Food for Thought: Exam Time Nutrition

Adele Gagnon, RD, Human Nutrition Research Unit Coordinator, University of Alberta

http://www.pamper.my/news/health/diet-nutrition/brain-food-can-improve-brain-power/

https://ueat.utoronto.ca/a-chronicle-of-brain-foods

Outline• Basic Metabolism & Brain Function

• Cognition & Macronutrients• Carbohydrate, fat

• Macronutrient manipulations

• Cognition & Hydration

• Cognition & Specific Nutrients

• Cognition & Other Habits

• Exam Nutrition• Practical tips, meal ideas, snack ideas

• Questions

Overview of basic metabolism, brain function• Your brain needs fuel!

• 2% of total body weight, but 20% of our energy needs

• Energy is needed for:

• Neurotransmitter synthesis & action

• Neuronal computation & information processing

• Foundations for learning & memory

• Your brain needs carbohydrate (CHO)

• Glucose is only usable source of energy

• Can be produced from alternate forms of energy (fat, protein) if neededhttps://www.arcticapples.com/feed-your-brain

What should I eat in order to perform well on my exams?

Cognition

• What is cognition?

• Attention, perception, memory, reasoning, planning, problem solving, decision making, language, multitasking

• How do we measure it?

• Generalizability?

• Demographics of research participants

Nutrition

• Single nutrient versus whole food

• Single food versus dietary pattern

• Nutritional status?

• Research methodology

• Animal versus human studies

• Intervention studies

• Randomized control trials

• Observational studies

Macronutrients: Carbohydrate• Glucose is the only usable metabolic fuel for the

brain

• ↑ cognitive demand = ↑ glucose metabolism in the brain

• Hypoglycemia: low blood glucose

• Hypoglycemia negatively affects mental performance• Visual, auditory processing

• Response to hypoglycemia affected by several variables:• Sex, previous hypoglycemic episodes, hypoglycemic

unawareness, IQ

• Threshold of cognitive impairment 2.2-2.8 mmol/L

https://www.everydayhealth.com/weight/why-carbohydrates-are-important-for-your-diet.aspx

Macronutrients: Fat• Saturated – ex. animal fat, butter, cheese, milk,

coconut oil, palm oil

• Unsaturated• Monounsaturated – Olive, canola, peanut, safflower, sesame

oils; almonds, pecans, cashews, avocado

• Polyunsaturated – salmon, mackerel, sardines, flaxseed, walnuts, soybean oil, canola oil

• Diets higher in saturated fats may increase inflammation in the brain• Impairment of signal transmission in the brain

• Type of fat in diet may impact learning acquisition• Saturated versus unsaturated

• Performance of variable (interval delayed) alteration task worsened with higher saturated fat intake

• BUT…..http://www.heartandstroke.ca/get-healthy/healthy-eating/fats-and-oils

https://statistically-funny.blogspot.com/2014/10/sheesh-what-are-those-humans-thinking.html

Macronutrient Manipulations:Carbohydrate & Protein• High Carbohydrate meals versus high protein meals• ↑ CHO meals produce greater drowsiness, sleepiness, calmness

• Slower reaction time, impaired attention after high CHO meals

• High protein meals produce susceptibility to distraction, slower memory scanning

• Since CHO & protein have different effects on cognitive tasks, they are likely important for different cognitive processes

• Effect of stress in macronutrient manipulations• Alterations in availability of tryptophan and brain serotonin concentrations

• Improvement of memory scanning task in stress prone subjects when fed CHO rich, protein poor diet compared with CHO poor, protein rich

Macronutrient Manipulations:Carbohydrate & Fat• Inconsistencies in methodology, outcomes

• Small sample sizes, insufficient power

• High fat lunch produce slower reaction time• But more accurate performance on selective-attention tasks

• High fat, low CHO versus low fat, high CHO versus medium fat, medium CHO• Reaction time was slower with high fat, low CHO and low fat, high CHO compared to

medium fat/CHO

• Higher than usual CHO or fat may cause ↑drowsiness, uncertainty, muddled thoughts

Meal Timing & Novelty• Effect of macronutrients may be mediated by time of ingestion, also in relation to time of

testing

• Cognitive performance improves until midday, then declines

• Breakfast• ?Improvement with consumption (word recall, spatial memory)

• Effect of caffeine

• Lunch

• Most studies show a decline in performance (perceptual discrimination vigilance)• Snacks

• AM & PM snacks show varying results on cognitive performance

• Dinner• Limited data, since most work happens during the day (except for students!)

• Novelty of meal

Macronutrients: Take home messages?• Eating a variety of foods is important

• Everyone is different

• Generally, people need to eat every 4-6 hours

• Listen to your body

• Following habitual intake on exam day or studying for exams may be best

https://studybreaks.com/college/eat-2

Hydration & Cognitive Performance• One of the most important aspects of nutrition

to protect cognitive functioning

• Changes in electrolytes can alter neurotransmitter functioning

• Compromise blood flow to brain

• Attention, psychomotor, immediate memory skills

• Cognitive compensation through increasing subjective task effort

• 2% loss in hydration status can lead to impaired cognitive functioning• More pronounced in women than men

https://www.hawaiipacifichealth.org/healthier-hawaii/live-healthy/drink-up-the-importance-of-hydration/

Am I well hydrated?• Colour of urine

• Other symptoms: thirst, dry lips, flushed skin, tiredness, headache, dizziness, etc

• Recommendations• Men: 3.7 L/d

• Women: 2.7 L/d

• 30-35 ml/kg body weight Best food & drink sources for hydration

• Sources of water• Water & other beverages, fruits, vegetables

• Sports drinks generally are not necessary

• Caffeine does not have a diuretic effect*

https://mcgregorfast.com/fitness/hydration-status-measured-2/

Specific Nutrients & Cognition

Specific Nutrients & Cognition:Omega-3 Fatty Acids• Various forms found in food, synthesized in body• ALA → DHA, EPA

• ALA requirement• 1.6 g/d males; 1.1 g/d females

• 1 tbsp. chia seeds: 1.9 g

• 1 tbsp. flaxseeds (ground) 2.43 g

• DHA, EPA no requirement set• Cold water fatty fish, algae, fortified foods, supplements

• Highly researched in health, disease prevention & management• Cancer

• Heart disease

• Depression

• Aging

• MANY MORE!

https://oceanblueomega.com/how-to-balance-your-omega-6-to-omega-3-ratio/

Specific Nutrients & Cognition:Omega-3 Fatty Acids• Lots of research, but…• Neurodegeneration, school aged children

• Observational studies• Associations between cognitive performance & fatty acid

status

• Mixed results

• Contribution of n-3 to cognitive performance seems to be more important in females

• Intervention studies• Provision of n-3 as DHA capsules

• Mixed results: some improvement, or no benefit

• Men: improved reaction time of working memory

• Women: improved accuracy of episodic memory

• Differences in results: dose used, DHA vs EPA?, dietary history of n-3 intake, relevance of cognitive tests

https://vancouverbia.org/omega-3-fatty-acid-intake-treatment-traumatic-brain-injury/

Specific Nutrients & Cognition: Iron• Most well known for role in transporting oxygen

to cells

• Men 19 & older: 8 mg/d

• Women 19-50: 18 mg/d• Upper limit: 45 g /d

• Vegetarians*

• Heme iron (animal sources)- meat, fish poultry; more easily absorbed

• Non-heme iron (plant sources)- dried beans, peas, lentils, some fruits & vegetables; less easily absorbed

• Inadequate dietary intake an lead to iron deficiency, or iron deficiency anemia

https://parenting.firstcry.com/articles/15-iron-rich-foods-for-babies-and-toddler/

Specific Nutrients & Cognition: Iron• Iron deficiency may disrupt metabolic

processes, change cognitive/ behavior functioning

• Women of reproductive age particularly susceptible to deficiency

• Intervention study: • Women 18-35 y/o of varied iron status

• Assigned to Iron or placebo x 4 mo

• Improvement in iron status associated with 5-7 fold improvement in cognitive performance

http://www.diagnosisdiet.com/micronutrients-mental-health/brain-needs-iron/

Specific Nutrients & Cognition: Caffeine• Naturally occurring in food/drink

• Additive to food, drink, or supplements

• Increases wakefulness, mental alertness, cognitive functioning

• Negative effects on withdrawal, or excess consumption

• Differences in individual sensitivity

• Health Canada Recommendations:• Men & Women > 19 y/o: 400 mg/d

• Pregnant/breastfeeding women > 19: 300 mg/d

• *Most serving sizes of coffee, energy drinks are greater than 250 ml• Large coffee ~ 450 ml

• Monster Energy Drink 480 ml

Food Serving Size Caffeine (mg)

Coffee, brewed 250 ml (1 cup)* 100-170 mg

Espresso 30 ml (1 oz) 43-90 mg

Tea (black) 250 ml (1 cup)* 43-80 mg

Energy drink, various

250 ml (1 cup)* 80-100 mg

Diet cola 355 ml (1 can) 25-43 mg

Chocolate, dark 40 g 27 mg

Caffeine pills 1 serving 100-200 mg

Specific Nutrients & Cognition: Caffeine• Low to moderate doses improve cognition (40- 300 mg)

• Lower cognitive functions are improved- ex. Reaction time

• Higher cognitive functions- ex problem solving, decision making are debated

• Effects on cognition follow a U-shaped curve• Low arousal associated with poor performance, increased mental arousal associated with improved performance but only to a

point

• Caffeine consumers (average ~400 mg/d) exposed to long term or acute caffeine withdrawal• Cognitive testing in state of ‘sleep restriction’ with placebo or caffeine administration

• Acute caffeine withdrawal had a number of negative effects- impairment of cognitive performance, increased headache, reduced alertness & clear-headedness

• Caffeine administration following acute withdrawal prevented further decline in cognitive performance

• Caffeine administration after long term withdrawal did not improve cognitive performance

• If you are consuming caffeine regularly, don’t stop right before an exam!

• Effect of caffeine on cognition is relatively well established, less is known regarding effect when administered with other components (ie, energy drinks)

Cognitive Performance & Other Health Habits: Exercise• Reports that brief bouts of exercise improve

mood, psychological well being, and ability to think clearly

• General improvement of cognitive performance following exercise

• Submaximal aerobic exercise performed for periods up to 60 minutes facilitate specific aspects of information processing

• May be more energizing than caffeine in young women with chronic insufficient sleep• 10 minutes of stair walking versus 50 mg caffeine versus

placebo

• No difference in aspects of cognitive performance, but does have transient energizing effect

http://www.bewegenvoorjebrein.nl/page/2/

Cognitive Performance & Other Health: Sleep• Sleep is becoming a more studied variable in

several aspects of health and disease

• Regular and long timer disruptions in circadian rhythm can increase risk of disease

• Sleep of university students can be variable in duration & timing

• Consistently low sleep duration associated with cognitive impairments• Increased reaction times, reduced cognitive throughput

• Misalignment of circadian rhythms may also impair cognitive performance

• Sleep regularity is positively associated with academic performance

https://www.kisspng.com/png-brain-cartoon-sleep-clip-art-vector-brain-charge-163181/

So….back to our original question:

What should I eat in order to perform well on my exams?

A Guide for Food Choices• Most people need to eat every 4-6 hrs

• Include a combination of carbohydrate, fat, and protein

• Make sure you are well hydrated

• Include Iron rich foods

• Consume caffeine as per usual intake (if applicable)

• Don’t change what you are currently eating drastically

• Eatwell Plate

http://www.hypertensiontalk.com/new-healthy-eating-tools/

General Tips• Making sure you have good eating habits is like studying for exams- don’t wait until the last minute to

start

• Make sure you freezer & pantry is well stocked before exam time• Will make grocery store trips faster

• Batch cooking

• Have a plan for the day, and time meals & snacks accordingly• Most people need to eat meals every 4-6 hrs (beyond this may need to snack)

• Listen to you hunger cues• Very normal to use food to soothe in times of stress

• Get away from books & computer while eating, if you can

• Other ways to relieve stress

Exam Meal Ideas- Breakfast• Banana, tortilla, nut butter**

• Instant oatmeal*, walnuts**, raisins

• Cold cereal*, milk (or alt), banana, hempseeds**

• English muffin, egg*, tomato slices

• Yogurt, granola*, frozen berries, chia seeds**

• Scrambled eggs*, cheese, tortilla, salsa

• Granola bar, banana

• Smoothie (frozen banana, ground flaxeed**, cocoa powder, milk or alt)

• Bagel with hummus*, tomato slices

• Leftover quinoa, milk, banana, nuts**

• Trail mix* (**) & apple

**Good source of N-3; *Good source of iron

Exam Meal Ideas- Lunch/Dinner• Leftovers!

• Sandwich + fruit• Meat (or tofu, smashed beans, hummus, etc)*, lettuce, tomato cucumber, mustard, bread or pita

• Scrambled eggs, peppers, spinach*, cheese, toast

• Pizza: premade shell or pita w/ cheese, spinach*, fried egg*, pasta sauce

• Burrito bowls: black beans*, rice, tomato salsa (tomato, green onion, cilantro, lime juice, S&P)

• Stir-fry: rice or noodles, tofu (or meat)*, frozen broccoli* sautéed with soy sauce, ginger, garlic, chilies

• Lentil stew (onions, carrot, kale*, ginger, garlic, red lentils*, coconut milk, tomato paste, spices, water)

• Chili: +/- ground beef, beans, canned tomatoes, green peppers, frozen corn, spices

• Instant ramen: add frozen veggies, edamame* soft boiled egg*, soy sauce/miso paste

• Salad: Kale*, quinoa, leftover salmon**, roasted beets, ginger vinaigrette

**Good source of N-3; *Good source of iron

Exam snack ideas• Try incorporating protein and a carbohydrate

(and/or veggies)

• Carbohydrate: • crackers, fruit, bread/pita bread, granola, popcorn, instant

oatmeal etc

• Protein: • nuts, nut butters, hummus, canned tuna, yogurt, tzatziki,

boiled eggs, etc

• Veggies• Cucumber, carrot, celery, cherry tomatoes, bell peppers

• Snack ideas:

• Trail mix (nuts*(**) & dried fruit)

• Frozen berries & Greek yogurt

• Slice of toast with nut butter**

• Homemade muffin

• Fresh veggies & hummus* or tzatziki

• Cheese & crackers

• Guacamole & tortilla chips

• Hard boiled egg* & fruit

• Canned tuna & crackers

• Granola bar

**Good source of N-3; *Good source of iron

ReferencesAdan, A. (2012). Cognitive performance and dehydration. Journal of the American College of Nutrition, 31(2), 71-78. doi:31/2/71 [pii]

Bellman, J., & Petrie, H. (2013). Caffeine (background). Retrieved from http://www.pennutrition.com/KnowledgePathway.aspx?kpid=1029&trid=1046&trcatid=38

Busch, & Taylor, K. (2005). The acute effects of meals on cognitive performance. New York: Taylor and Francis.

Dye, L., Lluch, A., & Blundell, J. E. (2000). Macronutrients and mental performance. Nutrition (Burbank, Los Angeles County, Calif.), 16(10), 1021-1034. doi:S0899-9007(00)00450-0 [pii]

Gomez-Pinilla, F. (2008). Brain foods: The effects of nutrients on brain function. Nature Reviews Neuroscience, 9(7), 568-578.

Hematology-anemia: Iron deficiency. (2018). Retrieved from http://www.pennutrition.com/KnowledgePathway.aspx?kpid=403&trid=22667&trcatid=38

Jiao, J., Li, Q., Chu, J., Zeng, W., Yang, M., & Zhu, S. (2014). Effect of n-3 PUFA supplementation on cognitive function throughout the life span from infancy to old age: A systematic review and meta-analysis of randomized controlled trials. The American Journal of Clinical Nutrition, 100(6), 1422-1436. doi:10.3945/ajcn.114.095315 [doi]

Joffre, C., Nadjar, A., Lebbadi, M., Calon, F., & Laye, S. (2014a). N-3 LCPUFA improves cognition: The young, the old and the sick. Prostaglandins, Leukotrienes, and Essential Fatty Acids, 91(1-2), 1-20. doi:10.1016/j.plefa.2014.05.001 [doi]

Joffre, C., Nadjar, A., Lebbadi, M., Calon, F., & Laye, S. (2014b). N-3 LCPUFA improves cognition: The young, the old and the sick. Prostaglandins, Leukotrienes, and Essential Fatty Acids, 91(1-2), 1-20. doi:10.1016/j.plefa.2014.05.001 [doi]

McLellan, T. M., Caldwell, J. A., & Lieberman, H. R. (2016). A review of caffeine's effects on cognitive, physical and occupational performance. Neuroscience and Biobehavioral Reviews, 71, 294-312. doi:S0149-7634(16)30069-0 [pii]

References Cont’dMurray-Kolb, L. E., & Beard, J. L. (2007). Iron treatment normalizes cognitive functioning in young women. The American Journal of Clinical Nutrition, 85(3), 778-787. doi:85/3/778 [pii]

Phillips, A. J. K., Clerx, W. M., O'Brien, C. S., Sano, A., Barger, L. K., Picard, R. W., . . . Czeisler, C. A. (2017). Irregular sleep/wake patterns are associated with poorer academic performance and delayed circadian and sleep/wake timing. Scientific Reports, 7(1), 4. doi:10.1038/s41598-017-03171-4 [doi]

Randolph, D. D., & O'Connor, P. J. (2017). Stair walking is more energizing than low dose caffeine in sleep deprived young women. Physiology & Behavior, 174, 128-135.

Rogers, P. J., Heatherley, S. V., Hayward, R. C., Seers, H. E., Hill, J., & Kane, M. (2005). Effects of caffeine and caffeine withdrawal on mood and cognitive performance degraded by sleep restriction. Psychopharmacology, 179(4), 742-752. doi:10.1007/s00213-004-2097-y [doi]

Spencer, S., Korosi, A., Laye, S., Shukitt-Hale, B., & Barrientos, R. M. (2017). Food for thought: How nutrition impacts cognition and emotion. NPJ: Science of Food, 7

Tomporowski, P. D. (2003). Effects of acute bouts of exercise on cognition. Acta Psychologica, 112(3), 297-324. doi:S0001691802001348 [pii]

Trockel, M. T., Barnes, M. D., & Egget, D. L. (2000). Health-related variables and academic performance among first-year college students: Implications for sleep and other behaviors.Journal of American College Health : J of ACH, 49(3), 125-131. doi:10.1080/07448480009596294 [doi]

Thank you!

https://ueat.utoronto.ca/a-chronicle-of-brain-foods/