carbohydrates: the energy nutrient - pbworkslatifa.pbworks.com/w/file/fetch/51326817/lecture 3...

Carbohydrates:

The Energy Nutrient©2001 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning™ is a trademark used herein under license.

Dr. Latifah Al-Oboudi 2012

CARBOHYDRATES

Functions of Carbohydrates

1. Energy

2. Regulation

3. Structure


Carbohydrates

Two kinds:

1. Simple

2. Complex


Simple Sugars

Monosaccharides

What are they?

A 6 Carbon ring with a water attached

Monosaccharides = One Sugar

3 Types : glucose, fructose and galactose

Which is sweetest?


Monosaccharides

Figure 4.2Dr. Latifah Al-Oboudi 2012

Simple Sugars

1. Glucose

Blood sugar

Basic “currency” of

energy in the body

Storage = glycogen


2. Fructose

Major sugar found in fruit and honey

Sweetest monosaccharide

Where else is Fructose found in your food?

Sunny Delight

Cereals

Cookies

Simple Sugars)


3. Galactose

Rarely found by itself in food…complex with

glucose

Its ½ of the milk sugar “Lactose”

Lactose = galactose + glucose

What does it Mean if you are “Lactose Intolerant”?

Simple Sugars


Simple Sugars: Disaccharides

Maltose

Sucrose

Lactose


Disaccharides


1. Sucrose

Glucose + Fructose

Each contain a 6-Carbon ring and water

Food Sources: Candies, cake, cookies, table sugar

Disaccharides


Disaccharides2. Maltose

Glucose + Glucose

Uncommon in food sources, except barley

Breakdown product of Starch

Product of fermentation Alcohol


Disaccharides3. Lactose

Glucose + Galactose

Milk Sugar

Food Sources:

Milk, Yogurt, Cheese, Ice Cream

One of a very few sugars found in animal products


Oligosaccharides

Sources: dried beans,

soybeans, peas,

lentils

Components of cell

membranes

Humans lack

enzymes to digest

oligosaccharides

causing bloating,

cramps, & gas


Complex Carbohydrates

Polysaccharides



Polysaccharides

1- Glycogen

• Made and found in our bodies

• Not found in plants

• Storage form of Carbohydrate in the body

• Saved for later use

• Stored in liver and muscle



Polysaccharides

2- Starches Most common food polysaccharide

Long branched or unbranched chain of glucose molecules

Food sources of starch:

Vegetables: yams, corn, potatoes

Legumes: peas, beans

Grains: wheat, rice, oats, breads, pasta, barley, rye

Unripe Fruit


Complex CarbohydratesPolysaccharides

3- Fiber

Only found in plants

We don’t have fiber

digesting enzymes


FIBER

What exactly is fiber?


Pick “Whole Grains” & “Whole

Wheat”!

2 main categories of fiber

1. Insoluble fiber (does not dissolve in water)

2. Soluble fiber


FIBER

Water Soluble (Dissolves in water)- form gels

What does it do in your body?


Fiber

Why can Cows eat grass and digest it for

energy but humans can not?

Cows have bacteria to break down fiber

to glucose energy


Increasing Dietary Fiber Intake

FIBER

Poor Fiber Intake Results in:

Small waste = moves slow in GI tract

Body takes water out of waste => dry and hard stool

Must strain to expel this dry, hard waste =

• Constipation

• Diverticula

• Hemorrhoids


Diverticular Disease

Caused from: hard, dry feces, characteristic

of a low-fiber diet

Prevention

Diet high in fiber

Plenty of fluids

Diverticulosis and Fiber


FIBERHealth Benefits:

Decreased Risk for:


Dietary Fiber Benefits

High water-holding capacities

Fermentable fibers


FIBER

Review:

How can you tell if a food contains any fiber?

*Remember…

NO food from animal sources have fiber

Chicken, Eggs, Tuna?

Potatoes, whole wheat bread, whole grain

cereal, pinto beans, zucchini, apples?

*Best Sources:


Carbohydrates: Digestion

What happens when you eat a carbohydrate

meal: milk, bagel with jam

MILK: Lactose (disaccharide)

Bagel: Starch (polysaccharide)

Jam: Sucrose (disaccharide)

Doesn’t take much to break down a

disaccharide….but what about the starch?Dr. Latifah Al-Oboudi 2012


Eat milk, bagel and jam

Mouth:

Small Intestine:

* Now…bagel starch = maltose

jam = sucrose

milk = lactoseDr. Latifah Al-Oboudi 2012


Eat milk, bagel and jam

Each Disaccharide has its own enzyme that

breaks it down to a Monosaccharide

Disaccharide Enzyme End Product

Maltose Maltase glucose & glucose

Sucrose Sucrase glucose & fructose

Lactose Lactase glucose & galactose


Carbohydrates

How Does Glucose get into our cells?

Glucose + Insulin Inside Cells

Then, what do we do with it?


Carbohydrates

What if cells don’t get glucose?

No Insulin No glucose in Cells Starved Cells

No Insulin Type I Diabetes Require Insulin

Not responsive to insulin Type II Diabetes


Metabolism

Process by which nutrients are

broken down to yield energy or

rearranged into body structures


Carbohydrate Energy

How does glucose become energy?

Each of the 6 Carbon bonds of glucose can be

broken for energy

End products of carbohydrate energy

metabolism:

CO2, Water, Energy (4 kcal/g carbohydrate)


Carbohydrates

Excess glucose stored as glycogen

How much can we store?

What foods contain glycogen?


Carbohydrates

What if we run out of glycogen stores?


Carbohydrate Energy Use

What if I eat 10 bagels, a jar of jam and a carton of

milk for breakfast?

Eat too much carbohydrate Stored as fat


Carbohydrate EnergyWhat if I didn’t eat anything for days or a very low CHO

diet?

Use up my glycogen stores for energy

-Depleted in 24-36 hrs

Protein broken into amino acids blood

-Form glucose from amino acid

-Nitrogen goes to the kidney as waste

-Helps provide fuel for brain

Fats are not a significant source of glucose


Carbohydrate EnergyConsequences of breaking down Protein for

Fuel?

No storage form of proteins

So this takes functional-needed protein from

the body

How can this be prevented?


The Need for Carbohydrates

The DRI committee recommends:


Sugars

Health effects of

excess sugars

Cavities


Carbohydrates

TOO MUCH of a GOOD THING?

Think in terms of caloric intake

Empty Calories

Don’t over indulge…limit sugar intake to 10% of

calories (200 g for 2,000 kcal diet)Dr. Latifah Al-Oboudi 2012

Carbohydrates

TOO MUCH of a GOOD THING?

UNPROVEN Health Effects of Excess CHO intake

1. Causes Obesity?

2. Causes Diabetes?

3. Causes Heart Disease?

4. Causes Kids to Misbehave?

5. Causes Criminal Behavior?


DiabetesDo carbohydrates cause diabetes?

NO!

Type I

Less common

Pancreas does not make insulin

Type 2

Most common and on the rise

Linked to being overweight

Fat cells are resistant to insulin


Alternatives to Sugar Artificial sweeteners (nonnutritive) vs. sugar

alcohols (nutritive sweeteners)


Artificial Sweetners

Aspartame

Saccharin

Sucralose

Stevia- Herbal alternative, not approved

by the FDA for widespread use


Alternative Sweeteners


Alcohol

Contributes 7 calories/g

2-carbon molecule made from fermented carbohydrates

IT IS NOT A NUTRIENT

Can adversely affect liver function, caloric intake, absorption, metabolism and excretion.


Alcohol

Fermentation

Carbohydrate Ethanol


carbohydrates: the energy nutrient - pbworkslatifa.pbworks.com/w/file/fetch/51326817/lecture 3...

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