Influence of Imidazole-Dipeptides on Cognitive Status and Preservation in Elders: A Narrative Review

The worldwide increase in the number of patients with dementia is becoming a growing problem, while Alzheimer’s disease (AD), a primary neurodegenerative disorder, accounts for more than 70% of all dementia cases. Research on the prevention or reduction of AD occurrence through food ingredients has been widely conducted. In particular, histidine-containing dipeptides, also known as imidazole dipeptides derived from meat, have received much attention. Imidazole dipeptides are abundant in meats such as poultry, fish, and pork. As evidenced by data from recent human intervention trials conducted worldwide, daily supplementation of carnosine and anserine, which are both imidazole dipeptides, can improve memory loss in the elderly and reduce the risk of developing AD. This article also summarizes the latest researches on the biochemical properties of imidazole dipeptides and their effects on animal models associated with age-related cognitive decline. In this review, we focus on the results of human intervention studies using supplements of poultry-derived imidazole dipeptides, including anserine and carnosine, affecting the preservation of cognitive function in the elderly, and discuss how imidazole dipeptides act in the brain to prevent age-related cognitive decline and the onset of dementia.     

Diet Quality and Cognitive Performance in Australian Adults Aged 55–85 Years: A Cross-Sectional Analysis of the Hunter Community Study Cohort

There is a lack of evidence to determine if diet quality is associated with cognitive performance in older adults. Therefore, the aim of this study was to examine whether diet quality is associated with cognitive performance among older adults. A cross-sectional, secondary analysis of baseline data from the Hunter Community Study (HCS), comparing diet quality, measured using the Australian Recommended Food Score (ARFS), along with validated cognitive performance instruments the Audio Recorded Cognitive Screen (ARCS) and the Mini-Mental State Examination (MMSE) were undertaken in adults aged 55–85 years, living in Newcastle, NSW, Australia. Adjusted linear regression analyses showed that, compared with the lowest ARFS quintile, those in the highest quintile had an ARCS score 5.883 units greater (p < 0.001; R² = 0.0098). Furthermore, when quintiles of ARFS score were tested against each ARCS sub-scale score, statistically significant associations were observed with the greatest effect for the Memory (β = 4.055; p = 0.001; R² = 0.0065) and Attention (β = 4.136; p = 0.002; R² = 0.0047) domains. No statistically significant associations were observed between quintiles of ARFS and MMSE score in the adjusted linear regression analyses. In conclusion, a positive association was observed between diet quality and cognitive performance within this sample of older Australian adults. Further investigation of the above association over time, when follow-up data becomes available, in longitudinal analysis is recommended.     

Palm Fruit Bioactive Complex (PFBc), a Source of Polyphenols,Demonstrates Potential Benefits for Inflammaging and Related Cognitive Function

Cognitive function is a key aspect of healthy aging. Inflammation associated with normal aging, also called inflammaging is a primary risk factor for cognitive decline. A diet high in fruits and vegetable and lower in calories, particularly a Mediterranean Diet, may lower the risk of age-related cognitive decline due in part to the associated high intake of antioxidants and polyphenols. A phenolic, Palm Fruit Bioactive complex (PFBc) derived from the extraction process of palm oil from oil palm fruit (Elaeis guineensis), is reported to offset inflammation due to its high antioxidant, especially vitamin E, and polyphenol content. The benefit is thought to be achieved via the influence of antioxidants on gene expression. It is the purpose of this comprehensive review to discuss the etiology, including gene expression, of mild cognitive impairment (MCI) specific to dietary intake of antioxidants and polyphenols and to focus on the potential impact of nutritional interventions specifically PFBc has on MCI. Several in vitro, in vivo and animal studies support multiple benefits of PFBc especially for improving cognitive function via anti-inflammatory and antioxidant mechanisms. While more human studies are needed, those completed thus far support the benefit of consuming PFBc to enhance cognitive function via its anti-inflammatory antioxidant functions.     

The Hunger Games: Homeostatic State-Dependent Fluctuations in Disinhibition Measured with a Novel Gamified Test Battery

Food homeostatic states (hunger and satiety) influence the cognitive systems regulating impulsive responses, but the direction and specific mechanisms involved in this effect remain elusive. We examined how fasting, and satiety, affect cognitive mechanisms underpinning disinhibition using a novel framework and a gamified test-battery. Thirty-four participants completed the test-battery measuring three cognitive facets of disinhibition: attentional control, information gathering and monitoring of feedback, across two experimental sessions: one after overnight fasting and another after a standardised meal. Homeostatic state was assessed using subjective self-reports and biological markers (i.e., blood-derived liver-expressed antimicrobial protein 2 (LEAP-2), insulin and leptin). We found that participants who experienced greater subjective hunger during the satiety session were more impulsive in the information gathering task; results were not confounded by changes in mood or anxiety. Homeostatic state did not significantly influence disinhibition mechanisms linked to attentional control or feedback monitoring. However, we found a significant interaction between homeostatic state and LEAP-2 on attentional control, with higher LEAP-2 associated with faster reaction times in the fasted condition only. Our findings indicate lingering hunger after eating increases impulsive behaviour via reduced information gathering. These findings identify a novel mechanism that may underpin the tendency to overeat and/or engage in broader impulsive behaviours.     

Effects of Daily Matcha and Caffeine Intake on Mild Acute Psychological Stress-Related Cognitive Function in Middle-Aged and Older Adults: A Randomized Placebo-Controlled Study

Matcha, a type of green tea, has a higher amino acid content than other types of tea. We previously examined the ability of matcha to improve cognitive function in older adults and determined that continuous matcha intake improves attention and executive function. This study aimed to compare the effects of matcha and caffeine and clarify the differences between these effects. The study was registered at the University Hospital Medical Information Network (UMIN000036578). The effect of single and continuous intake was compared, and the usefulness of continuous intake was evaluated under the stress condition. The Uchida–Kraepelin test (UKT) was used to induce mild acute stress, and the Cognitrax was used to evaluate cognitive function. A single dose of caffeine improved attentional function during or after stress loading. The reduced reaction time in the Cognitrax, observed following a single dose of matcha, was likely due to caffeine. The matcha group showed an increase in the amount of work after continuous intake, whereas the caffeine group only showed an increase in the amount of work for the UKT after a single dose. Ingesting matcha with caffeine improves both attention and work performance when suffering from psychological stress compared with caffeine alone.     

On-Road Behavior in Older Drivers With Mild Cognitive Impairment

ObjectivesDementia increases the risk of unsafe driving, but this is less apparent in preclinical stages such as mild cognitive impairment (MCI). There is, however, limited detailed data on the patterns of driving errors associated with MCI. Here, we examined whether drivers with MCI exhibited different on-road error profiles compared with cognitively normal (CN) older drivers.DesignObservational.Setting and ParticipantsA total of 296 licensed older drivers [mean age 75.5 (SD = 6.2) years, 120 (40.5%) women] recruited from the community.MethodParticipants completed a health and driving history survey, a neuropsychological test battery, and an on-road driving assessment including driver-instructed and self-navigation components. Driving assessors were blind to participant cognitive status. Participants were categorized as safe or unsafe based on a validated on-road safety scale, and as having MCI based on International Working Group diagnostic criteria. Proportion of errors incurred as a function of error type and traffic context were compared across safe and unsafe MCI and CN drivers.ResultsCompared with safe CN drivers (n = 225), safe MCI drivers (n = 45) showed a similar pattern of errors in different traffic contexts. Compared with safe CN drivers, unsafe CN drivers (n = 17) were more likely to make errors in observation, speed control, lane position, and approach, and at stop/give-way signs, lane changes, and curved driving. Unsafe MCI drivers (n = 9) had additional difficulties at intersections, roundabouts, parking, straight driving, and under self-navigation conditions. A higher proportion of unsafe MCI drivers had multidomain subtype [n = 6 (67%)] than safe MCI drivers [n = 11 (25%)], odds ratio 6.2 (95% confidence interval, 1.4–29.6).Conclusion and ImplicationsAmong safe drivers, MCI and CN drivers exhibit similar on-road error profiles, suggesting driver restrictions based on MCI status alone are unwarranted. However, formal evaluation is recommended in such cases, as there is evidence drivers with multiple domains of cognitive impairment may require additional interventions to support safe driving.     

孕期胆固醇和氧化固醇与子代认知发育

胆固醇是大脑发育的重要物质基础,胚胎和胎儿发育需要母体持续转运胆固醇,氧化固醇是胆固醇的代谢物,包括胆固醇合成途径中的前体物和分结代谢过程中产生的代谢产物,可能与大脑功能密切相关。人群研究发现,孕妇血清/浆胆固醇水平与子代多动症、孤独症谱系障碍发病风险有关,但尚需进一步确证。     

Combined Effects of Cognitive Impairment and Nutritional Trajectories on Functional Recovery for Older Patients after Hip-Fracture Surgery

ObjectivesMalnutrition and cognitive impairment are associated with poor functional recovery in older adults following hip-fracture surgery. This study examined the combined effects of cognitive impairment and nutritional trajectories on postoperative functional recovery for older adults following hip-fracture surgery.DesignProspective longitudinal correlational study.Setting and ParticipantsThis study recruited 350 older adults (≥60 years of age) who received hip-fracture surgery at a 3000-bed medical center in northern Taiwan from September 2012 to March 2020.MethodsParticipant data were collected over a 2-year period after surgery for nutritional and cognitive status and activities of daily living (ADLs). Participants were grouped by type of nutritional trajectory using group-based trajectory modeling. Generalized estimating equations analyzed associations between trajectory groups/cognitive status at discharge and performance of ADLs.ResultsNutritional trajectories best fit a 3-group trajectory model: malnourished (19%), at-risk of malnutrition (40%), and well-nourished (41%). Nutritional status for the malnourished group declined from 12 months to 24 months following surgery; nutritional status remained stable for at-risk of malnutrition and well-nourished groups. Interactions for cognitive impairment-by-nutritional status were significant: the malnourished + intact cognition subgroup had significantly better ADLs than the malnourished + cognitive impairment subgroup (b = 27.1, 95% confidence interval = 14.0–40.2; P < .001). For at-risk of malnutrition and well-nourished groups, there were no significant differences between cognitive impairment and intact cognition in ADLs. These findings suggest that nutritional status may buffer the negative effect of cognitive impairment on ADLs.Conclusions and ImplicationsBetter nutritional status over time for older adults following hip fracture can protect against adverse influences of cognitive impairment on ADLs during postoperative recovery. Participants with malnutrition and cognitive impairment had the poorest ADLs. These findings suggest interventions tailored to improving nutritional status may improve recovery for older adults following hip-fracture surgery.     

飞行人员场依存性-独立性认知方式分析

目的：分析现役飞行人员的认知方式,为招飞、选拔工作提供依据。方法：用棒框仪对152名飞行人员进行测试,并用SPSS6．0软件包进行统计处理。结果：不同机种、不同飞行等级的飞行人员认知方式无显著差异;但相关分析显示认知方式分值与飞行人员年龄呈正相关,而与飞行等级呈负相关;31－35岁组与36－40岁及41岁以上组比较其差异均显著（P＜0．05）,并且此年龄段的优秀飞行人员占全部优秀飞行人员的63％,占此年龄段全部飞行人员的77％,表明31－35岁的飞行人员是技术和认知方式均趋向成熟的最佳年龄。结论：场独立性的认知特点对于掌握飞行技能有重要意义,战斗机飞行人员所具备的认知方式应以31－35岁现役飞行人员为标准,并作为飞行学员和特殊飞行人员选拔的依据。