Selected Micronutrients in Cognitive Decline Prevention and Therapy

Milk fat globule membrane and its polar lipids: reviewing preclinical and clinical trials on cognition

In most parts of the world, life expectancy is increasing thanks to improved healthcare, public health policies, nutrition, and treatment. This increase in lifespan is often not accompanied by an increase in health span, which severely affects people as they age. One notable consequence of this is the increasing prevalence of neurodegenerative diseases such as mild cognitive impairment, dementia, and Alzheimer's disease. Therefore, dietary and pharmaceutical measures must be taken to reduce the burden of such pathologies. Among the different types of nutrients found in the diet, lipids and especially polar lipids are very important for cognition due to their abundance in the brain. Amid the most studied sources of polar lipids, milk fat globule membrane (MFGM) stands out as it is abundant in industrial by-products such as buttermilk. In this narrative review, we discuss the latest, i.e. less than five years old, scientific evidence on the use of MFGM and its polar lipids in cognitive neurodevelopment in early life and their potential effect in preventing neurodegeneration in old age. We conclude that MFGM is an interesting, abundant and exploitable source of relatively inexpensive bioactive molecules that could be properly formulated and utilized in the areas of neurodevelopment and cognitive decline. Sufficiently large randomized controlled trials are required before health-related statements can be made. However, research in this area is progressing rapidly and the evidence gathered points to biological, health-promoting effects.

Causal Relationship Between Basal Metabolic Rate and Alzheimer's Disease: A Bidirectional Two-sample Mendelian Randomization Study

INTRODUCTION

Objective observational studies have shown that basal metabolic rate (BMR) decreases in patients with Alzheimer's disease (AD), but the causal relationship between BMR and AD has not been established. We determined the causal relationship between BMR and AD by two-way Mendelian randomization (MR) and investigated the impact of factors associated with BMR on AD.

METHODS

We obtained BMR (n = 454,874) and AD from a large genome-wide association study (GWAS) database (21,982 patients with AD, 41,944 controls). The causal relationship between AD and BMR was investigated using two-way MR. Additionally, we identified the causal relationship between AD and factors related with BMR, hyperthyroidism (hy/thy) and type 2 diabetes (T2D), height and weight.

RESULTS

BMR had a causal relationship with AD [451 single nucleotide polymorphisms (SNPs), odds ratio (OR) 0.749, 95% confidence intervals (CIs) 0.663-0.858, P = 2.40E-03]. There was no causal relationship between hy/thy or T2D and AD (P > 0.05). The bidirectional MR showed that there was also a causal relationship between AD and BMR (OR 0.992, Cls 0.987-0.997, N_SNPs18, P = 1.50E-03). BMR, height and weight have a protective effect on AD. Based on MVMR analysis, we found that genetically determined height and weight may be adjusted by BMR to have a causal effect on AD, not height and weight themselves.

CONCLUSION

Our study showed that higher BMR reduced the risk of AD, and patients with AD had a lower BMR. Because of a positive correlation with BMR, height and weight may have a protective effect on AD. The two metabolism-related diseases, hy/thy and T2D, had no causal relationship with AD.

Milk fat globule membrane concentrate as a nutritional supplement prevents age-related cognitive decline in old rats: A lipidomic study of synaptosomes

Aging is associated with a decline in cognitive abilities, mainly in memory and executive functioning. A similar but premature deterioration in cognitive capacities is the hallmark of mild cognitive impairment, Alzeimer's disease and dementia. The biochemical mechanisms that cause these neurodegenerative disorders are poorly understood. However, some evidence suggests that insufficient dietary intakes of some phospholipids could impact on brain function and increase the risk of future cognitive impairment and dementia. We evaluated the cognitive and biochemical effects of supplementation with a milk fat globule membrane (MFGM) concentrate in aged rats. We observed that, compared to control animals, MFGM supplemented rats showed enhanced spatial working memory, but both groups exhibited similar reference spatial learning and emotional memory abilities. No significant differences between BDNF levels in the hippocampus and frontal cortex of treated rats as compared to controls were found. The nootropic effects observed were accompanied by significant changes in the lipid composition of synaptic membranes. MFGM supplementation increased the levels of EPA and DHA acids as well as the plasmalogens content in the synaptosomes isolated from the hippocampus (Synapt-HP) and the frontal cortex (Synapt-FC). In addition enhanced levels of phosphatidyl serine (PS), particularly PS(18:1/18:1), and phosphatidyl inositol (PI) molecular species were observed in Synapt-HP and Synapt-FC of treated animals.Lipidomic analysis also revealed greater concentration of phosphatidyl ethanolamine (PE) molecular species containing very long-chain fatty acids and PE plasmenyls in Synapt-HP as well as an increase of the SM content in Synapt-FC from the MFGM group. Although further studies are needed to confirm the underlying mechanism (individual or synergistic), these results suggest that MFGM supplementation could be employed as a dietary implement to restore the proper cerebral concentration of some bioactive lipids and prevent or slow the progression of age-related cognitive impairment.

Strategies to protect against age-related mitochondrial decay: Do natural products and their derivatives help?

Mitochondria serve vital roles critical for overall cellular function outside of energy transduction. Thus, mitochondrial decay is postulated to be a key factor in aging and in age-related diseases. Mitochondria may be targets of their own decay through oxidative damage. However, treating animals with antioxidants has been met with only limited success in rejuvenating mitochondrial function or in increasing lifespan. A host of nutritional strategies outside of using traditional antioxidants have been devised to promote mitochondrial function. Dietary compounds are under study that induce gene expression, enhance mitochondrial biogenesis, mitophagy, or replenish key metabolites that decline with age. Moreover, redox-active compounds may now be targeted to mitochondria which improve their effectiveness. Herein we review the evidence that representative dietary effectors modulate mitochondrial function by stimulating their renewal or reversing the age-related loss of key metabolites. While in vitro evidence continues to accumulate that many of these compounds benefit mitochondrial function and/or prevent their decay, the results using animal models and, in some instances human clinical trials, are more mixed and sometimes even contraindicated. Thus, further research on optimal dosage and age of intervention are warranted before recommending potential mitochondrial rejuvenating compounds for human use.

Mediterranean diet and cognitive function: From methodology to mechanisms of action

The traditional Mediterranean diet (MedDiet), rich in minimally processed plant foods and fish, has been widely recognized to be one of the healthiest diets. Data from multiple randomized clinical trials have demonstrated its powerful effect against oxidative stress, inflammation and the development and progression of cardiovascular disease, type 2 diabetes, and other metabolic conditions that play a crucial role in the pathogenesis of neurodegenerative diseases. The protecting effects of the MedDiet against cognitive decline have been investigated in several observational and experimental studies. Data from observational studies suggest that the MedDiet may represent an effective dietary strategy for the early prevention of dementia, although these findings require further substantiation in clinical trials which have so far produced inconclusive results. Moreover, as we discuss in this review, accumulating data emphasizes the importance of: 1) maintaining an optimal nutritional and metabolic status for the promotion of healthy cognitive aging, and 2) implementing cognition-sparing dietary and lifestyle interventions during early time-sensitive windows before the pathological cascades turn into an irreversible state. In summary, components of the MedDiet pattern, such as essential fatty acids, polyphenols and vitamins, have been associated with reduced oxidative stress and the current evidence from observational studies seems to assign to the MedDiet a beneficial role in promoting brain health; however, results from clinical trials have been inconsistent. While we advocate for longitudinal analyses and for larger and longer clinical trials to be conducted, we assert our interim support to the use of the MedDiet as a protective dietary intervention for cognitive function based on its proven cardiovascular and metabolic benefits.

Weight Loss and the Risk of Dementia: A Meta-analysis of Cohort Studies

BACKGROUND

Weight loss is a common phenomenon among the elderly and is identified as an important indicator of health status. Many epidemiology studies have investigated the association between weight loss and dementia, but the results were inconsistent.

OBJECTIVE

To examine and determine the association between weight loss and the risk of dementia.

METHODS

Eligible cohort studies involving weight loss and dementia were searched from PubMed, Embase, and Ovid databases through October 2018. Pooled relative risks (RRs) with its 95% confidence intervals (CIs) were used to estimate the effects of weight loss on the risk of dementia. Subgroup and sensitivity analyses were performed to explore the potential sources of heterogeneity. The Begg's test and Egger's test were used to assess the publication bias.

RESULTS

A total of 20 cohort studies with 38,141 participants were included in this meta-analysis. Weight loss was significantly associated with the risk of dementia (RR=1.26, 95% CI=1.15-1.38). BMI decline ≥0.8 units (RR=1.31, 95% CI=1.10-1.56) and ≥4% (RR=1.19, 95% CI=1.03-1.38) could increase the risk of dementia. The risk of all-cause dementia for people with weight loss increased by 31% (RR=1.31, 95% CI=1.15-1.49), and 25% higher for incident Alzheimer's disease (RR=1.25, 95% CI=1.07-1.46). Weight loss in participants with normal weight had a similar dementia risk (RR=1.21, 95% CI=1.06-1.38) with the overweight individuals (RR=1.22, 95% CI=1.11-1.34).

CONCLUSION

Weight loss may be associated with an increased risk of dementia, especially for Alzheimer's disease. Maintaining weight stability may help prevent dementia.

Regulation of Reactive Oxygen Species-Mediated Damage in the Pathogenesis of Schizophrenia

The biochemical integrity of the brain is paramount to the function of the central nervous system, and oxidative stress is a key contributor to cerebral biochemical impairment. Oxidative stress, which occurs when an imbalance arises between the production of reactive oxygen species (ROS) and the efficacy of the antioxidant defense mechanism, is believed to play a role in the pathophysiology of various brain disorders. One such disorder, schizophrenia, not only causes lifelong disability but also induces severe emotional distress; however, because of its onset in early adolescence or adulthood and its progressive development, consuming natural antioxidant products may help regulate the pathogenesis of schizophrenia. Therefore, elucidating the functions of ROS and dietary antioxidants in the pathogenesis of schizophrenia could help formulate improved therapeutic strategies for its prevention and treatment. This review focuses specifically on the roles of ROS and oxidative damage in the pathophysiology of schizophrenia, as well as the effects of nutrition, antipsychotic use, cognitive therapies, and quality of life on patients with schizophrenia. By improving our understanding of the effects of various nutrients on schizophrenia, it may become possible to develop nutritional strategies and supplements to treat the disorder, alleviate its symptoms, and facilitate long-term recovery.

Improving Mental Performance in an Athletic Population with the Use of Ārepa®, a Blackcurrant Based Nootropic Drink: A Randomized Control Trial

A range of dietary bioactive ingredients have claimed to improve mental clarity and reduce fatigue, including blackcurrant, pine bark, and l-theanine. These active ingredients provide a good source of dietary polyphenols which could be useful in reducing mental fatigue in a sports setting. The aim of the investigation was to test the effect of Ārepa^® a blackcurrant-based nootropic-drink also containing pine-bark and l-theanine (BC+), on mental clarity in a sport setting. Twenty-three rugby league players completed a cross-over design, randomized, double-blind, controlled trial. Intervention and control phases lasted 7 days, with a washout in between. Cognition was assessed pre and post intervention following a standardized training session. Our study found the total score, accuracy, and average time per response scores improved significantly more after drinking the BC+ drink (p = 0.001, 0.003, and 0.043 respectively). The BC+ improved the perception that participants were reliable (p = 0.02) and less distracted (p = 0.03), while placebo supplementation increased participant perception they could control their nervousness (p = 0.03). Thematic analysis of post-trial questionnaire indicated participants found the BC+ sour, most reported no side effects, and opinion on which drink was more effective was not unanimous. The results indicate that the BC+ drink may be useful for athletes.

Concentrates of buttermilk and krill oil improve cognition in aged rats

Cognitive decline is one of the hallmarks of aging and can vary from mild cognitive impairment to dementia to Alzheimer's disease. In addition to some lifestyle interventions, there is room for the use of nutraceuticals/functional foods as pharma-nutritional tools to lessen the burden of cognitive decline before it worsens. We previously reported the promising molecular actions of milk fat globule membranes and krill oil concentrates in a rat model of aging. In this study, we concentrated on the activities on cognition, using an array of validated tests. We also performed lipidomic analyses of plasma, erythrocytes, and different brain areas. We report lower emotional memory (contextual fear conditioning) in aged rats supplemented with concentrates of polar lipids from buttermilk or krill oil at doses that approximate human consumption. No other behavioral parameter was significantly influenced by the supplements, calling for further research to confirm or not the purported salubrious activities of polar lipids, namely those rich in ω3 long-chain polyunsaturated fatty acids, on cognitive decline.

Chemical composition and health properties of coffee and coffee by-products

Coffee can be an ally in the fight against diseases such as type 2 diabetes, cancer, hepatic injury, cirrhosis, depression, suicidal behavior, and neurological and cardiovascular disorders. The properties of coffee also favor gastrointestinal tract and gut microbiota establishment. Coffee bioactive components include phenolic compounds (chlorogenic acids, cafestol and kahweol), alkaloids (caffeine and trigonelin), diterpenes (cafestol and kahweol) and other secondary metabolites. The image of coffee as a super functional food has helped to increase coffee consumption across the globe. This chapter addresses the main health promotion mechanisms associated with coffee consumption. Related topics on coffee production chain, world consumption and reuse of coffee by-products in the production of high-value-adding molecules with potential applications in the food industry are addressed and discussed.

Dietary Micronutrients Intake Status among Chinese Elderly People Living at Home: Data from CNNHS 2010-2012

The aim of this study was to examine the status of usual dietary micronutrient intakes among Chinese elderly living at home. The data was based on China National Nutrition and Health Survey (CNNHS) 2010-2012. We analyzed data from the participants aged 60-year-old and more (n = 16,612) living at home, who provided dietary data on three days 24 h dietary survey combining with the household weighing method. The means and distribution percentiles for usual intakes of dietary micronutrients were estimated using the Multiple Source Method (MSM). The prevalence of inadequacy for the selected micronutrients was expressed using the proportion of individuals with usual intakes below the Estimated Average Requirement (EAR). For vitamin E, sodium and potassium, the means and the distribution of intakes were compared to the Adequate Intake (AI) level. Usual dietary intakes of most micronutrients were inadequate in the participants, especially folate, calcium, vitamin B6 and vitamin B2, with the prevalence of inadequacy more than 90%. However, dietary sodium intake was extremely high with an average usual intake of 4702 mg/day. The usual dietary intakes of all selected micronutrients in old males were higher than females, and the prevalence of inadequacy of most micronutrients was higher in old women (p < 0.01). The subjects aged 60-74 years tended to have higher usual dietary micronutrient intakes and lower prevalence of inadequate micronutrients than those aged 75 years and over (p < 0.01). Higher usual dietary intakes and lower prevalence of inadequacy of most micronutrients were found in the elderly living in the southern region (p < 0.01). The average usual intakes of most micronutrients declined with socioeconomic status. The prevalence of inadequate vitamin A, B2, C, calcium and selenium below EAR increased with socioeconomic status (p < 0.01, p for trend < 0.01). Thus, essential micronutrients insufficient intake is a public health concern among Chinese community-dwelling old population, especially the females, older people, the elderly in undeveloped areas or living in northern regions. Nutrition education and appropriate approach should be undertaken to address these problems.

Modulating Effect of Diet on Alzheimer's Disease

As life expectancy is growing, neurodegenerative disorders, such as Alzheimer's disease, are increasing. This disease is characterised by the accumulation of intracellular neurofibrillary tangles formed by hyperphosphorylated tau protein, senile plaques composed of an extracellular deposit of β-amyloid peptide (Aβ), and neuronal loss. This is accompanied by deficient mitochondrial function, increased oxidative stress, altered inflammatory response, and autophagy process impairment. The present study gathers scientific evidence that demonstrates that specific nutrients exert a direct effect on both Aβ production and Tau processing and their elimination by autophagy activation. Likewise, certain nutrients can modulate the inflammatory response and the oxidative stress related to the disease. However, the extent to which these effects come with beneficial clinical outcomes remains unclear. Even so, several studies have shown the benefits of the Mediterranean diet on Alzheimer's disease, due to its richness in many of these compounds, to which can be attributed their neuroprotective properties due to the pleiotropic effect they show on the aforementioned processes. These indications highlight the potential role of adequate dietary recommendations for clinical management of both Alzheimer's diagnosed patients and those in risk of developing it, emphasising once again the importance of diet on health.

Tea, cocoa, coffee, and affective disorders: vicious or virtuous cycle?

BACKGROUND

The prevalence of psychiatric disorders is increasing worldwide, which underscores the importance of increasing research in this field, in terms of better detection, prevention based on improvement of lifestyle and diet, and effectiveness of treatment. Increasing evidence suggest that diet and exercise can affect proper neuronal development and physiology and protect the brain from neurological illnesses or injuries. Of note, cocoa, tea, and coffee are being actively investigated because they are rich in (poly)phenolic compounds that can modulate mental health, namely brain plasticity, behavior, mood, depression, and cognition.

METHODS

We here systematically review human studies conducted on tea, cocoa, and coffee as related to affective disorders such as depression and anxiety. We carried out a systematic literature search in April 2016, using MEDLINE, on data from the last 10 years. After screening 955 articles, we selected 17 articles that met the criteria of being human studies and that used whole foods or their components.

RESULTS

The results of our systematic review indicate that consumption of tea, cocoa, or coffee might have protective effects against depression.

CONCLUSIONS

Even though this is encouraging, it should be underscored that the near totality of the current evidence comes from observational studies. Ad-hoc human trials and mechanistic, basic science studies are needed before we can provide sound advice to the public.