are necessarily beneficial for dementia or depression. This study aimed to prospectively investigate the association between an overall plant-based diet and the incidence of dementia or depression.

METHODS

we included 180,532 participants from the UK Biobank cohort study, free of a history of cardiovascular disease, cancer, dementia and depression at baseline. We calculated an overall plant-based diet index (PDI), a healthful plant-based diet index (hPDI) and an unhealthful plant-based diet index (uPDI) based on 17 major food groups from Oxford WebQ. Dementia and depression were evaluated using hospital inpatient records in UK Biobank. Cox proportional hazards regression models were used to estimate the association between PDIs and the incidence of dementia or depression.

RESULTS

during the follow-up, 1,428 dementia cases and 6,781 depression cases were documented. After adjusting for several potential confounders and comparing the highest with the lowest quintile of three plant-based diet indices, the multivariable hazard ratios (95% confidence intervals (CIs)) for dementia were 1.03 (0.87, 1.23) for PDI, 0.82 (0.68, 0.98) for hPDI and 1.29 (1.08, 1.53) for uPDI. The hazard ratios (95% CI) for depression were 1.06 (0.98, 1.14) for PDI, 0.92 (0.85, 0.99) for hPDI and 1.15 (1.07, 1.24) for uPDI.

CONCLUSION

a plant-based diet rich in healthier plant foods was associated with a lower risk of dementia and depression, whereas a plant-based diet that emphasises less-healthy plant foods was associated with a higher risk of dementia and depression.

Arrhythmia and other modifiable risk factors in incident dementia and MCI among elderly individuals with low educational levels in Taiwan

Introduction

There is increasing evidence that arrhythmia is a risk factor for dementia; however, it appears that arrhythmia affects the cognitive function of individuals differentially across age groups, races, and educational levels. Demographic differences including educational level have also been found to moderate the effects of modifiable risk factors for cognitive decline.

Methods

This study recruited 1,361 individuals including a group of cognitively unimpaired (CU) individuals, a group of patients with mild cognitive impairment (MCI), and a group of patients with dementia with low education levels. The participants were evaluated in terms of modifiable risk factors for dementia, including arrhythmia and neuropsychiatric symptoms.

Results

Cox proportional hazard regression models revealed that among older MCI patients (>75 years), those with arrhythmia faced an elevated risk of dementia. Among younger MCI patients, those taking anti-hypertensive drugs faced a relatively low risk of dementia. Among younger MCI patients, male sex and higher educational level were associated with an elevated risk of dementia. Among CU individuals, those with coronary heart disease and taking anti-lipid compounds faced an elevated risk of MCI and those with symptoms of depression faced an elevated risk of dementia.

Discussion

The risk and protective factors mentioned above could potentially be used as markers in predicting the onset of dementia in clinical settings, especially for individuals with low educational levels.

Global incidence of young-onset dementia: A systematic review and meta-analysis

INTRODUCTION

Reliable data on the incidence rates for young-onset dementia (YOD) are lacking, but are necessary for research on disease etiology and to raise awareness among health care professionals.

METHODS

We performed a systematic review and meta-analysis on population-based studies on the incidence of YOD, published between January 1, 1990 and February 1, 2022, according to Meta-analyses of Observational Studies in Epidemiology (MOOSE) guidelines. Data were analyzed using random-effects meta-analyses. Results were age-standardized, and heterogeneity was assessed by subgroup analyses and meta-regression.

RESULTS

Sixty-one articles were included. Global age-standardized incidence rates increased from 0.17/100,000 in age 30 to 34 years, to 5.14/100,000 in age 60 to 64 years, giving a global total age-standardized incidence rate of 11 per 100,000 in age 30 to 64. This corresponds to 370,000 new YOD cases annually worldwide. Heterogeneity was high and meta-regression showed geographic location significantly influenced this heterogeneity.

DISCUSSION

This meta-analysis shows the current best estimate of YOD incidence. New prospective cohort studies are needed.

Profiles of Physical Activity and Physical Performance in Matched Religious Vegetarian and Nonvegetarian Women: A Preliminary Observational Study in Taiwan

Religious vegetarianism has become more popular with women and increases with age. However, concerns have been raised that vegetarians are less productive than nonvegetarians. Thus, we aimed to compare the characteristics of physical activity and physical performance in properly matched religious vegetarian and nonvegetarian women aged ≥ 45 years. Participants (n = 160) were recruited via convenience sampling in the community of Hualien, Taiwan, and matched by demographic and cognitive characteristics. Physical activity was assessed using the International Physical Activity Questionnaire-Short Form (IPAQ-SF). Physical performance was assessed with handgrip strength, five-times-sit-to-stand, gait speed, timed up-and-go, and functional reach tests (FRT). Overall, 90% of religious vegetarians practiced lacto-ovo-vegetarianism. The proportions of those with low physical activity levels and poor physical performance did not significantly differ between religious vegetarians and nonvegetarians. Additionally, there were no significant between-group differences in IPAQ-SF scores and physical performance, except for FRT performance (mean 24.5 cm vs. 19.7 cm, p < 0.001). Exhaustion after work, busyness, and a lack of interest were three main reasons for low physical activity levels, and none of these had significant between-group differences (p = 0.936). Our results show a similar profile of physical activity and physical performance in religious vegetarian and nonvegetarian women.

Are dietary patterns becoming more processed? The effects of different dietary patterns on cognition: A review

Background: Identifying dietary patterns that promote healthy aging has become increasingly important due to changes in food processing and consumption of processed foods. Recently, the effects of these foods and unhealthy dietary patterns on cognitive function have become more widely recognized. Aim: The aim of this review is to discuss the association between various dietary patterns and cognition in older age, while also highlighting growing evidence that ultra processed food (UPF) may negatively impact healthy aging. Methods: We have performed a non-systematic literature review searches in Google Scholar electronic database with pre-defined terms relating to UPF, diet, dietary patterns, cognition and ageing. Results: The most prevalent diets in the literature include the Western, Mediterranean, Dietary Approach to Stop Hypertension (DASH), Mediterranean-DASH Intervention for Neurogenerative Delay (MIND), Japanese, Nordic, and plant-based diets. Based on the findings, higher intakes of fresh fruit and vegetables, wholegrains and oily fish are common components of dietary patterns that are positively associated with better cognitive function. In contrast, the characteristics of a Western style dietary pattern, consisting of high amounts of UPF's, are increasing in many countries even where the staple dietary pattern was identified as healthy (i.e. Japan). Conclusion: The consumption of UPF, classified by the NOVA food classification system as industrially manufactured foods containing high levels of starches, vegetable oils, sugar, emulsifiers, and foods additives, has a negative impact on the overall nutritional quality of individual diets.