Chapter 2Chapter 2Nutritional NeedsNutritional Needs

Part 1Part 1

The Importance of The Importance of FoodFood

ObjectiveObjective

• Name the key nutrients, describe their functions, and list important sources of each.

© 2002 Wisconsin Milk Marketing Board, Inc.

The NutrientsThe Nutrients

• A nutrient is a chemical substance that helps maintain the body.

• You need over 50 nutrients, which can be divided into six groups.

– Carbohydrates– Fats– Proteins– Vitamins– Minerals– Water

Key Nutrient: Key Nutrient: CarbohydratesCarbohydrates

Functions

• Supply energy• Provide bulk• Help the body

digest fats• Spare proteins

Sources of CarbohydratesSources of Carbohydrates

• Sugars—honey, jam• Fiber sources—fruits,

vegetables, whole grains

• Starch sources—breads, cereals, pasta

What is your favorite source of carbohydrates?

photo courtesy of Fleischmann’s Yeast

Key Nutrient: FatsKey Nutrient: Fats

Functions

• Supply energy• Carry fat-soluble

vitamins• Insulate the body• Protect organs• Provide essential

fatty acids

• Saturated—dairy products, meats• Mono- and Polyunsaturated—fish, nuts,

vegetable oils

Sources of FatsSources of Fats

Functions

• Build and repair tissues

• Help body make important substances

• Regulate body processes

• Supply energy

Key Nutrient: ProteinsKey Nutrient: Proteins

Sources of ProteinsSources of Proteins

• Complete proteins—dairy products, eggs, fish, meat, poultry

• Incomplete proteins—beans, grains, nuts

How can you find out if a food is a good source of protein?

National Chicken Council

Key Nutrient: VitaminsKey Nutrient: Vitamins

Vitamins can be divided into two main groups.

• Fat-soluble vitamins– dissolve in fats– can be stored in fatty

tissues of the body• Water-soluble vitamins

– dissolve in water– are not stored in the

body

Fat-Soluble VitaminsFat-Soluble Vitamins

Nutrient Functions Sources

Vitamin A Keeps skin and mucus membranes healthy

Prevents night blindness

Promotes growth

Butter, dark green and yellow fruits and vegetables, egg yolk, liver, whole and fortified milk

Vitamin D Builds strong bones and teeth

Egg yolk; fortified butter, margarine, and milk; the sun

Vitamin E Acts as an antioxidant to protect cell membranes

Eggs, liver, salad oils, whole grain cereals

Vitamin K Helps blood clot Cauliflower, egg yolk, organ meats

Water-Soluble VitaminsWater-Soluble Vitamins

Nutrient Functions SourcesVitamin C Helps wounds heal

Helps fight infection

Broccoli, citrus fruits, tomatoes

Thiamin Keeps nervous system healthy

Releases energy from food

Pork, whole grain breads and cereals

Riboflavin

Helps cells use oxygen

Breaks down carbohydrates

Cheese, eggs, milk, poultry

Niacin Keeps nervous system healthy

Helps cells use other nutrients

Dried beans and peas, peanuts

Folate Helps protect brain and spinal cord of unborn babies

Bananas, fortified breads and cereals

Key Nutrient: MineralsKey Nutrient: Minerals

Minerals can be divided into two main groups.

• Macrominerals are needed in amounts of 100 mg or more per day.

• Trace elements are needed in amounts less than 100 mg per day.

MacromineralsMacrominerals

Nutrient Functions SourcesCalcium Builds bones and teeth

Helps muscles and nerves work

Dairy products, leafy green vegetables

Magnesium Helps cells use energy nutrients

Regulates body temperature

Beans, dark green leafy vegetables, whole grains

Phosphorus Builds bones and teeth

Regulates bodily activities

Protein and calcium food sources

Sodium, chloride, potassium

Control osmosis

Maintain acid-base balance in the body

Sodium and chloride: Table salt

Potassium: Potatoes

Trace ElementsTrace Elements

Nutrient

Functions Sources

Fluorine Helps teeth resist decay

Maintains bone health

Fluoridated drinking water, toothpaste

Iodine Promotes normal function of thyroid gland

Iodized table salt, saltwater fish and shellfish

Iron Helps cells use oxygen Dried beans and fruits, egg yolk, lean meats, whole grains

Zinc Helps wounds heal

Promotes normal growth

Legumes, meat, poultry, seafood, whole grains

Key Nutrient: WaterKey Nutrient: Water

Functions

• Aids digestion and cell growth and maintenance

• Facilitates chemical reactions

• Lubricates joints and cells

• Regulates body temperature

Sources of WaterSources of Water

• Liquids• Food• Breakdown of

energy nutrients

Which source do you think provides most of your water needs?

Agricultural Research Service, USDA

ObjectiveObjective

• Analyze the effects of various nutrient deficiencies and excesses.

Nutrient DeficienciesNutrient Deficiencies

Failure to get a sufficient amount of a nutrient may result in an illness called a deficiency disease.

Such diseases include

• protein-energy malnutrition (protein)

• night blindness (vitamin A)• rickets (vitamin D)• scurvy (vitamin C)• osteoporosis (calcium)

Nutrient ExcessesNutrient Excesses

Excess energy nutrients—carbohydrates, fats, and proteins—can lead to unhealthful weight gain.

Excesses of some vitamins and minerals can lead to toxicity (poisoning) and other complications.

Apply It!Apply It!

Your grandmother has been diagnosed with osteoporosis.

What is the likely cause of this affliction? What health effects may your grandmother suffer as a result of this disease?

ObjectiveObjective

• Explain the processes of digestion, absorption, and metabolism.

The Digestion ProcessThe Digestion Process

Digestion is the bodily process of breaking food down into simpler compounds the body can use.

• The mechanical phase involves the physical breakdown of food caused by chewing and muscle activity in the digestive tract.

• The chemical phase involves the chemical breakdown of food caused by enzymes in saliva and digestive juices.

The Absorption ProcessThe Absorption Process

Absorption is the process of taking in nutrients and making them part of the body. A large surface area in the small intestine allows tiny nutrient particles to pass into the blood and lymph systems and travel where needed.

What would happen if your body were unable to absorb the nutrients you consumed through foods?

MetabolismMetabolism

Metabolism is the chemical processes that take place in the cells after the body absorbs nutrients.• Carbohydrates are converted

into glucose for use as an energy source.

• Fatty acid chains from fats are shortened and fats are used for fuel.

• Amino acids from proteins are used for maintenance, growth, production of enzymes and antibodies, and energy.

Key QuestionKey Question

What are your nutritional needs?

Other Questions to Other Questions to ConsiderConsider

• What role should dietary supplements play in meeting nutrient needs?

• What is cholesterol and why is it a nutritional concern?