Dietary factors and MRI biomarkers of brain ageing in general populations: a comprehensive systematic review.

The aim of this study was to evaluate the relationship between olfactory function and hippocampal volume in patients with mild cognitive impairment (MCI). We enrolled a total of 31 MCI patients and 9 normal control subjects. All participants underwent 3.0 T-magnetic resonance imaging scanning. The scan results were processed using GE ADW4.6 processing software and V0xar 3D workstation to acquire the hippocampal volume. The University of Pennsylvania Smell Identification Test (UPSIT) was used to evaluate the olfactory function of MCI patients. The correlations of UPSIT score with hippocampal volume and hippocampal head volume were evaluated by Pearson correlation coefficient analysis. MCI patients had significantly smaller left (2.78±0.50 vs. 3.19±0.31 cm(3)) and right (2.97±0.42 vs. 3.31±0.25 cm(3)) hippocampal volumes compared with normal controls (P<0.05). In addition, patients with olfactory dysfunction had smaller volumes of the hippocampus (left hippocampal volume, 2.57±0.39 vs. 3.23±0.40 cm(3); right hippocampal volume, 2.86±0.43 vs. 3.22±0.30 cm(3)) and hippocampal head (left hippocampal head volume, 1.18±0.16 vs. 1.53±0.25 cm(3); right hippocampal head volume, 1.25±0.22 vs. 1.54±0.22 cm(3)) compared with those with normal olfactory function (P<0.05). No significant difference in the hippocampal body volume and hippocampal tail volume was found between MCI patients with olfactory loss and those with normal olfactory function. The UPSIT score was significantly positively correlated with left hippocampal volume (r=0.55, P<0.05), right hippocampal volume (r=0.42, P<0.05), left hippocampal head volume (r=0.53, P<0.05), and right hippocampal head volume (r=0.45, P<0.05). Olfactory function correlates well with hippocampal volume among patients with MCI.

BackgroundRecent meta-analyses confirm a relationship between diet quality and both depression and cognitive health in adults. While the biological pathways that underpin these relationships are likely multitudinous, extensive evidence from animal studies points to the involvement of the hippocampus. The aim of this study was to examine the association between dietary patterns and hippocampal volume in humans, and to assess whether diet was associated with differential rates of hippocampal atrophy over time.MethodsData were drawn from the Personality and Total Health Through Life Study and focused on a subsample of the cohort (n = 255) who were aged 60–64 years at baseline in 2001, completed a food frequency questionnaire, and underwent two magnetic resonance imaging scans approximately 4 years apart. Longitudinal generalized estimating equation linear regression models were used to assess the association between dietary factors and left and right hippocampal volumes over time.ResultsEvery one standard deviation increase in healthy “prudent” dietary pattern was associated with a 45.7 mm3 (standard error 22.9 mm3) larger left hippocampal volume, while higher consumption of an unhealthy “Western” dietary pattern was (independently) associated with a 52.6 mm3 (SE 26.6 mm3) smaller left hippocampal volume. These relationships were independent of covariates including age, gender, education, labour-force status, depressive symptoms and medication, physical activity, smoking, hypertension and diabetes. While hippocampal volume declined over time, there was no evidence that dietary patterns influenced this decline. No relationships were observed between dietary patterns and right hippocampal volume.ConclusionsLower intakes of nutrient-dense foods and higher intakes of unhealthy foods are each independently associated with smaller left hippocampal volume. To our knowledge, this is the first human study to demonstrate associations between diet and hippocampal volume concordant with data previously observed in animal models.

Modern epidemiology suggests a potential interactive association between diet, lifestyle, genetics and the risk of many chronic diseases. As such, many epidemiologic studies attempt to consider assessment of dietary intake alongside genetic measures and other variables of interest. However, given the multi-factorial complexities of dietary exposures, all dietary intake assessment methods are associated with measurement errors which affect dietary estimates and may obscure disease risk associations. For this reason, dietary biomarkers measured in biological specimens are being increasingly used as additional or substitute estimates of dietary intake and nutrient status. Genetic variation may influence dietary intake and nutrient metabolism and may affect the utility of a dietary biomarker to properly reflect dietary exposures. Although there are many functional dietary biomarkers that, if utilized appropriately, can be very informative, a better understanding of the interactions between diet and genes as potentially determining factors in the validity, application and interpretation of dietary biomarkers is necessary. It is the aim of this review to highlight how some important biomarkers are being applied in nutrition epidemiology and to address some associated questions and limitations. This review also emphasizes the need to identify new dietary biomarkers and highlights the emerging field of nutritional metabonomics as an analytical method to assess metabolic profiles as measures of dietary exposures and indicators of dietary patterns, dietary changes or effectiveness of dietary interventions. The review will also touch upon new statistical methodologies for the combination of dietary questionnaire and biomarker data for disease risk assessment. It is clear that dietary biomarkers require much further research in order to be better applied and interpreted. Future priorities should be to integrate high quality dietary intake information, measurements of dietary biomarkers, metabolic profiles of specific dietary patterns, genetics and novel statistical methodology in order to provide important new insights into gene-diet-lifestyle-disease risk associations.

Objective: To examine whether educational attainment, as a proxy of cognitive reserve, moderated the association between hippocampal volumes and episodic verbal memory performances in healthy older adults.Methods: Data from 76 community dwelling older adults were included in the present study. Measures of hippocampal volumes (total, left, and right) were obtained using FreeSurfer software. Immediate and delayed verbal recall scores were derived from performances on the California Verbal Learning Test-Second Edition and the Wechsler Memory Scale- Third Edition. Educational attainment was defined by years of education. Linear regression analyses were performed using immediate and delayed recall as dependent variables and hippocampal volumes, years of education, and their interaction terms as independent variables. All analyses were controlled for age, sex, depression, and health status.Results: Total and left Hippocampal volumes had a positive main effect on delayed recall only. Additionally, the interaction between total, left, and right hippocampal volumes and education was a significant predictor for delayed recall performance but not for immediate recall performance. The positive association between hippocampal volumes and delayed recall was greatest in those with more years of education.Conclusion: Larger hippocampal volumes were associated with better delayed verbal recall and the effect on delayed recall was greatest in those with more years of education. Having higher levels of education, or cognitive reserve, may enable individuals to capitalize on greater structural integrity in the hippocampus to support delayed recall in old age. However, longitudinal research is needed to investigate the directionality of these associations.

Gastric cancer is the fifth most common cancer and a leading cause of death worldwide. Despite a substantial body of research exploring individual food groups or dietary patterns in isolation, few studies have assessed the overall strength of the association between multiple dietary factors and gastric cancer risk. The aim for this meta-analysis was to identify the associations between dietary factors and gastric cancer risk in the Asian population. The PubMed, Web of Science, Embase, and Scopus databases were systematically searched up to December 31, 2022. Hazard ratios (HRs) with their 95% CIs were used to calculate pooled risk estimates, and Cochran's Q and I2 statistics were used to assess heterogeneity. Funnel plot and Egger's tests were used to estimate publication bias. Through stepwise screening, 30 cohort studies were deemed eligible for inclusion in this review. Results indicated a high total fruit consumption may reduce gastric cancer risk by 11% (HR = 0.89; 95% CI, 0.83-0.96), whereas high salt consumption potentially increases the risk by 97% (HR = 1.97; 95% CI, 1.34-2.90) in the Asian population. However, no associations of the other 21 food groups and 2 dietary patterns (healthy and unhealthy dietary patterns) with gastric cancer risk were found. Overall, this review demonstrates that consumption of high amounts of fruit and low amounts of salt may effectively prevent gastric cancer incidence in the Asian population. More cohort studies based on the Asian population are required to confirm the association of fish, meat, coffee consumption, and dietary pattern with gastric cancer risk.

Background:Cognitive disorders and dementia are common problems, and Alzheimer's disease is one of the major leading causes of death worldwide. Thyroid hormone disorders as a common problem effect on hippocampus size which as a prognostic factor in dementia. The aim of the present study was to investigate the relationship between serum thyroid-stimulating hormone (TSH) level and the size of hippocampus in patients with mild cognitive disorders.Materials and Methods:In a descriptive-analytical study, 41 patients with symptoms of mild cognitive disorders whom referred to take the brain magnetic resonance image (MRI) in a radiology center under the direction of Tabriz University of Medical Sciences (Tabriz, Iran) were evaluated. The right and left hippocampal and brain volume was calculated by MRI at coronal T1-weighted. Serum TSH level was also measured in these patients. Correlation between serum TSH level and hippocampal volume size was evaluated.Results:Male to female ratio was 1.05:1 with mean age of 54.09 ± 3.11 years. Mean serum TSH level of patients was 1.55 ± 1.45 uU/ml. The right and left hippocampal volumes were 1.61 ± 0.42 and 1.62 ± 0.39 ml, respectively. There were slight negative correlations between the right and left hippocampal volumes with TSH level (r = −0.133 and r = −0.092, respectively). Correlations between the right and left hippocampal volumes with TSH level were not statistically significant (P = 0.406, P = 0.566, respectively).Conclusion:Based on findings of the present study, there was a weak negative correlation between serum level of TSH with the right and left hippocampal and brain volume ratio, but the correlation was not statistically significant. It seems that controlling of clinical or subclinical hypothyroidism may have a role in slowing of dementia progression and also have a preventive role.

ContextMost methods for assessing dietary intake have considerable measurement error. Dietary biomarkers are objective tools for dietary assessment. Dietary biomarkers of dietary patterns have not been well described, despite modern dietary guidelines endorsing dietary patterns.ObjectiveThis systematic review sought to describe the dietary biomarkers commonly used to assess dietary patterns, and the novel biomarkers of dietary patterns identified by exploratory studies.Data SourcesMEDLINE, Embase, Cochrane Central, PreMEDLINE, and CINAHL databases were searched.Data ExtractionData extraction and bias assessment were undertaken in duplicate.Data AnalysisA qualitative approach was applied, without statistical analysis.ConclusionIn controlled settings, dietary biomarkers of single nutrients or of individual foods or food groups are commonly used to assess compliance with dietary patterns. However, currently, there are no dietary biomarkers or biomarker profiles that are able to identify the specific dietary pattern that has been consumed by an individual. Future work should seek to validate novel dietary biomarkers and biomarker profiles that are indicative of specific dietary patterns and their characteristics. A dietary biomarker panel consisting of multiple biomarkers is almost certainly necessary to capture the complexity of dietary patterns.Systematic Review RegistrationPROSPERO registration no. CRD42019129839.

To interrogate hippocampal morphology and structural co-variance patterns in migraine patients and to investigate whether structural co-variance patterns relate to migraine disease characteristics. Migraine is associated with structural alterations in widespread cortical and subcortical regions associated with the sensory, cognitive, and affective components of pain processing. Recent studies have shown that migraine patients have differences in hippocampal structure and function relative to healthy control subjects, but whether hippocampal structure relates to disease characteristics including frequency of attacks, years lived with migraine and symptoms of allodynia remains unknown. Furthermore, this study investigated hippocampal volume co-variance patterns in migraineurs, an indirect measure of brain network connectivity. Here, we explore differences in hippocampal volume and structural co-variance patterns in migraine patients relative to healthy controls and examine whether these hippocampal measures relate to migraine disease burden. This study included 61 migraine patients and 57 healthy control subjects (healthy controls: median age = 34.0, IQR = 19.0; migraine patients: median age = 35.0, IQR = 17.5; P = .65). Regional brain volumes were automatically calculated using FreeSurfer version 5.3. Symptoms of allodynia were determined using the Allodynia Symptom Checklist 12 (ASC-12). Structural co-variance patterns were interrogated using pairwise correlations and group differences in correlation strength were estimated using Euclidian distance. A stepwise regression was used to investigate the relationship between structural co-variance patterns with migraine burden. Migraine patients had less left hippocampal volume (healthy controls: left hippocampal volume = 4276.8mm3 , SD = 425.3mm3 , migraine patients: left hippocampal volume = 4089.5mm3 , SD = 453.9mm3 , P = .02) and less total (right plus left) hippocampal volume (healthy controls: total hippocampal volume= 8690.8mm3 , SD = 855.1mm3 ; migraine patients: total hippocampal volume = 8341.8mm3 , SD = 917.9mm3 ; P = .03) compared to healthy controls. Migraineurs had stronger structural covariance between the hippocampi and cortico-limbic regions in the frontal lobe (inferior opercular gyrus), temporal lobe (planum temporale, amygdala), parietal lobe (angular gyrus, precuneus), and the cerebellar white matter. Results of a stepwise regression showed that hippocampal volumes and the interactions between hippocampal volumes with the volumes of other cortico-limbic regions associate with migraine-related allodynia but not with headache frequency or years lived with migraine. Migraineurs have less hippocampal volume and stronger hippocampal-cortico-limbic connectivity compared to healthy controls. Hippocampal volumes and measures of hippocampal volume connectivity with other cortico-limbic network regions associate with symptoms of allodynia.

Novel strategies for improving dietary exposure assessment: Multiple-data fusion is a more accurate measure than the traditional single-biomarker approach

The food metabolome is an area of research that is of rising interest, particularly the association of chronic diseases to dietary biomarkers. This chapter will review and assess the current literature of the novel biomarkers used to track dietary intake of carbohydrates, fats, proteins, vitamin C, and carotenoids, as well as to explore the relationship between dietary patterns and biomarkers associated with disease processes. There is good evidence for the use of certain novel biomarkers for each of the aforementioned dietary components. A review of the literature also reveals a relationship between a “Western” dietary pattern, characterized by higher intakes of red meat, processed meat, French fries, eggs, high-fat dairy products, sweets, and refined grains and that of increased risk for systemic inflammation, endothelial dysfunction, cardiovascular disease, metabolic syndrome, hypertension, and diabetes. Contrasting this is the “prudent” dietary pattern characterized by increased fruit, vegetables, poultry, fish, whole grains, and legumes which had improved biomarker profiles of the aforementioned diseases. Similar to the “Western” pattern is a diet with high saturated fat/high simple carbohydrate that correlates with increased biomarkers of Alzheimer’s disease. There appears to be a large volume of literature investigating biomarkers of dietary intake and the relationship between dietary patterns and chronic diseases. However there is still need for literature looking into the relationship of novel biomarkers of fats, carbohydrates, protein, vitamin C, and carotenoids and the biomarkers of chronic diseases.

Objective: The association between hippocampal volume and memory is continuing to be characterized in healthy older adults. Prior research suggests smaller hippocampal volume in healthy older adults is associated with poorer episodic memory and processing speed, as well as working memory, verbal learning, and executive functioning as measured by the NIH Toolbox Fluid (Fluid Cognition Composite, FCC) and Crystalized Cognition Composites (CCC). This study aimed to replicate these findings and to evaluate the association between: (1) hippocampal asymmetry index and cognition; and (2) independent contributions of the left and right hippocampal volume and cognition in a large sample of healthy older adults.Participants and Methods: One-hundred and eighty-three healthy older adults (M age = 71.72, SD = 5.3) received a T1-weighted sequence on a 3T scanner. Hippocampal subfields were extracted using FreeSurfer 6.0 and combined to provide left, right, and total hippocampal volumes. FCC subtests include Dimensional Change Card Sort, Flanker Inhibitory Control and Attention, List Sorting, Picture Sequence Memory, and Pattern Comparison. CCC subtests include Picture Vocabulary and Oral Reading Recognition. Multiple linear regressions were performed predicting cognition composites from the total, left and right, and asymmetry of hippocampal volume, controlling for sex, education, scanner, and total intracranial volume. Multiple comparisons in primary analyses were corrected using a false discovery rate (FDR) of p < 0.05.Results: FCC scores were positively associated with total (β = 0.226, FDR q = 0.044) and left (β = 0.257, FDR q = 0.024) hippocampal volume. Within FCC, Picture Sequence Memory scores positively associated with total (β = 0.284, p = 0.001) and left (β = 0.98, p = 0.001) hippocampal volume. List Sorting scores were also positively associated with left hippocampal volume (β = 0.189, p = 0.029).Conclusions: These results confirm previous research suggesting that bilateral hippocampal volume is associated with FCC, namely episodic memory. The present study also suggests the left hippocampal volume may be more broadly associated with both episodic and working memory. Studies should continue to investigate lateralized hippocampal contributions to aging processes to better identify predictors of cognitive decline.

A variation in the infant oxytocin receptor gene modulates infant hippocampal volumes in association with sex and prenatal maternal anxiety

Association between dietary factors and brown adipose tissue volume/18F-FDG uptake in young adults

Aim: This study tested sex differences in the association between hippocampal volume and working memory of a national sample of 9–10-year-old children in the US. As the hippocampus is functionally lateralized (especially in task-related activities), we explored the results for the right and the left hippocampus. Methods: This is a cross-sectional study using the Adolescent Brain Cognitive Development (ABCD) Study data. This analysis included baseline ABCD data (n = 10,093) of children between ages 9 and 10 years. The predictor variable was right and left hippocampal volume measured by structural magnetic resonance imaging (sMRI). The primary outcome, list sorting working memory, was measured using the NIH toolbox measure. Sex was the moderator. Age, race, ethnicity, household income, parental education, and family structure were the covariates. Results: In the overall sample, larger right (b = 0.0013; p < 0.001) and left (b = 0.0013; p < 0.001) hippocampal volumes were associated with higher children’s working memory. Sex had statistically significant interactions with the right (b = −0.0018; p = 0.001) and left (b = −0.0012; p = 0.022) hippocampal volumes on children’s working memory. These interactions indicated stronger positive associations between right and left hippocampal volume and working memory for females compared to males. Conclusion: While right and left hippocampal volumes are determinants of children’s list sorting working memory, these effects seem to be more salient for female than male children. Research is needed on the role of socialization, sex hormones, and brain functional connectivity as potential mechanisms that may explain the observed sex differences in the role of hippocampal volume as a correlate of working memory.

BackgroundDiet could be a modifiable factor in the prevention of Alzheimer’s disease (AD). Western‐style dietary patterns are considered to increase the risk, while Mediterranean‐style dietary patterns are considered protective. The aim of this study was to investigate the relation between dietary patterns and CSF biomarkers of relevance for AD.MethodData was derived from the population based Gothenburg H70 Birth Cohort Studies, Sweden (n=1203). CSF levels of β‐amyloid (Aβ)42, total tau, and phosphorylated tau were measured with ELISA. Dietary intake was determined by the diet history method (n=861). Principal component analysis were performed to reduce 21 food groups into factors representing dietary patterns. Logistic regression analyses, with CSF biomarkers as dependent variables (pathological, yes/no), and linear regression analyses with CSF biomarkers as continuous variables, were performed on the dementia‐free participants with both CSF and dietary data (n=269, 49% women). Analyses were adjusted for APOE ε4 status, energy intake, education, BMI and physical activity and sex. Analyses were also performed stratified by sex.ResultFour dietary patterns were derived from the principal component analysis. A western‐style dietary pattern, a Mediterranean‐style dietary pattern, a mixed dietary pattern with alcoholic beverages and a dietary pattern of high fat dairy products, eggs and refined cereal products. The odds ratio of having pathological values of total tau was higher among those with a higher compliance to a western‐style dietary pattern (OR 1.37; 95%CI 1.02‐1.85). The linear regression model indicate the same trend (r2=0.06, B=0.04, p=0.08). When stratified by sex, the odds ratio of having pathological values of phosphorylated tau was higher for men with a higher intake of high fat dairy products, eggs and refined cereal products (OR 3.38; 95%CI 1.22‐9.36). There were no associations between the other dietary patterns and CSF biomarkers.ConclusionOur results indicate an association between western‐style dietary patterns and increased levels of total tau and phosphorylated tau. There was no relation between a healthier Mediterranean‐style dietary pattern and CSF biomarkers for AD, however.