Carbohydrates Flashcards
do dairy, fruits and whole grain consist of carbs?
yes, in their refined state
how is the nutrient content reduced in carbs?
when it is refined
what does refining carbs remove from the carbs?
parts of the grain that contain vitamins, minerals and fiber
what are examples of bran?
Fiber and vitamins
what are examples of germ?
Vegetable oils and vitamin E
what are examples of Endosperm?
Starch and some protein
When a grain is refined, the endosperm is being collected
the WHO recommends that no more than 10% of calories come from:
free sugars
what does the Canada food guide recommend for diet:
more unrefined carbohydrates, whole grains, fruits, vegetables and legumes
Long term consumption of sugar sweetened beverages was associated with mortality primarily through what disease?
CVD
how does photosynthesis work?
plants use energy from the sun to convert CO2 and H2O into a glucose, releasing oxygen
what are carbs called in their simplest and purest form?
monosaccharides
each monosaccharide contains what?
6 carbons, 12 hydrogens and 6 oxygens
When two monosaccharides are combined they form what?
disaccharide
Oligosaccharides (3-10) and polysaccharides (10+) are formed when?
when many monosaccharides are linked together
- this is how plants an animals can store carbs for later use
how are Di-, oligo- and poly- saccharides formed?
formed from condensation reactions using enzymes
-A specific enzyme is needed to break down each type of glycosidic bond
why can fibre not be digested?
consists of polysaccharides that can’t be digested because there is no human enzyme to break it down
functional fibre
is added fibre due to beneficial impact
what solution does soluble fibre form with water in the intestine?
gelatinous
where is soluble fibre partially digested?
in the large intestine by bacteria
GI tract contents are diluted by what fibre? making it more difficult for what?
soluble fibre, making it more difficult for enzymes to interact with the food
- This results in slower digestion and absorption of nutrients
- This also makes it more likely that cholesterol and bile acids will be excreted instead of absorbed.
how is insoluble fibre different then soluble fibre?
- Does Not dissolve in water
- Excreted whole
Greater quantities of fiber in the diet will _________the transit time but_________ absorption time.
speed (decrease)
slow (increase)
how long does fibre stay in the small intestine?
2-6 hours
how long does fibre stay in the large intestine?
24-36 hours
is stool weight heaver or lighter with fibre?
heavier
how is ATP and electrons (NADH) generated in the fed state?
Glucose is broken down to pyruvate through glycolysis
(fed state) after Pyruvate is converted to Acetyl-CoA, how is it stored?
stored as fat or broken down in the TCA cycle
how is the citric acid cycle started?
Acetyl-CoA combines with oxaloacetate to form citric acid, beginning the citric acid cycle and generating ATP, electrons (NADH), carbon dioxide and regenerating oxaloacetate.
The electrons generated (NADH) enter the electron transport chain where they are eventually passed onto oxygen generating:
ATP and water
how does metabolism work if carbohydrates is available?
Acetyl-CoA from fatty acid oxidation has oxaloacetate to combine with in the TCA cycle
how does metabolism work if carbohydrates are not available?
the liver metabolizes Acetyl-CoA to ketone bodies to provide energy for the brain.
when glucose is high, what is the purpose of beta cells?
release insulin into the blood and signal to other cells that glucose is available and should be used
When blood glucose levels are low, what is the purpose of alpha cells?
release glucagon signaling the liver to release stored glucose
what two hormones work to keep blood glucose in a normal range?
beta and alpha cells
what is the process with using extra glucose (GLUT4)?
In the muscle and adipose cells, insulin reacts with insulin receptors on the surface of the cells, starting a signaling cascade
This leads to the glucose transporter, GLUT4, moving to the cell surface and facilitating glucose transport into the cell
This process continues until blood glucose levels decrease, and insulin is no longer being released by the pancreas
What is the Glycemic Response?
is the effect of a food on blood glucose levels
Factors that impact glycemic response include:
- Carbohydrate content of food
- amount of protein, fat and fiber
- Activity level
what does the glycemic index measure?
The ability for a food to increase our blood sugar
what is a high and low glycemic index?
High glycemic index = bigger increase in our blood sugar
> 70 = high GI
< 55 = low GI
what is the glycemic load?
considers the amount of carbohydrates in a serving of food
- Amount of carbohydrate in the food multiplied by glycemic index
name some long term complications of diabetes:
- Constant exposure to high levels of blood glucose causes many biochemical changes
- Glycation of proteins (AGE formation)
- Conversion of glucose into toxic molecules
- Oxidative stress
- Changes in gene expression
what is Diverticulitis?
Excess pressure can cause the colon wall to bulge out forming pouches called diverticula leading to the condition called diverticulosis
what happens if fecal matter collects in the pouches with diverticulosis?
it may cause pain, inflammation and infection
For diverticulitis- is lower or higher fiber intake recommended?
lower fiber intake is recommended temporarily to reduce irritation, along with antibiotics to clear the infection
- Once the infection is resolved THEN increased fiber intake is recommended, along with increased fluid intake to keep fluid soft.
why may higher fibre diets decrease your risk of colon cancer?
may be due to faster transit time allowing less contact of mucosal cells with toxins
