CARBOHYDRATES

Nutrition

Chapter 4

• Carbohydrates are the primary source of nutrients in the body that provide energy

• Carbs. Are the least expensive and most abundant nutrient

• Carbs provide ½ of the calories for people living in the U.S.

Where are carbs stored for later use?

• The body needs to maintain a constant supply of energy, (even at rest) therefore, the body stores ½ of its days supply of carbs in the liver and muscle to be used when needed

• The liver and muscle stores carbs in the form of glycogen

12-24 hours later

• Glycogen can be converted back to glucose for use

• F.Y.I. The hormone that converts glycogen to glucose is glucagon. Glucagon comes from the pancreas

• Are you confused yet?

There’s one problem….

• If a person eats too many carbs and doesn’t need all of that energy, the liver and muscles take what it needs and stores it as glycogen but…

• The rest goes into adipose tissue and is stored as fat

How many kcals in 1 gm of carbohydrate?

• 4kcals/serving

What is a carb made up of?

• Carbs are named for the chemical elements they are made up of:

• CARBON

• HYDROGEN

• OXYGEN

3 Function of carbohydrates

• 1) PROVIDE ENERGY AND HEAT

• When carbs digest and absorb, the body mixes them with O2 and oxidation occurs

• Oxidation= heat & energy

2nd Function of carbs

• 2) Carbs have a protein-sparing action

• When enough carbs are eaten in a day, (at least 50-100g/day) carbs supply the body’s energy needs, carbs leave protein alone so protein can focus on their primary function of building and repairing tissues

3rd function of carbs

• 3) Normal metabolism of fats• Requires a normal amount of carbs however…

• Your body ALWAYS burns energy, even when you are at rest (BMR). If you don’t eat carbs, what will your body use as energy?

• FAT

Yes, fat is burned and used for energy

• What’s the problem with this? If too much fat is burned because you haven’t eaten enough carbs, your body burns fat…

• PROBLEM…..

• Burning of fat releases ketones into your body

• VERY BAD. Can cause an acidosis

Diabetes Type I

• This is what happens in a diabetic

SOURCES OF CARBS

• Principal source is from plant foods like:

• Rice

• Potatoes

• Corn

• Apples

• Sugars

• And desserts

Carbs are classified into 3 groups

• 1) Monosaccharides

• 2) Disaccharides

• 3) Polysaccharides

MONOSACCHARIDES

• These are simple sugars that are sweet and require no digestion

• They are absorbed directly into the bloodstream from the intestine

• Some include

• These are bad for the diabetic, they need more complex carbs

Monosaccharides include:(GFG)

• Glucose- all sugars are converted to this for metabolism. The brain, nervous system an blood cells only use glucose for energy, it is continually needed

• Fructose- fruit sugar, is the sweetest of all monosaccharides

• Galactose- is a product of milk digestion, it isn’t found naturally

Disaccharides

• Are pairs of the 3 sugars glucose, fructose and galactose

• They are sweet and must be changed to simple sugars by hydrolysis before they can be absorbed

3 types of disaccharides(SML)

• 1)Sucrose

• 2)Maltose

• 3)Lactose

Sucrose

• Is a complex carbohydrate that is a mixture of glucose and fructose

• Found in any sugars like white granulated sugar, brown sugar, powdered sugar, and molasses It is naturally found in fruits and vegetables, sugar cane and sugar beets and extracted for use as a sweetener.

MALTOSE

• A dissaccharide found in malt, malt products and sprouting seeds

LACTOSE

• Is the sugar found in milk, it helps the body absorb calcium

Polysaccharides

• These are commonly called “complex carbohydrates”

• They are compounds of monosaccharides

3 polysaccharides are important in nutrition:

• 1) starch

• 2) glycogen

• 3) fiber

Monosaccharides Disaccharides Polysaccharides

• Glucose Sucrose Starch

• Fructose Maltose Glycogen

• Galactose Lactose Fiber

starch

• Is found in grains and vegetables

GRAINS

• 3 parts to a grain that are important:• Bran-outer covering, used in coarse cereals, must

be broken down by heat and moisture in order to be used as a starch, undigestible source of fiber

• Endosperm-center, this is where white flour comes from, this is where the starch is

• Germ- smallest part rich in vit. B, proteins, minerals and vit E

Grain

DEXTRIN• Dextrin is the product that comes from a starch

when water (hydrolysis) occurs and then the starch is cooked

• Example: when bread is toasted, it turns golden brown and tastes sweeter because the starch has been changed to dextrin due to cooking the bread

CELLULOSE

• Is an indigestible carbohydrate, it is therefore a primary source of dietary fiber

• It’s found in the skins of fruits and leaves and stems of vegetables

• It has no energy value but provides the bulk for stool

DIGESTIONof

monosaccharides• Simple sugars (monosaccharides) may be

absorbed from the small intestine, go directly to the blood, then they are carried to the liver where they are changed to glucose, then they are then carried by the blood to cells

Digestion of

Disaccharides• Must be changed to simple sugars by the

use of enzymes

• Sucrose – to – sucrase

• Lactose – to – lactase

• Maltose – to - maltase

Digestion of

polysaccharides

• You eat starch, ptylin (amylase), changes it to dextrin, it gets mixed with gastric juices, it enters the sm. Intestine, changes to a simple sugar, is absorbed by the blood and goes to cells

Metabolism & Elimination

• All carbs must be changed to simplier sugars like glucose, fructose and galactose before metabolism can take place.

• After glucose has been carried to the cells by the blood, it can be oxidized

• When there is too much sugar, more than the body needs, glucose is converted to glycogen and stored in liver and muscles

• When more glucose is eaten than the body can use and store, it is stored in the fat

What keeps your sugar levels normal?

• Glucose metabolism is controlled by Insulin.

• Insulin is released from the Islets of Langerhans in the pancreas to balance out the sugar you ate

• Normal blood glucose: 70-110mg/dL

Endocrine or Exocrine

• Remember, the pancreas is BOTH• Endocrine: releases insulin when the body takes

in sugar. (Releases or secretes hormones)

• Exocrine: the pancreas HAS DUCTS that release pancreatic enzymes during digestion that enter the stomach through the common bile DUCT

HYPERglycemia

• When the blood sugar is too high

• Above 110mg/dl

• Your body doesn’t like this

• Can cause clogging up of arteries= heart attack, stroke

What causes hyperglycemia?

• Not enough insulin• Either your pancreas isn’t making insulin

DM-I• OR…it only releases a little at a time DM-II

Insulin will need to be replaced by SQ for DMI

oral medications are given for DM-II

What is HYPOglycemia

• Low blood sugar of 70mg/dl or less• We get this when we don’t take in enough

carbs, our body needs that carb energy.• Carbs are quick and efficient• Waiting for fat to burn for energy takes a

long time.• Also, person could have had too much

insulin that lowered the blood sugar

• HYPOGLYCEMIA• Sweating• Irritability• Confusion• Shaking

• Cool & clammy need some candy

• HYPERGLYCEMIA• Body tries to get rid• Of the extra sugar• On its own

Normal Blood Glucose Levels

• 70-110mg/dl

• A person’s blood sugar should remain in this zone to achieve HOMEOSTASIS

Hypoglycemia of a diabetic pt

• What to do?

• Offer quick sugars IN SMALL AMTS

• Offer milk, will last longer

• NEVER feed food, takes too long to digest

Oxidation

• Oxidation of glucose = ENERGY and of course, heat

Waste product of carbohydrate metabolism

• Is carbon dioxide and water

• CO2 and H2O

Adkins Diet

• Person eats NO carbs but fats and proteins

• Goal is to make your body burn fat directly off of you for energy = wt loss

• You put yourself in what state when you burn fat?

• You can test your urine for ketones with a dipstick to be sure you are in ketosis

Ketosis

• If you are not eating carbs (orally), the body uses up all of the glycogen it stored earlier and when that store is depleted, it burns fat directly off of you.

• At this point, protein is also called up to help supply energy…bad

Results of ketosis

• Fat is burned

• Bi-product released are ketones

• Body gets acidic and you become dehydrated, kidney comes to the rescue and makes bicarb to neutralize the acid

• Protein is also burned and not spared like it’s supposed to be

Eating an excess of carbohydrates

• Loss of appetite, loss of other nutrients, you’re full from carbs

• Tooth decay

• Lining of stomach is irritated

• Flatulence due to the carb metabolism process

The End