Nutrition: Carbohydrates CH 4
Function of carbs
Provides energy Dietary fiber Naturally occurring sweeteners (sucrose and fructose) Brain and nerve tissues require CHO (glucose) as fuel Protein-sparing effect
insulin primary function is to
lower glucose levels
Carbs are classified according to the number of saccharide units making up their structure. The 3 different sizes are:
monosaccharides polysaccharides disaccharides
absorbed like fructose, galactose is converted to glucose by the
liver
Our food sources of carbs tend to be ____________ and _______________.
disaccharides (sugars) polysaccharides (starches)
Two categories of carbs:
simple and complex
Glycemic load
total glycemic index; effect of mixed meal or dietary plan
True or false: galactose is rarely found in nature by itself
true
Unrefined vs refined grains
unrefined are prepared for consumption while they contain their original components. refined have been taken apart.
maltose is
used in the production of beer and other malt beverages
Fiber recommended intake
25 to 38 g/day
Artificial sweeteners:
Aspartame Saccharin Acesulfame potassium Sucralose Stevia
Factors affecting glycemic index
Glycemic load health effects
Health effects of fiber
Obesity- reduce or prevent Constipation- ensure slarger, softer stool. Diverticular disease- affects large intestine Colon cancer- reduces risk Heart disease Diabetes control
After an active absorption process,
absorptive cells in the small intestine take up these monosaccharides
insufficient amounts of dietary carbohydrates cause a buildup of ketones. This can lead to
acid-base imbalances in the body (ketosis)
monosaccharides basic function
basic energy for cells
Insulin produced by
beta cells of the islets of langerhans
Carbohydrate metabolism: What does it maintain and in what range?
blood glucose homeostasis at 70 to 100 mg/ dL
The thyroid hormone thyroxine affects..
blood glucose levels by enchancing intestinal absorption of glucose and releasing epinephrine.
Glucose is essential for _______________ and ___________, especially during ____________ and ________________.
brain function and cell formation. pregnancy and growth
Glycogen
carbohydrate energy that is stored in liver and muscles
The GI tract has the role of:
digesting carbs into monosaccharides for easy absorption.
Soluble fiber
dissolve in fluids
insoluble fiber
do not dissolve in fluids and therefore provide structure and protection in plants.
insulin also ...
eases the absorption of glucose into the cells so the use of glucose as energy is increased.
insulin lowers glucose levels by
enchancing the conversion of excess glucose to glycogen through glycogenesis or to fat stored in adipose tissue.
polysaccharides
energy storage (starches) digestive aid (fiber)
disaccharides
energy, aids calcium and phosphorus absorption (lactose)
Carbs are a source of
energy, sweetness, and dietary fiber
The adrenal gland hormone, Epinephrine, ....
enhances the fast conversion of liver glycogen to glucose
Ketone bodies are created when...
fatty acids are broken down for energy when sufficient carbohydrates are unavailable
the liver converts _______ and ________ into ___________.
fructose and galactose into glucose.
The two hormones that help raise glucose levels are:
glucagon and somatostatin
Protein may be a source of
glucose
With insulin production...
glucose is moved out of the bloodstream into cells in order to meet energy needs.
Monosaccharides: 3 types
glucose, fructose, and galactose
Glycemic index
level to which food raises blood glucose levels in comparison with reference food; highest ranking is 100
Mechanical digestion in the mouth starts the ...
hydrolysis of starch into the simpler carb intermediary forms of dextrin and maltose
Once the enzymes are secreted by the small intestine's brush-border cells, they then..
hydrolyze disaccharides into monosaccharides
Pituitry gland hormones such as growth hormone and ACTH function as
insulin inhibitors
In the small intestine ...
intestinal enzymes and specific pancreatic amylase work on starch intermediary products to continue the breakdown to monosaccharides.
The digestive process starts in the:
mouth
the health concerns regarding sugar consumption include:
nutrient displacement, dental caries, and the related issues of obesity and diabetes.
Carbohydrates
organic compounds composed of carbon, hydrogen, and oxygen in form of simple carbohydrates or sugars
glucagon and somtostatin is produced by the
pancreas
Complex carbohydrates:
polysaccharides composed of many units of monosaccharides held together by different kinds of chemical bonds
lactose
primary carbohydrate in milk.
Glycogenesis
process of converting glucose to glycogen
During mechanical digestion, food mixes with saliva, which contains an amylase called:
ptyalin
whole (unrefined) grains
refer to food items made using all the edible portions of kernels.
Once the liver converts fructose and galactose into glucose, glucose is then ...
released in the blood stream which elevates blood glucose levels, which causes the release of insulin from the pancreas.
somatostatin
secreted by the hypothalamus and pancreas. inhibits the functions of insulin and glucagon.
Fiber is a type of complex carb. Cannot be digested by humans. Two types of fiber are:
soluble and insoluble fiber
three types of sugar alcohols are:
sorbitol, mannitol, and xylitol
glucagon
stimulates the conversion of liver glycogen to glucose, assisting the regulation of glucose levels during the night.
Starch is a type of complex carb. They are the.... Food sources that contain starch are..
storage form of plant carbohydrate grains, legumes, root vegetables
disaccharides: 3 types
sucrose= glucose + fructose maltose = glucose + glucose lactose = glucose + galactose
Fructose is the ______ of the sugars. After absorption from the small intestine.....
sweetest fructose circulates in the bloodstream. When it passes through to the liver, liver cells rearrange fructose into glucose.
Sucrose is
table sugar sugar cane sugar beets
Although glycogen can be converted back to glucose ...
the conversion of glucose to fat is irreversible.
What happens after glucose, fructose, and galactose enter the villi?
the portal blood circulatory system transports them to the liver.
glycogenolysis
the process in which glycogen stored in the liver and muscle tissue is converted back to glucose
Gluconeogenesis
the process of producing glucose from fat
enrichment
the replacement of nutrients to the level that was present before processing.
Enzymes specific for disaccharides are secreted by:
the small intestine's brush-border cells.