Unit 12 Flashcards
Useful facts about sugars, starches and fibres
What are the 2 major classes of carbohydrates?
- simple
- complex
What do simple sugars refer to?
monosaccharides and/or disaccharides
What are examples of monosaccharides?
- glucose (blood sugar and dextrose)
- fructose (fruit sugar)
- galactose
What is the most abundant and nutritionally relevant monosaccharide?
glucose
What type of simple sugar is absorbed into the bloodstrem?
monosaccharides
What is a disaccharide?
2 monosaccharides joined by a covalent bond
What is the health risk of simple carbohydrates?
they are rapidly absorbed into the bloodstream, increased insulin resistance and inflammation
What are the disaccharides?
- lactose
- maltose
- sucrose
What is sucrose made up of?
glucose + fructose
What is the most widely used natural sweetner? Where does it come from?
Sucrose
Can be cane sugar or beet sugar
What is maltose formed from?
The partial breakdown of starch
What makes up maltose?
What 2 monosaccharides?
glucose + glucose
What makes up lactose?
What 2 monosaccharides?
gluctose + galactose
What is one of the only animal sugars besides glucose?
Lactose
What are the 2 complex carbohydrates?
- oligosaccharides
- polysaccharides
What complex carbohydrates are usually 3 monosaccharide units?
oligosaccharides
Can the bonds that join the monosaccharides and make up oligosaccharides be broken by human enzymes?
No
T/F: oligosaccharides are a fibre source
true
Where do find oligosaccharides?
What foods, kind of?
- garlic
- onions
- inulin
What are long chains of monosaccharides called?
up to 1000s
polysaccharides
What are the 3 primary nutritional polysaccharides?
- glycogen
- starch
- cellulose
In what foods do we find polysaccharides?
- potato
- rice
- pasta
- corn
- cereal
- bread
- apple peel
- seeds
- nuts
What is energy storage in plants? Is it digestible?
starch, is digestible
What is energy storage in animals? Is it digestible?
glycogen, is digestible
What does cellulose do? Is it digestible?
Provides structure in plants, not digestible
What are the bonds found in polysaccharides that can be broken down by human enzymes? Where are they found?
Alpha glycosidic bonds
found in starch and glycogen
What are the bonds found in polysaccharides that cannot be broken down by human enzymes? Where are they found?
beta glycosidic bonds
found in cellulose
What happens to fiber in the colon?
bacterial enzymes break down fiber to form short chain fatty acids and gas as a byproduct
What does fiber feed?
Our gut microbiota
What are some brain diseases related to the microbiota?
- anxiety
- depression
- autism
- parkinsons
What are some metabolism diseases related to the microbiota?
- obesity
- type 2 diabetes
- fatty liver disease
What are some intestinal diseases related to the microbiota?
- Crohns disease
- ulcerative collitis
- irritable bowl syndrome
What are pathogen is related to the microbiota?
clostridium diffical infection (C. diff)
What is primarly found in the endosperm?
Starch (storage form of glucose in plants)
What part of the grain is removed in the refining process making white flour?
the bran and the germ
What layer of a grain of wheat is a rich source of dietary fiber?
outer bran
What does the germ contain?
- unsaturated fats
- thiamin
- niacin
- iron
- riboflavin
Where is soluble fibre found?
- oats
- barley
- psyllium
Why is soluble fiber good?
What does it do
slows down glucose absorption therby lowering blood glucose levels
reduces fat and cholesterol absorptio
Does soluble fiber have lower or high calories than digestible carbohydrates?
lower
What is the typical calorie range fro soluble fibres?
1-2 kcal/g
Where can we find psyllium?
All-Bran buds
What is insoluble fibre found in?
- wheat bran
- seeds
- nuts
Why is insoluble fibre good?
What does it do
- moves bulk through gut
- controls gut pH
- removes toxic waste
- prevents constipation
What has the biggest impact on blood glucose? What has the smallest?
Biggest: Carbohydrate
Middle: Protein
Smallest: fat
How does the body manage glucose?
Outline the steps
- blood glucose rises when you eat
- stimulates pancreas to realease insulin
- insulin stimulates uptake of glucose into cells and storage as glycogen in liver and muscles. also helps convert excess glucose into fat stores
- as body uses glucose, blood levels decline
- stimulates pancrease to release glucagon
- glucagon stimulates liver cells to break down glycogen and release glucose
- blood glucose begins to rise
Do nutrition labesl distinguish between natural sugars and added sugars?
No
They only contain info on total sugars per serving
Do added sugars add nutrients?
no, only calories
What are some negative effects of sugar?
- tooth decay
- empty calories
- often mixed with fats
What are non-nutritive sweetners?
Zero-calorie or low-calorie sweetners that are either artificially synthesized or naturally derived
What are the sugar intake recommendations for women, men and children?
Calories + amount of sugar in grams
Women: 100 calories, 24 grams
Men: 150 calores, 36 grams
Children: less than 24 grams per day, sugary bevergaes no more than 8 ounces a week
What % of total calories should come from added sugars?
10%
What are the alcohol sugars?
- xylitol
- mannitol
- sorbitol
How many calories come from alcohol sugars?
2.6 kcal/g
What are alcohol sugars most often found in?
gum and candies
What is sometimes used to mask the unpleasant taste of artifical sweetners?
alcohol sugars
Are alcohol sugars well absorbed in the gut?
No, large amounts can cause diarrhea
Where does stevia come from?
Comes from a plant
What is aspartame made up of?
2 a.a - aspartic acid + phenylalanine
What is released in the digestion of aspartame?
methanol (10%)
aspartic acid (40%)
phenylalanine (50%)
How much sweeter is aspartame than sucrose?
200x
Is aspartame compatible with high temperatures?
No (>30 degrees celsius)
what is the acceptable daily intake for aspartame?
40mg/kg BW
What are 2 name brand of aspartame?
‘Equal’ and ‘Nutrasweet’
How is sucralose made?
chlorinated sugar
What is 600x sweeter than sugar?
sucralose
What artifical sweetner is splenda?
sucralose
Is sucralose safe whent heated?
Yes
Is acesulfame K stable at high temps?
Yes
Where is acesulfame K often used?
in combination with other sweetners
What artifical sweetner is 300x sweeter than sucrose?
saccharin
Does saccharin cause bladder cancer?
No, it does in rats but human do not have the same mechanisms
How was saccharin discovered?
By accident by a chemist working on coal tar derivatives
What does WHO suggest in terms of non-sugar sweetners?
that they not be used as a means of acheiving weight control or reducing risk of concommunicable disease (obesity, type II diabetes)
may cause insulin resistance
What is the mechanism of tooth decay due to sugar?
sugar ffeds bacteria, bacteria produces acid, acid decays teeth
bacteria forms plaque
What are the promoters of tooth decay due to sugar?
- increased frequency of stickey foods
- acidic beverages
- excessive cleaning/polishing
- nursing bottle syndrome (babies being put to sleep with a bottle)
What are protective foods against tooth decay?
- cheese (increases pH of plaque - decreased acidity)
- protein (with calcium it strenthens enamel)
- low calories sweetners such as sorbitol, mannitol and xylitol (stimulate saliva)
What does fluoride do?
Promote remineralization of eroded enamel
What does excess fluoride lead to?
fluorosis or mottled enamel during tooth development (cosmetic condition onlyseen in children who are 8 or younger when permanent teeth are developing)
