Week 12: Nutrition and the brain Flashcards
Cognition
Process of acquiring knowledge and understanding, remembering and using info
Memory
- Sensory memory
- Working memory
- Long-term memory
Sensory memory
Remembering what you see in environment
Working memory
Used in execution of cognitive tasks
Long-term memory
Storage and recall of info over a long period of time
Memory formation
Involves changing the neurons involved in a neural activity and makes it easier to reactivate them in the future
Hippocampus
Involved in memory, learning and emotion, holds short term memories and transfers them to long term storage
Saturated fats and cognition
Increased saturated fats intake is associated with increased risk of cognitive impairment
What two things does increased saturated fat intake lead to?
- Increased risk of Alzeimer’s disease
- Perform worse on cognitive tasks
Why do saturated fats negatively impact cognition?
- Oxidative stress
- Reduced BDNF levels
- Increased insulin resistance
- Inflammatory response
Roles of brain-derived neurotrophic factor (BDNF)
- Neuroprotection
- Neuroplasticity
- Regulation of mood
- Long-term memory formation
- Neurogenesis
Neuroprotection
Protects existing neurons and encourages growth and differentiation of new neurons
Neuroplasticity
Ability of synapses to strengthen or weaken
Regulation of mood
Low levels of BDNF leads to mood disorders
What is low levels of BDNF associated with?
Neurodegenerative disorders such as Parkinson’s disease, Alzheimer’s disease and Huntington’s
Oxidative stress
Occurs when there is more free radicals than antioxidants
Free radicals
Atoms/molecules with unpaired electrons; highly reactive/unstable molecules that can cause damage to cells, proteins and DNA
Antioxidants
Substance that protects cells from damage caused by free radicals bc they provide a free electron to free radicals to stabilize them
Vitamin E supplementation
Antioxidants attenuate declines in cognition caused by a high fat diet
Inflammatory response and saturated fat
High-fat diet increases pro-inflammatory cytokines, causing more to cross the blood-brain barrier and act on the hippocampus to negatively affect its circuitry
Function of Omega-3 in the brain
- Structural component of brain cell membrane
- Neurotransmitter function
- Neuroprotection
- Brain development and function
What percentage of brain weight is from lipids?
50-60% (35% from omega-3 PUFAs)
How does omega-3 improve brain development and function?
Building blocks for proper fetal and early childhood brain development
What is Omega-3 deficiency associated with?
Elevated risk of developing depression, dementia, schizophrenia, bipolar disorder and ADHD
What omega-3 is more common in neuronal membranes?
EPA, can’t synthesize DHA
What does consumption of omega-3 improve?
Learning, memory and blood flow to brain
Potential mechanisms of omega-3s affect on cognition
- Reduction in oxidative stress
- Increased BDNF levels in hippocampus
- Facilitate synaptic plasticity
Mild cognitive impairment
Impaired mental processing that is noticeable but doesn’t interfere with independent living
Dementia
Several diseases that affect memory, thinking and the ability to perform daily activities
Omega-3 supplementation and mild cognitive impairment
Attenuates cognitive decline in those with mild cognitive impairment but not alzheimer’s
Omega-3 supplementation and cognition in healthy aging population
Increases cognitive performance
Omega-3s and depression
Decrease risk of depression and depressive symptoms in those suffering from depressive disorder
Omega-3 effect on people without depressive disorder
No effect
Sugar intake and cognition
Higher intake of sugary beverages is associated with lower total brain volume and poorer performance on tests of episodic memory
Sugar intake and incidence of dementia
More sugar=increased hazard ratio of developing dementia
Glucose facilitation effect
Phenomenon whereby following the ingestion of a glucose drink, there are transient improvements in cognitive performance bc of this acute carb consumption
Positive effects of acute carb consumption
- Long term memory
- Processing speed and reaction time
- Working memory performance (declarative and episodic memory)
- Executive function
- Attention
What effect do more cognitively demanding tasks have on glucose loading?
More cognitively demanding tasks are more sensitive to the effects of glucose loading
Study on cognitive tasks and glucose loading
Beneficial effect of glucose on memory was detected after the more cognitively demanding tasks (hand and key conditions)
What is the only cognitive ability that doesn’t decline with age?
Vocabulary
Glucoregulation
Ability to regulate blood glucose
Declines w age
Elevated blood glucose and cognition
Leads to cognitive impairments in healthy population and diseased states such as diabetes
Glycemic control and cognition
Improvements in glycemic control improve cognitive performance
What produces the greatest degree of cognitive impairment?
Both poor glucose regulation and increasing age interact
How does glucose administration effect cognitive performance?
Improves cognitive performance in those with worse glucoregulation but had little effects in people with better glucoregulation bc it attenuates the effects of poor glucoregulation
What population does glucose have more of an effect on regarding cognitive functioning?
Older population
Long-term exposure to simple sugar
Associated with cognitive decline
In what population is the glucose facilitation effect more pronounced?
More pronounced in those with poor glucose regulation and in older populations
How to improve glycemic control?
High fiber diet
Exercise
Weight management
Low GI foods
Protein consumption
Reduce carbohydrate consumption
Ingest omega’s
Polyphenols
Micronutrient characterized by presence of multiple phenol (hydroxyl groups)
Whats foods contain polyphenols?
Berries
Cocoa powder
Nuts and flaxseed
Coffee and tea
Vegetables and olives
Effect of polyphenols on cognition
Reduced risk of developing dementia and improved cognitive performance in normal aging
Potential mechanisms of the effects of polyphenols on cognition
- Decrease neuroinflammation
- Increase cerebral blood flow
- decrease oxidative stress
- Decrease inflammation
High flavenoid diet and cognitive function
Significant improvement
Polyphenols and BDNF
Significant increase
Effects of acute polyphenol supplementation
Improved visual spatial memory and faster reaction time
Potential mechanisms of acute polyphenol supplementation
- Improved cerebral blood flow
- Enhance BDNF concentration
- Improve connectivity of hippocampus
- Reduction in inflammation and oxidative stress
Minerals associated with mental health
Zinc
B vitamins
Vitamin D
Zinc deficiency
Associated with depressive symptoms, affects BDNF levels
B vitamins
Associated with depressive symptoms
Vitamin D
Associated with schizophrenia and depression
How do bacteria communicate with the CNS?
- Producing neurotransmitters
- Secreting amino acids and short chain fatty acids
Gut dysbiosis and cognition
Neuroinflammation caused by gut dysbiosis results in reduced BDNF, leading to cognitive impairment, anxiety and depression
Healthy gut
Anti-inflammatory, results in increased BDNF, cognitive improvements, anxiety and depressive symptoms
How does stress affect the microbiome?
Induces leaky gut leading to metabolic disease
Prebiotic
Non-digestible food whose fermentation in the GI tract stimulates either bacterial growth or activity
Probiotic
Living organism, that when consumed in adequate amounts, have positive effects on the body
Probiotics and depressive symptoms
Attenuate depressive symptoms
Microbiome and behavioural patterns
Colonization of germ free mice with microbiota from NIH swiss mice increased exploratory behaviour and hippocampal levels of BDNF
- behaviour transplanted along with microbiome
Microbiome and non-spatial and working memory
Germ-free mice lacked non-spatial and working memory in response to novel object test and T-maze compared to SPF swiss webster mice
(absence of microbiome led to low exploration)
Bacterial infection and memory
Bacterial infection causes stress-induced memory dysfunction in mice
Treatment with probiotics for bacterial infections and cognition
Attenuates effects of bacterial infection and has positive effects on cognition
Probiotic administration in older adults
Improves cognitive functioning, depressive symptoms and stress
Mediterranean diet overview
Minimally processed plant-based diet based on the diet of those living in the Mediterranean region
Mediterranean diet foods included
Extra virgin olive oil
Fruit
Legumes
Nuts and seeds
Vegetables
Whole grains
Lean meats, fish and dairy
Mediterranean diet foods excluded
Red meat, refined and processed food and sugars
DASH diet overview
Minimally processed plant-based dietary intervention for cardiometabolic conditions
DASH diet foods included
Fruit
Lean meat
Low-fat dairy
Nuts
Vegetables
Whole grains
DASH diet foods excluded
Fat intake
Red meat
Sugar containing beverages and sweets
MIND diet overview
Minimally processed plant-based dietary intervention of cognitive decline and certain age-related neurodegenerative conditions
MIND diet foods included
Beans, berries, olive oil, fish, green leafy vegetables, nuts, poultry, vegetables, whole grains
MIND diet foods excluded
Butter and margarine
Cheese
Fried or fast foods
Red meats
Sweets
What is the mediterranean diet linked with?
Low risk of cognitive decline, dementia and Alzheimer’s disease
What does the MIND diet combine?
Components of mediterranean and DASH diets that have the compelling research for preventing cognitive decline
MIND diet and cognitive decline
High adherence to MIND diet delays cognitive decline with aging
Order of best diet for delaying cognitive decline
- MIND
- Mediterranean
- DASH
** all associated with less cognitive decline and lower risk of alzheimer’s
Effects of MIND diet
Increased antioxidants
Increased gut microbiota
Reduced neuroinflammation
Reduced insulin resistance
What is Omega-3?
Refers to the position of the final double bond in the molecular chain; 3 carbon molecules away from omega end of chain
Which type of working memory shows greatest declines with aging?
Episodic
Memory formation and neurotransmitters
Increased number of neurotransmitters and increased receptors at synapse
