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.