Chap1 Flashcards
5 food groups
Grains, vegetables and legumes, fruit, dairy( and alternatives), meat (and alternatives).
NRVs
Nutrient reference values: set of targets for micro and macronutrients (age and sex specific) aimed at preventing deficiencies and toxicity in the general healthy population.
EAR
estimated average requirement (determined by biomarker)
RDI
Recommended dietary intake
AI
Adequate intake
UL
Upper level
SDT
Suggested dietary targets (to help prevent chronic disease) (+14)
EEL
Estimated Energy requirement
AMDR
Acceptable macronutrient distribution range - maximise general health outcomes) (% of total energy requirement range)
fat % recommended of total energy
20-35%
Protein % of total energy
15-25%
Carbs % recommended of total energy
45-65%
5 ADG
(Australian dietary guidelines) 1. be physically active and choose amounts of foods to meet energy needs
- Wide variety of foods from the 5 food groups
- Limit intake of foods containing saturated fat, added salt, sugars and alcohol.
- encourage, support and promote breastfeeding
- care for food, prepare and store safely.
GIT order (sphincters)
mouth, oesophagus, ( lower oesophageal) stom, (phyloric sphincter) SI (illiocecal) , LI , Rectum, anus.
Four layers of GIT ( in- out)
Mucosa (innermost hollow is the lumen) , submucosa (contains blood vessels) , Muscle, Serosa
Peristalsis
Longitudinal contraction–> drive food forward
Segmentation
Circular –> mix up
Lysosomes
In saliva: break down bacteria
Mucus
In saliva: lubricates and holds bolus together
Salivary amylase
In saliva: breaking down starch
Lingual Lipase
In saliva: breaks lipids down.
Digestion
Breaking down of Foods into molecules that can be absorbed by enterocytes and delivered into blood of lymphatic circulation. Macromolecules–> monomers. Micronutrients are freed
Absorption
uptake of monomers and micronutrients from the lumen of the GIT through the absorptive cells into the blood and lymph for transport to organs/ cells.
Gastric inhibitory peptide (GIT)
Slows release of chyme from Stom to SI
Parietal Cells
Hydrochloric acid
Hydrochloric acid (4)
- denatures proteins
- Kills bacteria and viruses
- aids in mineral absorption (increasing solubility)
- coverts pepsinogen to pepsin (protein digestion)
> only in stom
Chief cells
Gastric lipase
Mucus
Protects stom from being digested by HCL
found in mouth, stom, SI, LI
Gastrin
Hormone that controls the release of HCL and pepsinogen
Stimulates Gastric and intentional motility.
Goblet cells
Mucus
Villi are lined with?
Goblet cells, Endocrine cells, Enterocytes
Line microvilli?
Glycocalyx: Brush borders made of microvilli
Enterocytes
Absorb nutrients and produce metabolic enzymes
Bile
> in liver
Aids in Fat digestion
Bicarbonate
> pancreas, SI
neutralises stomach acid when it reaches SI
CKK: Cholecystokinin
hormone: produced in response to dietary fat in chyme- stim release of pancreatic enzymes and release of bile from gallbladder.
Secretin
Stim in response to chyme, stim release of pancreatic bicarbonate
Gastric inhibitory peptide
released by SI : signals stom to limit release f gastric juices and slows gastric motility.
4 types of Absorption
- Passive: With concentration gradient.
- Facilitated: carrier protein (w concentration gradient)
- Active: requires Energy
- Endocytosis: cell wall engulfs substance
Gut bacteria profile
types present. Changes with env. age, health status, medication, diet.
Probiotic
Live bacteria, identical to what is found in gut. Consumed as supplement or via food to populate adequately.
Prebiotic
non- digestible carbohydrates that ‘feed’ bacteria and promote their growth.
Entero-hepatic recirculation
recycling of bile
Diverticulosis and diverticulitis:
pockets formed in the intestinal
wall from constipation and strain. May become inflamed and infected
Diarrhoea
Rapid transition time and watery stool, mostly caused by bacterial and viral infection, contaminated water. Loss of fluid and electrolytes and mineral absorption of nutrients.
Leaky gut:
space between mucosal cells
Irritable bowel syndrome
Causes are not well understood: genetic, stress,
allergies, autoimmune disease (functional disorders)
> a mix of diarrhoea, constipation and pain
inflammatory bowel disease
includes Crohn’s disease and ulcerative colitis
Metabolism
All Biochemical reactions that occur throughout the body (usually involving enzymes and cofactors)
Catabolic pathways
Pathways that break down molecules/ substrates. Typically produces Energy. Produces ATP
Anabolism
Pathways that build molecules. Typically use Energy
Energy Metabolism
regulation (6)
Regulation: 1. Well functioning liver 2. Substrates. 3. ATP concentrations (high concentrations= no metabolism, low concentrations= atp production). Functioning and sufficient intermediates 3. enzymes, 4. hormones, 5. vitamins and 6. minerals all required for pathway: are rate limiting. 5+6 = cofactors.
key hormones: glucagon and insulin
Intermediate
compounds formed Throughout the pathway
Oxidisation reactions
Loss of Electrons= Increased oxidation state
Metabolic pathway
Biochemical reactions that occur in progression from beginning to end.
Beta oxidation
Fatty acid oxidation. (inside mitochondria) Carnitine based carriers shuffle fatty acids from the cytosol into the mitochondria. Long chain fatty acids are broken down to two carbon segments- Results in Acetyl CoA formation. 1 FFA (16 C)= 106 ATP
Cori cycle
The liver can convert lactate back to glucose or pyruvaet
Electron transport system
= oxidative phosphorylation. ATP is derived from NADH + H+and FADH2 as H+ travel down the concentration gradient from the inter-membrane space via ATP synthase. Requires copperand iron
Net 32ATP
Glycogenesis pathway (+ role in fasted state)
Forming ‘new’ Glucose from glycogenic amino acids.
Ketosis
Raised levels of ketone bodies in the body tissues- typical of when the body starts to burn fat as fuel (lowered levels of glucose). = main reason for starting ketogenic diet.
Keto-acidosis
pathological metabolic state marked by extreme and uncontrolled ketosis. Body fails to regulate ketone production. = lowered Ph from elevated concentrations of ketone bodies.
Ketogenesis
biochemical process whereby the body produces ketone bodies by the breakdown of Fatty acids and ketogenic amino acids (in the absence of glycogen) . These become the alternate source of energy for the heart, muscles and kidneys.
Ketone bodies
Formed in the liver from the breakdown of Fatty acids (2 Acetyl CoA bound together) occurs in metabolic environments where fat is the primary source of fuel ( fasting, glucose deprivation or energy restriction). Used in hepatic tissues only.
Deamination
Removal of the amine group from the carbon skeleton. requires B3, B6, B12, folate, biotin.
Anaerobic respiration (glycolysis) ATP production (glucose molecule)
Net 2 ATP produced. Occurs in cells with very little mitochondria = no oxygen available. pyruvate is converted to lactate–> glycolysis
Aerobic respiration (1 glucose molecule)
Net 32 ATP produced. Glycolysis + Pyruvate to Acetyl CoA + Cytric acid cycle + Electron transport chain.
Lipolysis
Dietary and adipose Triglycerides broken down to free fatty acids and glycerol. (broken down by lipase)
Alcohol metabolism
3 pathways: 1 Alcohol dehydrogenase. 2. MEOS (high alcohol intake) requires oxygen 3. Catalase Liver metabolises 80%
Liver
1st organ to receive most nutrients from GIT via portal vein. Major site of nutrient conversion and metabolism. storage of glycogen and some triglycerides.
AMPK
AMP activated kinase= responds to high ratio of AMP : ATP in cells and promotes nutrient catabolism to increase ATP production. (Increase ATP levels).
Alcohol metabolism
3 pathways: 1 Alcohol dehydrogenase. 2. MEOS (high alcohol intake) requires oxygen 3. Catalase (high intake) Liver metabolises 80%
Feasting metabolism
Anabolism. primary hormone: insulin
Fasting
Catabolism. Primary hormone: Glucagon.
1- Hepatic glycogen breakdown: to maintain blood
glucose level (BGL) and initial source of energy until stores
last
2- Muscle glycogen provides energy source in muscle until
store last (not BGL)
3- Protein breakdowns: substrate for gluconeogenesis once
glycogen runs out. Also used for energy production.
4- Fat breakdown: becomes main source of energy in
extended fasting
5- Ketogenesis: ketone bodies become the alternate
source of energy for the heart, muscles, kidneys. Ketones
are being produced increasingly as body fat storage
becomes the main source of energy in prolonged fasting )
Diabetes Mellitus type 1
No insulin produced by pancreas- glucose cannot get into the cell to be stored= starving cells. Alot of Acetyl CoA is produced. But little oxaoacetate. CAC is impaired.
may result in Ketoacidosis.
Diabetes Mellitus Type 2
Lifestyle and nutrition derived. Dominant Carbs lifestyle.
Can also get pancreatic exhaustion, insulin resistance.