Integration Flashcards
what is the gut microbiome?
microbiota and their genetic capacity (microbes and what they can do)
what are 4 essesntial functions of gut micrbobes?
1) nutrient aquisition
2) immune regulation
3) pathogenic protection
4) metabolic signaling
how are “we” separated from the gut microbiome? why is this needed?
the microbes are separated from intestinal cels by a layer of mucus
-the mucus layer prevents the microbes from attacking the immune cells, acting as a control to only allow a small passage of micorbes
explain the role of the gut microbiome in nutrient aquisition:
the food don’t digest in the small intestine become availible for microbes in the gut
-this alows us to breakdown nutrients from the undigested food
how does gut physiology explain the interactions with the microbiome in herbivores vs carnivores?
herbivores: have large fermentation chambers to increase the microbiome and be able to digest food we dont have enzymes for
carnivores: contain all the enzymes needed to breakdown the food they eat
provide 3 examples of SCFA? what is their function? provide 6 examples of how do they do this?
Acetate, propionate, butyrate:
they act as signaling molecules in the body
-substrates for molecules
-fuel for epithelial cells
-improve barrier function
-reduce inflammation
-increase satiety
-improve insulin sensitivity
what is dysbiosis? why is this controversial?
an alteration in the gut microbiome that is linked to disease
-it is hard to determine what occured first, the disease or the gut alteration
what impact does industrialization have on the gut microbiome?
it decreases the diversity as compared to non-industrialized populations
explain the fibre gap in non-industrialized, acestral, recommended and current fiber intake?
ancestral diet: > 100g day
Non-industrial diet: 60-100g / day
recommended intake: 25g/day F 38g/day M
current intake: 12-20g/day
what happens when we dont feed our microbes? where will they get their food from if not from fibre?
reduced intake of dietary fibre reduces the survival of a large number of microbes, once these microbes are lost they do not come back, evern with the intake of a high fibre diet
if we starve our microbes from fibre, they will breakdown the mucus layer in order to use glycoproteins for energy
-allowing the microbes to interact with the epithelial cells, causing an immune response
how can excess protien intake impact the gut microbiome? what harmful products are made?
the shift from carb sources to protein sources causes protein degradation which decreases the abundance of beneficial gut microbes
-produces BCFAs and ammonia
-decreases SCFAs
what do gut microbiota do to tryptophan?
convert it into ligands for receptors involved in immune response and 5-hydroxytryptophan which is a NT in the gut brain axis (beneficial changes)
what impact does increased consumption of dietary fat have on the gut microbiome?
1)promotes growth of bile-tolerant microbes
-considered carcinogenic (convert primary bile acids into secondary)
2) increases gut permeability
-compounds cross intestinal barrier
provide an example for how a change in diet can impact colon cancer risk
what impact does PUFA have on the gut microbiome?
it has similar effects as fibre
1) increases health-promoting bacteria
2) increases SCFA production
3) increases diversity
4) mediates anti-inflammatory effects
do dietary guidlines align with knowledge on how diet influences the gut microbiome?
Yes
what are targeted strategies to modulate the gut microbiome? what is the challenge with this?
1) nutritional support (fermentable fibres, prebiotics, microbiota-accessible carbs)
2) introduction of health promoting microbes (probiotics, live biotherapeutics, fermented foods)
The challenge is that we are all different and the same diet for one person may have a different effect
how can nutrition be personalized based on the gut microbiome?
prediction of individual GI responses to food postprandially may allow for more precise nutrition
what can we do to reduce the burden of cancer?
1) early detection and adequate treatment are key
2) screening
3) early diagnosis
-many cancers have a high chance of being cured if detected early
what does healthy metabolism mean?
a state of operational function (homeostasis) of every cell in the body
-proper cell function and mitochondira function
what 2 main factors cause tumour developmemt?
1) genetic alterations
2) lifestyle factors
what is the warburg effect?
a specific type of metabolism in cancer cells where it will use anaerobic metabolism even if O2 is availible in order to increase the rate of growth
-produces less ATP but is faster, decreases harmful by-products and help adapt to hypoxic environments
explain how cancer can cause metabolic reprogramming for protein, glucose and lipids?
1) cancers will increase protein synthesis to supprt rapid growth
2) GLU is highly consumed for energy and the by-products are used to produce nucletides for DNA synthesis
3) Cancer cells enhance lipid synthesis to create new membranes for new cells and support signaling pathways
what 4 ways does cancer change metabolism?
1) secretion of factors that interact w immune system
2) inflammatory response which can impact energy metabolism
3) indirect changes in body composition, food intake and activity due to changes in CNS activity
4) cancer treatment can cause negative symptoms which decrease food intake and activity
what is the difference between cachexia and sarcopenia?
cachexia: rapid loss of mass and fat mass at the same time
sarcopenia: loss of muscle mass and physical function that doesn’t depend on nutrional status
provide 4 physical impacts of cancer on the body, what symptoms may cause a diagnosis?
1) malnutrition
-GLIM criteria, weight/ body mass loss , decreased food intake
2) cachexia
-Fearon criteria, weight loss, decreased food intake
3) sarcopenia
-decreased muscle function, decreased muscle quantitiy
4) frailty
-FRIED 5 criteria, weight loss, slowness
what can be used as a surogate to measure muscle mass when alternate tools are not available?
calf circumference
what are the 3 major roles of dietitions in cancer care? provide an example of how they do this
1) nutritional assessment
-detailed screenin and evaluation
2) tailor nutrition interventions
-estimate nutrition requirements and supplement needs
3) support cancer treatments
-suport px’s with the side effects from treatment (cold meals, smaller portions, replacing fluids lost, increasing fibre)
what can muscle mass circumference tell us about a cancer px? what must be done to ensure the values reflect the px health?
it is an independent predictor of mortality in cancer patients
-low CC shows an increased risk
-the CC must be adjusted based off of the px BMI to ensure accuracy of healthy risk
provide 5 examples of current reseach for cancer treatment?
1) ketogenic diet
2) supporting immune systme through diet
3) tailoring diet to individual metabolic profiles
4) personalized nutrition and cancer metabolism
5) nutrigenomics
what is the definition of fitness?
wide ranging activites (any movement)
what encompasses fitness level?
endurance, strength, flexibility body composition
how does exercise and being fit benefit physciological states?
increases response to infections, anti-inflammatory state, function of organs and cell turnover
what is cardiorespiratory fitness?
aerobic endurance
-capacity to make ATP to maintain activity
what is strength?
anaerobic muscle capacity and endurance
-reistance activities
what is flexibility categorized as?
range on motion
what is body comp categorized as?
proportion of fat stores
what does the canadian guildline recommend for aerobic activity?
150 min / week
provide 2 examples of moderate vs vigorous activity?
moderate: biking, fast walking
vigorous: focused training, team sports
what does fueling during exercise depend on? how is this determined by physiological states?
1) duration and intensity
2) < 30 s uses ATP-creatine (instant), anaerobic energy < 3 min (short term), aerobic enegry (long term)
what is the main fuel source mobilized at rest, during moderate intensity activity and high intensity activity?
1) FA
2) FA /glucose
3) glucose
how does body weight imapct energy expenditure during activty?
higher body weight individuals will burn more energy doing the same activity as lighter individuals
how do dietary recommendations for macros change for athletes as compared to the general public?
minimal difference
carbs (40-60%)
fat (20-25%)
protein (0.8-2.0g/kg)
-endurance / resistance athletes may have higher protein requirements
what factors determine the rate of fuel utilization and fatigue? what causes fatigue?
intensity and duration
-fatigue caused by lactic acid build up, decrease O2 availibility, change in muscle blood gases, decreased GLU availibility, glycogen depletion (can onset overwhelming fatigue)
how long do glycogen stores last when doing vigorous activity?
1 hr
what is hypo-natremia? at what level is someone considered to have this? what are symptoms?
water loss sufficient enough to reduce blood volume
-2-3% of body weight lost in water
-core body T increases, cramps, heat stroke, low BP, confusion
what is the first thing to consider after 1hr of exercise? what else should be considered
> 1hr
-water should always be consumed during exercise but after one hour water and electrolytes should be the main priority
-replenishment or fluid balance must also include electrolytes because they are drawn out when we sweat
what are the general recommendations for fluids prior, during and after exercise?
1) 500mL < 4hr prior
2) 200-300mL /15 min during
-electrolytes consumed with water after 1hr
3) 500ml for every 0.5kg bw lost during activity
what is a reason why hydration before, during and after exercise is very important?
because the body is unable to replace water at the same rate that it is lost
what are the general recommendations for fueling prior, during and after exercise?
1) 2-4 hr before: maximize glycogen stores (carb load)
-CHO rich (60-70%), low in protein / fat
-consider small volume and easily absorbale meals very close to activity
2) during (activity > 60 min) : maintain [GLU]
-30-60g CHO/hr (banana, gels)
3) after: recover / replenish glycogen, protein, water and electrolytes
-replace fluid first
-CHO / protein rich foods within 30 min
-solid foods 2hr and 6hr post
how long does it take to replace glycogen stores?
12-24 hr depending on loss
should solid foods or liquid foods be eaten during exercise? what should be considered?
it depends on the person
-GI issues most common
-GI tract can be trainable
-Glycemic index (want high GI foods)
-takes trial and error for individuals to find what works for them
what are ergogenic aids? are they helpful? provide some examples.
supplements / stimulents that give an acut or long term exercise advatage
-there is little data to support their advantages (may help certain individuals for specific event)
-caffeine, creatine, glutamine, arginine
what are the pros and cons of fasted training?
pros:
-stimulates fat utilization
-benefits on post exercise glycogen stores
-increase in VO2 max
-can be beneficial for endurance training
cons:
-mixed evidence on the benefits for body comp and performance
-may not help professional athletes since they typically already up regulate their metabolism at a high rate
-caution should be taken for recreational athletes
what is calorie restriction defined as? how does it affect people over time?
consumption under energy balance without malnutrition
-reduces body weight, extend life span, improve cardiometabolic risk factors, insulin sensitivity and mitochondria function
-not sustainable
what is intermittent fasting?
fasting for varying periods of time]
-12hr or longer
what is alternate-day-fasting?
consuming NO calories on fasting days, alternating with unrestricted feeding days
what is alternat-day modified-fasting?
consuming less than 25% of baseline energy needs on fasting days, alternated with a day of unrestricted feeding days
what is time restricted feeding?
restricted food intake to specific time periods of the day
-typically 12 hr a day
what is periodic fasting?
fasting 1-2 days a week with unrestricted feeding on the other days
what is metabolic switching? when does this occur? how does this occur? what is the purpose of this?
1)shift from utilization of glucose to FA derived ketones
-switch from lipid synthesis and fat storage to mobilization of fat (FFA and Ketones)
2) switch occurs when glycogen stores in the liver are depleted (12 -36 hr after eating)
3) FFA are transported to liver and oxidized into ketones
-ketones are metabolized into Acetyl coA, which enter the CAC to generate ATP
The purpose is to sustain muscle and brain function during fasting (help preserve muscle mass)
what type of diet will have increased adpatation over time?
longer fasting periods (18 hr fast every day)
-causes multiple adaptation periods throughout the day
what constitutes a ketogenic diet?
1) moderate-high protein (80% of calories or 1g/kg bw)
2) low carbohydrate (40-60g /day)
3) blood ketones > 0.5mmol/L
what are health benefits of a ketogenic diet?
1) improves CVD risk factors
-increases HDL, decreases TG and changes LDL size
2) Improves T2D management
3) weight loss
-reduced apetite, increased metabolic rate
what are side effects of ketogenuc diet?
dehydration, lethargy, kidney damage, constipation, micronutrient deficiencies
what is considered a carb restrictive diet?
<50g/day
what are the steps in a yoyo diet?
1) normal eating
2) weight gain
3) diet
4) decreased metabolism
5) end of diet
6) repeat
what effect does grehlin have? what part of the brain does it act on?
stimulates hunger
-acts on NPY neurons
what do CCK, GLP-1, PYY, and insulin have in common? what neurons do they act on?
decrease hunger
-act on NPY neurons (inhibit)
what is the effect of leptin? what part of the brain does this work on?
increases satiety
-stimulates melanocortin secreting neurons
what is the effect of DPP-4? what does an inhibitor do?
DPP-4 acts to breakdown GLP-1 and GIP
-an inhibitor would prevent their breakdown, prolonging their action
what do incretin hormones do? give 2 examples.
they are released in the gut prior to insulin secretion to stimulate insulin secretion from pancreas and decrease glucagon secretion
-GLP-1 and GIP (GLP-1 has a larger range of effects)
what does GLP-1 do? how?
1) enhances insulin secretion
-improves fasting and postprandial glucose (decreased hepatic glucose production)
2) delays gastric emptying to increase satiety and reduce food intake
what is semaglutide? what is another name for it?
initially a drug for diabtes, now gaining popularity as a weight loss drug that acts similarly to GLP-1, producing the many health benefits such as satiety, regulation of blood glucose levels and insulin response
-ozempic
what is Hb A1C? why is it important? what is the impact of semaglutide on it?
Hb A1C is a blood test that reflects the average blood glucose levels in the past 3 months
-it measures the % of Hb that is coated in sugar
-higher levels indicate higher risks of complications
semaglutide lowers Hb A1C levels, decreasing risks
what level of Hb A1C is considered normal vs at risk?
< 5. 7= normal
> 6.5 = at risk
how does the efficacy of semaglutide differ when higher doses are administered? what is the most optimal dosage as of right now?
efficacy increases with higher doses
-2.4 mg once a week
what are the side effects of semaglutide? how do higher doses impact this?
GI effects are most common: nausea, vomitting and diarrhea
-gallstone formation in very severe cases due to rapid weight loss
-typically not sever, but with higher doses more people noted symptoms
how sustainable is semaglutide for weight loss? are people able to maintain the weight lost?
weight loss was recorded to be maintained long term, with a quick loss in weight, followed by a plateu around a year
-avergae loss of 15% bw compared to 2.4 in placebo
-loss of both fat and muscle
why do some people lose the desire to drink when taking ozempy?
the effects of GLP-1 on the brain may reduce reward behaviour and cravings
-modulates dopamine release to decrease urge to drink
-may also reduce alcohol absorption and the rate of intoxication, making it less appealing
what are effects of GLP-1 on the kidney?
increase diuresis
what are effects of GLP-1 on the brain?
-decrease food and water intake
-increases learning / memory
-decreases reward behaviour
what are effects of GLP-1 on the heart?
-increases contractibility, cardiac output, vasodilation, glucose uptake, ventricle function, myocyte survival
what are effects of GLP-1 on the bones?
-increases insulin sensitivity and glucose uptake
