Nutrition

Life Science Grade 7

What is a Nutrient?

A nutrient is a chemical substance in food needed by the body for growth, energy, and life processes.

The six nutrients are carbohydrates, proteins, fats, vitamins, minerals, and water.

Carbohydrates

Carbohydrates are nutrients that supply your body with energy.

There are three kinds: sugar cellulose starch

Sugar – A Simple Carbohydrate

Are “simpler” compounds

They are digested and used quickly by your body.

Sugar examples are glucose, sucrose, fructose, and lactose.

They give your body short, quick bursts of energy.

Starch and Cellulose - Complex carbohydrates

Are more “complex” molecules

They take longer to digest and use.

They give your body energy over long periods of time. starch

cellulose

Proteins

Proteins are nutrients that help your body grow, build, and repair body tissues.

You need 8 essential “amino acids” from food (the building blocks of protein).

When carbohydrates and fats have been used up, proteins can also be used for energy.

Proteins

Some food sources of protein are: milk products, fish, meat, poultry, beans, grains, and nuts.

Fats

Fats are energy-storage nutrients.

Fat that is stored in the body is used for insulation and cushioning of internal organs.

Fats are classified as unsaturated and saturated.

Unsaturated Fats

come from plant sourcesare usually liquid at room temperatureare often called “oils”are considered

healthier for you

Saturated Fats

come mainly from animal sources such as meat, eggs, and milk products

are usually solid at room temperaturecan give you too much cholesterol

which can clog your arteries

Vitamins

help your body use other nutrients

help promote growth and regulate body functions

no one food contains them all, but some foods supply more than others

Common Vitamins

Minerals

are inorganic nutrients

regulate many chemical reactions in your body

about 14 are used by your body, calcium and phosphorus being used in the largest amounts

Minerals

Water

most chemical reactions in the body need to take place in water

body is 60% water by weightwater is found in and around cells

and in plasma and lymphyou lose about 2 Liters of water

every day through excretion, perspiration, and respiration

Food Groups

Nutritionists recommend eating a variety of foods.

Foods that contain the same nutrients belong to a “food group”.

Recommendations for how much of each food group should be in your daily diet are changing along with new research.

Old Food Pyramid

New Food Pyramid

Alternate Food

Pyramid

Antioxidants

Some chemicals that enter the body can react with oxygen and cause cancer.

Antioxidants prevent this from happening.

They are “substances that prevent other chemicals from reacting with oxygen”.

There are antioxidants in fruits and vegetables, especially yellow-orange pigmented ones.