Week 4 (Ch 4 and 5)

What are carbohydrates?

Nutrients made of carbon hydrogen and oxygen

What is one of the body's main sources of energy?

Carbohydrates

What are the two main types of carbohydrates?

Simple and complex carbohydrates

What are simple carbohydrates?

Sugars made of one or two sugar units

What are complex carbohydrates?

Carbohydrates made of longer chains of sugar units

What is the DRI for carbohydrates for adults ages 19–30?

130 grams per day

What does DRI stand for?

Dietary Reference Intake

What does the DRI measure for carbohydrates?

The recommended daily amount in grams

What is the AMDR for carbohydrates?

45%–65% of daily calories

What does AMDR stand for?

Acceptable Macronutrient Distribution Range

What does the AMDR measure?

The percentage of daily calories that should come from carbohydrates

Which type of carbohydrates should make up most carbohydrate intake?

Primarily complex carbohydrates

What is the difference between DRI and AMDR?

DRI measures grams per day while AMDR measures percentage of daily calories

What are monosaccharides?

Carbohydrates containing one sugar unit

What are disaccharides?

Carbohydrates containing two sugar units joined together

What are polysaccharides?

Carbohydrates containing many sugar units joined together

What is glucose?

The main sugar cells use for energy

Where is fructose found naturally?

Fruits and honey

What is galactose?

A monosaccharide containing one sugar unit

What is sucrose?

Table sugar

What is maltose?

A disaccharide made of two glucose molecules

What is lactose?

The sugar found in milk

What is starch?

A complex carbohydrate found in foods such as potatoes rice and bread

What is glycogen?

The stored form of glucose in humans

What is dietary fiber?

Material in plant foods that the body cannot fully digest

What is one main function of carbohydrates?

Providing energy

How do carbohydrates provide energy?

The body breaks them down to produce energy

Which tissues normally rely heavily on glucose?

The brain and nerves

How does fiber support digestive health?

It helps maintain normal bowel movements

Which carbohydrates make foods taste sweet?

Sugars such as sucrose and fructose

What does digestion mean?

Breaking food down into smaller substances the body can absorb

Where does carbohydrate digestion begin?

The mouth

What is mechanical digestion in the mouth?

Teeth physically break food into smaller pieces

Which enzyme in saliva begins starch digestion?

Amylase

What happens to carbohydrates in the small intestine?

Enzymes continue breaking them down

What is the goal of digestible carbohydrate digestion?

To break carbohydrates into absorbable monosaccharides

Where are simple sugars absorbed into the blood?

The small intestine

What happens to absorbed glucose?

It travels to body cells to provide energy

What does amylase break down?

Starch

What does lactase break down?

Lactose or milk sugar

What does sucrase break down?

Sucrose or table sugar

What is lactase?

An enzyme that breaks down lactose

What is lactose?

A sugar found in milk

What causes lactose intolerance?

The body does not produce enough lactase to digest lactose properly

What symptoms can undigested lactose cause?

Gas bloating cramps and diarrhea

What is the difference between lactase and lactose?

Lactase is an enzyme while lactose is a sugar

Where does glucose go after absorption?

From the small intestine into the blood

What does the liver do with fructose and galactose?

Converts them into substances the body can use for energy

What is the general process of carbohydrate absorption?

Carbohydrates are broken into simple sugars absorbed into blood and used or stored

What are the three main steps of carbohydrate digestion?

Mouth digestion small intestine digestion and absorption

What is glycogen used for?

Storing extra glucose for later energy

Where does the body store glycogen?

The liver and muscles

What is glycogenesis?

The process of turning glucose into glycogen for storage

What is the sequence of glycogenesis?

Extra glucose becomes glycogen which is stored for later

How does the body use stored glycogen?

It breaks glycogen down into glucose for energy

How can regular endurance exercise affect muscle glycogen?

It can help muscles store more glycogen

What helps refill muscle glycogen after exercise?

Eating carbohydrates

Why is glycogen a limited energy source?

The body can store only a limited amount of glycogen

How does glycogen storage compare with fat storage?

Glycogen stores less energy than fat

What is glycogen like as an energy supply?

A small quick-access energy supply

What is fat like as an energy supply?

A much larger long-term energy reserve

What is blood glucose?

Sugar in the blood that provides energy to body cells

What is blood glucose homeostasis?

Maintaining blood sugar within a healthy range

What blood glucose target range is listed in the notes?

70–100 mg/dL

What is metabolism?

The processes used to break down and use nutrients for energy and other functions

What happens when blood glucose gets too low?

The body releases stored glucose or makes new glucose

What happens to blood glucose after eating?

Hormones help cells take up and store glucose

What is glycogenolysis?

The breakdown of stored glycogen

What happens during glycogenolysis?

The liver breaks down glycogen and releases glucose into the blood

What is gluconeogenesis?

Making new glucose from substances that are not carbohydrates

What can the body use to make new glucose?

Certain parts of proteins and other noncarbohydrate substances

When does gluconeogenesis occur during prolonged fasting?

When food is unavailable and the body needs glucose

What are ketones?

Energy-producing substances made when the body breaks down fat

When does the body produce more ketones?

When carbohydrate availability is low

What happens during starvation?

The body relies more heavily on fat and ketones for energy

What is the difference between glycogenolysis and gluconeogenesis?

Glycogenolysis breaks down stored glycogen while gluconeogenesis makes new glucose

What is the difference between gluconeogenesis and ketone production?

Gluconeogenesis makes glucose while ketones are produced during fat breakdown

What does insulin do to blood glucose?

Lowers blood glucose

How does insulin lower blood glucose?

It helps cells take up glucose and encourages glucose storage

What does glucagon do to blood glucose?

Raises blood glucose

How does glucagon raise blood glucose?

It signals the liver to break down glycogen and release glucose

What does somatostatin do?

Slows or inhibits the release of insulin and glucagon

Which hormone lowers blood glucose?

Insulin

Which hormone raises blood glucose?

Glucagon

What is the glycemic index (GI)?

A measure of how much and how quickly carbohydrate foods raise blood glucose

What is the maximum value on the glycemic index scale?

100

How do high-GI foods generally affect blood glucose?

They raise it faster

How do low-GI foods generally affect blood glucose?

They raise it more slowly

What health risks can a diet high in refined carbohydrates and added sugars and low in fiber contribute to?

Type 2 diabetes cardiovascular disease and some diet-related cancers

Which cancers are mentioned in the notes as diet-related risks?

Colon and breast cancer

What are the three monosaccharides?

Glucose fructose and galactose

What is sucrose made from?

Glucose and fructose

What is maltose made from?

Glucose and glucose

What is lactose made from?

Glucose and galactose

What is table sugar called?

Sucrose

What are natural or commercial sources of sugar listed in the notes?

Sugar cane sugar beets honey syrups brown sugar molasses corn syrup and high-fructose corn syrup

Where can sugars occur naturally?

Foods such as whole fruit and plain milk

What is added sugar?

Sugar added to food or drinks during preparation or manufacturing

How does added sugar differ from naturally occurring sugar?

Added sugar is put into foods while natural sugar is already present in foods such as whole fruit and plain milk

What is the recommended limit for calories from added sugars for people ages 2 and older?

Less than 10% of total daily calories