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HLTH 331 > Advanced Nutrition Midterm (2) > Flashcards

Advanced Nutrition Midterm (2) Flashcards

1
Q

Protein is involved in almost every function of our body:

A
  • Fluid balance
  • Acid base balance
  • Transport
  • Enzymes
  • Hormones
  • Structural and mechanical
  • Antibodies/immune support
  • Channels and pumps
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2
Q

Skeletal muscle is a critical organ and is linked with

A

1) Mortality and morbidity (we lose muscle as we age where longevity depends on muscle mass)
2) Diabetes
3) Recovery from surgery
4) Disability
5) Athletic performance

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3
Q

Importance of skeletal muscle in insulin resistance

A
  • Skeletal muscle is responsible for taking up to 80% of glucose from the body
  • Skeletal muscle is considered the primary whole body insulin resistance
  • If skeletal muscle is not healthy it can lead to insulin resistance
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4
Q

Structure of amino acids

A

Amino group, carboxyl group, side chain. Side chain is what differs (each corresponds to a different amino acid)

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5
Q

Essentiality of Amino Acids

A

Essential amino acids are those that the body cannot synthesize this means we must digest them

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6
Q

Nonessential amino acids

A

Body has the ability to create and digest on its own

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7
Q

Leucine

A

The most important amino acid for muscle. It activates protein synthesis. It is an essential amino acid

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8
Q

Essential Amino Acid List

A
  1. Histidine
  2. Isoleucine
  3. Leucine
  4. Lysine
  5. Methionine
  6. Phenylalanine
  7. Threonine
  8. Tryptophan
  9. Valine
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9
Q

Nonessential amino acid list

A
  1. Alanine
  2. Arginine
  3. Asparagine
  4. Aspartate
  5. Cysteine
  6. Glutamate
  7. Glutamine
  8. Glycine
  9. Proline
  10. Serine
  11. Tyrosine
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10
Q

Proteins are made of amino acids

A

Made of both essential and nonessential. Leucine, isoleucine, valine

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11
Q

Endogenous amino acids

A

Made within the body (nonessential)

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12
Q

Metabolic fate of dietary protein

A

We eat an amount - don’t need that much so start to break it down. Body protein degradation, dietary proteins (what you eat) and synthesis of NEAA all contribute to the amino acid pool.

Results in anabolism or catabolism.

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13
Q

Anabolism

A

1) Protein (hormones, enzymes, protein)
2) Nitrogenous compounds (neurotransmitters, niacin, creatine, heme)

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14
Q

Catabolism

A

By products from the breakdown of protein.
1) Ketone bodies, fatty acids
2) Urea, CO2, H2O
3) Glucose, gluconeogenesis

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15
Q

Protein Structure

A

2 amino acids create a peptide bond = dipeptide? As they get bigger they contort into a different structure

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16
Q

Primary structure

A

Amino acid

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17
Q

Secondary structure

A

Helix (long round circle)

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18
Q

Tertiary structure

A

Polypeptide chains (starting to loop)

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19
Q

Quaternary structure

A

Complex of protein molecules.

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20
Q

Protein digestion (stomach)

A

stomach:
1) whole proteins chewed and swallowed into the stomach
2) hydrochloric acid denatures proteins, unfolding 3D structure to reveal polypeptide chain
3) enzymatic digestion by pepsin forms shorter polypeptides

small intestine:
1) trypsin, chymotrypsin, and proteases continue enzymatic digestion forming tripeptides, dipeptides, and amino acids
2) In enterocytes, tripeptides, and dipeptides are further broken down into amino acids which are absorbed into the bloodstream

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21
Q

Protein digestion

A

1) gastric cells release hormone gastrin, which enters blood causing release of gastric juices
2) hydrochloric acid in gastric juice denatures proteins and converts pepsinogen to pepsin which begins to digest proteins by hydrolyzing peptide bonds
3) Partially digested proteins enter small intestine and cause release of hormones secretin and cholecystokinin
4) hormones stimulate the pancreas to release pro-enzymes and bicarbonate into the intestine. Bicarbonate neutralizes chyme
5) Pancreatic proenzymes are converted to active enzymes in the small intestine. They digest polypeptides into tripeptides, dipeptides, and free amino acids
6) Intestinal enzymes in the lumen of the small intestine and within the mucosal cells complete protein digestion

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22
Q

Protein catabolism: transamination

A

Transamination is the process by which amino acids are transferred to acceptor keto-acids to generate the amino acid version of the keto-acid and keto-acid version of the original amino acid. Basically transferring one R group to another R group.

How nonessential amino acids can be created!

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23
Q

Protein catabolism: deamination

A

Reaction that involves the removal of an amino group from an amino acid, with no transfer of the amino group to another compound.

Ex, ammonia excreted into intestinal tract and fermented by gut, others excreted through the urea

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24
Q

Estimated Average Requirement (EAR)

A

Daily intake value that is estimated to meet the nutrient requirements of half the healthy individuals in a population

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25
Q

Recommended dietary allowance (RDA)

A

Daily dietary intake level that is sufficient to meet the nutrient requirements of 97-98% of the healthy individuals in a population

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26
Q

Adequate Intake (AI)

A

Expected amount to meet or exceed the needs of most individuals in the population

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27
Q

Tolerable upper intake level (UL)

A

Highest daily nutrient intake level likely to pose no risk of adverse health effects to almost all individuals in a population. Having excess would indicate health risks

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28
Q

Dietary reference intakes on a normal distribution

A

EAR = 1.0g/kg/bm
AI = 1.6 g/kg/bm
UL = 1.8 g/kg/bm

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29
Q

Protein dietary allowance

A

RDA as 0.8-0.9g protein/kg/day to meet the requirement for 98% of healthy individuals over 19. To not be deficient this is the amount you need

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30
Q

Nitrogen balance technique

A

If nitrogen intake is equivalent to excretion (sweat, nails, urine, feces, etc) they can say whether you are in a protein deficit or out of balance.

Positive balance = excreting more than keeping, eating too much then being used
Negative = consuming more than losing, not sufficient eating

Balance: N intake = n losses

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31
Q

Nitrogen balance for estimating protein in healthy adults

A

Two arguments:
1) RDA is based on whole body data.
2) Not all proteins are created equal and not all are tissue specific

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32
Q

Defining protein quality

A

Quality is defined as the ability of a given dietary protein to fulfill human amino acid requirements based on its amino acid composition and digesibility. Different proteins have varying abilities to be digested in the body:
- Some proteins harder than others
- Not used as efficiently as others
- Higher means better (more easily absorbed)
- Whey is 99% and cooked rice is 87% so whey is more digestible by the human body. Red meat is also a good source

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33
Q

Regulation of skeletal muscle mass by nutrition and contractile activity

A

Balance between muscle protein synthesis and muscle protein breakdown determines the amount in the body.

Positive synthesis vs breakdown = building more than breaking down

Positive breakdown vs synthesis = loss of muscle mass

Amino acids have the ability to stimulate protein synthesis

Catabolic state
- Higher rate of breakdown compared to synthesis

Drinking a protein shake = gradual growth of muscle

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34
Q

Feeding and contraction regulate skeletal muscle mass

A

0 = not in either state (rested)
Negative = breakdown exceeds synthesis
Positive = synthesis exceeds breakdown

If you don’t eat enough protein you will not gain muscle even with resistance training

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35
Q

Essential amino acids drive increases in MPS

A

MPS = muscle protein synthesis

Hypothesis that essential amino acids increase MPS compared to non essential, but studies show no difference

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36
Q

Protein/amino acid feeding transiently elevate rates of MPS

A

Hyperaminoacidemia = having lots of amino acids in protein. Study suggests there is a cap at how much protein a body can take before it doesn’t do anything.

46-90 min mark is cap, where eating protein after this will not maximize response of exercise

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37
Q

MPS elevated 48h

A

MPS still active 48h post a bout of exercise. Protein balance is still negative after training

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38
Q

Protein Sources

A

BCAA (branched chain amino acids) = leucine, isoleucine, etc

Whey = has a combination of essential (EAAs), NEAA, BCAA. Whey is typically is the best source

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39
Q

Dose of proper protein intake

A

Myofibrillar = what the muscle is made of (myosin, tropomyosin)

When we exercise we stress the muscle which increases myofibrillar. Shows no advantage to consuming 20 vs 40 grams of protein, MPS response will be the same once reaching 20g of whey protein

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40
Q

How often should you eat protein

A

20g every 3 hours is most efficient. 40g you wouldn’t maximally stimulate from going up and down. Therefore, to optimize protein intake more than 20g every 3 hours is not necessary

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41
Q

During sleep why are we in a negative state of protein balance?

A

During breakfast we stimulate synthesis from not eating overnight. Because we don’t eat for a while = negative. Protein right before bed causes a catabolic state overnight. studies shows pre sleep digestion has an effect on muscle mass gains and strength

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42
Q

Pre sleep protein ingestion

A

Study shows significant values and effects. protein group gained more muscle than the placebo group

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43
Q

Protein supplementation and resistance training

A

1.6g/kg is best for resistance training. Dose response relationship so it caps out… only so much window for eating protein throughout the day.

As you age, the ability to stimulate protein synthesis decreases

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44
Q

Endurance training

A

Has different benefits than resistance training. There is a less large requirement to stimulate protein and not the same anabolic stimulus as resistance training

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45
Q

Does type of protein matter (anabolic effect)

A

Whey protein is the gold standard. Casein is a slower pace protein. Soy is plant based

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46
Q

Difference between plant and animal proteins

A

Animals have more complete amino acids - has all essential amino acids. Plant proteins are missing amino acids and are inferior to digest

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47
Q

Protein quality

A

relates to the bioavailability of its constitutive acids and depends on the efficiency of their metabolic utilization to meet the amino acid requirements necessary for growth and protein turnover.

PDCAAs = higher the better. It is a type of measure to calculate protein quality and digestion

Graph shows peas and oats are harder to digest - lower in the ranking. Milk and whey are highest

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48
Q

Factors affecting the MPS response from protein

A

1) plant protein digestibility is typically lower than animal proteins
2) metabolic fate of animal vs plant proteins (plant proteins are more oxidized)
3) essential amino acid composition (plants don’t have all essential amino acids in the given food)

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49
Q

Lower digestibility

A

Digestibility refers to how efficiently the body can extract nutrients from the ingested food. Plant based protein are less digestible than animal based protein - greater proportion of nutrients are not being absorbed and utilized by the body. For ex, consuming 2g, only 1g might reach the muscle

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50
Q

Metabolic fate of animal vs plant proteins

A

Dietary protein derived amino acid from plant based proteins (soy and wheat) are more readily converted to urea when to animal based proteins.

Caused by oxidation. Ie, soy is more readily converted to urea. Animal is superior in this sense

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51
Q

Amino acid composition

A

Leucine content is higher in animal proteins vs plants. Need less in animals to get the same effect of plants. Because many plant proteins are deficient in one or more essential amino acids

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52
Q

Lack EEAA

A

For amino acid composition, plants have a less large percentage of EAA compared to animal based protein. ex, quinoa has high rates of lysine but low rates of methionine

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53
Q

Strategies to address concerns with consuming plant based protein

A

Eat more! If 20g is necessary for whey, we need to eat more plants. Eating a variety to get all amino acids. To maximize MPS we need to increase plant intake in comparison to animals for the same effect. Increasing more at a given dose can help maximize protein synthesis. Ex, you might need less than a serving of steak but 4 servings of rice to get the same effect which is many more calories

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54
Q

Blend

A

Blend different plant based protein sources to maximize essential amino acid content. Ingestion of mixed high quality protein sources is a favourable approach to meet requirements (mix veg and animals)

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55
Q

Protein fortification

A

Chemically processing food to add more of a certain protein. Ex, wheat can be fortified to have more leucine.

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56
Q

Leucine effects

A

As long as you are consuming equal amount of leucine (primary anabolic amino acid) you can gain proper muscle mass. No difference between whey and soy groups if they’re matching leucine content

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57
Q

During a negative energy balance up to 30% of body mass loss can be lean tissue

A

Losing weight can equate to losing muscle. Low muscle mass is associated with diabetes, disability, cardiovascular disease. So when we lose weight we want to preserve muscle mass

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58
Q

Why is protein the macronutrient of choice

A
  • thermogenic effects
  • May promote fat loss
  • increased satiety
  • Nutrient dense
  • Poor lipogenic substrate
  • Preserves lean tissue
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59
Q

Study on men and muscle mass

A

4 weeks of resistance and interval training. 40% calorie restriction. One group 2.4g/kg of protein, other group 1.2g/kg. Shows that higher protein group maintains leaner body mass when eating more protein, but might still have the same overall body mass

60
Q

Protein intake and thermogenesis

A

protein rich meal burns more calories compared to fat rich meals

61
Q

Protein does not turn to fat

A

A protein rich meal has more protein and fat oxidation and especially glucose oxidation. Fat has negative glucose oxidation

62
Q

Protein intake and insulin sensitivity

A

A high protein diet coupled with exercise creates better insulin sensitivity which is better for health. Overall better effect on metabolic health. So combining protein and exercise is BEST

63
Q

Optimal dose of protein to maximize hypertrophic response

A

1.6g/kg/bm

64
Q

The Microbiome

A

Micro-organisms change in response to different environmental factors such as exercise, diet, medication, disease. We have 100 trillion microbiota in the human body

65
Q

What is the microbiome

A

The microbiota is the community of microorganisms (fungi, bacteria, viruses) that exists in a particular environment. We have a microbiome on skin, teeth, gut, urogenital

66
Q

Microbiota

A

All microorganisms present in that environment

67
Q

Microbiome

A

The collection of all microbial genes (collective genomes). Genes associated in that environment

68
Q

What is a healthy microbiome

A

A healthy microbiome is a diverse microbiome. We. want a range of bacteria as they all have a different role in the body. 90% of microbiome are bacteroidetes and firmicutes. 10% are actinobacteria and proteobacteria. Varies from person to person so there isn’t a precise definition

69
Q

Bacteroidetes

A

Beneficial for the immune system and human health. Large proportion is associated with positive health outcomes. May help prevent or mitigate diseases such as cancer, diarrhea, IBS

70
Q

Firmicutes

A

Responsible for carbohydrate metabolism. Reduction is associated with depressive like symptoms

71
Q

Actinobacteria

A

Important for gut homeostasis including gut barrier, immune system, metabolism. Ex is bifidobacteria

72
Q

Proteobacteria

A

Microbial signature of disease - thought to be the most negative of the 4.

73
Q

Bacteroidetes and Firmicutes Ratio (biomarker)

A

Firmicutes to bacteroidetes - the relationship between has been associated with several pathological conditions. There is a higher ratio of firm : bact in those with obesity

74
Q

Microbes commonly affected by diet

A

1) Bifidobacterium
2) Lactobacillus
3) alistipes
4) Roseburia
5) Eubacterium
6) faecalibacterium
7) enterobacteria

75
Q

Bifidobacterium

A

Good.
Reduced abundance in obesity

76
Q

Lactobacillus

A

Good
Attenuates IBD

77
Q

Alistipes

A

Bad
Associated with disease

78
Q

Bacteroides

A

Good
Anti-inflammatory

79
Q

Roseburia

A

Good
Reduced abundance in IBD

80
Q

Eubacterium

A

Good
Reduced abundance in IBD

81
Q

Faecalibacterium

A

Good
Reduced abundance in obesity and IBD

82
Q

Enterobacteria

A

Bad
Increased abundance in IBD

83
Q

Metagenomic profiling

A

Analysis of all genes that are present which shows abundance of each type of bacteria in the body

84
Q

Microbiome correlation network

A

Seeing common trends to identify microbial biomarkers

85
Q

Fecal Transplant Study

A

Take a control and disease population and transplant the microbiome of those populations into mice. Control mice have a regular microbiome and others are germ free (no microbiome). Put the feces of a human into the rat and seeing if they develop certain diseases

86
Q

Studying causality of gut microbial components

A

Have a control and intervention group. Looking at changes in abundance of different microbiomes

87
Q

What changes the microbiota

A
  • Changes in diet (nutrition)
  • Medications and antibiotics
  • Probiotics
  • Prebiotics
  • Exercise
  • Fecal microbiota transplant?
88
Q

Function of the gut microbiome

A

1) Immunomodulation - modifies immune response
2) Gut brain axis - mood
3) Gut mucosal barrier - maintains structure of gastrointestinal tract
4) Nutrient metabolism - metabolizes fiber, non digestible carbs, produces vitamins
5) Antimicrobial protection

89
Q

Gut brain axis

A

Bidirectional communication between the nervous system and gut. Ie, butterflies in stomach when nervous - there is interplay between the 2. 3 systems: nervous system, immune system, endocrine (hromones).

The enteric nervous (communication between gut and brain),

90
Q

Stress response and gut microbiota

A

psychological stress - impacts gut microbiota composition, microbial metabolites, influences enteric nerves and thus anxiety and depression. Shows bidirectional communication exists where microbiota affects nervous system and mood

91
Q

Hormones impact appetite regulation

A

Ex, leptin suppresses appetite, ghrelin stimulates?

3 systems which control:
1) cognition - your decisions, am I hungry, do I want ice cream
2) reward/hedonic - hormones wanting cookie after working hard all day
3) homeostasis - just worked out, hungry for food.

92
Q

Appetite Regulation Mechanisms

A

SLIDE 16 of lecture 7
1) food stimulus - metabolic feedback - hypothalamus - unconscious subcortical areas - conscious cortical - integration of hedonic and homeostatic food intake

much more to this

93
Q

Homeostatic control of food intake

A

Picture 17 of lecture 7
Idea of suppressing and activating hunger

94
Q

Nutrient metabolism - dietary fiber

A

Fiber is important for microbes, basically their food source. Products of fermentation = byruvate, acetate, propionate. Dietary fiber produces good benefits and is associated with decreased appetite. Helps to produce more glycogen synthesis into muscle, increases satiety, secretion of more insulin

95
Q

Factors affecting the gut microbiota

A

1) age
2) diet
3) mode of birth
4) stress
5) breastfeeding
6) medication

96
Q

Aging and microbiome

A

As we get older the microbiome becomes more diverse - exposed to new things, having pets can help your gut. In adulthood your microbiome stabilizes more.

Exposure of mom during pregnancy can affect the microbiome of the infant. How the baby was delivered, breastfed vs formula

97
Q

Breastfeeding and mode of birth

A

30% of babies microbiome is from breastfeeding. Human milk microbiota is both a prebiotic and probiotic, and are the nutritional and bioactive molecules present in human milk. Breastfeeding is a significant factor associated with microbiota composition. Breastfed babies have a lower diversity compared to formula fed children - cessation (stoppage) is associated with a shift towards a more mature adult like microbiome

98
Q

Direct (probiotic)

A

Alter the gut microbiota through the transmission of bacteria

99
Q

Indirect (prebiotic)

A

Contains oligosaccharides that promotes the growth of specific bacteria

100
Q

Breastfeeding function

A

Shapes the composition of gut and respiratory microbiota. 1) promotes intestinal immune homeostasis
2) facilitates digestive processes (promotes intestinal immune system activation)

101
Q

Risk factors of a worse microbiome

A

After taking antibiotics, person with a healthy microbiome might have better effects - more resilient to microbiome being destroyed.

Dysbiosis is an unhealthy microbiome. After a challenge it does not return to baseline. Risk of asthma and obesity in children.

102
Q

Delivery mode

A

C section can lead to dysbiosis in newborn gut microbiome. Lack of exposure to maternal vaginal and fecal bacteria that occurs from vaginal birth. Overall decreased microbial diversity and may be a risk factor for allergic outcomes (asthma)

103
Q

Antibiotics

A

Healthy gut has a good ratio of bacteroidetes to firmicutes which is usually before antibiotics. They wipe the gut of good bacteria. More firmicutes would be a predictor of obesity

104
Q

Difference between microbiomes of different countries

A

Foragers - not eating processed foods, non agricultural.
Agriculturalists - african farmers, grains, dairy, meat.
USA - highly processed foods, low fiber. Alistipes associated with the western diet which is not good.

No causality in diagram

105
Q

Effect of diet on the microbiome

A

Fecal transplant of human microbiome to rat. 1) low fat diet. 2) western diet.

Western has many more firmicutes than bacteroidetes - showing more chances of obesity. Just changing the diet shifts the microbiome

106
Q

Effect of diet p2

A

Body fat is higher on western diet. Shows eating high fat diet does change microbiome

107
Q

Microbiome diet trends

A

Western diet - abundance of total bacteria = negative. It decreases the total amount. Shows unfavorable change in bifidobacterium, lactobacilli, eubacteria. Increase in bacteroids and enterobacteria which are not good.

Mediterranean diet = increase in favorable bacteria.

108
Q

Western diet microbiome

A

Diet high in animal fat, protein, sugar, low plant fiber. Proteolysis leads to microbiota related to metabolic disease. Increased blood glucose, decreased metabolic endotoxemia, decreased glucose stimulated insulin secretion

Associated with negative health outcomes such as inflammation, CVD, IBD, obesity

109
Q

Mediterranean diet microbiome

A

diet low in animal fat, protein but high in plant fibers. Fermentation leads to good metabolic health. Formation of short chain fatty acids, lowered blood glucose, greater energy expenditure, more glucose stimulated insulin secretion

Associated with positive health outcomes such as reduced risks of metabolic disease

110
Q

Protein consumption

A

Positively correlated with overall microbial diversity

111
Q

Plant protein

A

Change in bacteria: More bifido, less lacto, more bacteroidetes.

Effect: more short chain fatty acids - improved insulin sensitivity

Risks: less inflammation and increased gut barrier

112
Q

Animal protein

A

Change in bacteria: more bacteroides, more bifido

Effect: less short chain fatty acids

Risks: greater cardiovascular disease, more IBS

113
Q

Fat and the microbiome

A

6 month, randomized controlled feeding trial. Carbs, fiber intake, protein all need to be controlled to see the results of just fat

114
Q

Summary of results for fat and microbiome

A

Short chain fatty acid synthesis decreased with high fat diet (not good for you). Increase in alistipes also not good. Decrease in microbial diversity

115
Q

Saturated vs unsaturated

A

Saturated fat caused the most decrease in diversity . Decrease in bacteroidetes and increase in firmicutes associated with obesity

116
Q

Sugar and the microbiome

A

Proteobacteria is inflammatory and there is more with a high sugar diet. Bacteroides are anti-inflammatory and reduce with high sugar diet. Sugar promotes leaky gut in which the gut barrier is letting things through which can lead to metabolic disorders

117
Q

Gut and overall health

A

Interplay between the immune system, metabolic system, and mental health. Gut is at the center and impacts all. Gut-brain axis

118
Q

Dysbiosis

A

Unhealthy microbiome - imbalance between good and bad bacteria (more bad). Loss of beneficial bacteria, overgrowth of pathogenic bacteria, loss of diversity. Healthy intestine is diverse, dysbiosis is an imbalance that causes various pathological problems

119
Q

Intestinal barrier

A

In your small intestine. Healthy barrier allows process to happen with selectivity - not letting microbes and things not supposed to be there pass.

Roles
1) Absorption of water, electrolytes, essential dietary nutrients from intestinal lumen into circulation
2) first line of defense against external pathogens

Structure
1) outer mucus layer - microbiota, antimicrobial proteins, secretary hemoglobin A molecules
2) inner mucus layer - physical barrier that covers the epithelial cells - protective shield

120
Q

Intestinal barrier and microbiome

A

Microbiome helps to repair mucosa. Intestinal barrier also affects microbiome. It is the habitat for the microbiome, food source, breached barrier can invoke leaky gut

Need short chain fatty acids such as butyrate to maintain intestinal barrier, those with IBD are impaired

Slide 45

121
Q

Leaky gut

A

Tight junctions open up allowing things which shouldn’t to pass through

122
Q

LPS and gut microbiome

A

LPS = lipopolysaccharide
Component of outer cell wall of gram-negative bacteria. Microbiota is the main source of LPS in humans
Involved in macrophage activation and stimulates inflammation. Involved in sepsis, septic shock, organ failure

123
Q

Intestinal barrier and LPS progression

A

Leaky gut causes microbiota derived LPS to enter the circulatory system - passes through entire body. Causes chronic inflammation and impaired immune response. Promotes the progression of metabolic diseases

Can lead to insulin resistance (diabetes)

124
Q

Dysbiosis continued

A

Associated with cognitive disorders (mental, autism), pulmonary disorders (asthma), cardiovascular (hypertension), metabolic (obesity, type 2 diabetes), gastrointestinal (IBD). Slide 49

125
Q

Depression and microbiome

A

Poor mental health = high fat, high sugar, processed. Causes increase in all bad bacteria - unfavorable microbes. LPS correlated with poor mental health

Positive mental health = veggies, fiber, fermented foods. Reduced bad bacteria

126
Q

Gastrointestinal disorder

A

Chronic, recurrent abdominal discomfort and pain, with changes in bowel habits

127
Q

IBS Composition

A

SCFA producing bacteria: IBS have lower abundance of butyrate producing bacteria. Butyrate known to improve intestinal barrier function. Reduction means we have a decrease in tight junctions which promote leaky gut

Methanogens (archea): microbes responsible for removing excess hydrogen by converting to methane. Methane production linked to low transit time and anti-inflammatory colon effects. IBS have lower methanogens = reduced ability for gas removal so they have more gas in tummy

Slide 53 explains

128
Q

Irritable bowel syndrome

A

Small intestinal bacterial overgrowth associated with IBS. Bidirectional meaning IBS can cause overgrowth too.

Causes GI symptoms such as GI motility, visceral sensation, immune activation, intestinal permeability

Increase in negative bacteria - high abundance of proteobacteria

129
Q

Microbiome and type 2 diabetes

A

Decrease in short chain fatty acid production. More bacterial butyrate producers and pro inflammatory species

Slide 56

130
Q

Microbiome and obesity study

A

Transporting microbiome of an obese person into fat versus lean person. They used twins for the study - similar genetics in their microbiomes. Diagram shows rodents who were given microbiome of obese individuals gained weight, lean ones remained the same

131
Q

How to enhance gut microbiome

A

1) eat a diverse range of food
2) eat fiber
3) eat fermentable food

132
Q

Eating fiber for gut

A

Fiber is a prebiotic - promotes growth and activity of beneficial bacteria in the gastrointestinal tract by acting as a source of nutrition. Provides fuel for microbiome. Increases all positive microbes

133
Q

Nutrient metabolism and dietary fiber

A

More fiber = more short chain fatty acid production. Fiber is broken down into short chain fatty acids. Bacteria in large intestine relies on dietary substrates (fiber)

134
Q

Eating fermented foods

A

Foods that have undergone the fermentation process. Process whereby alcohols, carbon dioxide, and organic acids are produced by microorganisms from carbs for energy production. 1) nutritional value of fermented foods.2) provides nutrients that promote the growth of gut microbes. 3) microbes survive the gastric transit (become a component of the gut microbiome)

135
Q

Fermentation

A

Foods associated with decreased blood pressure, cholesterol, improve metabolic syndrome, anti cancer effects, reduced risk of cardiovascular disease.

Foods: kimchi, yogurt, miso
Have bioactive ingredients

Increase in microbiome diversity. Decreases inflammatory signals

136
Q

Bioactive compounds

A

Bioactive compounds are a product through fermentation. Include vitamins, phenolic compounds, organic acids, exo polysaccharides, bioactive peptides, enzymes

137
Q

Future directions of research

A

Difficult to establish a causal relationship rather than associative between specific microbes and physiological or diseased state.

138
Q

Why has diabetes occurred?

A
  • Increase in portion sizes
  • Technology has decreased physical activity
  • Generating positive energy balance (eating more than expending)
139
Q

Decision to eat food is complex

A

Psychological and environmental - smelling/hungry, initiation and termination of meals, composition, lifestyle habits - eating to enjoy or do you like veggies?

140
Q

Appetite (orexigenic)

A

Appetite stimulating hormonal signalling

141
Q

Satiety (anorexigenic)

A

Full stimulating hormonal signalling

142
Q

Important areas of stomach

A

Stomach
- Releases ghrelin
- Appetite stimulating
- Orexigenic

Intestine
- PYY and GLP1 released
- Travel to brain to generate satiety
- Anorexigenic hormone

Pancreas
- PP released
- Anorexigenic

Adipose tissue
- Release of leptin (regulates energy balance by suppressing hunger)
- Anorexigenic

143
Q

Neuropeptides

A

Hormones travel to ARC region in brain - integration of peripheral signals generates release of neuropeptides.

Orexigenic neuropeptides
- NPY, AgRP
- Stimulate appetite

Anorexigenic neuropeptides
- POMC converted to alpha MSH
- Behaviour of not being hungry
- CART
- Satiety stimulating

144
Q

Vagus Nerve

A

Focus for treatment for obesity. Source of indirect neuronal stimulation - taking info from gut and bringing to brain. Efferent and afferent sensory fibers - meaning info travels both ways.

145
Q

Effects of exercise intensity on plasma

A

Idea that higher intensity exercise restricts blood flow to gut impacting appetite GI motility. More info in lecture 8

HLTH 331 (3 decks)

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