Chapter 3 – How Nutrients Become

YouThe Basics of Nutrition

“You are what you eat” Food is your body’s fuel Food is eaten

◦ It is broken down into simpler elements◦ Energy is released and nutrients are used to help

build, repair, and maintain body cells◦ By-products are discarded as waste

The Basic Truth of Nutrition

These substances are best obtained from the food you eat

The body needs elements from all 6 groups in order to function properly and maintain good health◦ Carbohydrates◦ Fats◦ Proteins◦ Vitamins◦ Minerals◦ Water

There Are 6 Nutrient Groups

Where do they fit?◦ Nectarine◦ Wheat bread◦ Trail mix◦ Water

Why wouldn’t an unlimited supply of only one of these foods sustain life?

Variety Is Key

I know, I know – who wants to learn chemistry in HCR???

To understand the basics of nutrition, there has to be some understanding of basic chemistry – SORRY!

No worries – we won’t get too crazy with it

The Chemistry of Nutrition ()

Your body and the foods you eat are composed of chemical elements

Elements are the simplest substances from which all matter is formed◦ An atom is the smallest part of an element

A molecule is the smallest amount of a substance that has all the characteristics of the substance◦ Molecules are 2 or more atoms bonded together

The Chemistry of Nutrition

The atoms in a molecule may be all the same element, or they may be different elements

When atoms of different elements bond together, they form compounds

The Chemistry of Nutrition

5 of the basic nutrient groups are compounds (combination of different elements)◦ Carbohydrates◦ Fats◦ Proteins◦ Vitamins◦ Water

1 basic nutrient group is elements (simplest substance)◦ Minerals

The Chemistry of Nutrition

The essential nutrients from food are used to◦ Build and repair body tissues◦ Regulate all body processes◦ Provide energy

When provided with the proper nutrients, your body can perform all of these functions in harmony, which optimizes health, wellness, and performance

Functions of Nutrients

The body is made up of billions of cells◦ Cells divide, producing 2 new cells each time,

which accounts for your growth◦ New cells also repair damaged body tissues and

replace old cells All cells are formed with materials that

come from food Therefore, your body needs proper amounts

of nutrients to help make new cells

Building and Repairing Body Tissues

Periods of rapid growth require greater amounts of nutrients◦ Pregnancy◦ Infancy◦ Adolescence◦ Illness/injury recovery

Lacking proper nutrients during these periods can negatively affect growth potential, strength, health, healing, learning abilities, and behavior patterns

Building and Repairing Body Tissues

Mood? Attitude? Thinking? Physical performance?

How Does Hunger Affect Your:

The proper amounts and types of nutrients keep body processes running smoothly

Examples of body processes that rely on nutritional components◦ Circulation of body fluids◦ Maintaining the correct acid-base level in the

blood◦ Digestion◦ Absorption◦ Metabolism

Regulate Body Processes

Food is a source of energy for performance The quality of the food you eat affects how

your body will run The more active you are, the more energy

you will need to fuel your body processes

Provide Energy

Chemical reactions that take place in your cells release energy from nutrients that you get from food◦ Carbohydrates and fats are the main nutrients

used for energy◦ Proteins can be used, but the body prefers to save

them for other vital functions Vitamins, minerals, and water do not

provide energy, but the body needs them to help regulate the release of energy from carbs, fats, and proteins

Provide Energy

Measured in units called kilocalories (kcal) Commonly known as calories Only certain nutrients provide energy

◦ 1 gram of carbohydrate = 4 kcal of energy◦ 1 gram of fat = 9 kcal of energy◦ 1 gram of protein = 4 kcal of energy

Water, vitamins, and minerals do not yield energy, and therefore do not have a calorie content

The Energy Value of Food

Alcohol does have a calorie content◦ 1 gram of alcohol = 7 kcal of energy

It is not considered a nutrient because:◦ It does not promote growth (it inhibits)◦ It does not maintain cells (it destroys)◦ It does not repair tissues (it inhibits healing)

Determining Energy Values

Alcohol

The process by which your body breaks down food, and the nutrients in food, into simpler substances◦ The blood can carry these simpler substances to the cells

for use in growth, repair, and maintenance Digestion occurs throughout the digestive system

through mechanical and chemical means◦ Mechanical digestion – occurs when food is crushed and

churned◦ Chemical digestion – occurs when food is mixed with acids

and enzymes Enzyme – a type of protein produced by cells that cause specific

chemical reactions In digestion, they cause food particles to break apart into

simpler substances

Digestion

The muscular tube through which food passes from the mouth to the anus

Roughly 25-30 feet in length Each section has different functions Mouth → esophagus → stomach → small

intestine → large intestine

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Gastrointestinal Tract (GI Tract)

Mastication (chewing) is the1st step in digestion

Important mechanical digestive process as chewed food is broken down more easily by the body

Food is mixed with saliva in the mouth, which helps to moisten, soften, and dissolve food◦ Included in saliva is salivary amylase, an enzyme

which helps to break down starches

Mouth

Passageway from mouth to stomach About 10 inches long Food moves along this passageway through

a series of muscular squeezing actions called peristalsis

Involuntary muscle action that is part of mechanical digestion

Esophagus

The stomach produces gastric juices to aid in digestion◦ Made up of acids, enzymes, and mucus◦ Acids and enzymes break down food, and mucus softens

and lubricates chyme The gastric juices mix with the chewed food to form

chyme The stomach can typically hold about a quart of

food Food generally stays in the stomach for 2-3 hours,

depending on the type of food◦ Liquids leave first◦ Fats leave last

Stomach

About 95% of digestion takes place here Has 3 sections, and is roughly 20 feet in

length and 1 inch in diameter Takes food about 5-14 hours to move

through the small intestine through peristalsis action

The small intestine is aided by other organs during digestion◦ Pancreas – adds digestive enzymes◦ Liver – adds bile for breaking down fats

*Nutrient Digestion in the Small Intestine

Small Intestine

Also known as the colon Main job is to reabsorb water Very little digestion occurs here About 5-6 feet long Chyme stays in the colon for 1-3 days

before elimination Solid wastes that result from digestion are

eliminated as feces *Food Breakdown

Large Intestine

Absorption is the passage of nutrients from the digestive tract into the circulatory or the lymphatic system◦ Circulatory system – amino acids, monosaccharides,

minerals, and most vitamins◦ Lymphatic system – nutrients from fats

Most nutrients pass through the walls of the small intestine

The small intestine is lined with tiny, finger-like projections called villi ◦ Villi increase the surface area of the small intestine

and aid in absorption of nutrients

Absorption of Nutrients

Intestinal Villi

Once digestion and absorption have taken place, the circulatory system carries the nutrients to individual cells

Metabolism is all the chemical changes that occur as cells produce energy and materials needed to sustain life◦ Cells break down nutrients to release energy,

which is stored in the muscles as ATP◦ The waste products created through cell

metabolism are eliminated through the kidneys, lungs, and skin

Metabolism

Eating Habits Affect Digestion◦ Don’t eat too much or too little◦ Eat a variety of foods in order to get all of the

required nutrients◦ Include high-fiber foods to provide bulk and aid in

removing toxins◦ Foods high in fat will take longer to digest as fats

are the last nutrient component to leave the stomach

Factors That Affect Digestion and Absorption

Emotions◦ Fear, anger, and tension can lead to digestive

difficulties◦ Reducing stress and tension during mealtimes will

allow for better absorption of nutrients

Factors That Affect Digestion and Absorption

Food Allergies◦ A food allergy is a reaction of the immune system to

certain proteins found in food◦ The immune system protects the body from

invaders by forming antibodies◦ When you are allergic to a food, your body releases

antibodies in response to that food, leading to allergy symptoms

◦ These symptoms can include, but are not limited to, vomiting, intestinal distress, rashes, and swelling

This is different from a food sensitivity, such as lactose intolerance

Factors That Affect Digestion and Absorption

Factors That Affect Digestion and Absorption Physical Activity

◦ Aids digestion and metabolism

◦ Stimulates a healthy appetite and strengthens the muscles of the internal organs

◦ Helps move food through the GI tract

◦ Reduces stress

A nutritious diet can help to avoid or manage most digestive disorders

Some disorders require medical treatment in order to make certain that all required nutrients make it to the cells in order to maintain life

Digestive Disorders

Diarrhea◦ Frequent expulsion of watery feces◦ Causes food to move through the digestive

system too quickly for nutrients to be absorbed◦ Also leads to loss of body fluids as the food moves

too quickly through the large intestine for the water to be reabsorbed

Digestive Disorders

Constipation◦ Occurs when chyme moves too slowly through the

large intestine, leading to the reabsorption of too much water

◦ Causes the feces to become too hard and dry, which can lead to painful elimination and hemorrhoids

◦ Often caused by erratic eating habits, low fiber intake, lack of physical activity, and inadequate fluid intake

Digestive Disorders

Indigestion◦ Difficulty in digesting food◦ Can be caused by stress, eating too much or

eating too fast, or eating particular foods◦ Can include gas, stomach cramps, and nausea

Digestive Disorders

Heartburn◦ A burning pain in the middle of the chest caused

by stomach acid flowing back into the esophagus◦ Can be reduced by avoiding acidic foods, stress,

lying down right after eating, and taking antacids

Digestive Disorders

Ulcer◦ An open sore in the lining of the stomach or small

intestine caused by bacterium◦ Risk is increased by stress, heredity, alcohol use,

and aspirin abuse◦ Usually treated with antibiotics, as well as

decreasing stress, alcohol, caffeine, and tobacco use

Digestive Disorders

Gallstones◦ Small crystals that form from bile in the

gallbladder◦ These stones block the release of bile into the

small intestine, causing pain and slowing the digestion of fats

◦ Treatment includes a diet low in fats, and often requires surgery to remove the gallbladder

Digestive Disorders

Diverticulosis◦ The formation of abnormal pouches in the

intestinal wall◦ Can occur when the intestinal muscles become

weak, such as when a diet is low in fiber◦ These pouches can become inflamed, leading to a

painful condition called diverticulitis

◦ *What Could Be Wrong

◦ *Digestive Disorders

Digestive Disorders