Chapter 4: Carbohydrate Flashcards
(86 cards)
1
Q
What is Carbohydrate?
A
Contains carbons, hydrogens, and oxygen in the proportion of 1:2:1.
2
Q
What are the two types of carbohydrates?
A
Simple and Complex.
3
Q
All Carbohydrates are made up of sugars called: (list three examples).
A
Monosaccharides. 1. Glucose2. Fructose3. Galactose
4
Q
What is maltose comprised of?
A
Two glucose.
5
Q
What is lactose comprised of?
A
One glucose and one galactose.
6
Q
What is sucrose comprised of?
A
One glucose and one fructose.
7
Q
True or False: Hydrolysis adds water to make a disaccharide into two monosaccharides.
A
True. This happens in the gut.
8
Q
What are simple sugars?
A
Monosaccharides (glucose, galactose, fructose) and dissaccharides (lactose, maltose, sucrose).
9
Q
What are oligosaccharides?
A
3 - 12 sugar units, majority of breakdown occurs in the large intestine (bacteria breaks them down and produce gas). Also known as prebiotics.
10
Q
What are polysaccharides?
A
100s or 1000s of sugar units.Dextins, glycogens, sugar alcohols (maltitol, sorbital).
11
Q
What are complex carbohydrates?
A
Starch, a giant polysaccharide consisting of only glucose.
12
Q
True or False: Starch is the problem, not what else is in the food.
A
False. Starch is not the problem, it is what it is paired with that can make it unhealthy. Products with starch and fibre can be quite healthy.
13
Q
What is glycogen?
A
Similar structure to starch. Found in animals, starch is found in plants. A place to store energy (mostly in liver).
14
Q
What is cellulose?
A
Fibre, a bunch of glucose units. Humans do not have enzymes to break the bonds in fibre apart.
15
Q
DRI values of Carbohydrates?
A
45-65% of total kcal.
16
Q
What is the fibre recommendation?
A
14g/1000 kcal.
17
Q
What vegetables are high in carbohydrates? (Starch)
A
Potatoes, peas, corn, carrots.
18
Q
What fruits are high in carbohydrates? (Mostly simple sugars)
A
Bananas (very filling, starchy).
19
Q
What carbohydrate is found in grain products?
A
Starch.
20
Q
What carbohydrate is found in milk?
A
Lactose.
21
Q
What carbohydrates are found in milk alternatives?
A
Simple sugars, starch, oligosaccharides.
22
Q
Pattern of carbohydrate intake in North America?
A
Since 1900s, N. A. CHO intake has decreased 25-30%, while fat and protein intake has increased. Refined carbohydrate intake has also increase.
23
Q
What does the mouth do with carbohydrate digestion?
A
Some starch is broken down into maltose units by salivary amylase. This is more effective is people eat slowly.
24
Q
What is in the stomach that helps with carbohydrate digestion and absorption?
A
The hydrochloric acid in the stomach denatures/inactivates the salivary amylase. No actual carbohydrate digestion takes place here.
25
Where does most of the digestion and absorption for carbohydrate take place?
The small intestine.
26
What does pancreatic amylase do?
Digests starch in the small intestine, creates maltose.
27
What does maltase do?
Breaks down maltose into two glucose units.
28
Where does glucose, fructose, and galactose get absorbed after the small intestine?
Absorbed through the intestinal wall and into the portal vein (vascular system) to the liver.
29
What is monosaccharide metabolism in the liver?
First, the fructose and galactose is converted into glucose. Glucose then is used for five main purposes:1. Energy needs of the liver2. (Excess glucose) Stored as liver glycogen 3. Made into nonessential amino acids4. (All previous steps have happened, still have excess) Converted into fat, transported by VLDL to adipose tissue5. Set out into bloodstream to fuel body cells.
30
What happens when glucose is released into the bloodstream?
Provide energy for most body cells. Goes to the muscles to be used as muscle glycogen.
31
True or False: brain, CNS, red blood cell only use glucose for energy
True.
32
True or False: muscle glycogen only fuels muscle cells.
True.
33
What are three basic facts about glucose?
1. Found in small amounts in only plant foods.2. It is an essential nutrient. 3. Main energy source for brain, CNS, and RBC.
34
What happens to glucose when it is released from the liver?
Arise in the the glucose level in blood. Insulin allows glucose to be used as glycogen in muscles, used by cells for energy, and stored as fat.
35
What causes insulin to be secreted?
Insulin is secreted in response to eating.
36
What are the effects of insulin?
1. Facilitates uptake of glucose from blood into cells. 2. Stimulates production of glycogen. 3. Blood glucose levels return to normal levels or basal levels.
37
What happens when blood levels begin to fall?
Drop in blood glucose stimulates hunger response.
38
What happens when blood glucose drops?
Insulin levels drop, glucagon levels increase.
39
What does glucagon do?
Mobilizes stored liver glycogen, breaking it down, causing glucose to be released into bloodstream.Causes blood glucose to increase back to normal, or basal, levels.
40
What is Type 1 Diabetes mellitus?
Lack of effective/functional insulin. The pancreas has stopped making insulin. Found in teens - 20s mostly. An autoimmune disease, linked to early life viral infections and genetic predispositions. Can be treated with injections of insulin.
41
What is Type 2 Diabetes mellitus?
Over 90% of diabetes cases, the body cells become glucose intolerant (insulin resistant). It can be genetic, but most cases are linked to dietary and lifestyle choices. Can be treated with an improved diet and exercise, and medication.
42
What is glucose tolerance?
A measure of a person's ability to remove excess blood glucose following a meal. The range of glucose tolerance is quite large.
43
What is the Glucose Tolerance Test?
1. Given glucose drink (very sweet).2. Take blood sample periodically over 2-3 hours. Blood glucose increases and glucose is absorbed from the GIT. The body should respond by producing insulin.3. Measure blood glucose levels in samples and create a glucose tolerance curve.
44
What four points are important on a glucose tolerance curve for a diabetic person?
1. Higher fasting blood glucose levels 2. A higher blood glucose peak/level is attained3. The peak is delayed4. The blood glucose levels stay higher longer.
45
What is the renal threshold?
10mmol/litre blood glucose, higher levels overwhelm the kidney's ability to hold glucose and it flows over into the urine.
46
Define "Glycemic Response"
Blood glucose response upon eating certain foods.
47
What are some food sources of fructose?
Honey, fruit, high fructose corn syrup (55% fructose).
48
What is High Fructose Corn Syrup?
Used to sweeten soft drinks, it is a liquid sweetener made from corn syrup. Cheaper than sucrose. Intake of HFCS has grown from 0% to about 33% of all sugar intake. Average American consumes over 62 pounds of HFCS/yr (approx. 130 kcal/day).
49
Is HFCS contributing to the Obesity Epidemic?
The body uses fructose differently than other sugars, it does not stimulate insulin secretion or enhance leptin production. It does not give normal satiety cues to stop eating. HFCS stimulates fat synthesis, which is sent out of liver by VLDLs which increases CHD risk. HFCS also can stimulate an increase of blood pressure. Just 1 daily 16 oz of soda provides about 200 kcal, which can add up to 20 lb weight gain in one year.
50
What is Sucrose?
Table sugar, has a sweetness value of one. It's isolated/purified from sugar beets and sugar canes.
51
What is the only sugar "myth" that is actually true?
Excess sugar intake may lead to Dental Caries.
52
What sugar "myths" may be true?
Excess sugar intake may lead to lipidemias (increase TG, decrease HDL), obesity, and increased risk of CHD.
53
What sugar "myths" are not true?
Excess sugar intake may lead to glucose intolerance (type two diabetes), behavioural problems, food allergies, kidney disease, nutrient deficiencies, and carcinogencity.
54
Does sugar cause obesity?
Excess calories from anything can cause weight gain. Calories in beverages are not detected in the same away as solid food calories, so they can "sneak" into the diet.
55
What are refined carbohydrates?
Mainly white flour based foods. Not filling, no fibre. Mostly simple sugars.
56
What are sugars called empty calories?
They contain no nutritional values (no vitamins/minerals) other than kcalories.
57
Should nutrient dense or kcalorie dense foods be chosen?
Nutrient dense.
58
What is Metabolic Syndrome?
A constellation of five features (having three means you have metabolic syndrome):1. Abdominal obesity2. High fasting glucose levels 2. High amounts of TG4. Low levels of HDLs5. High blood pressure
59
True or False: people who have a high CHO diet that is mostly comprised of simple sugars and processed grains they are more likely to have metabolic syndrome.
True, this can then lead to heart disease.
60
How many added tsp of sugars should women have a day?
6 tsp/day. (less than 100 kcal/day [25g])
61
How many added tsp of sugars should men have a day?
9 tsp/day. (less than 150 kcal/day [37.5g])
62
Conversion factor for tsp to g of sugar.
tsp x 4 = ___ g sugar.
63
Conversion factor for tsp to kcal sugar.
tsp x 16 = ___ kcal sugar.
64
What is Lactose?
Milk sugar, relative sweetness of 0.2, all infants (and young children) have the enzyme lactase.
65
What is Lactase Deficiency?
Majority of the world's people cease making lactase as they age (between ages 4 - 16).
66
What is Lactose Intolerance?
Refers to the symptoms of becoming lactase deficient.
67
What are the consequences of undigested lactose?
Lactose does not breakdown into galactose and glucose, and the the undigested lactose travels through the small intestine , attracting water, until it travels to the colon. Some of this water is reabsorbed in the colon. The colon's bacteria ferments the lactose and CH4, CO2, and H2 gas is produced.
68
What is a Milk Allergy?
An exaggerated immune response to a protein in milk. The milk proteins in the GIT cross over into the blood stream (vascular system), becoming immunogenic peptides, and antibodies are produced against the milk protein. Can induce anaphylaxis (effect breathing among other things).
69
Is dietary fibre digestible?
Nope. No fibre is digestible.
70
What is resistant starch?
Resists digestion, acts like fibre but structurally resembles starch.
71
What are some food sources of Soluble Fibres?
Pectin, guar gum, locust bean gum, beet gum, xanthan gum. Oat bran, inside of legumes, barley, and fruit pulp.
72
What are some food sources of Insoluble Fibres?
Cellulose, lignan. Vegetable and fruit skins, whole grains (e.g. wheat bran), outer coats of legumes.
73
What does soluble fibre do in the colon?
Digesta enters the colon as a loose weave, bacteria can easily break the bonds of the soluble fibre through fermentation. The result is short chain fatty acids and gases. The fecal matter is mainly bacteria.
74
What does insoluble fibre do in the colon?
Digest enters the colon as a tight weave, bacteria cannot easily break the bonds and there is less fermentation. A large amount of fibre remains in the feces. Leads to the "bulking effect" (keeps people regular).
75
What are the short chain fatty acids that come from the fermentation of soluble fibre?
1. 4:0 butyrate (preferred energy source of the colon) 2. 3:0 propionate (absorbed through the mucosa, vascular system goes to the liver, shuts down cholesterol synthesis) 3. 2:0 acetate (provides an immediate small energy source)
76
What is considered the gold standard for insoluble fibre?
Wheat Bran.
77
What is Wheat Germ high in?
B vitamins, PUFA/MUFA, fat soluble vitamins (especially vitamin E). White flour takes this away.
78
What is Bran Layer made of?
Insoluble fibre. White flour takes this away.
79
What is the Aleurone layer high in?
B vitamins and iron. White flour takes this away.
80
What is the Endosperm rich in?
Carbohydrates (starch) and protein.
81
What does Soluble Fibre have to do with Colorectal Cancer?
Production of short chain fatty acids (4:0), lowers pH which raises acidity and means more fermentation, stimulation of microbial cell growth (more 4:0 produced), results in lower ammonia levels (ammonia is potentially carcinogenic). Lowers risk of colorectal cancer.
82
What does Insoluble Fibre have to do with Colorectal Cancer?
"Bulking Effect" means dilution of colonic contents, provides a surface of adsorption (sticking to), decreased transit time, and altered bile acid metabolism.
83
What are secondary bile acids?
Insoluble fibre helps with stopping the production of secondary bile acids. When bile acids get to the colon, bad bacteria may act on them and convert bile acids into secondary bile acids which are cancer promoters.
84
Does soluble fibre or insoluble fibre help with lowering blood cholesterol?
Soluble fibre.
85
How does soluble fibre lower blood cholesterol?
It binds bile acids and prevents the recycling of bile acids, which increases fecal excretion of bile acids. Cholesterol then is taken up by the blood to make more bile acids. Soluble fibre forms 3:0 (propianate) during fermentation, which returns to the liver and inhibits cholesterol synthesis. Forces the liver to get cholesterol from other places.
86
What role does fibre have in weight loss and weight management?
1. More fibre increases satiety 2. Delays gastric emptying (takes stomach longer to pass food)3. Takes longer to eat, allowing the body to detect and respond to satiety cues. 4. High fibre diets tend to be low fat diets.
