Effect of the replacement of dietary vegetable oils with a low dose of extravirgin olive oil in the Mediterranean Diet on cognitive functions in the elderly

Mediterranean diet enriched with olive oil shows no consistent benefits on cardiometabolic and anthropometric parameters: a systematic review with meta-analysis of randomized controlled trials

PURPOSE

Cardiovascular disease (CVD) is the primary cause of death worldwide but there is a variation in its burden across some nations that seems to be related to dietary habits. Mediterranean populations have lower rates of morbidity and mortality from CVD. Thus, this systematic review and meta-analysis aimed to assess the impacts of the Mediterranean diet (MedDiet) enriched with olive oil on blood lipids, glycemic indices, blood pressure, and anthropometric indices.

METHODS

A comprehensive search of the Web of Science, PubMed (MEDLINE), Scopus, Cochrane Library, Google Scholar, Embase, and CINAHL databases until March 2024 was conducted to identify clinical trials studying the effects of MedDiet enriched with olive oil on the aforementioned parameters.

RESULTS

In total, 3303 records were retrieved. A total of 18 clinical trials met the inclusion criteria after records were screened for eligibility. According to the pooled analysis from the random-effects model, the MedDiet enriched with olive oil significantly reduced triglycerides (TG) compared with the control group (WMD = -2.40 mg/dl; 95%CI, -4.533 to -0.262; P = 0.027). Strong heterogeneity was observed. Sensitivity analysis did not change our results and no significant effect of any trial on the overall effect sizes of all variables were found. There was a concern about the reporting bias for some studies which reported some main outcomes.

CONCLUSION

MedDiet enriched with olive oil showed no consistent effects on any of the reported markers of cardiovascular health except on TG.

SYSTEMATIC REVIEW REGISTRATION

CRD42023424641.

Effects of saturated and monounsaturated fatty acids on cognitive impairment: evidence from Mendelian randomization study

BACKGROUND

Prior observational studies have suggested correlations between saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) with cognitive function. However, causal relationships remains unclear.

METHODS

We assessed the causal impact of two SFAs (palmitic acid [PA] and stearic acid [SA]) and two MUFAs (oleic acid [OA] and palmitoleic acid [POA]) on cognitive function-related traits, and dementia-related traits by univariable Mendelian randomization (UVMR) and multivariable Mendelian randomization (MVMR) analyses.

RESULTS

UVMR indicated β of 0.060 (P = 4.05E-06) for cognitive performance score and 0.066 (P = 4.21E-04) for fluid intelligence per standard deviation (SD) increase in OA level. MVMR indicated: (i) β of -0.608 (P = 8.37E-05) for fluid intelligence score per SD increase in POA; (ii) β of 0.074 (P = 0.018) for fluid intelligence score per SD increase in OA; (iii) β of 0.029 (P = 0.033) for number of incorrect matches in round per SD increase in PA; and (iv) β of 0.039 (P = 0.032) for number of incorrect matches in round per SD increase in SA. In addition, a secondary MVMR analysis after excluding the effect of polyunsaturated fatty acids suggested that: (i) β of -0.043 (P = 1.97E-02) for cognitive performance score per SD increase in PA and (ii) β of -0.079 (P = 1.79E-03) for cognitive performance score per SD increase in SA.

CONCLUSIONS

Overall, UVMR and MVMR suggest that OA may be beneficial for cognitive function, while POA, PA, and SA may have detrimental effects on cognitive function.

Systematic evaluation and meta-analysis of the effects of major dietary patterns on cognitive function in healthy adults

PURPOSE

Evidence shows diet promotes brain health. Combining foods and nutrients may have beneficial synergistic effects, but the effects on cognitive function interventions are inconsistent. So, a meta-analysis of RCTs was conducted to examine the specific effects on cognitive function.

METHODS

We searched four databases from creation to April 2023. Eligible randomized controlled trials were identified. A random-effects meta-analysis was used to combine standardized mean differences (SMD) (95% confidence intervals [CI]), and homogeneity tests for a variance were calculated.

RESULTS

A total of 19 studies involving 12,119 participants were included in this systematic review. The dietary intervention group had a positive effect on overall cognitive functioning compared to the control group (SMD = 0.14, 95% CI [0.08, 0.20], P < 0.00001). The dietary intervention improved executive function, processing speed and language skills (SMD = -0.10, 95% CI [-0.17,-0.04], P = 0.002, I2 = 0%), (SMD = -0.16, 95% CI [-0.23,-0.09], P < 0.00001, I2 = 0%), (SMD = 0.10, 95% CI [0.01, 0.20], P = 0.03, I2 = 0%). The dietary intervention had no effect on delayed memory and spatial ability (SMD = 0.04, 95% CI [-0.02, 0.09], P = 0.20, I2 = 0%), (SMD = 0.08, 95% CI [-0.01, 0.16], P = 0.08, I2 = 0%).

CONCLUSION

The Mediterranean diet, a diet with restricted caloric intake, a diet incorporating aerobic exercise, a low-carbohydrate diet, and a healthy lifestyle diet (increased intake of fruits and vegetables, and weight and blood pressure management) appear to have positive effects on cognitively healthy adults, as reflected in their overall cognitive, processing speed, executive, and language functions.

PROSPERO REGISTRATION NUMBER

CRD42023414704.

Torreya grandis oil attenuates cognitive impairment in scopolamine-induced mice

The oil of Torreya grandis (TGO), a common nut in China, is considered to be a bioactive edible oil and has a great value in functional food development. In this study, the neuroprotective effects of TGO were investigated on a scopolamine (SCOP)-induced C57BL/6J mouse model. The mice were pretreated with TGO for 30 days (1000 mg per kg per day and 3000 mg per kg per day, i.g.). Behavioral tests showed that the supplementation of TGO could prevent the cognitive deficits induced by SCOP. TGO rebalanced the disorder of the cholinergic system by upgrading the level of acetylcholine. TGO also alleviated the over-activation of microglia and inhibited neuroinflammation and oxidative stress. Additionally, TGO could regulate the composition of gut microbiota, increase the production of short-chain fatty acids, and decrease the content of lipopolysaccharides in the serum. In conclusion, TGO has the potential to prevent loss of memory and impairment of cognition, which may be related to its regulation of the gut microbiota-metabolite-brain axis.

The effects of olive oil consumption on cognitive performance: a systematic review

Introduction

The Mediterranean diet is marked by the regular intake of olive oil, which may play a role in preventing and protecting against cognitive deterioration and dementia. The strength of these effects have been examined by several recent randomized controlled trials (RCTs), but their findings have not been consistent. In light of this inconsistency, the present study performed a systematic review to examine the relationship between the consumption of olive oil and cognition.

Methods

The Web of Science, Scopus, PubMed, and Google Scholar were systematically searched up to August 11, 2023. The review included RCTs, cross-sectional studies, cohort studies and case-control studies that explored the impact of olive oil consumption on cognitive performance among those older than 55 years old. Studies were excluded if they employed a design other than those mentioned above, involved participants under 55 years old, or did not specifically examine the cognitive effects of olive oil consumption. The quality of the included studies were measured using the Cochrane risk-of-bias tool and the Newcastle Ottawa Scale checklists.

Results

Eleven studies were identified, which were comprised of four cross-sectional studies, four prospective cohort studies and three RCTs. The cohort studies and RCTs consistently found that olive oil consumption had a favorable effect on cognitive performance across a number of cognitive domains over time. Similarly, all of the cross-sectional studies reported that the consumption of olive oil was positively associated with cognitive health.

Conclusion

The consumption of olive oil was found to enhance cognitive functioning and to reduce cognitive decline. Further large-scale investigations are required to strengthen this conclusion.

Is There More to Olive Oil than Healthy Lipids?

The Mediterranean diet is a healthy dietary pattern whose main characteristic is olive oil consumption. The potential health benefits of olive oil have been extensively investigated and the present review provides the more recent clinical evidence supporting the positive impact of olive oil intake on human health. PubMed (n = 227) and Scopus (n = 308) databases were searched for published clinical studies in English over the past six years (October 2016 to December 2022), following key word searches of "olive oil" and "health". Major findings associated olive oil with antioxidant and anti-inflammatory effects, improvement in endothelial function and lipid profile, prevention of obesity, diabetes, cardiovascular and neurodegenerative diseases, and modulation of the gut microbiota. These benefits are attributed to the nutritional composition of olive oil, which has a high content of monounsaturated fatty acids (MUFA) (oleic acid in particular) and minor compounds such as polyphenols (oleuropein and hydroxytyrosol). Although additional research continues to be required, the more recently generated evidence supports the potential of olive oil to contribute beneficially to health and to the prevention and management of a variety of non-communicable diseases, as a consequence of the synergism between its components' complexity.

Olive Oil Phenolic Compounds' Activity against Age-Associated Cognitive Decline: Clinical and Experimental Evidence

Epidemiological studies have shown that consuming olive oil rich in phenolic bioactive compounds is associated with a lower risk of neurodegenerative diseases and better cognitive performance in aged populations. Since oxidative stress is a common hallmark of age-related cognitive decline, incorporating exogenous antioxidants could have beneficial effects on brain aging. In this review, we firstly summarize and critically discuss the current preclinical evidence and the potential neuroprotective mechanisms. Existing studies indicate that olive oil phenolic compounds can modulate and counteract oxidative stress and neuroinflammation, two relevant pathways linked to the onset and progression of neurodegenerative processes. Secondly, we summarize the current clinical evidence. In contrast to preclinical studies, there is no direct evidence in humans of the bioactivity of olive oil phenolic compounds. Instead, we have summarized current findings regarding nutritional interventions supplemented with olive oil on cognition. A growing body of research indicates that high consumption of olive oil phenolic compounds is associated with better preservation of cognitive performance, conferring an additional benefit, independent of the dietary pattern. In conclusion, the consumption of olive oil rich in phenolic bioactive compounds has potential neuroprotective effects. Further research is needed to understand the underlying mechanisms and potential clinical applications.

Diet and lifestyle impact the development and progression of Alzheimer's dementia

Dementia is a growing public health concern, with an estimated prevalence of 57 million adults worldwide. Alzheimer's disease (AD) accounts for 60-80% of the cases. Clinical trials testing potential drugs and neuroprotective agents have proven futile, and currently approved drugs only provide symptomatic benefits. Emerging epidemiological and clinical studies suggest that lifestyle changes, including diet and physical activity, offer an alternative therapeutic route for slowing and preventing cognitive decline and dementia. Age is the single most common risk factor for dementia, and it is associated with slowing cellular bioenergetics and metabolic processes. Therefore, a nutrient-rich diet is critical for optimal brain health. Furthermore, type 2 diabetes (T2D) is a risk factor for AD, and diets that reduce the risk of T2D may confer neuroprotection. Foods predominant in Mediterranean, MIND, and DASH diets, including fruits, leafy green vegetables, fish, nuts, and olive oil, may prevent or slow cognitive decline. The mechanisms by which these nutrients promote brain health, however, are not yet completely understood. Other dietary approaches and eating regimes, including ketogenic and intermittent fasting, are also emerging as beneficial for brain health. This review summarizes the pathophysiology, associated risk factors, and the potential neuroprotective pathways activated by several diets and eating regimes that have shown promising results in promoting brain health and preventing dementia.

The Role of Diet as a Modulator of the Inflammatory Process in the Neurological Diseases

Neurological diseases are recognized as major causes of disability and mortality worldwide. Due to the dynamic progress of diseases such as Alzheimer’s disease (AD), Parkinson’s Disease (PD), Schizophrenia, Depression, and Multiple Sclerosis (MD), scientists are mobilized to look for new and more effective methods of interventions. A growing body of evidence suggests that inflammatory processes and an imbalance in the composition and function of the gut microbiome, which play a critical role in the pathogenesis of various neurological diseases and dietary interventions, such as the Mediterranean diet the DASH diet, or the ketogenic diet can have beneficial effects on their course. The aim of this review was to take a closer look at the role of diet and its ingredients in modulating inflammation associated with the development and/or progression of central nervous system diseases. Presented data shows that consuming a diet abundant in fruits, vegetables, nuts, herbs, spices, and legumes that are sources of anti-inflammatory elements such as omega-3 fatty acids, polyphenols, vitamins, essential minerals, and probiotics while avoiding foods that promote inflammation, create a positive brain environment and is associated with a reduced risk of neurological diseases. Personalized nutritional interventions may constitute a non-invasive and effective strategy in combating neurological disorders.

Effect of dietary patterns on cognitive functions of older adults: A systematic review and meta-analysis of randomized controlled trials: Dietary Patterns on Cognition of Older Adults

BACKGROUND

Dietary patterns are associated with cognitive benefits, but inconsistent findings have been reported concerning this association. This study aims to provide a more comprehensive review and higher evidence level by evaluating evidence from randomized controlled trials (RCTs) exploring effects of various dietary patterns on cognitive function outcomes in older adults.

METHODS

This systematic review and meta-analysis study followed the PRISMA guidelines. Twelves search engines and databases were searched for papers published up until March 2022. Random-effects models were used to calculate effect size (ES).

RESULTS

Twenty-two RCTs met our inclusion criteria. A wide range of cognitive measures were used across the included studies. To reduce heterogeneity and to ensure a sufficient number of studies for meaningful interpretation, we utilized global cognition as the outcome measure. Only nine studies used global cognition measures, including the Mini-Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog), Cognitive Abilities Screening Instrument (CASI), or neuropsychological test battery. Additionally, seven dietary patterns were identified in these studies. The results demonstrated that dietary patterns achieved a significant improvement on cognitive function outcomes including the MMSE/CASI (ES = 0.303; 95% CI [0.045, 0.560]), the ADAS-Cog (ES = -0.277; 95% CI [-0.515, -0.039]), and the cognitive battery (ES = 0.132; 95% CI [0.010, 0.255]).

CONCLUSIONS

Multidisciplinary health-care professionals may use this information as a reference when planning elder care. More large-scale, high-quality studies are required to explore the long-term effects of healthy dietary patterns on global cognition, other cognitive domains, and life quality among older adults.

Mediterranean Diet, Ketogenic Diet or MIND Diet for Aging Populations with Cognitive Decline: A Systematic Review

(1) Background: Compelling evidence shows that dietary patterns can slow the rate of cognitive decline, suggesting diet is a promising preventive measure against dementia. (2) Objective: This systematic review summarizes the evidence of three dietary patterns, the Mediterranean diet, the ketogenic diet and the MIND diet, for the prevention of cognitive decline. (3) Methods: A systematic search was conducted in major electronic databases (PubMed, ScienceDirect and Web of Science) up until 31 January 2022, using the key search terms "Mediterranean diet", "ketogenic diet", "MIND diet", "dementia", "cognition" and "aging". A statistical analysis was performed using RoB 2 and the Jadad scale to assess the risk of bias and methodological quality in randomized controlled trials. (4) Results: Only RCTs were included in this study; there were eleven studies (n = 2609 participants) of the Mediterranean diet, seven studies (n = 313) of the ketogenic diet and one study (n = 37) of the MIND diet. The participants' cognitive statuses were normal in seven studies, ten studies included patients with mild cognitive impairments and two studies included Alzheimer's disease patients. (5) Conclusion: All three dietary interventions have been shown to slow the rate of cognitive decline in the included studies. The Mediterranean diet was shown to be beneficial for global cognition after 10 weeks of adherence, the ketogenic diet had a beneficial effect for patients with diabetes mellitus and improved verbal recognition, while the MIND diet showed benefits in obese patients, improving working memory, verbal recognition, memory and attention.

Ageing, Metabolic Dysfunction, and the Therapeutic Role of Antioxidants

The gradual ageing of the world population has been accompanied by a dramatic increase in the prevalence of obesity and metabolic diseases, especially type 2 diabetes. The adipose tissue dysfunction associated with ageing and obesity shares many common physiological features, including increased oxidative stress and inflammation. Understanding the mechanisms responsible for adipose tissue dysfunction in obesity may help elucidate the processes that contribute to the metabolic disturbances that occur with ageing. This, in turn, may help identify therapeutic targets for the treatment of obesity and age-related metabolic disorders. Because oxidative stress plays a critical role in these pathological processes, antioxidant dietary interventions could be of therapeutic value for the prevention and/or treatment of age-related diseases and obesity and their complications. In this chapter, we review the molecular and cellular mechanisms by which obesity predisposes individuals to accelerated ageing. Additionally, we critically review the potential of antioxidant dietary interventions to counteract obesity and ageing.

Mechanisms Underlying Neurodegenerative Disorders and Potential Neuroprotective Activity of Agrifood By-Products

Neurodegenerative diseases, characterized by progressive loss in selected areas of the nervous system, are becoming increasingly prevalent worldwide due to an aging population. Despite their diverse clinical manifestations, neurodegenerative diseases are multifactorial disorders with standard features and mechanisms such as abnormal protein aggregation, mitochondrial dysfunction, oxidative stress and inflammation. As there are no effective treatments to counteract neurodegenerative diseases, increasing interest has been directed to the potential neuroprotective activities of plant-derived compounds found abundantly in food and in agrifood by-products. Food waste has an extremely negative impact on the environment, and recycling is needed to promote their disposal and overcome this problem. Many studies have been carried out to develop green and effective strategies to extract bioactive compounds from food by-products, such as peel, leaves, seeds, bran, kernel, pomace, and oil cake, and to investigate their biological activity. In this review, we focused on the potential neuroprotective activity of agrifood wastes obtained by common products widely produced and consumed in Italy, such as grapes, coffee, tomatoes, olives, chestnuts, onions, apples, and pomegranates.

Olive- and Coconut-Oil-Enriched Diets Decreased Secondary Bile Acids and Regulated Metabolic and Transcriptomic Markers of Brain Injury in the Frontal Cortexes of NAFLD Pigs

The objective of this study was to investigate the effect of dietary fatty acid (FA) saturation and carbon chain length on brain bile acid (BA) metabolism and neuronal number in a pig model of pediatric NAFLD. Thirty 20-day-old Iberian pigs, pair-housed in pens, were randomly assigned to receive one of three hypercaloric diets for 10 weeks: (1) lard-enriched (LAR; n = 5 pens), (2) olive-oil-enriched (OLI, n = 5), and (3) coconut-oil-enriched (COC; n = 5). Pig behavior and activity were analyzed throughout the study. All animals were euthanized on week 10 and frontal cortex (FC) samples were collected for immunohistochemistry, metabolomic, and transcriptomic analyses. Data were analyzed by multivariate and univariate statistics. No differences were observed in relative brain weight, neuronal number, or cognitive functioning between diets. Pig activity and FC levels of neuroprotective secondary BAs and betaine decreased in the COC and OLI groups compared with LAR, and paralleled the severity of NAFLD. In addition, OLI-fed pigs showed downregulation of genes involved in neurotransmission, synaptic transmission, and nervous tissue development. Similarly, COC-fed pigs showed upregulation of neurogenesis and myelin repair genes, which caused the accumulation of medium-chain acylcarnitines in brain tissue. In conclusion, our results indicate that secondary BA levels in the FCs of NAFLD pigs are affected by dietary FA composition and are associated with metabolic and transcriptomic markers of brain injury. Dietary interventions that aim to replace saturated FAs by medium-chain or monounsaturated FAs in high-fat hypercaloric diets may have a negative effect on brain health in NAFLD patients.

A new nutraceutical (Livogen Plus®) improves liver steatosis in adults with non-alcoholic fatty liver disease

Background

Currently, there is no approved medication for non-alcoholic fatty liver disease management. Pre-clinical and clinical studies showed that several bioactive molecules in plants or foods (i.e., curcumin complex, bergamot polyphenol fraction, artichoke leaf extract, black seed oil, concentrate fish oil, picroliv root, glutathione, S-adenosyl-l-methionine and other natural ingredients) have been associated with improved fatty liver disease. Starting from these evidences, our purpose was to evaluate the effects of a novel combination of abovementioned nutraceuticals as a treatment for adults with fatty liver disease.

Methods

A total of 140 participants with liver steatosis were enrolled in a randomized, double-blind, placebo controlled clinical trial. The intervention group received six softgel capsules daily of a nutraceutical (namely Livogen Plus®) containing a combination of natural bioactive components for 12 weeks. The control group received six softgel capsules daily of a placebo containing maltodextrin for 12 weeks. The primary outcome measure was the change in liver fat content (CAP score). CAP score, by transient elastography, serum glucose, lipids, transaminases, and cytokines were measured at baseline and after intervention.

Results

After adjustment for confounding variables (i.e., CAP score and triglyceride at baseline, and changes of serum γGT, and vegetable and animal proteins, cholesterol intake at the follow-up), we found a greater CAP score reduction in the nutraceutical group rather than placebo (− 34 ± 5 dB/m vs. − 20 ± 5 dB/m, respectively; p = 0.045). The CAP score reduction (%) was even greater in those with aged 60 or less, low baseline HDL-C, AST reduction as well as in men.

Conclusion

Our results showed that a new combination of bioactive molecules as nutraceutical was safe and effective in reducing liver fat content over 12 weeks in individuals with hepatic steatosis.

Trial registration ISRCTN, ISRCTN70887063. Registered 03 August 2021—retrospectively registered, https://doi.org/10.1186/ISRCTN70887063

Greater intake of the MEDI diet is associated with better cognitive trajectory in older adults with type 2 diabetes

AIMS

To determine associations of three dietary patterns (Mediterranean (MEDI) diet, the Dietary Approaches to Stop Hypertension (DASH) diet and the Mediterranean- DASH Intervention for Neurodegenerative Delay (MIND) diet) with cognitive decline in older adults with type 2 diabetes mellitus (T2D).

METHODS

This is a longitudinal observational study. Participants (N = 960) from the Israel Diabetes and Cognitive Decline (IDCD) study were included in this study. A multivariable-adjusted model including all three dietary patterns concurrently was developed to investigate their independent effect on cognitive decline.

RESULTS

The mean follow up was 4.1 ± 2.1 years. While high adherence to both the MIND and the MEDI diet was associated with a slower decline, in the multivariable model only the associations of higher MEDI diet intake with greater decline in global cognition and in executive functions remained significant (β = 0.013, SE = 0.006; P = 0.042; β = 0.001, SE = 0.008, Pv = 0.023 respectively).

CONCLUSIONS

In older adults with T2D, adherence to the MEDI is related to better cognitive trajectory. Diet is a meaningful factor in the path linking T2D and cognition.

Liver Stiffness in Obese Hypothyroid Patients Taking Levothyroxine

Background and Objectives: Thyroid dysfunction is associated with non-alcoholic fatty liver disease, but its role in the progression of liver damage in obese patients remains unclear. In addition, several case reports have suggested the existence of a levothyroxine-induced liver injury, which has been poorly investigated. Our aim was to verify whether a difference in the prevalence of liver fibrosis exists in a population of obese individuals taking Levothyroxine. Materials and Methods: We conducted a cross-sectional study on a population of 137 obese individuals, of which 49 were on replacement therapy with Levothyroxine. We excluded those who had hypertriglyceridemia and diabetes mellitus. All participants underwent a liver stiffness assessment by transient elastography as well as biochemical measurements. In subjects with liver fibrosis, other cause of liver fibrosis were ruled out. Results: Participants taking Levothyroxine had a higher prevalence of liver fibrosis than those not taking Levothyroxine (30.6% vs. 2.3%; p < 0.001), and these results were obtained after we made an adjustment for age (Exp(B) = 18.9; 95% CI = 4.1−87.4; p < 0.001). The liver stiffness value differed significantly between groups (6.0 ± 3.6 and 5.1 ± 1.2, p = 0.033). Of those subjects taking Levothyroxine, there were no significant differences in the dose of medication (1.21 ± 0.36 vs. 1.07 ± 0.42; p = 0.240) and treatment duration (13.7 ± 7.43 vs. 11.13 ± 6.23; p = 0.380) between those with and without liver fibrosis. Conclusions: We found, for the first time, a greater prevalence of liver fibrosis in obese individuals taking Levothyroxine than in those not taking this medication. This finding needs to be confirmed by longitudinal population studies as well as by cellular studies.

Effect of Dietary Intake Through Whole Foods on Cognitive Function: Review of Randomized Controlled Trials

PURPOSE OF REVIEW

This review evaluated recent randomized controlled trials (RCTs) examining the chronic intake of whole foods associated with the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), Mediterranean-DASH Intervention for Neurogenerative Delay (MIND), and ketogenic (KETO) diets on cognitive function.

RECENT FINDINGS

We identified RCTs related to olive oil (N = 3), nuts (N = 7), fatty fish (N = 1), lean meats (N = 4), fruits and vegetables (N = 9), legumes (N = 1), and low-fat dairy (N = 4), with 26/29 reporting positive results on at least one measure of cognition. We also identified 6 RCTs related to whole food-induced KETO diets, with half reporting positive effects on cognition. Variations in study design (i.e., generally the studies are < 6 months and include middle-aged and older, cognitively intact participants) and small sample sizes make it difficult to draw conclusions across studies; however, the current evidence from RCTs generally supports individual component intakes of these dietary patterns as an effective, nonpharmacological approach to improve cognitive health in adults.

A mini-flipped, game-based Mediterranean diet learning program on dietary behavior and cognitive function among community-dwelling older adults in Taiwan: A cluster-randomized controlled trial

The Mediterranean diet has been recommended to delay cognitive decline, but adherence to the diet among older adults remain poor, and research on interventions that effectively promote the diet has been inconclusive. This study examined the effects of a mini-flipped, game-based Mediterranean diet learning program in improving dietary behavior and cognitive function in community-dwelling older adults in Taiwan. A cluster randomized controlled trial was conducted. The experimental group completed an 8-week, mini-flipped, game-based learning program. Data were collected at baseline and 8 weeks after intervention. Outcome measures included dietary behavior, global cognitive function, and subjective cognitive dysfunction. Compared with the control group, the experimental group exhibited significantly improved Mediterranean diet behavior and global cognitive function after the intervention, although there was no significant difference in subjective cognitive function. Future research should be conducted with larger populations and longer-term follow-up to evaluate the effect of this learning program.

Dietary fatty acids affect learning and memory ability via regulating inflammatory factors in obese mice

OBJECTIVE

High-fat diets are linked to obesity, contributing to the alterations in inflammatory signaling pathways, which is associated with cognitive function. We aim to investigate the mechanisms by which various different types of dietary fatty acids affecting cognitive function in obese mice through the gut/brain axis-inflammatory signaling pathway.

METHODS AND RESULTS

Eight-week-old male C57BL/6 mice were fed with basal diet (control group), lard high-fat diet (containing long-chain saturated fatty acid (LCSFA group)), coconut oil high-fat diet (containing medium-chain saturated fatty acid (MCSFA group)), linseed oil high-fat diet (containing n-3 polyunsaturated fatty acid (n-3 PUFA group)), soybean oil high-fat diet (containing n-6 polyunsaturated fatty acid (n-6 PUFA group)), olive oil high-fat diet (containing monounsaturated fatty acid (MUFA group)) and 8% hydrogenated soybean oil high-fat diet (containing trans fatty acid (TFA group)) respectively for 16 weeks. Our results revealed that the mean escape latency was significantly prolonged in LCSFA group, and the latency to cross the platform location of n-6 PUFA and TFA groups were increased significantly. The differences of inflammatory markers and toll-like receptor-myeloid differentiation factor-88-nuclear factor kappa-B (TLR-MyD88-NF-κB) inflammatory signaling pathway expressions among all groups reached statistical significances.

CONCLUSION

Compared to basal diet, high-fat diets enriched in LCSFA, MCSFA, n-6 PUFA, MUFA, and TFA might exert detrimental effects on cognitive function in obese mice via regulating the inflammatory markers and inflammatory signaling pathway in brain and intestine. High-fat diet enriched in n-3 PUFA might exhibit different effect on modulating inflammatory responses in different tissues and might benefit to cognitive function.

Mediterranean Diet a Potential Strategy against SARS-CoV-2 Infection: A Narrative Review

Mediterranean Diet represents the traditional eating habits of populations living around the Mediterranean Sea, and it is associated with a lower risk of overall mortality and cancer incidence and cardiovascular diseases. Severe acute respiratory syndrome coronavirus 2 is a new pandemic, and represents a significant and critical threat to global human health. In this study, we aimed to review the possible effects of Mediterranean Diet against the risk of the coronavirus disease 2019. Several vitamins, minerals, fatty acids, and phytochemicals with their potential anti-COVID-19 activity are presented. Different risk factors may increase or reduce the probability of contracting the disease. Mediterranean Diet has also a positive action on inflammation and immune system and could have a protective effect against severe acute respiratory syndrome coronavirus 2. Further studies are needed to corroborate the benefits of the Mediterranean Diet protective role on infection with SARS-CoV-2.

Protective effect of olive leaves phenolic compounds against neurodegenerative disorders: Promising alternative for Alzheimer and Parkinson diseases modulation

The main objective of this work was to review literature on compounds extracted from olive tree leaves, such as simple phenols (hydroxytyrosol) and flavonoids (Apigenin, apigenin-7-O-glucoside, luteolin.) and their diverse pharmacological activities as antioxidant, antimicrobial, anti-viral, anti-obesity, anti-inflammatory and neuroprotective properties. In addition, the study discussed the key mechanisms underlying their neuroprotective effects. This study adopted an approach of collecting data through the databases provided by ScienceDirect, SCOPUS, MEDLINE, PubMed and Google Scholar. This review revealed that there was an agreement on the great impact of olive tree leaves phenolic compounds on many metabolic syndromes as well as on the most prevalent neurodegenerative diseases such as Alzheimer and Parkinson. These findings would be of great importance for the use of olive tree leaves extracts as a food supplement and/or a source of drugs for many diseases. In addition, this review would of great help to beginning researchers in the field since it would offer them a general overview of the studies undertaken in the last two decades on the topic.

Diet May Moderate the Relationship Between Arterial Stiffness and Cognitive Performance in Older Adults

BACKGROUND

Cognitive decline is influenced by various factors including diet, cardiovascular disease, and glucose control. However, the combined effect of these risk factors on cognitive performance is yet to be fully understood.

OBJECTIVE

The current study aimed to explore the inter-relationship between these risk factors and cognitive performance in older adults at risk of future cognitive decline.

METHODS

The sample comprised 163 (Age: M = 65.23 years, SD = 6.50) participants. Food Frequency Questionnaire data was used to score diet quality and adherence to the Western Style Diet (WSD) and Prudent Style Diet (PSD). Glucose control was gauged by serum levels of glycated hemoglobin (HbA1c) and arterial stiffness was measured using carotid to femoral pulse wave velocity. Cognitive performance was assessed using two subtests of the Swinburne University Computerized Cognitive Assessment Battery (SUCCAB) and Rey's Verbal Learning Test (RVLT).

RESULTS

Diet quality, adherence to the WSD or PSD, and glucose control were not significantly related to cognitive outcomes. However, a significant negative association was found between arterial stiffness and the spatial working memory subtest of SUCCAB (β= -0.21, p <  0.05). Arterial stiffness also significantly interacted with the PSD to impact total recall (F change (1,134) = 5.37, p <  0.05) and the composite score of RVLT (F change (1,134) = 4.03, p <  0.05).

CONCLUSION

In this sample of older adults at risk of cognitive decline, diet alone was not found to predict cognitive performance; however, it was found to moderate the relationship between arterial stiffness and cognition.

Polyphenols and neuroprotection: Therapeutic implications for cognitive decline

Dietary polyphenols have been the focus of major interest for their potential benefits on human health. Several preclinical studies have been conducted to provide a rationale for their potential use as therapeutic agents in preventing or ameliorating cognitive decline. However, results from human studies are scarce and poorly documented. The aim of this review was to discuss the potential mechanisms involved in age-related cognitive decline or early stage cognitive impairment and current evidence from clinical human studies conducted on polyphenols and the aforementioned outcomes. The evidence published so far is encouraging but contrasting findings are to be taken into account. Most studies on anthocyanins showed a consistent positive effect on various cognitive aspects related to aging or early stages of cognitive impairment. Studies on cocoa flavanols, resveratrol, and isoflavones provided substantial contrasting results and further research is needed to clarify the therapeutic potential of these compounds. Results from other studies on quercetin, green tea flavanols, hydroxycinnamic acids (such as chlorogenic acid), curcumin, and olive oil tyrosol and derivatives are rather promising but still too few to provide any real conclusions. Future translational studies are needed to address issues related to dosage, optimal formulations to improve bioavailability, as well as better control for the overall diet, and correct target population.

The Effect of Mediterranean Diet on Cognitive Functions in the Elderly Population

At present, due to the demographic changes and the rise of senior population worldwide, there is effort to prolong an active life of these people by both pharmacological and non-pharmacological strategies. The purpose of this article is, on the basis of the literature review of recent clinical studies, to discuss one of such strategy, i.e., the effect of Mediterranean Diet (MedDiet) on the cognitive functions among both the cognitively unimpaired and impaired elderly people. The methodology includes a literature review of full-text, peer-reviewed journal studies written in English and published in Web of Science and PubMed between 1 January 2016 and 28 February 2021. The findings indicate that the adherence to MedDiet has a positive effect on both cognitively impaired and unimpaired older population, especially on their memory, both in the short and long run. The results show that the higher adherence to MedDiet proves to have a better effect on global cognitive performance of older people. In addition, the adherence to MedDiet offers other benefits to older people, such as reduction of depressive symptoms, lowered frailty, as well as reduced length of hospital stays.

Impact of Polyphenolic-Food on Longevity: An Elixir of Life. An Overview

Aging and, particularly, the onset of age-related diseases are associated with tissue dysfunction and macromolecular damage, some of which can be attributed to accumulation of oxidative damage. Recently, growing interest has emerged on the beneficial effects of plant-based diets for the prevention of chronic diseases including obesity, diabetes, and cardiovascular disease. Several studies collectively suggests that the intake of polyphenols and their major food sources may exert beneficial effects on improving insulin resistance and related diabetes risk factors, such as inflammation and oxidative stress. They are the most abundant antioxidants in the diet, and their intake has been associated with a reduced aging in humans. Polyphenolic intake has been shown to be effective at ameliorating several age-related phenotypes, including oxidative stress, inflammation, impaired proteostasis, and cellular senescence, both in vitro and in vivo. In this paper, effects of these phytochemicals (either pure forms or polyphenolic-food) are reviewed and summarized according to affected cellular signaling pathways. Finally, the effectiveness of the anti-aging preventive action of nutritional interventions based on diets rich in polyphenolic food, such as the diets of the Blue zones, are discussed.

Adherence to the Mediterranean Diet and Healthy Aging: A Narrative Review over the Last Decade

Objective: Even though modern medicine has significantly contributed to the extension of human lifespan, it has failed to delay the upsurge of chronic diseases. Health benefits of the Mediterranean diet are well established. Thus, adherence to this diet pattern may be the key to healthy aging. Ôhe aim of this review is to investigate the potential benefits of the Mediterranean diet on healthy aging. Methods: A literature search of three databases (ScienceDirect, MEDLINE and The Cochrane Library) was conducted in order to trace all relevant studies published between January 1st 2010 and June 6th 2020 that focused on the impact of adherence to the Mediterranean diet on the physical and mental well-being of individuals aged 60 or older. Results:Twenty-two studies fulfilled the selection criteria and were classified into six groups, according to the main outcome of each study: mental health (eight studies), frailty (6), cardiovascular risk factors (3), plasma levels of uric acid (1), length of hospital stay (1), and aging mechanisms (3). Based on these studies, the protective role of Mediterranean diet on depression, cardiovascular and frailty risk was established. Moreover, adherence to the Mediterranean diet resulted in reduced plasma uric acid levels as well as decreased length of hospital stay and mortality risk among patients who were urgently admitted for any cause in a tertiary hospital. In contrast, results on the effect of Mediterranean diet on cognition were controversial, as studies presented positive or neutral correlations. Conclusions: This review provides evidence on the association between adherence to the Mediterranean diet and healthy aging and highlights the importance of conducting more studies among seniors in order to provide further insight into this matter.

Ginger and turmeric lipid-solubles attenuate heated oil-induced oxidative stress in the brain via the upregulation of NRF2 and improve cognitive function in rats

In this study, we elucidated the modulatory potentials of lipid-solubles from ginger and turmeric that may migrate to oils during heating on the brain antioxidant defense and cognitive response in rats. Male Wistar rats were fed with control diet [including native canola oil (N-CNO), and native sunflower oil (N-SFO)], or experimental diets [including heated canola oil (H-CNO), heated sunflower oil (H-SFO), heated canola oil with ginger (H-CNO + GI), heated canola oil with turmeric (H-CNO + TU), heated sunflower oil with ginger (H-SFO + GI), heated sunflower oil with turmeric (H-SFO + TU)] for 90 days. Memory parameters [Morris water maze, elevated plus maze, novel object recognition test, T-maze (spontaneous alteration)], locomotor skills (open field test and rotarod test), antioxidant defense enzymes, reactive oxygen species, NOS2, ICAM-1, and NRF-2 level in the brain were assessed. Compared to their respective controls, heated oil-fed rats, but not those fed oils heated with ginger or turmeric, showed significant (p < 0.05) reduction in the memory, motor coordination skills, antioxidant defense enzymes, and NRF-2 activation in the brain. Compared to their respective controls, the brain NOS-2 and ICAM-1 were significantly (p < 0.05) increased in heated oil-fed rats, but not those fed oils heated with ginger or turmeric. Chronic intake of repeatedly heated oil causes brain dysfunction by inducing oxidative stress through NRF-2 downregulation. Lipid-solubles from ginger and turmeric that may migrate to oil during heating prevent the oxidative stress and cognitive dysfunction triggered by heated oils in rats.

Consumption of Oleic Acid on the Preservation of Cognitive Functions in Japanese Elderly Individuals

We recruited 154 community-dwelling elderly individuals and conducted a cohort study to find out the nutrient intake that is suitable for maintaining cognitive function in Japanese elders. Cognitive function was evaluated by the two functional tests, the Montreal Cognitive Assessment (MoCA) and Wechsler Memory Scale-Delayed Recall (WMS-DR), and daily nutrient intake was estimated from a Brief-type Self-administered Diet History Questionnaire (BDHQ). By a multiple regression analysis, among the four major nutrients (protein, fat, carbohydrate and ash), we detected a significant correlation between the score of cognitive functions assessed by both MoCA and WMS-DR and daily consumption of fat (p = 0.0317 and p = 0.0111, respectively). Among categories of fatty acid, we found a significant correlation between the score of both MoCA and WMS-DR and consumption of monounsaturated fatty acid (MUFA) (p = 0.0157 and p = 0.0136, respectively). Finally, among MUFAs, we observed a significant correlation between the score of both MoCA and WMS-DR and consumption of oleic acid (p = 0.0405 and p = 0.0165, respectively). From these observations, we can propose that daily consumption of fat, especially in oleic acid, has a beneficial effect against cognitive decline in community-dwelling Japanese elderly individuals.

Effect of a novel functional tomato sauce (OsteoCol) from vine-ripened tomatoes on serum lipids in individuals with common hypercholesterolemia: tomato sauce and hypercholesterolemia

Background

Most studies focused on the benefits of lycopene on serum lipids but no studies have been specifically designed to assess the role of a tomato sauce from vine-ripened tomatoes on patients affected by polygenic hypercholesterolemia. The aim of this study was to compare the lipid-lowering effect of a novel functional tomato sauce with a well-known functional food with a lipid-lowering effect, i.e. a sterol-enriched yogurt.

Methods

In this cross-over study, we evaluated a population of 108 ambulatory patients affected by polygenic hypercholesterolemia of both gender, who were allocated to a tomato sauce (namely OsteoCol) 150 ml/day or a sterol-enriched yogurt (containing sterols 1.6 g/die) treatment, for 6 weeks. Carotenoids content was 3.5 mg per gram of product. We measured serum lipids and creatinine and transaminases at basal and follow-up visit.

Results

A total of 91 subjects completed the protocol. A significant difference in LDL-cholesterol change was found between participants taking yogurt, tomato sauce (high adherence) and tomato sauce (low adherence) (− 16; − 12; + 8 mg/dl respectively; p < 0.001). We found a greater LDL-cholesterol reduction in the participants with a basal LDL-cholesterol more than 152 mg/dl (15% for sterol-enriched yogurt and 12% for tomato sauce at high adherence).

Conclusion

A novel functional tomato sauce from vine-ripened tomatoes compares favourably with a commercialised sterol-enriched yogurt in term of absolute LDL-cholesterol change. Intake of a tomato sauce with a high carotenoid content may support treatment of patients affected by common hypercholesterolemia. The present study has various limitations. The presence of other dietary components, which may have influenced the results, cannot be ruled out. Of course, these results cannot be extrapolated to other populations. Furthermore, there was a low adherence rate in the tomato sauce group. Moreover, we did not report serum carotenoids data.

Trial registration: ID: 13244115 on the ISRCTN registry, retrospectively registered in 2019-5-14. URL: http://www.isrctn.com/ISRCTN13244115

Mediterranean Diet In Healthy Aging

The World elderly population is expected to double before 2050. Unhealthy habits and unhealthy lifestyles are commonly associated with age-related diseases or their worsening. Modification in daily lifestyle and diet may help preventing age-related diseases onset and efficiently affecting their evolution, thus promoting the Healthy Aging process, concept recently coined to describe the disease-free aging process. This review highlights the role of nutrition science in promoting healthy aging. Since the Mediterranean Model demonstrated to be a useful style in supporting healthy aging, promotion of this correct lifestyle by health policies seems to be the best approach to achieve this target.

Dietary Fatty Acid Factors in Alzheimer's Disease: A Review

Alzheimer's disease (AD) is an irreversible neurodegenerative disease characterized by brain function disorder and chronic cognitive function impairment. The onset of AD is complex and is mostly attributed to interactions between genetic factors and environmental factors. Lifestyle, dietary habits, and food consumption are likely to play indispensable functions in aged-related neurodegenerative diseases in elderly people. An increasing number of epidemiological studies have linked dietary fatty acid factors to AD, raising the point of view that fatty acid metabolism plays an important role in AD initiation and progression as well as in other central nervous system disorders. In this paper, we review the effects of the consumption of various dietary fatty acids on AD onset and progression and discuss the detrimental and beneficial effects of some typical fatty acids derived from dietary patterns on the pathology of AD. We outline these recent advances, and we recommend that healthy dietary lifestyles may contribute to preventing the occurrence and decreasing the pathology of AD.

Dietary Mitophagy Enhancer: A Strategy for Healthy Brain Aging?

Recently, nutritional interventions have received attention as promising approaches to promote human health during a lifespan. The Mediterranean and Okinawan diets have been associated with longevity and decreasing risk for age-related diseases in contrast to the Western diet. The effect might be due to several antioxidative bioactive compounds highly consumed in both diets, namely, resveratrol, hydroxytyrosol, oleuropein, curcumin, and spermidine. This review aims to address the underlying mechanisms of these compounds to enhance mental fitness throughout life with a focus on brain mitophagy. Mitophagy is the autophagic clearance of dysfunctional, redundant, and aged mitochondria. In aging and neurodegenerative disorders, mitophagy is crucial to preserve the autophagy mechanism of the whole cell, especially during oxidative stress. Growing evidence indicates that curcumin, astaxanthin, resveratrol, hydroxytyrosol, oleuropein, and spermidine might exert protective functions via antioxidative properties and as well the enhanced induction of mitophagy mediators. The compounds seem to upregulate mitophagy and thereby alleviate the clearance of dysfunctional and aged mitochondria as well as mitogenesis. Thus, the Mediterranean or Okinawan diet could represent a feasible nutritional approach to reduce the risk of developing age-related cognitive impairment and corresponding disorders via the stimulation of mitophagy and thereby ensure a balanced redox state of brain cells.

The Effect of Healthy Diet on Cognitive Performance Among Healthy Seniors - A Mini Review

At present, a healthy diet appears to be one of the suitable strategies in slowing down cognitive decline in the process of aging. A number of evidence-based studies confirm its efficacy, safety, and cost-effectiveness. The aim of this mini review is to evaluate and describe recent randomized clinical and cohort studies exploring the effect of healthy diet on cognitive performance among healthy seniors, as well as to update the existing information on this research issue. For these reasons, the authors reviewed full-text, peer-reviewed journal articles written in English and available in Web of Science and PubMed between September 2017 and February 2020. Altogether nine original studies were detected. The results indicate that healthy diet and healthy diet components generally have a positive impact on the enhancement of cognitive functions. Furthermore, the findings reveal that dietary patterns, as well as single nutrients might have a significant effect on specific cognitive domains, such as memory in general, episodic memory, or processing speed. It also seems that a strict adherence to the dietary patterns and a higher diet variety have a more significant effect on the improvement of cognitive functions. Nevertheless, there seem to be gender differences in dietary behavior. More recently, personalized dietary interventions started to be used in delaying cognitive decline among healthy seniors. Therefore, more randomized control trials or N-of-1 trials should be performed in this research area in order to detect the most suitable dietary pattern or nutrients, which would, together with other modifiable lifestyle factors, contribute to the improvement of quality of life of the aging population.

The role of diet in preventing and reducing cognitive decline

PURPOSE OF REVIEW

This review summarises the most recent evidence regarding the effects of diet in preventing and reducing age-related cognitive decline and neurodegenerative diseases.

RECENT FINDINGS

Recent evidence indicates that nutraceuticals and whole diet approaches may protect against the development of age-related cognitive decline and pathological neurodegeneration. The neuroprotective effects are diverse depending on the nutrient employed and may involve a reduction of neuroinflammation, an activation of the endogenous antioxidant defence system and a modulation of the gut microbiota structure and function.

SUMMARY

This review summarises the existing evidence in favour of diet as a viable alternative approach to directly impact cognitive decline and neurodegenerative diseases. The single nutrient (polyphenols, B vitamins, long-chain polyunsaturated fatty acids) versus whole diet approach (Mediterranean diet, Dietary Approaches to Stop Hypertension, MIND, Nordic, ketogenic) is presented and discussed. Potential mechanisms of action underlying the beneficial effects of these diets are also described. Implementation of large-scale preventive interventions based on dietary patterns identified as being beneficial to brain health should be a research and public health priority, ideally in conjunction with other health-promoting lifestyle factors.

Effects of a Portfolio-Mediterranean Diet and a Mediterranean Diet with or without a Sterol-Enriched Yogurt in Individuals with Hypercholesterolemia

BACKGROUND

A growing number of functional foods have been proposed to reduce cholesterol levels and the Portfolio Diet, which includes a combination of plant sterols, fibres, nuts, and soy protein, reduces low density lipoprotein cholesterol (LDL-C) from 20% to 30% in individuals with hyperlipidaemia. In this pilot study, the aim was to investigate whether a Mediterranean Diet incorporating a new and simple combination of cholesterol-lowering foods, excluding soy and nuts (namely the Portfolio-Mediterranean Diet), would reduce LDL-C levels, in the short-term, better than a Mediterranean Diet plus a sterol-enriched yogurt or a Mediterranean Diet alone.

METHODS

We retrospectively evaluated 24 individuals on a Portfolio-Mediterranean Diet and 48 matched individuals on a Mediterranean Diet with or without a sterol-enriched yogurt (24 each groups) as controls.

RESULTS

At follow-up (after 48±12 days), we observed an LDL reduction of 21±4, 23±4, and 44±4 mg/dL in the Mediterranean Diet alone, Mediterranean Diet plus yogurt and Portfolio-Mediterranean Diet respectively (P&lt;0.001).

CONCLUSION

A Portfolio-Mediterranean Diet, incorporating a new combination of functional foods such as oats or barley, plant sterols, chitosan, and green tea but not soy and nuts, may reduce LDL of 25% in the short term in individuals with hypercholesterolemia.

Nutritional Determinants of Quality of Life in a Mediterranean Cohort: The SUN Study

Health related quality of life (HRQoL) is a subjective appreciation of how personal characteristics and health influence well-being. This cross-sectional analysis aimed to quantitatively measure the influence of dietary, lifestyle, and demographic factors on HRQoL. A sub-sample of the Seguimiento Universidad de Navarra (SUN) Project, a Mediterranean cohort, was analyzed (n = 15,674). Through self-administered questionnaires the relationship between HRQoL and dietary patterns (Mediterranean-diet (MedDiet) and provegetarian food pattern (FP) assessment), lifestyles (sleeping hours, physical activity) and demographic characteristics were measured. Multivariate linear regression and flexible regression models were used to estimate the pondered effect of personal factors on Short Form-36 (SF-36) scores. Coefficients for MedDiet and provegetarian scores (β-coefficient for global SF-36 score: 0.32 (0.22, 0.42); 0.09 (0.06, 0.12) respectively for every unit increase), physical activity (β: 0.03 (0.02, 0.03) for every metabolic equivalent of task indexes (MET)-h/week) had a positive association to HRQoL. The female sex (β: −3.28 (−3.68, −2.89)), and pre-existing diseases (diabetes, β: −2.27 (−3.48, −1.06), hypertension β: −1.79 (−2.36, −1.22), hypercholesterolemia β: −1.04 (−1.48, −0.59)) account for lower SF-36 scores. Adherence to MedDiet or provegetarian FP, physical activity and sleep are associated with higher HRQoL, whereas the female sex, “other” (versus married status) and the presence of chronic diseases were associated with lower SF-36 scores in this sample.

Dietary Factors and Neurodegenerative Disorders: An Umbrella Review of Meta-Analyses of Prospective Studies

Diet has been hypothesized to be associated with neurodegenerative disorders. The aim was to conduct an umbrella review to summarize and evaluate the current evidence of prospective associations between any dietary factors and the incidence of neurodegenerative disorders. We conducted a systematic search in PubMed, Embase, and the Cochrane library up to November 2019 to identify systematic reviews with meta-analyses of prospective studies investigating the association between dietary factors (dietary patterns, foods and beverages, nutrients, and phytochemicals) and neurodegenerative disorders (cognitive decline, cognitive impairment, Alzheimer disease, all-cause dementia, and Parkinson disease). Summary risk ratios (SRRs) and 95% CIs were recalculated using a random effects model. We evaluated the risk of bias of identified meta-analyses and the quality of evidence for all associations. In total, 20 meta-analyses including 98 SRRs were identified. All original meta-analyses were rated as being at high risk of bias. Methodological concerns related mainly to the inappropriate synthesis, assessment, and discussion of the risk of bias of primary studies. For the recalculated meta-analyses, quality of evidence was moderate for inverse associations between higher adherence to the Mediterranean diet (SRR: 0.63; 95% CI: 0.48, 0.82; n = 4 primary studies) and higher fish intake (SRR: 0.72; 95% CI: 0.59, 0.89; n = 6) and Alzheimer disease, as well as for tea consumption and all-cause dementia (SRR: 0.74; 95% CI: 0.63, 0.88; n = 2) and Parkinson disease (SRR per 2 cups/d: 0.69; 95% CI: 0.54, 0.87; n = 5). This umbrella review provides a comprehensive overview of the available evidence on dietary factors and neurodegenerative disorders. The results indicate that the Mediterranean diet, fish, and tea could be inversely associated with neurodegenerative disorders. However, the quality of evidence was generally low, suggesting that further studies are likely to change the overall estimates. Thus, more well-conducted research, also investigating other dietary factors in association with neurodegenerative disorders, is warranted.

Dietary Patterns and Cognitive Health in Older Adults: A Systematic Review

While the role of diet and nutrition in cognitive health and prevention of dementia in older adults has attracted much attention, the efficacy of different dietary patterns remains uncertain. Previous reviews have mainly focused on the Mediterranean diet, but either omitted other dietary patterns, lacked more recent studies, were based on cross-sectional studies, or combined older and younger populations. We followed PRISMA guidelines, and examined the efficacy of current research from randomized controlled trials and cohort studies on the effects of different dietary patterns. We reviewed the Mediterranean diet, Dietary Approach to Stop Hypertension (DASH) diet, the Mediterranean-DASH diet Intervention for Neurodegenerative Delay (MIND) diet, Anti-inflammatory diet, Healthy diet recommended by guidelines via dietary index, or Prudent healthy diets generated via statistical approaches, and their impact on cognitive health among older adults. Of 38 studies, the Mediterranean diet was the most investigated with evidence supporting protection against cognitive decline among older adults. Evidence from other dietary patterns such as the MIND, DASH, Anti-inflammatory, and Prudent healthy diets was more limited but showed promising results, especially for those at risk of cardiovascular disease. Overall, this review found positive effects of dietary patterns including the Mediterranean, DASH, MIND, and Anti-inflammatory diets on cognitive health outcomes in older adults. These dietary patterns are plant-based, rich in poly- and mono-unsaturated fatty acids with lower consumption of processed foods. Better understanding of the underlying mechanisms and effectiveness is needed to develop comprehensive and practical dietary recommendations against age-related cognitive decline among older adult.

Randomized Clinical Trial: Bergamot Citrus and Wild Cardoon Reduce Liver Steatosis and Body Weight in Non-diabetic Individuals Aged Over 50 Years

Background: Non-alcoholic fatty liver disease is the most common cause of liver-related morbidity and mortality in the world. However, no effective pharmacological treatment for this condition has been found. Purpose: This study evaluated the effect of a nutraceutical containing bioactive components from Bergamot citrus and wild cardoon as a treatment for individuals with fatty liver disease. The primary outcome measure was the change in liver fat content. Methods: A total of 102 patients with liver steatosis were enrolled in a double-blind placebo controlled clinical trial. The intervention group received a nutraceutical containing a Bergamot polyphenol fraction and Cynara Cardunculus extract, 300 mg/day for 12 weeks. The control group received a placebo daily. Liver fat content, by transient elastography, serum transaminases, lipids and glucose were measured at the baseline and the end of the study. Results: We found a greater liver fat content reduction in the participants taking the nutraceutical rather than placebo (-48.2 ± 39 vs. -26.9 ± 43 dB/m, p = 0.02); The percentage CAP score reduction was statistically significant in those with android obesity, overweight/obesity as well as in women. However, after adjustment for weight change, the percentage CAP score reduction was statistically significant only in those over 50 years (44 vs. 78% in placebo and nutraceutical, respectively, p = 0.007). Conclusions: This specific nutraceutical containing bioactive components from Bergamot and wild cardoon reduced the liver fat content during 12 weeks in individuals with liver steatosis over 50 years. If confirmed, this nutraceutical could become the cornerstone treatment of patients affected by liver steatosis. Clinical Trial Registration: www.isrctn.com, identifier ISRCTN12833814.

Plant-Based Dietary Patterns, Plant Foods, and Age-Related Cognitive Decline

The aging population is expanding, as is the prevalence of age-related cognitive decline (ARCD). Of the several risk factors that predict the onset and progression of ARCD, 2 important modifiable risk factors are diet and physical activity. Dietary patterns that emphasize plant foods can exert neuroprotective effects. In this comprehensive review, we examine studies in humans of plant-based dietary patterns and polyphenol-rich plant foods and their role in either preventing ARCD and/or improving cognitive function. As yet, there is no direct evidence to support the benefits of a vegetarian diet in preventing cognitive decline. However, there is emerging evidence for brain-health-promoting effects of several plant foods rich in polyphenols, anti-inflammatory dietary patterns, and plant-based dietary patterns such as the Mediterranean diet that include a variety of fruits, vegetables, legumes, nuts, and whole grains. The bioactive compounds present in these dietary patterns include antioxidant vitamins, polyphenols, other phytochemicals, and unsaturated fatty acids. In animal models these nutrients and non-nutrients have been shown to enhance neurogenesis, synaptic plasticity, and neuronal survival by reducing oxidative stress and neuroinflammation. In this review, we summarize the mounting evidence in favor of plant-centered dietary patterns, inclusive of polyphenol-rich foods for cognitive well-being. Randomized clinical trials support the role of plant foods (citrus fruits, grapes, berries, cocoa, nuts, green tea, and coffee) in improving specific domains of cognition, most notably frontal executive function. We also identify knowledge gaps and recommend future studies to identify whether plant-exclusive diets have an added cognitive advantage compared with plant-centered diets with fish and/or small amounts of animal foods.

Effect Of An Extra-Virgin Olive Oil Intake On The Delay Of Cognitive Decline: Role Of Secoiridoid Oleuropein?

Currently, there is an increase in the number of the world's aging population. This aging process is often connected with cognitive decline of some functions such as memory or speed processing loss. Since Alzheimer's disease cannot be cured yet, considerable efforts are being made to at least delay this cognitive decline among elderly in order to maintain and prolong the quality of their life. This can also be achieved by non-pharmacological approaches such as performing physical activities, cognitive training, or adhering to a Mediterranean Diet (MedDiet). One of the components of MedDiet - extra-virgin olive oil (EVOO) - has considerable health benefits. The purpose of this review is to examine the effect of EVOO intake on the delay of cognitive decline among the elderly. The methodology is based on a literature review of available sources found on the research topic in three acknowledged databases: Web of Science, Scopus, and PubMed. The results of in vitro and in vivo studies indicate that the regular intake of EVOO is associated with enhanced cognitive functions, which means that this oil may have a neuroprotective effect and could positively prevent the development of dementia, especially Alzheimer's dementia. It is believed that secoiridoid oleuropein is responsible for this effectiveness. Furthermore, there is also a need of more randomized controlled studies or longitudinal observational studies to be performed to confirm the efficacy of the beneficial health effect of EVOO on the delay of cognitive decline.

Mediterranean and MIND Diets Containing Olive Biophenols Reduces the Prevalence of Alzheimer's Disease

The risk of Alzheimer’s disease (AD) increases with nonmodifiable conditions including age and lack of effective efficacious pharmacotherapy. During the past decades, the non-pharmacotherapy mode of treatment of dietary modification received extensive attention in AD research. In order to reduce the AD pathology and cognitive decline, various dietary patterns have been attempted including caloric restriction (CR), dietary approaches to stop hypertension (DASH), ketogenic diets (KD), Mediterranean diet (MedDi) and Mediterranean-DASH diet Intervention for Neurological Delay (MIND) diet. Higher adherence to the MedDi diet was associated with decreases in cardiovascular and neurological disorders including AD and related cognitive decline. However, another emerging healthy dietary pattern MIND diet has also been associated with slower rates of cognitive decline and significant reduction of AD rate. Olive serves as one of the building block components of MedDi and MIND diets and the exerted potential health beneficial might be suggested due to the presence of its bioactive constituents such as oleic acids and phenolic compounds (biophenols). A few trials using medical food showed an optimal result in presymptomatic or early stages of AD. The review supports the notion that MedDi and MIND diets display potential for maintaining the cognitive function as nonpharmacological agents against AD pathology and proposed preventative mechanism through the presence of olive biophenols and presents the gaps along with the future directions.

Interventions involving a major dietary component improve cognitive function in cognitively healthy adults: a systematic review and meta-analysis

Accumulating evidence suggests a role for diet in promoting brain health. The purpose of this systematic review was to (1) quantitatively assess whether interventions with a major dietary component can enhance cognition in cognitively healthy adults and (2) identify responsive domains of cognition to inform the design of future dietary trials. Electronic databases were systematically searched to find eligible randomized controlled trials that assessed the effect of interventions with a major dietary component on cognitive function or incident dementia in adults without known cognitive impairment. Standardized mean differences (SMDs) (95% confidence interval [CI]) were combined using a random-effects meta-analysis, and tests of homogeneity of variance were calculated. Two trials reported dementia outcomes and were qualitatively described. Fifteen trials encompassing 6480 participants were eligible for meta-analysis. Compared to control, intervention improved performance on measures of global cognition (SMD = 0.14, 95% CI 0.01-0.27, P = .05, I² 76%), executive function (SMD = 0.11, 95% CI 0.04-0.18, P = .003, I² 0%), and processing speed (SMD = 0.12, 95% CI 0.05-0.19, P = .001, I² 0%). There was no effect of intervention on delayed memory (SMD = 0.04, 95% CI -0.02 to 0.09, P = .18, I² 4%). Significant heterogeneity and funnel plot asymmetry were detected for global cognition, but removal of studies with high risk of bias did not change the pooled findings. Current evidence is limited but indicates that diverse interventions improve nonmemory cognitive functions during normal cognitive aging. Measures of executive function and processing speed should be considered as feasible end points in future dietary intervention trials.