Brain Health

Peer-Reviewed Scientific Articles​

Meat and mental health: A meta-analysis of meat consumption, depression, and anxiety

URL: https://www.tandfonline.com/doi/full/10.1080/10408398.2021.1974336

Journal: Critical Reviews in Food Science and Nutrition

Publication Date: 10/2021

Summary: In this meta-analysis, we examined the quantitative relation between meat consumption or avoidance, depression, and anxiety. in June 2020, we searched five online databases for primary studies examining differences in depression and anxiety between meat abstainers and meat consumers that offered a clear (dichotomous) distinction between these groups. Twenty studies met the selection criteria representing 171,802 participants with 157,778 meat consumers and 13,259 meat abstainers. we calculated the magnitude of the effect between meat consumers and meat abstainers with bias correction (Hedges’s g effect size) where higher and positive scores reflect better outcomes for meat consumers. Meat consumption was associated with lower depression (Hedges’s g=0.216, 95% Ci [0.14 to 0.30], p < .001) and lower anxiety (g=0.17, 95% Ci [0.03 to 0.31], p = .02) compared to meat abstention. Compared to vegans, meat consumers experienced both lower depression (g=0.26, 95% Ci [0.01 to 0.51], p = .041) and anxiety (g=0.15, 95% Ci [-0.40 to 0.69], p = .598). Sex did not modify these relations. Study quality explained 58% and 76% of between-studies heterogeneity in depression and anxiety, respectively. The analysis also showed that the more rigorous the study, the more positive and consistent the relation between meat consumption and better mental health. The current body of evidence precludes causal and temporal inferences.

Key Takeaways

Individuals who consume meat had lower rates of anxiety and depression than vegans.

Vegans Are More Anxious and Depressed than Meat Eaters

Ketone Bodies can provide Neuroprotection in Neurological Diseases

URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6581710/

Journal: Front Neurol

Publication Date: 05/2016

Summary: There is growing evidence that ketone bodies, which are derived from fatty acid oxidation and usually produced in fasting state or on high-fat diets have broad neuroprotective effects. Although the mechanisms underlying the neuroprotective effects of ketone bodies have not yet been fully elucidated, studies in recent years provided abundant shreds of evidence that ketone bodies exert neuroprotective effects through possible mechanisms of anti-oxidative stress, maintaining energy supply, modulating the activity of deacetylation and inflammatory responses. Based on the neuroprotective effects, the ketogenic diet has been used in the treatment of several neurological diseases such as refractory epilepsy, Parkinson’s disease, Alzheimer’s disease, and traumatic brain injury. The ketogenic diet has great potential clinically, which should be further explored in future studies. It is necessary to specify the roles of components in ketone bodies and their therapeutic targets and related pathways to optimize the strategy and efficacy of ketogenic diet therapy in the future.

Key Takeaways

Ketone bodies produced by fat burning metabolism likely have a protective effect on the brain. Ketogenic diets have been used in the treatment of neurologic diseases such as epilepsy, Parkinson's, Alzheimer's, and traumatic brain injury. The exact mechanism that ketones play in protecting the brain is still being studied, but the current evidence points to the ketone's ability to reduce oxidative stress, reduce inflammation, and maintain energy supply in the brain.

Ketones Protect The Brain From Injury and Degeneration

Nutrition and Alzheimer’s disease: The detrimental role of a high carbohydrate diet

URL: https://www.ejinme.com/article/S0953-6205(11)00004-5/fulltext

Journal: European Journal of Internal Medicine

Publication Date: 04/2011

Summary: Alzheimer’s disease is a devastating disease whose recent increase in incidence rates has broad implications for rising health care costs. Huge amounts of research money are currently being invested in seeking the underlying cause, with corresponding progress in understanding the disease progression. In this paper, we highlight how an excess of dietary carbohydrates, particularly fructose, alongside a relative deficiency in dietary fats and cholesterol, may lead to the development of Alzheimer’s disease. A first step in the pathophysiology of the disease is represented by advanced glycation end-products in crucial plasma proteins concerned with fat, cholesterol, and oxygen transport. This leads to cholesterol deficiency in neurons, which significantly impairs their ability to function. Over time, a cascade response leads to impaired glutamate signaling, increased oxidative damage, mitochondrial and lysosomal dysfunction, increased risk to microbial infection, and, ultimately, apoptosis. Other neurodegenerative diseases share many properties with Alzheimer’s disease, and may also be due in large part to this same underlying cause.

Key Takeaways

Excess carbohydrates in the diet play an important role in the development of Alzheimer's disease. Carbohydrates in the diet are broken down to sugars that when present in excessive quantities allows them to bind to proteins and impair their function. When these sugars bind to proteins essential for carrying fat, cholesterol, and oxygen to the brain, signaling mechanisms in the brain become impaired, which leads to inflammation, mitochondrial and lysosomal dysfunction, infection susceptibility, and cell death.

Are Carbohydrates Causing Alzheimer's Disease?

The ketogenic diet as a treatment paradigm for diverse neurological disorders

URL: https://www.frontiersin.org/articles/10.3389/fphar.2012.00059/full

Journal: Frontiers in Pharmacology

Publication Date: 04/2012

Summary: Dietary and metabolic therapies have been attempted in a wide variety of neurological diseases, including epilepsy, headache, neurotrauma, Alzheimer disease, Parkinson disease, sleep disorders, brain cancer, autism, pain, and multiple sclerosis. The impetus for using various diets to treat – or at least ameliorate symptoms of – these disorders stems from both a lack of effectiveness of pharmacological therapies, and also the intrinsic appeal of implementing a more “natural” treatment. The enormous spectrum of pathophysiological mechanisms underlying the aforementioned diseases would suggest a degree of complexity that cannot be impacted universally by any single dietary treatment. Yet, it is conceivable that alterations in certain dietary constituents could affect the course and impact the outcome of these brain disorders. Further, it is possible that a final common neurometabolic pathway might be influenced by a variety of dietary interventions. The most notable example of a dietary treatment with proven efficacy against a neurological condition is the high-fat, low-carbohydrate ketogenic diet (KD) used in patients with medically intractable epilepsy. While the mechanisms through which the KD works remain unclear, there is now compelling evidence that its efficacy is likely related to the normalization of aberrant energy metabolism. The concept that many neurological conditions are linked pathophysiologically to energy dysregulation could well provide a common research and experimental therapeutics platform, from which the course of several neurological diseases could be favorably influenced by dietary means. Here we provide an overview of studies using the KD in a wide panoply of neurologic disorders in which neuroprotection is an essential component.

Key Takeaways

The ketogenic diet has been shown to be neuroprotective and used in the treatment of epilepsy. The exact mechanisms of how the diet is protective against epilepsy is unclear, but it is thought that energy regulation plays a major role. Because the ketogenic diet does not rely on continuous inputs of carbohydrates, blood sugar levels remain constant. Without these large fluctuations in blood sugar, the energy supply to the brain is stable resulting in a reduction in seizures. Additionally, ketone bodies produced by burning fat are neuroprotective in their own way through a variety of actions. This dietary approach has been shown to be helpful in treating other neurologic conditions such as headache, neurotrauma, Alzheimer disease, Parkinson disease, sleep disorders, brain cancer, autism, pain, and multiple sclerosis.

Is The Ketogenic Diet The Best Treatment For Neurologic Diseases?

Dietary ketosis enhances memory in mild cognitive impairment

URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3116949/

Journal: Nuerobiology of Aging

Publication Date: 02/2012

Summary: We randomly assigned 23 older adults with Mild Cognitive Impairment to either a high carbohydrate or very low carbohydrate diet. Following the six-week intervention period, we observed improved verbal memory performance for the low carbohydrate subjects (p = 0.01) as well as reductions in weight (p < 0.0001), waist circumference (p < 0.0001), fasting glucose (p = 0.009), and fasting insulin (p = 0.005). Level of depressive symptoms was not affected. Change in calorie intake, insulin level, and weight were not correlated with memory performance for the entire sample, although a trend toward a moderate relationship between insulin and memory was observed within the low carbohydrate group. Ketone levels were positively correlated with memory performance (p = 0.04). These findings indicate that very low carbohydrate consumption, even in the short-term, can improve memory function in older adults with increased risk for Alzheimer’s disease. While this effect may be attributable in part to correction of hyperinsulinemia, other mechanisms associated with ketosis such as reduced inflammation and enhanced energy metabolism also may have contributed to improved neurocognitive function. Further investigation of this intervention is warranted to evaluate its preventive potential and mechanisms of action in the context of early neurodegeneration.

Key Takeaways

Low carbohydrate ketogenic diets showed improved memory, weight loss, blood sugar, and fasting insulin in adults with mild cognitive impairment. Further research is needed to determine whether the improvement is due to correction of high insulin levels, or the reduction in inflammation brought about by the ketosis.

Ketogenic Diet Improves Memory in Adults With Cognitive Impairment

Meat and mental health: a systematic review of meat abstention and depression, anxiety, and related phenomena

URL: https://www.tandfonline.com/doi/full/10.1080/10408398.2020.1741505

Journal: Critical Reviews in Food Science and Nutrition

Publication Date: 04/2020

Summary: To examine the relation between the consumption or avoidance of meat and psychological health and well-being. A systematic search of online databases (PubMed, PsycINFO, CINAHL Plus, Medline, and Cochrane Library) was conducted for primary research examining psychological health in meat-consumers and meat-abstainers. Inclusion criteria were the provision of a clear distinction between meat-consumers and meat-abstainers, and data on factors related to psychological health. Studies examining meat consumption as a continuous or multi-level variable were excluded. Summary data were compiled, and qualitative analyses of methodologic rigor were conducted. The main outcome was the disparity in the prevalence of depression, anxiety, and related conditions in meat-consumers versus meat-abstainers. Secondary outcomes included mood and self-harm behaviors. Eighteen studies met the inclusion/exclusion criteria; representing 160,257 participants (85,843 females and 73,232 males) with 149,559 meat-consumers and 8584 meat-abstainers (11 to 96 years) from multiple geographic regions. Analysis of methodologic rigor revealed that the studies ranged from low to severe risk of bias with high to very low confidence in results. Eleven of the 18 studies demonstrated that meat-abstention was associated with poorer psychological health, four studies were equivocal, and three showed that meat-abstainers had better outcomes. The most rigorous studies demonstrated that the prevalence or risk of depression and/or anxiety were significantly greater in participants who avoided meat consumption. Studies examining the relation between the consumption or avoidance of meat and psychological health varied substantially in methodologic rigor, validity of interpretation, and confidence in results. The majority of studies, and especially the higher quality studies, showed that those who avoided meat consumption had significantly higher rates or risk of depression, anxiety, and/or self-harm behaviors. There was mixed evidence for temporal relations, but study designs and a lack of rigor precluded inferences of causal relations. Our study does not support meat avoidance as a strategy to benefit psychological health

Key Takeaways

Meat eaters had less anxiety and depression that those who abstain from eating meat.

Vegans are More Anxious and Depressed

Changes in Food Cravings and Eating Behavior after a Dietary Carbohydrate Restriction Intervention Trial

URL: https://www.mdpi.com/2072-6643/12/1/52

Journal: Nutrients

Publication Date: 12/2019

Summary: Compared to low-fat diets, low-carbohydrate (CHO) diets cause weight loss (WL) over a faster time frame; however, it is unknown how changes in food cravings and eating behavior contribute to this more rapid WL in the early phases of dieting. We hypothesized that reductions in food cravings and improved eating behaviors would be evident even after a relatively short (4-week) duration of CHO-restriction, and that these changes would be associated with WL. Adult participants (n = 19, 53% males, mean ± SD: BMI = 34.1 ± 0.8 kg/m2; age 40.6 ± 1.9 years) consumed a CHO-restricted diet (14% CHO, 58% fat, 28% protein) for 4 weeks. Before and after the intervention, specific and total cravings were measured with the Food Craving Inventory (FCI) and eating behaviors assessed with the Three-Factor Eating questionnaire. Food cravings were significantly reduced at week 4, while women had significantly greater reductions in sweet cravings than men. Dietary restraint was significantly increased by 102%, while disinhibiton and hunger scores were reduced (17% and 22%, respectively, p < 0.05). Changes in cravings were unrelated to changes in body weight except for the change in high-fat cravings where those who lost the most weight experienced the least reductions in fat cravings (r = −0.458, p = 0.049). Changes in dietary restraint were inversely related to several FCI subscales. A short-term, low-CHO diet was effective in reducing food cravings. These data suggest that in subjects that have successfully lost weight on a low-CHO diet, those who craved high-fat foods at the onset were able to satisfy their cravings—potentially due to the high-fat nature of this restricted diet.

Key Takeaways

Low carbohydrate diets for as short as 4 weeks can reduce food cravings, including sweet cravings, and accelerate weight loss.

Having Cravings While Dieting? A Ketogenic Diet Can Reduce Cravings and Improve Weight Loss

Treating binge eating and food addiction symptoms with low-carbohydrate Ketogenic diets: a case series

URL: https://jeatdisord.biomedcentral.com/track/pdf/10.1186/s40337-020-0278-7

Journal: Journal of Eating Disorders

Publication Date: 01/2020

Summary: Many patients with obesity and comorbid binge eating symptoms present with the desire to lose weight. Although some studies suggest that dietary restriction can exacerbate binge eating, others show dietary restriction is associated with significant reductions in binge eating. The effect of a particular type of dieting on binge eating, the ketogenic diet (a high fat, moderate protein, very low carbohydrate diet), is not known. We report on the feasibility of a low-carbohydrate ketogenic diet initiated by three patients (age 54, 34, and 63) with obesity (average BMI 43.5 kg/m2) with comorbid binge eating and food addiction symptoms. All patients tolerated following the ketogenic diet (macronutrient proportion 10% carbohydrate, 30% protein, and 60% fat; at least 5040 kJ) for the prescribed period (e.g., 6–7 months) and none reported any major adverse effects. Patients reported significant reductions in binge eating episodes and food addiction symptoms including cravings and lack of control as measured by the Binge-Eating Scale, Yale Food Addiction Scale, or Yale- Brown Obsessive-Compulsive Scale modified for Binge Eating, depending on the case. Additionally, the patients lost a range of 10–24% of their body weight. Participants reported maintenance of treatment gains (with respect to weight, binge eating, and food addiction symptoms) to date of up to 9–17 months after initiation and continued adherence to diet. Although the absence of control cases precludes conclusions regarding the specific role of ketogenic diets versus other forms of dietary restriction, this is the first report to demonstrate the feasibility of prescribing a ketogenic diet for patients with obesity who report binge eating and food addiction symptoms. Further research should seek to reproduce the observed effects in controlled trials as well as to explore potential etiologies.

Key Takeaways

Low carbohydrate ketogenic diets can be an effective way of reducing binge eating episodes and stimulating weight loss in individuals with binge eating disorder.

Ketogenic Diets Can Reduce Binge Eating

Intermittent fasting from dawn to sunset for 30 consecutive days is associated with anticancer proteomic signature and upregulates key regulatory proteins of glucose and lipid metabolism, circadian clock, DNA repair, cytoskeleton remodeling, immune system and cognitive function in healthy subjects

URL: https://www.sciencedirect.com/science/article/pii/S1874391920300130

Journal: Journal of Proteomics

Date of Publication: 04/2020

Summary: Murine studies showed that disruption of circadian clock rhythmicity could lead to cancer and metabolic syndrome. Time-restricted feeding can reset the disrupted clock rhythm, protect against cancer and metabolic syndrome. Based on these observations, we hypothesized that intermittent fasting for several consecutive days without calorie restriction in humans would induce an anticarcinogenic proteome and the key regulatory proteins of glucose and lipid metabolism. Fourteen healthy subjects fasted from dawn to sunset for over 14 h daily. Fasting duration was 30 consecutive days. Serum samples were collected before 30-day intermittent fasting, at the end of 4th week during 30-day intermittent fasting, and one week after 30-day intermittent fasting. An untargeted serum proteomic profiling was performed using ultra high-performance liquid chromatography/tandem mass spectrometry. Our results showed that 30-day intermittent fasting was associated with an anticancer serum proteomic signature, upregulated key regulatory proteins of glucose and lipid metabolism, circadian clock, DNA repair, cytoskeleton remodeling, immune system, and cognitive function, and resulted in a serum proteome protective against cancer, metabolic syndrome, inflammation, Alzheimer’s disease, and several neuropsychiatric disorders. These findings suggest that fasting from dawn to sunset for 30 consecutive days can be preventive and adjunct therapy in cancer, metabolic syndrome, and several cognitive and neuropsychiatric diseases.

Key Takeaways

14 hour daily fasting from daw to sunset for 30 days showed upregulation of metabolic proteins, DNA repair enzymes, immune function, cognitive function, and circadian rhythm. This fasting regimen was also associated with protective effects against cancer, metabolic syndrome, inflammation, Alzheimer's disease, and psychiatric disorders.

Daily 14 Hour Fasting Provides a Host of Health Benefits

Higher Non-processed Red Meat Consumption Is Associated With a Reduced Risk of Central Nervous System Demyelination

URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6389668/pdf/fneur-10-00125.pdf

Journal: Frontiers in Neurology

Publication: 02/2019

Summary: The evidence associating red meat consumption and risk of multiple sclerosis is inconclusive. We tested associations between red meat consumption and risk of a first clinical diagnosis of central nervous system demyelination (FCD), often presaging a diagnosis of multiple sclerosis. We used food frequency questionnaire data from the 2003–2006 Ausimmune Study, an incident, matched, case-control study examining environmental risk factors for FCD. We calculated non-processed and processed red meat density (g/1,000 kcal/day). Conditional logistic regression models (with participants matched on age, sex, and study region) were used to estimate odds ratios (ORs), 95% confidence intervals (95% CI) and p-values for associations between non-processed (n = 689, 250 cases, 439 controls) and processed (n = 683, 248 cases, 435 controls) red meat density and risk of FCD. Models were adjusted for history of infectious mononucleosis, serum 25-hydroxyvitamin D concentrations, smoking, race, education, body mass index and dietary misreporting. A one standard deviation increase in non-processed red meat density (22 g/1,000 kcal/day) was associated with a 19% reduced risk of FCD (AOR = 0.81; 95%CI 0.68, 0.97; p = 0.02). When stratified by sex, higher non-processed red meat density (per 22 g/1,000 kcal/day) was associated with a 26% reduced risk of FCD in females (n = 519; AOR = 0.74; 95%CI 0.60, 0.92; p = 0.01). There was no statistically significant association between non-processed red meat density and risk of FCD in males (n = 170). We found no statistically significant association between processed red meat density and risk of FCD. Further investigation is warranted to understand the important components of a diet that includes non-processed red meat for lower FCD risk.

Key Takeaways

Increasing red meat consumption was associated with a 19% decrease in central nervous system demyelination, which can progress to multiple sclerosis.

Increased Red Meat Consumption Protective for Nervous System

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