NUTRITIONLO2

What Humans Eat and Why?

Food◦ Is any substance, usually composed of carbohydrates, fats, proteins and water, that can be eaten or drunk by an animal or human for

nutrition◦ Provides the energy and the materials needed to build and

maintain all body cells

Nutrients ◦ Are the nourishing substances(chemicals) we, for the most

part, must obtain from food, that we need to live and grow – to maintain a healthy body.

What is the difference between food and nutrients?

Click on the picture to find out …

How do we know if foods are good or bad??

Essential Nutrients Essential nutrients Are those nutrients

that a person must obtain from food because the body cannot produce them in large enough quantities.

Rules for identifying an essential nutrient: It must have a biological

function in the body.

If it is removed from the diet it has a negative effect on one or more biological functions.

If it is replaced in the diet it will restore the biological functions for which it is required.

Nutrients have several uses in the body:

Provide energy.

Provide materials for building, maintaining and repairing body tissues.

Provide factors that regulate chemical reactions in the body.

Uses of Nutrients

The body is made up of:

- 60% water.- 23 to 31% fat for young women.- 9 – 17% carbohydrates, proteins, minerals,

vitamins for young women.

Our diets provide these materials that make up the body.

Body CompositionCarbohydratesProteinsVitaminsMinerals

Fat

Water

Nutrients in the diet can be classified as:

Energy yielding: These include carbohydrates, fats and proteins. They release energy when broken down by the body.

Vitamins

Minerals

Water

Vitamins, Minerals and Water:Do not provide energy for the body

Types of Nutrients

CALORIESThe energy in food is

measured in calories or kilocalories.

A calorie is the amount of heat needed to raise 1g water by 1o C

In books or magazines when the term calorie is used it really means kilocalorie (kcal)

“C” = 1 kilocalorie = 1,000 calorieshttps://phet.colorado.edu/en/simulation/eating-and-exercise

Carbohydrates- the mina source of energy in the body

Carbohydrates include sugars and complex carbohydrates.

The complex carbohydrates that we can digest are called starches.

Carbohydrates are made up of the elements, carbon, hydrogen and oxygen.

Energy Yielding Nutrients

CHO--- made of carbons, oxygen and hydrogen; simple or complex based on the number of sugar molecules present; 45-55% of total calories

Functions:◦ Major source of energy (glucose). 1 g of carbohydrate

= 4 calorie◦ Provides fibre◦ Changed to protein- used to make tissues◦ Excess is stored as fat, produce heat

Sources: bread & cereal; pasta & rice; potato, lima beans, corn; dried beans and peas; fruit, vegetables & milk; sugar, syrup, jelly, jam, honey

Carbohydrates

Simple Carbohydrates Are sugars. Occur naturally in

some foods such as fruits and vegetables.

Also include candy, jelly, soft drinks, and cookies.

Supply energy.

Complex Carbohydrates

Are starches. Provide vitamins, minerals

and fiber as well as carbohydrates.

Include dry beans, starchy vegetables like potatoes, corn, and peas; rice, pasta, oatmeal; bread and cereal.

Fiber Plant materials that

are not digested completely by the body.

Keeps the digestive system healthy.

Reduces the risk of cancer and heart disease.

1 g of fibre = 1.5 calorie

Sources of Fiber:

Most Fruit and Vegetables – both dry and fresh;

Whole wheat and bran;

Pulses – peas and beans

Sources of Fiber

Lipids Lipids in our diet include fats and oils, and some

vitamins. Lipids are also composed of carbon, hydrogen and

oxygen but they have fewer oxygen atoms than carbohydrates.

Fats are lipids that are solid at room temperature

(20o C). – Example - butter Oils are lipids that are liquid at room temperature.

– Example – olive oil

9 cal/g of energy

Saturated and Unsaturated Fats We hear the term saturated fats and unsaturated fats in the media.

Saturated fats ( BAD) can raise blood cholesterol (animal fat and butter are saturated fats). These can clog up the arteries.

Many (but not all) oils are partly or mostly

unsaturated( GOOD) so are better for us.Examples: Fish Oil (omega 3 and 6); olive oil.

Functions of fatsFats:

- Can be used for energy (9 cal per g of energy).

- They aid in absorption of fat-soluble Vitamins (Vitamins A,D,E, K).

- Source of phospholipids (used to build cells).

- Insulate and protect body

ProteinsProteins are made up amino acids which

contain carbon, hydrogen, oxygen and also nitrogen.

Amino acids are small molecules which are joined together by bonds to make proteins.

The body contains 20 amino acids.

Main Function

Protein is needed for growth and repair. But it can also be used for energy supply if there is no other source (like carbohydrate and fats). 1 g of preotein generates 4 calories.

Beef burgerWhat other foods provide protein?

Tuna

ProteinsProteins are:- Used to build muscle and bone.- Used as enzymes in chemical reactions.- Used the body’s immune system which

fights disease.- Are an important part of the blood. - Provide a reserve energy source for the

body.

VITAMINSThe body makes some vitamins (Vit D and K)

but most vitamins come from food.

Kinds of vitamins:◦ Vit A: prevents night blindness, skin diseases

◦ Vit D: increases Ca and P absorption (helps in building and repairing bone).

◦ Vit E: increase Fe absorption

◦ Vit K: blood clotting

Vitamin A is needed for night vision.What other foods provide Vitamin A?Carrot Eggs

Vitamin C is needed for the maintenance of healthy skin.

What other foods provide Vitamin C?

Orange Kiwi Answer: all green vegetables – spinach, broccoli, green cabbage etc

◦Group of Vitamin B- B1(thiamine) - oxidize glucose- B2 (riboflavin) - cell growth- Niacin- B5 - Pantothenic acid - mental health

- B6 – red blood cells metabolism.

- B9 Folic acid - prevent anemia; important for pregnant women to avoid foetus abnormalities (spine bifida)

- B12 - prevent anemia- Biotin – nails and hair growth

Sources of vitamin B group

Action of vitamins:

- Vitamins act by helping chemical reactions to occur or to happen faster.

- They do not provide energy for the body but they help the body to release energy from other nutrients.

MINERALSMinerals are inorganic compounds which means that they do not contain carbon.

Macrominerals (minerals that are found in amounts larger than 5 grams):

Ca, P, Mg, Na, K, Cl

Trace minerals (minerals needed in daily quantities of less than 100 mg)

Fe, Cu, Se, I, Mn, Mo, Zn, Cr, F

Iron is a mineral which is needed for healthy blood.

What other food provides iron?

Roast beef Baked beans

Calcium is a mineral which is needed for the growth and maintenance of strong bones and teeth.

What other food provides calcium?Milk Cheese

WATER The human body is made up of about 63%

water.

Need 2.5 to 3 litres of water/day, but drink only about 2.0 to 2.5 litres.

Where do we get the rest??

The foods we eat contain water. For example lettuce is 95% water.

Functions of water

It acts as a solvent. (dissolves materials)Transports food substances to cells.Removes waste.Regulates temperature and metabolic rate

(rate of chemical reactions in body).

FOOD Pyramid: how muchand which foods to eat?

Design your own food pyramid:but follow the rules..

http://www.youtube.com/watch?v=IJnGFacO3Vs

Suffering health consequences –◦ Deficiency diseases

- Marasmus- Scurvy• Anemia• Osteoporosis• Rickets

◦ Afflictions of affluence- Obesity

Not meeting nutritional needs in younger/older years leads to:

Lack of protein

Lack of food

Marasmus

Deficiency of Vit C-needed for synthesis of collagen

Leads to the formation of spots(thighs&legs) on the skin, spongy gums, and bleeding from the mucous membranes.

Looks pale, feels depressed, and is partially immobilized.

In advanced scurvy there are open, suppurating wounds and loss of teeth.

Scurvy

Loss of bone fragile and brittle

Osteoporosis

Iron deficiency anemia Fatigue decreased energy weakness shortness of breath lightheadedness palpitations (feeling of the heart racing or

beating irregularly) looking pale

Anemia

heart disease, congestive heart failure, and stroke

High blood cholesterol and triglycerides (dislipidemia or high blood fats)

High blood pressure (hypertension) High blood sugar (glucose) or diabetes BMI >30

Obesity

Rickets

One of the primary causes – Vitamin Ddeficiency

www.healthfinder.gov www.nutrition.gov webmd.com www.navigator.tufts.edu www.eatright.org What is a nutrient?

http://nutrition.about.com/od/nutrition101/a/nutrients.htm

Good foods and Bad foods: http://images.google.com/imgres?imgurl=http://tiki.oneworld.net/food/food_title.jpg&imgrefurl=http://tiki.oneworld.net/food/food6.html&usg=__FRxmehwQup5MCHnK3LstTrLjz-4=&h=307&w=400&sz=17&hl=en&start=25&um=1&tbnid=-C3T2td9e7CGOM:&tbnh=95&tbnw=124&prev=/images%3Fq%3Ddefine:Foods%26ndsp%3D20%26hl%3Den%26rls%3Dcom.microsoft:*:IE-SearchBox%26rlz%3D1I7ADBF_en%26sa%3DN%26start%3D20%26um%3D1

http://www.mypyramid.gov/

Websites