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105 Cards in this Set
- Front
- Back
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Ketosis |
Insulin levels are low which induces lipolysis i.e. Atkins - low CHO consumption |
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Major nutritional role of CHOs |
Provide energy |
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CHOs include |
starch, cellulose/fiber and various sugars found in fruits, vegetables, milk products, and sweeteners |
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Daily CHO caloric intake |
40 - 50 % |
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What is Galactosemia? |
Autosomal recessive disorder inborn error of metabolism lacking or diminished enzyme activity and body cannot metabolize galactose This leads to toxic levels of G1P |
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What are the effects of Galactosemia? |
leads to liver and kidney failure, cataracts, brain damage, seizures - mortality of 75% |
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How to help Galactosemia? |
Strict removal of lactose and galactose from the diet |
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What are the effects of malabsorption of fructose? |
Unabsorbed fructose creates higher osmolarity in the small intestine which draws water into the GI tract - osmotic diarrhea |
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What is the relation between Fructose and Fermentation |
Fermentation in the LI by colonic bacteria can cause gas, bloating, and abdominal pain |
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What is the controversy around fructose? |
Liver cells use fructose without mediating the effects of insulin. It has been suggested that it is less problematic for dysglycemic people |
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Why is fructose recommended to diabetics? |
It does not trigger production of insulin by pancreatic beta cells and it also has a very low glycemic index (19) compared to glucose (100) and sucrose (68) It also tastes sweeter so you need less |
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What is the problem with high intake fructose? |
Insulin resistance Obesity Metabolic syndrome CV disease non-alcoholic fatty liver disease Increases visceral adipose and ectopic fat depostition |
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Does fructose activate leptin? |
No, which causes us to not feel full and increases fat deposition |
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Sucrose |
Glucose & Fructose |
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Lactose |
Galactose & Glucose |
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Maltose |
2 Glucose |
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how are disaccharides formed? |
Condensation reaction (loss of water) |
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How long are Oligosaccharides? |
2 to 10 monosaccharides |
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Fructooligosaccharides (FOS) |
Pre-biotics Naturally occurring polymers of fructose that are usually attached to a glucose molecule This is food for good gut bacteria/flora |
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Polysaccharide |
Long CHO molecule of repeat monomer units joined together via glycosidic bonds |
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Cellulose |
Linear chain hundreds to thousands of glucose units connected by beta (1-4) glycosidic bond |
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What is the function of cellulose in our digestive process? |
Acts as a hydrophilic bulking agents for feces - dietary finer |
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How can some animals digest cellulose? |
Some animals have symbiotic micro-organisms in their guts that help them digest cellulose |
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What are the two forms of Starch? |
1) Amylopectin - branched 2) Amylose - linear |
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What are some foods high in starch? |
Rice, corn, wheat, potatoes
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What is the major storage form of CHO in Animals? |
Glycogen |
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What is the major storage form of CHO in plants? |
Starch |
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What is the structure of glycogen? |
Long straight chains of glucose via alpha (1-4) glycosidic link and then a branching every 4 to 8 glucose via an alpha (1-6) glycosidic linkage |
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How does fasting affect our glycogen stores? |
Depletes our liver glycogen stores |
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When is glycogen stores in muscles depleted? |
Continuous or excessive exercise |
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T/F Is glycogen more branched than starch? |
True |
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What is the daily recommendation of a fiber a day? |
20 to 35 grams per day |
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How much fiber does the average american consume? |
12 grams |
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What is crude fiber? |
The amount of undigested material left after food has been digested |
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What else can be considered finer? |
hemicellulose, pectins, & lignin which are CHOs that tend to absorb water and form gels making stools bulky and soft |
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Why are pectins so great? |
Bind onto toxic substances in the colon and renders them harmless |
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Soluble fiber |
Slow fiber |
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Examples of soluble fiber |
pectins, gums, mucilage, and some hemicellulose |
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Functions of soluble fiber: |
1) Hydrophilic & form gels 2) Add bulk and softness to stools 3) Normalizes stool transit 4) Substrate for fermentation by bacteria in colon 5) Bind bile salts and prevent them from being reabsorbed into ileum 6) Delays gastric emptying, increasing nutrient absorption |
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Examples of food high in soluble fiber |
Banana, apple sauce, white rice |
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Insoluble fiber |
Bulking agents |
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insoluble fiber examples: |
cellulose, hemicellulose, and lignins |
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Function of insoluble fiber |
1) Increase the bulk of stools 2) Stimulate normal GI motility 3) Prevent constipation 4) Dilute colonic toxins 5) Prevent formation of diverticulosis |
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Why can't humans digest cellulose? |
We lack the beta (1-4) glycosidase enzyme |
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Foods high in insoluble finer: |
Skins of veggies, bran, whole grains etc. |
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Main functions of all fiber |
1) Chewing - increase gastric secretions 2) Increases satiety 3) Slow absorption of glucose and increase insulin sensitivity 4) Increase volume of stools 5) Dilute toxins 6) Decrease bowel transit time 7) Substrate for colonic bacteria 8) Lowers LDL (more soluble fiber) 9) Increase excretion of endogenous estrogens by binding them. |
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High fiber adverse effect |
Contains Phytic acid & oxalates Leads to problems associated with decreased absorption of minerals (iron, zinc, calcium, mg) because they readily bing to minerals Or an antigen response in some people |
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Complex CHOs examples |
Vegetables, legumes, whole grains, muesli etc. |
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Simple CHOs examples |
Table sugar, corn syrup, fruit juice, candy |
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Why are simple CHOs problematic? |
They burn quickly but lacks natural chemical and physical characteristics |
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CHO digestion and absorption chain of events |
Ingest-cleave-monosaccharides- absorption in SI-portal vein-liver (converts all forms to glucose)-uptake and utilized in tissues |
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Once introduced CHOs are either: |
Oxidized - Glycolysis Stored - in form of glycogen or adipose Converted - to fatty acids, glycogen, or energy |
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CHO digestion in the mouth
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Salivary amylase |
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CHO digestion in the stomach |
High acidity inactivates salivary amylase. Little CHO digestion |
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CHO digestion in the SI |
Pancreatic enzymes- amylase Brush border enzymes - dextrinase, sucrase etc. |
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How are end products of CHO digestion absorbed? |
Active - intestinal cell membrane has carrier protein - sodium dependent glucose transporter (SGL-T1) that transports glucose into cell via energy from Na/K+ pump Passive - pass with the concentration gradient through facilitative transporter (GLUT-5) - Slower but no energy |
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CHO digestion in the LI |
Takes 16 hours to finish the process Food is no longer broken down but bacteria will still continue to act on the indigestible fiber |
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Common effects of CHO malabsorption |
Gas & Bloating |
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Foods most common with gas & bloating |
high fat foods, fruits, juices, sorbitol/mannitol, high amounts of pectin, cabbage and other cruciferous vegetables beans and unripe fruit |
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Lactose Intolerance |
lack of enzyme lactase
Undigested lactose then makes it way into the LI where it is fermented by microbial flore causing gas and water retention |
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What population has a higher incidence of lactose intolerance |
Asians and african americans |
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Other causes of CHO malabsorption |
Parasitic infections Use of laxatives SI injury or inflammation |
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Microorganism species in the gut |
BIfidobacterium, staphylococcus, lactobacillus, clostridium and E. coli |
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Functions of the microbial flora |
Produce vitamins and nutrients metabolize food we can't digest on our own Break down drugs and toxins |
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Gluconeogenesis |
The synthesis of glucose from non-CHO sources such as AA, lactate/pyruvate and glycerol from lipids |
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Glycogenolysis |
Breaking down of glycogen (muscle or liver) to supply needed glucose |
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Impaired fasting glucose range ( Pre-diabetes) |
100 to 125 mg/dL |
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Norma Fasting Glucose |
70 to 99 mg/dL |
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Diabetic fasting glucose |
126 mg/dL or above |
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Oral Glucose Tolerance Test |
Sample drawn 2 hours after a 75g glucose drink- not applicable during pregnancy |
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Normal Glucose tolerance |
140 mg/dL |
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Impaired glucose tolerance |
140 to 200 mg/dL |
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Diabetes - impaired tolerance |
200mg/dL |
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Hyperglycemia= |
BG > 160mg/dL (8.9mmol) |
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Hypoglycaemia = |
BG<60mg/dL (3.3mmol/L) |
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Chronically high blood glucose levels can cause damage to what organs? |
Kidneys, Eyes, Nerves |
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T/F Extreme stress can cause a temporary rise in blood glucose |
True |
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What kind of drugs can increase blood glucose levels? |
antidepressants, diuretics, estrogens (birth control and hormone replacement) epinephrine |
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What happens to the kidneys when BG levels rise to high? |
Kidneys cannot reabsorb glucose fast enough and sugar spills into the urine ( frequent urination) |
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Hyperglycaemia symptoms |
Increased thirst Frequent urination weight loss exhaustion blurred vision migraines |
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Symptoms when blood glucose drops |
Hunger, blurred vision, pounding heart, shaking, sweating, difficulty concentrating |
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Spontaneous hypoglycemia |
State of excess insulin resulting in chronically low BG levels |
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Reactive hypoglycemia |
a drop in BG to due prolonged period between meals , excessive CHO's, an allergic reaction to food or consuming alcohol without eating |
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What can chronic hypoglycaemia lead to? |
Brain and nerve damage |
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What kind of drugs can decrease blood glucose levels? |
acetaminophen and anabolic steroids |
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Severe acute hyper or hypoglycaemia can be life-threatening leading to |
organ failure, brain damage, coma, and in extreme cases, death |
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What is the glycemic index? |
Measure of CHO digestion rate given for specific foods The rate BG levels rise after a particular food in comparison to pure glucose |
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Factors which determine rapidity of CHO digestion and absorption include: |
How swollen the starch grains are How much the food has been processed How much finer it contains How much fat |
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How does fiber help blood glucose? |
Spread out the release of glucose in the blood |
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Glycemic Load |
Amount of CHO in grams x the GI of that CHO /100 |
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Low glycemic load |
10 or less |
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Medium glycemic load |
11-19 |
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High glycemic load |
20 or more |
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What is "The second meal effect" |
1) Ability of one meal to improve glucose tolerance of the next meal 2) Slow & prolonged absorption of CHO at breakfast results in a slower rise in blood sugar levels (decrease insulin and decrease glycemic response) after lunch |
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Insulin Resistance |
more insulin is required to reduce blood glucose causing the pancreas to work harder to keep up with the demand |
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Possible Symptoms of insulin resistance |
Fatigue/brain fog Intestinal bloating weight gain/fat storage Depression Hypertension Increased blood TG levels Increased hunger |
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Contributing factors to insulin resistance |
Obesity, inactivity, and genetics |
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Metabolic Syndrome |
Accumulation of visceral fat Increased CV risk factors such as impaired glucose tolerance, dyslipidemia and hypertension |
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Diabetes |
Absolute or relative deficit of insulin - metabolic disorders of CHOS, lipids, & proteins |
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Metabolic disturbances of diabetes are accompanied by |
Loss of CHO tolerance Fasting hyperglycaemia Ketoacidosis ( increased ketone bodies) Decreased lipogenesis and increased lipolysis Increased proteolysis |
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Type 1 Diabetes |
Child onset Autoimmune- breakdown of pancreatic beta cells |
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Type 2 Diabetes |
Adult onset Metabolic disorder- fasting hyperglycaemia and and insulin resistane |
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Symptoms of diabetes include: |
Polyuria, polyphasia, polydypsia |
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Polyphasia |
Increased hunger |
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Polydypsia |
Increased thirst |
