Chapter 4 Carbs Flashcards
What is the monomer of carbohydrates? What are the 3 6C sugars? What are the 2 5C sugars? What structure do they have and what chemical formula? What form must they be in to be absorbed?
- monosacharides
- 4 simple sugars: glucose, fructose, galactose (hexose sugars, 6C), pentose (deoxyribose & ribose, 5C)
- they are all isomers of each other: same structure but rearranged (all have chemical formula C6H12O2)
- C:H:O 1:2:1 ratio
- to absorb sugar, must be in monosach form
“ose”
sugar
What are the 3 kinds of disaccharides? What kind of bond are they held together by? What kind of reaction takes place?
- 2 monosach joined together by covalent bond (glycosidic bonds)
- dehydration synthesis, anabolic
- table sugar = sucrose (G+F)
- milk = lactose (G+Gal)
- malt sugar = maltose (G+G)
Polysaccharides are ___ of monosaccharides. Is it a complex or simple sugar? They release quickly or slowly? In order to be absorbed, they must be ____. What is the most abundant polysach? What is its functions? (2)
- polymers of monosaccharides
- slow-releasing or complex sugar
- needs to be broken down to absorb
- glycogen the most abundant polysach (bunch of glucose)
- gives energy
- some for structural components, not for energy
important polysaccharides in humans (3)
- starches: plant version of glycogen (ex. potatoes, wheat, corn)
- fibers
- glycogen: animal storage of sugars
Soluble (6)
Insoluble Fibers (7)
Excess fiber results in ___ (3). It is a ___ that binds to metal so that it ___.
Soluble
- viscous fiber
- thick/paste consistency
- goes through bacterial fermentation (different word for digestion)
- helps slow down digestion & absorption of glucose (-> no spike in blood glucose levels)
- satiety (feeling of fullness) increased -> helps with losing weight
ex. oats, apples, strawberries
Insoluble
-pushes/paves way to get rid of it. picks up things along the way
-alleviates constipation
-lowers risk of hemorrhoids, appendicitis (feces move into appendix)
-cellulose (plant fiber): humans cannot digest cellulose but is important for cleaning the digestive tract
-nonviscous
-does not mix well with water so maintains shape
Ex. corn, whole grain, vegetables
Excess fiber
- diarrhea, dehydration, malnutrition
- a chelating agent: anything that binds to metal. too much fiber attaches to nutrient metals and cannot be absorbed
Adequate intake levels for total fiber
21g/day for women 50+
25g for women <50
30g for men 50+
38g for men <50
What are the byproducts of gut bacteria/microflora that we do and don’t want? _____ protects the large intestine.
- gas
- byproduct dont want - short-chain fatty acid: provide nutrients/energy to bacteria in large intestine
- anti-inflammatory protects large intestine
- byproduct we want
What is bile? What does it do? How is fiber associated with it? Where is it produced? Where is it stored? How does it move into the SI? What health effect does it have?
- fat that helps breakdown fat in small intestine
- soluble fiber helps bind to bile and eliminate out of GI tract
- produced by liver, stored in gallbladder
- movement by bile duct into SI
- elimination of excess fat (bile) out of body prevents heart disease
Table: Viscous/soluble fiber examples (5) Actions (5) health benefits (3)
Ex. beta glucans, gums, inulin, pectin, psyllium
Actions:
- bind bile to cholesterol
- slows glucose absorptions
- delays nutrient absorption
- nourish bacteria in colon (energy)
- increases satiety
Health Benefits
- alleviate constipation
- lowers risk of heart disease, diabetes, colorectal cancer
- weight management
Non-viscous/insoluble fiber Examples (4) Actions (3) Health benefits (3)
-cellulose, lignins, resistant starch, hemicellulose
Actions:
- increases fecal weight
- speeds up fecal passage
- increases satiety
Health benefits:
- alleviate constipation
- lowers risk of appendicitis and hemorrhoids
- lowers risk of colorectal cancer
Process of digestion and absorption of carbs (5). What is special about fiber digestion?
- starch digestion begins in the mouth: salivory amylase splits into shorter units
- moves down the esophagus (no digestion), enter stomach (no digestion here)
- chyme enters SI where digestion resumes: pancreatic amylase
- absorption into the bloodstream through primary active transport
- enters hepatic portal system and taken to the liver
fiber goes through SI untouched and goes to the colon
Why is active transportation needed for the transportation of monosaccharides? What is its process (5)
- because not fat
- primary active transport on basal surface, secondary on apical surface
- Na pumped out from cell into blood. K pumped into cell
- secondary transport recognizes drop in Na and allows Na to move through cell membrane (hi to low concentration)
- brings friends (glucose)
- once glucose goes into cell, released into the blood
Glucose regulation: what cells of which organ release insulin and glucagon? Are they catabolic or anabolic hormones? What is the value of homeostasis?
- beta cells of pancreas releases insulin (anabolic hormone to synthesize glycogen)
- alpha cells release glucagon (catabolic hormone to break down glycogen)
-homeostasis around 80-100mg/dl (below 80 release glucagon, above 80 release insulin)
What is the first thing made when having excess glucose? Which two organs make, break, and store glycogen (while using some as energy)? Which organ system uses all the glycogen?
- glucose used to make fat but the first thing made is glycogen
- liver and skeletal muscle makes, break down, and store glycogen (uses some energy)
- skeletal muscle uses all the glycogen
Glucose is a source of what cellular process?It is converted into what? How much energy do we need?
- cellular respiration
- convert glucose into ATP
- need energy 24/7, even when asleep
well fed state (finished eating) process (6)
- Blood glucose (and everything else from food) levels go up
- beta cells recognize increase in blood sugar and secrets insulin
- insulin levels goes up as released from pancreas
- insulin turns on phosphatase (dephosphorylation - takes phosphate off other structures)
- phosphatase turns on glycogen synthase by removing a phosphatase
- phosphatase turns off glycogen phosphorylase by removing phosphate
fasting state (6)
- blood glucose levels & insulin levels drop
- alpha cells in pancreas senses drop in glucose and release glucagon
- glucagon levels increase
- glucagon turns on kinase (phosphorylates - attached phosphate)
- kinase phosphorylates glycogen phosphorylase and turns it on
- kinase phosphorylates glycogen synthase and turns it off
What is glycemic index? What is it also called? What has high glycemic indexes? This is an example of ____. What is it called with regards to people with diabetes?
- measures degree of elevation of blood glucose and insulin (how fast blood glucose levels rise)
- “food score”
- high in simple sugars (mono, disach) that are rapidly metabolized
- metabolism affects body’s insulin response
- important for diabetics: glycemic load (lower GL less glucose build up and less insulin needed) - same thing as glycemic index
5 functions of carbs
- energy production - glycolysis breakdown of glucose to provide ATP. glucose the preferred form of energy
- energy storage - first, glycogen & second, fat
- building macromolecules - DNA, RNA, fat
- production of proteins
- assist in lipid metabolism - sparing fat
What is the first step after consuming glucose? What happens to fat in the blood? What is liver’s role? Is glycogen stored in fat tissue?
- most used as energy (esp in skeletal muscle)
- fat circulates blood and stored as fat
- liver uses some glucose, make glycogen and triglycerides
- v little glycogen stored in fat tissue
Do added sugars cause obesity? When is glucose made into fat? What is the trend in America for obesity? What are top calorie sources? (2)
- added sugar causes obesity (also type 2 diabetes)
- uses up glycogen storage then converted into fat
- americans have grown fatter in past decades
- top calorie sources: sugary desserts & beverages (liquid calories - soda & coffee)
What is high fructose corn syrup made of? How are they made? How does it alter our biochemical processes? (2) What disease is asoociated with HFCS?
- is made of fructose
- affects appetite differently: makes it taste sweet
- corn starch converted into glucose & fructose and then glucose converted into more fructose
- handled differently in body: fructose sent straight to make fat, not energy like glucose. Blood lipids stimulates body fat-making pathway. then liver can only make so many triglycerides at a time. so starts storing fat in the liver
- nonalcoholic fatty liver disease (NAFLD) - AFLD also formation of fat. liver does not know where protein needed, etc body doesn’t function
What are the dietary guidelines for Americans on whole-grain consumption? (2)
Dietary Guidelines for Americans recommendation:
- at least half daily grains should be whole
- DRI min of digestible carbs: 130g/day
parts to a whole grain (4)
4 types/parts to the kernel
- husk: waste of the kernel with no nutritional value
- germ/bran: where have nutrients
- endosperm: where have majority of the carbs
whole-grain vs refined vs enriched
Whole grain tries to keep things ___. Refined products strip away ___. what do refined foods add? (2) What gives it the taste? What is added back to enriched products?
- whole grain products keeps as much of it intact as possible
- vs refined products strip away bran & germ, only the endosperm remains. IN ADDITION adds more sugar and fat into the product. Endosperm is what gives it taste
- vs enriched: adds vitamins & minerals back into refined product
US enrichment Act of 1942 - What standard is whole-grain called? Which nutrients did they add to enriched products? (5) What disease is the deficiency of one of these minerals associated with?
- whole grain: the golden standard
- addition of iron, thiamin, riboflavin, and niacin
- folate (deficiency associated with spina bifida) added in 1996
Brown vs white grain (2) What do we want to look for in carb products (3)? What is stone prcocessing? What is bromated flour? What kind of flour is best?
- just because brown does not mean it is whole grain. can be dyed
- white wheat bleached because it “looks better,” taste better because added fat/sugar
- read subtitles of food labels. look for high fiber & no sugar added (for example like in cereals) & “whole wheat”
- stone ground processing minimal
- bromated flour: potassium bromide helps bread last but if not cooked, a carcinogen
- -> unbromated stone whole wheat flour the best
How do sugar alcohols & non-nutrient sweeteners work? What is good about them? (3) What is bad about them?
- mimics sugar structure in binding to sweet taste receptors but cannot be digested/absorbed (which is why zero cal)
- provide half the calories of sugars
- lower glycemic index
- safer for teeth than sugars
- high consumption leads to GI distress/diarrhea since body wants to get rid of it
FDA established ADI for artificial sweeteners (5)
- acesulfame potassium (sunett, sweet one) 15mg/kg bw/day
- asparatme (equal, nutrasweet) 50
- neotame 18
- saccharin (sugartwin, sweet’n low) 5
- sucralose (splenda) 5
source of carbs in food (8)
- vegetables
- fruits: vary in water/fiber/sugar (fructose) concentrations. limit because sugar. limit juices too.
- grains: low-fat/sugar choices
- protein foods: nuts & legumes
- milk & milk products: high quality protein
- oils, solid fats, added sugars: naturally occurring (honey) vs added -> recommend honey, stevia (comes from plants)
–> want carbs higher in fiber
Pre-diabetic tests (3)
Prediabetes: measure with
- fasting plasma glucose test: not eat anything before doc appointment so blood glucose should be low but if high diabetic
- HbA1C test: glucose attached to hemaglobin. normally 4-5% glycated but diabetics have 7-10% measures how bad glucose regulated over 6 month period
- oral glucose tolerance test: give glucose and measure over time to see if glucose levels come back down
What disease is the leading cause of death in the US? Dangers of diabetes (8)
-leading cause of death in the US
Dangerous because:
- storing more fat
- produce ketone bodies/acids that break down body tissue
- state of inflammation & circulation problem
- associated with cardiovascular disease, blindness/retinopathy, neuropathy, nephropathy
common symptoms of low blood sugar (8)
symptoms of v low blood sugar (4)
slide 23
gestational diabetes (3)
- diabetes during pregnancy
- signs/symptoms 2-3 weeks after baby born
- 60-70% risk for type 2 diabetes
What percentages of diabetes are type 1? What did it use to be called? What kind of condition is it? What causes it? What happens biologically? What is tragic about it? What is its treatment? Breakthrough in protein?
- 5 to 10% of cases
- used to be called juvenile onset diabetes malideous but now not since affects people of all ages. also have more kids getting type 2 diabetes
- autoimmune condition
- do not know cause
- beta cells inflamed. send immune cells to fix problem but makes it worse. body no longer able to produce insulin since beta cells destroyed. become insulin dependent
- by the time find out too late
- insulin can be fast acting and long acting insulin
insulin first protein to be sequenced! extracted out of pigs and give to humans
Type 2 diabetes the ____ prominent type of diabetes. What is insulin resistance? What is insulin insensitivity? What can it also do? What disease is a huge risk factor in developing diabetes? Factors affecting diabetes (4)
- predominant type of diabetes (90%)
- insulin resistance: producing insulin but cells do not respond to them. insulin cannot bind to receptor
- insulin insensitivity: insulin produced and can bind to receptor but not functioning. no uptaking & production of glycogen
- can stop producing insulin as well: diabetics need to inject insulin. metformin helps binding to receptors and stimulate activity
- obesity a huge risk factor to developing diabetes (obesity puts strain on pancreas)
Affecting factors: lifestyle
- middle age
- physical inactivity
- body fat accumulation
- genetic inheritance
Prevention of type 2 diabetes (5) What is the good thing about type 2 diabetes?
- maintain healthy body weight
- nutritious eating pattern (moderation calories, low in saturated fat, high in vegetables/legumes/fruit/fish/poultry/whole grains)
- physical activity
- carb intake control
- no smoking
-can be reversed!
