-
1.
Homocysteine: A modifiable culprit of cognitive impairment for us to conquer?
Ji, Y, Lyu, P, Jin, W, Li, X, Li, X, Dong, Y
Journal of the neurological sciences. 2019;:128-136
Abstract
BACKGROUND Cognitive impairment, including mild cognitive impairment and its progressive deterioration to dementia, results in great hazards to the patient and the surrounding society. While some of the risk factors are unmodifiable, such as age, lower educational attainment, and genetic factors, another proposed one-homocysteine, an amino acid produced in the methylation cycle of protein metabolism is modifiable by cheap and easily accessible B-vitamins treatments in medical practice. OBJECTIVE AND METHODS To investigate the relationship between homocysteine and cognitive impairment, elucidate the underlying pathophysiological mechanisms and exploit any potential therapeutic values of homocysteine-lowering treatments in prevention and/or treatment in cognitive decline, we searched on the PUBMED databases surrounding around the physiological homocysteine metabolism, detrimental effects of abnormal homocysteine concentrations on the brain, and review observational and interventional experiments to date estimating the relationship between homocysteine and cognitive impairment with relatively powerful evidence. RESULTS Intrinsic and environmental factors help maintain the normal homocysteine concentrations, and pathological homocysteine concentrations exert adverse effects mediated by cellular and vascular pathways. Although many observational studies have suggested a causal link between hyperhomocysteinemia and cognitive impairment, the majority of randomized controlled trials failed to observe marked benefits on cognition by homocysteine-lowering treatments using B-vitamins, partly arising from some design limitations including: not identifying individuals at earlier stages of cognitive impairment who are most likely to benefit, overlooking any latent safety hazards of multiple vitamin supplementation, lack of sensitive and domain-specific cognitive tests, and interference of other underappreciated factors. CONCLUSION More studies are required to better explain the related pathophysiological mechanisms, improve experimental methods, and investigate the preventive or/and therapeutic effects of homocysteine-lowering strategies on cognitive impairment.
-
2.
MIND not Mediterranean diet related to 12-year incidence of cognitive impairment in an Australian longitudinal cohort study.
Hosking, DE, Eramudugolla, R, Cherbuin, N, Anstey, KJ
Alzheimer's & dementia : the journal of the Alzheimer's Association. 2019;(4):581-589
Abstract
INTRODUCTION Associations between the Mediterranean-DASH diet Intervention for Neurological Delay (MIND) diet and incidence of cognitive impairment have not been evaluated outside the United States. METHODS We investigated MIND and Mediterranean diet relations with 12-year incidence of Alzheimer's disease/Vascular dementia (National Institute of Neurological Disorders criteria) and mild cognitive impairment (Winbald criteria) in the Personality and Total Health (PATH) Through Life cohort (n = 1220) set in Canberra, Australia: wave-1 2001-2002; wave-2 2005-2006; wave-3 2009-2010; and wave-4 2013-2014. MIND diet and two alternate Mediterranean diet scores were calculated from the baseline food frequency questionnaire responses. Higher dietary scores signified greater adherence. RESULTS In adjusted logistic regression models, 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. DISCUSSION Preliminary evidence suggests that protective effects of the MIND diet are geographically generalizable. Additional prospective studies are needed in diverse samples to determine the relative effects of the MIND and the Mediterranean diets against cognitive decline.
-
3.
Vitamin and mineral supplementation for preventing dementia or delaying cognitive decline in people with mild cognitive impairment.
McCleery, J, Abraham, RP, Denton, DA, Rutjes, AW, Chong, LY, Al-Assaf, AS, Griffith, DJ, Rafeeq, S, Yaman, H, Malik, MA, et al
The Cochrane database of systematic reviews. 2018;(11):CD011905
-
-
Free full text
-
Abstract
BACKGROUND Vitamins and minerals have many functions in the nervous system which are important for brain health. It has been suggested that various different vitamin and mineral supplements might be useful in maintaining cognitive function and delaying the onset of dementia. In this review, we sought to examine the evidence for this in people who already had mild cognitive impairment (MCI). OBJECTIVES To evaluate the effects of vitamin and mineral supplementation on cognitive function and the incidence of dementia in people with mild cognitive impairment. SEARCH METHODS We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group's (CDCIG) specialised register, as well as MEDLINE, Embase, PsycINFO, CENTRAL, CINAHL, LILACs, Web of Science Core Collection, ClinicalTrials.gov, and the WHO Portal/ICTRP, from inception to 25 January 2018. SELECTION CRITERIA We included randomised or quasi-randomised, placebo-controlled trials which evaluated orally administered vitamin or mineral supplements in participants with a diagnosis of mild cognitive impairment and which assessed the incidence of dementia or cognitive outcomes, or both. We were interested in studies applicable to the general population of older people and therefore excluded studies in which participants had severe vitamin or mineral deficiencies. DATA COLLECTION AND ANALYSIS We sought data on our primary outcomes of dementia incidence and overall cognitive function and on secondary outcomes of episodic memory, executive function, speed of processing, quality of life, functional performance, clinical global impression, adverse events, and mortality. We conducted data collection and analysis according to standard Cochrane systematic review methods. We assessed the risk of bias of included studies using the Cochrane 'Risk of bias' assessment tool. We grouped vitamins and minerals according to their putative mechanism of action and, where we considered it to be clinically appropriate, we pooled data using random-effects methods. We used GRADE methods to assess the overall quality of evidence for each comparison and outcome. MAIN RESULTS We included five trials with 879 participants which investigated B vitamin supplements. In four trials, the intervention was a combination of vitamins B6, B12, and folic acid; in one, it was folic acid only. Doses varied. We considered there to be some risks of performance and attrition bias and of selective outcome reporting among these trials. Our primary efficacy outcomes were the incidence of dementia and scores on measures of overall cognitive function. None of the trials reported the incidence of dementia and the evidence on overall cognitive function was of very low-quality. There was probably little or no effect of B vitamins taken for six to 24 months on episodic memory, executive function, speed of processing, or quality of life. The evidence on our other secondary clinical outcomes, including harms, was very sparse or very low-quality. There was evidence from one study that there may be a slower rate of brain atrophy over two years in participants taking B vitamins. The same study reported subgroup analyses based on the level of serum homocysteine (tHcy) at baseline and found evidence that B vitamins may improve episodic memory in those with tHcy above the median at baseline.We included one trial (n = 516) of vitamin E supplementation. Vitamin E was given as 1000 IU of alpha-tocopherol twice daily. We considered this trial to be at risk of attrition and selective reporting bias. There was probably no effect of vitamin E on the probability of progression from MCI to Alzheimer's dementia over three years (HR 1.02; 95% CI 0.74 to 1.41; n = 516; 1 study, moderate-quality evidence). There was also no evidence of an effect at intermediate time points. The available data did not allow us to conduct analyses, but the authors reported no significant effect of three years of supplementation with vitamin E on overall cognitive function, episodic memory, speed of processing, clinical global impression, functional performance, adverse events, or mortality (five deaths in each group). We considered this to be low-quality evidence.We included one trial (n = 256) of combined vitamin E and vitamin C supplementation and one trial (n = 26) of supplementation with chromium picolinate. In both cases, there was a single eligible cognitive outcome, but we considered the evidence to be very low-quality and so could not be sure of any effects. AUTHORS' CONCLUSIONS The evidence on vitamin and mineral supplements as treatments for MCI is very limited. Three years of treatment with high-dose vitamin E probably does not reduce the risk of progression to dementia, but we have no data on this outcome for other supplements. Only B vitamins have been assessed in more than one RCT. There is no evidence for beneficial effects on cognition of supplementation with B vitamins for six to 24 months. Evidence from a single study of a reduced rate of brain atrophy in participants taking vitamin B and a beneficial effect of vitamin B on episodic memory in those with higher tHcy at baseline warrants attempted replication.
-
4.
Diet, nutrition and the ageing brain: current evidence and new directions.
Moore, K, Hughes, CF, Ward, M, Hoey, L, McNulty, H
The Proceedings of the Nutrition Society. 2018;(2):152-163
Abstract
Globally populations are ageing. By 2050, it is estimated that there will be two billion people aged 60 years or over, of which 131 million are projected to be affected by dementia, while depression is predicted to be the second leading cause of disability worldwide by 2020. Preventing or delaying the onset of these disorders should therefore be a public health priority. There is some evidence linking certain dietary patterns, particularly the Mediterranean diet, with a reduced risk of dementia and depression. Specific dietary components have also been investigated in relation to brain health, with emerging evidence supporting protective roles for n-3 PUFA, polyphenols, vitamin D and B-vitamins. At this time, the totality of evidence is strongest in support of a role for folate and the metabolically related B-vitamins (vitamin B12, vitamin B6 and riboflavin) in slowing the progression of cognitive decline and possibly reducing the risk of depression in ageing. Future studies incorporating new technologies, such as MRI and magnetoencephalography, offer much promise in identifying effective nutrition interventions that could reduce the risk of cognitive and mental disorders. This review will explore the ageing brain and the emerging evidence linking diet and specific nutrients with cognitive function and depression in ageing, with the potential to develop strategies that could improve quality of life in our ageing population.
-
5.
The possible factors affecting microglial activation in cases of obesity with cognitive dysfunction.
Chunchai, T, Chattipakorn, N, Chattipakorn, SC
Metabolic brain disease. 2018;(3):615-635
Abstract
Obesity has reached epidemic proportions in many countries around the world. Several studies have reported that obesity can lead to the development of cognitive decline. There is increasing evidence to demonstrate that microglia play a crucial role in cognitive decline in cases of obesity, Alzheimer's disease and also in the aging process. Although there have been several studies into microglia over the past decades, the mechanistic link between microglia and cognitive decline in obese models is still not fully understood. In this review, the current available evidence from both in vitro and in vivo investigations regarding the association between the alteration in microglial activity in different obese models with respect to cognition are included. The metabolite profiles from obesity, adiposity, dietary and hormone affected microglial activation and its function in the brain are comprehensively summarized. In addition, the possible roles of microglial activation in relation to cognitive dysfunction are also presented and discussed. To ensure a balanced perspective controversial reports regarding these issues are included and discussed.
-
6.
Cerebellar injury in preterm infants.
Tam, EWY
Handbook of clinical neurology. 2018;:49-59
Abstract
Although preterm birth is best known to result in adverse neurodevelopmental outcomes through injury of the supratentorial structures, including intraventricular hemorrhage and periventricular leukomalacia, the cerebellum has become increasingly recognized as an important target for injury and adverse motor and cognitive outcomes. Undergoing the most dramatic growth during the preterm period, the cerebellum is vulnerable to large and small hemorrhages, as well as hypoplasia resulting from a number of potentially modifiable risk factors. These factors include contact with intraventricular blood, crossed cerebrocerebellar diaschisis, postnatal glucocorticoid exposure, pain and opioid exposure, nutrition and somatic growth, cardiorespiratory factors, and socioeconomic status. Strategies targeting these factors may result in prevention of the motor and cognitive deficits seen after cerebellar hemorrhage or hypoplasia.
-
7.
Adherence to Mediterranean diet and subjective cognitive function in men.
Bhushan, A, Fondell, E, Ascherio, A, Yuan, C, Grodstein, F, Willett, W
European journal of epidemiology. 2018;(2):223-234
Abstract
Benefits of a Mediterranean diet for cognition have been suggested, but epidemiologic studies have been relatively small and of limited duration. To prospectively assess the association between long-term adherence to a Mediterranean dietary pattern and self-reported subjective cognitive function (SCF). Prospective observational study. The Health Professionals' Follow-up Study, a prospective cohort of 51,529 men, 40-75 years of age when enrolled in 1986, of whom 27,842 were included in the primary analysis. Mediterranean diet (MD) score, computed from the mean of five food frequency questionnaires, assessed every 4 years from 1986 to 2002. Self-reported SCF assessed by a 6-item questionnaire in 2008 and 2012, and validated by association with genetic variants in apolipoprotein-4. Using the average of 2008 and 2012 SCF scores, 38.0% of men were considered to have moderate memory scores and 7.3% were considered to have poor scores. In a multivariate model, compared with men having a MD score in the lowest quintile, those in the highest quintile had a 36% lower odds of a poor SCF score (odds ratio 0.64, 95% CI 0.55-0.75; P, trend < 0.001) and a 24% lower odds of a moderate SCF score (OR 0.76, 95% CI 0.70-0.83; P, trend < 0.001). Both remote and more recent diet contributed to this relation. Associations were only slightly weaker using baseline dietary data and a lag of 22 years. Long-term adherence to the Mediterranean diet pattern was strongly related to lower subjective cognitive function. These findings provide further evidence that a healthy dietary pattern may prevent or delay cognitive decline.
-
8.
The Role of Nutrition in Cognitive Function and Brain Ageing in the Elderly.
Gardener, SL, Rainey-Smith, SR
Current nutrition reports. 2018;(3):139-149
Abstract
PURPOSE OF REVIEW The purposes of this review were to examine literature published over the last 5 years and to evaluate the role of nutrition in cognitive function and brain ageing, focussing on the Mediterranean diet (MeDi), Dietary Approaches to Stop Hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diets. RECENT FINDINGS Results suggest that higher adherence to a healthy dietary pattern is associated with preservation of brain structure and function as well as slower cognitive decline, with the MIND diet substantially slowing cognitive decline, over and above the MeDi and DASH diets. Whilst results to-date suggest adherence to a healthy diet, such as the MeDi, DASH, or MIND, is an important modifiable risk factor in the quest to develop strategies aimed at increasing likelihood of healthy brain ageing, further work is required to develop dietary guidelines with the greatest potential benefit for public health; a research topic of increasing importance as the world's population ages.
-
9.
Mediterranean Diet and Cognitive Status in Free-Living Elderly: A Cross-Sectional Study in Northern Italy.
De Amicis, R, Leone, A, Foppiani, A, Osio, D, Lewandowski, L, Giustizieri, V, Cornelio, P, Cornelio, F, Fusari Imperatori, S, Cappa, SF, et al
Journal of the American College of Nutrition. 2018;(6):494-500
Abstract
OBJECTIVE Few data are available on the Italian elderly population with regard to adherence to the Mediterranean diet (MD) and cognitive impairment. Our aim was to investigate adherence to the MD and its association with cognitive function in an Italian urban sample. METHODS A cross-sectional study of 279 participants aged ≥ 65 years (80 men, 199 women) was carried out at a nutritional center. Adherence to the MD was evaluated using a 14-item questionnaire. Cognitive function was assessed with the Mini-Mental State Examination (MMSE). RESULTS The clinical and nutritional assessments performed revealed 30.1% to have a dietary pattern in accordance with the MD; 13.6% had suspected or mild cognitive impairment (MMSE score ≤ 23). The MD pattern was associated with a lower risk of cognitive impairment (odds ratio [OR] = 0.39; 95% confidence interval [CI], 0.15-0.99; p = 0.045), as was the consumption of wine (OR = 0.37; 95% CI, 0.16-0.84; p = 0.018) and nuts (OR = 0.30; 95% CI, 0.13-0.69, p = 0.005). No association was found with other food groups. CONCLUSION A closer adherence to the MD was associated with a better cognitive status. Further cohort studies and randomized controlled trials are warranted.
-
10.
Vitamin C Status and Cognitive Function: A Systematic Review.
Travica, N, Ried, K, Sali, A, Scholey, A, Hudson, I, Pipingas, A
Nutrients. 2017;(9)
Abstract
Vitamin C plays a role in neuronal differentiation, maturation, myelin formation and modulation of the cholinergic, catecholinergic, and glutaminergic systems. This review evaluates the link between vitamin C status and cognitive performance, in both cognitively intact and impaired individuals. We searched the PUBMED, SCOPUS, SciSearch and the Cochrane Library from 1980 to January 2017, finding 50 studies, with randomised controlled trials (RCTs, n = 5), prospective (n = 24), cross-sectional (n = 17) and case-control (n = 4) studies. Of these, 36 studies were conducted in healthy participants and 14 on cognitively impaired individuals (including Alzheimer's and dementia). Vitamin C status was measured using food frequency questionnaires or plasma vitamin C. Cognition was assessed using a variety of tests, mostly the Mini-Mental-State-Examination (MMSE). In summary, studies demonstrated higher mean vitamin C concentrations in the cognitively intact groups of participants compared to cognitively impaired groups. No correlation between vitamin C concentrations and MMSE cognitive function was apparent in the cognitively impaired individuals. The MMSE was not suitable to detect a variance in cognition in the healthy group. Analysis of the studies that used a variety of cognitive assessments in the cognitively intact was beyond the scope of this review; however, qualitative assessment revealed a potential association between plasma vitamin C concentrations and cognition. Due to a number of limitations in these studies, further research is needed, utilizing plasma vitamin C concentrations and sensitive cognitive assessments that are suitable for cognitively intact adults.