Food tests

Food type

• Protein

• Sugar

• Fat

• Carbohydrate

Test

• Biuret turns purple if protein is present

• Benedicts turns from blue to red/brown if sugar is present

• Greaseproof paper gets an oily residue

• Iodine turns blue/black if starch is present

Carnivore

• Only eats meat– E.g. Spider, lion

• Its survival is dependent on finding and catching prey

Top predator – Nothing eats him!

Carnivore Teeth Adaptation

Herbivore

• Only eats plants– E.g. Cow, aphid

• Depends on a large supply of plant matter.

• Longer gut as less energy available in their food.

Herbivore Teeth Adaptation

Omnivore

• Eats a mixture of plants and animals– E.g. Pigs, humans

• Increased chance of survival as they are not restricted to one diet.

Decomposers

• Breaks down and recycles dead material.– E.g. Bacteria, fungi

Primary Producers (Plants)

• Plants can make their own food using– Sunlight– Chlorophyll– Water– Carbon dioxide

• How are all the consumers and producers linked?

3 main functions

of digestive system

Digestionbreaks down

food into molecules

body can use

Absorptionmolecules absorbedinto blood & carried thru. body

Eliminationwastes

eliminatedfrom body

2 kinds of digestion

mechanical chemical

food ground intosmall pieces

large food moleculesbroken small

molecules by enzymes

Path of digestion

The Digestive System

• Mouth• esophagus• Stomach• Small Intestine• Liver• Large Intestine• Gall Bladder• Pancreas• Rectum• Anus

Let’s find out what happened to your breakfast today!

(Breaking food down into smaller pieces)

1. mouth- releases saliva- moistens food

• chemical digestion:enzyme- protein

speeds chemical reactions

• mechanical digestion- teeth

Mouth• Teeth

(mechanical breakdown)– Incisors used for cutting

– Canines used for stabbing and holding

– Molars large surface area used for grinding

• Saliva

(chemical breakdown)– Enzyme (speeds up

reactions in the body)

– Breaks down carbohydrate

2. esophagus

• muscular tube - connects mouth stomach

• lined w/ mucus

flap of tissue that seals off windpipe-prevents food from entering lungs

2. esophagus

• peristalsis= involuntary waves of muscle contractions that move food stomach

esophagus

• Approximately 25cm long

• Moves food from the throat to the stomach– Muscle movement

called peristalsis

• If acid from the stomach gets in here that’s heartburn.

3. stomach-• most mechanical digestion occurs here

• some chemical digestion

–enzymes- pepsin

–hydrochloric acid

Mechanical digestion in the stomach

is like the clothes and soapy water

mix in a washing machine.

YouTube video-digestion

Stomach

• Stores the food you eat

• Chemically breaks it down into tiny pieces

• Mixes food with digestive juices

• Acid in the stomach kills bacteria

small intestine• most chemical digestion & absorption takes place here

• receives bile

small intestine

• lined with villi= –absorb nutrient molecules

Millions of tiny finger shaped structures called villi (villus) cover the surface of the small intestine.

Small Intestine

• Small intestines are roughly 6 metres long.

• Enzymes and bile are added.

• Villi increase the surface area to help absorbtion.

• Nutrients from the food pass into the bloodstream through the small intestine walls.

liver• in upper portion of abdomen• makes bile= breaks up fat

Liver

• Directly affects digestion by producing bile– Bile is an enzyme that

helps dissolve fat

• Processes nutrients in the blood, filters out toxins and waste.

• Is often called the body’s energy factory

gallbladder

• stores bile

Gall Bladder

• Stores bile from the liver

• Delivers bile when food is digested

• Fatty diets can cause gallstones

pancreas• between

stomach & small intestine

• produces enzymes - break down starches, proteins & fats

Pancreas

• Produces compounds to digest fats and proteins

• Neutralizes acids that enter small intestine

• Regulates blood sugar by producing insulin

large intestine• last part of digestive

system• contains bacteria that

make Vitamin K• absorbs water • eliminates remaining

material

large intestine

•ends in short tube-rectum

Large Intestine

• About 1.5 metres long• Accepts what small

intestines don’t absorb.

• Absorbs water and minerals from the waste matter.

• Absorption means taking into the body via the blood stream.

anus• muscular opening @ end of rectum

Rectum and Anus

• Rectum– About 15cm long– Stores waste

before egestion.

• Anus– Muscular ring that

controls egestion.

gallbladder

liver

large intestine

small intestine

stomach

anus

esophagus

mouth

epiglottis

appendix

Write the name of each colored organ:

• Green:• Red:• Pink:• Brown:• Purple:• Green:• Yellow:

Answers

• Green: Oesophagus• Red: Stomach• Pink: Small Intestine• Brown: Large Intestine• Purple: Liver• Green: Gall Bladder• Yellow: Pancreas

What are nutrients?• Essential substances that your

body needs in order to grow and stay healthy

• Six categories of nutrients:• Carbohydrates• Fats• Proteins• Vitamins• Minerals• Water

6 Key Nutrients

• Carbohydrate

• Fat

• Protein

• Vitamins

• Minerals

• Water

• C ould • F anny

• P lay

• V iolin

• M uch

• W orse

Energy content of food

1 gram of carbohydrateequals 4.15kcal of energy

EnergyBUTTER

1 gram of fatequals 9.4kcal of energy

1 gram of proteinequals 5.65kcal of energy

Energy efficiency

gases

Energy used

Heat

urine

faeces

No animal is able to utilise all the energy in its food !

Energy Needs

• Body Size

• Body composition

• Degree of exercise

• Physiological state and

• Ambient temperature

Carbohydrates

• All carbohydrates are composed of carbon, hydrogen, and oxygen in a 1:2:1 empirical ratio.

• The general empirical formula for a carbohydrate is CH2O.

If a carbohydrate has 5 carbons atoms, what would be its empirical formula?

If a carbohydrate has 12 hydrogen atoms present, what would be its empirical formula?

CC55HH1010OO55

CC66HH1212OO66

Carbohydrates• Structure and function: Carbohydrates are

sugars and starches that the body uses for ENERGY!

• PLANTS are the major source of carbohydrates in the food we eat.

Simple Carbohydrates

• Sugars that are quickly digested and provide a BOOST of energy for the body

• Foods with LOTS of sugar: oranges, milk, cookies, candy

• 1

Carbohydrates

Complex Carbohydrates• Starches that are composed of

many sugars linked together

• They provide the body with long-term energy since they are digested more slowly than sugars.

• Foods with LOTS of starch: rice, beans, potatoes

• 1

Carbohydrates

1. JOBS OF CARBOHYDRATES

ENERGY = major jobprovides 4 calories per gram

Not enough carb’s eaten = lose weight

Too many carb’s eaten = gain weight

“Fiber” in foods is another part of the carbohydrate family.

**Fiber, or cellulose, does not completely digest

We need it to: 1. help the body digest other foods and

2. to help eliminate waste-- (NATURE’S BROOM) Examples of fiber are: “strings” in celery, pulp of oranges,

peel of apples, etc.

Have You Had Your Fiber Today?

Nutritional concernsof lack of carbohydrates in diet

symptoms = TIRED

Functions:• ENERGY source for the body

(more than carbs and proteins)• Help protect and cushion vital

organs as well as joints • Insulate the body

.• 1

Fat

JOBS OF FAT

• 1. ENERGY – 9 CALORIES PER GRAM

• 2. PROVIDE BODY HEAT, INSULATE• 3. CARRIES FAT SOLUBLE

VITAMINS TO THE CELLS• 4. ADD FLAVOR TO FOOD• 5. SATIETY VALUE = makes you feel

full longer

Unsaturated fats:

• At room temperature, they are typically in liquid form.

• They are less harmful to the circulatory system than saturated fats.

• Foods with a lot of unsaturated fat: canola, safflower, and peanut oils

• 1

Fat

Saturated fats:

• At room temperature, they are typically in solid form.

• Diets with TOO MUCH saturated fat have been known to cause heart disease.

• Foods with a lot of saturated fat: beef fat, egg yolks, dairy products

• 1

Fat

FAT is both a nutrient and a food—butter on bread is an

example of eating fat.

Fat is sometimes “hidden” in food—examples: salad

dressing, gravy, sour cream, cookies, pies, cakes

Saturated fat is SOLID at room temperature. (notice S’s in

saturated and solid—a clue to help you remember!)

Unsaturated fat is LIQUID at room temperature.

Fat food sources

butter, lardfat present in meat

baconoils of all kinds

egg yolksdairy foods

• 1

ProteinProteins

• Function: Provide the building materials your body needs to grow and repair itself

JOBS OF PROTEIN

• BUILD AND REPAIR BODY TISSUE is the main job.

• Energy— 4 calories per gram

(What other nutrient also provides 4 calories of energy per gram?)

CARBOHYDRATES

What is a calorie?• The energy obtained from

carbohydrates, proteins, and fats is measured in units called calories.

Calories

Food

Type

• Carbohydrate

• Fat

• Protein

• Sugars

Use

• Long term energy

• Protecting organs and long term energy store

• Making muscle, enzymes, skin, hair

• Fast energy

Vitamins and Minerals

Vitamins and minerals are essential for the maintenance of good health and the prevention of a number of diseases.

Vitamins

Vitamins are naturally occurring organic compounds that are essential to metabolic or other functions in the body.

Most vitamins cannot be synthesized by the body. They must be supplied in the diet.

Vitamins are usually classified as water soluble or fat soluble

 

Minerals

Minerals are inorganic and are found in the soil and water absorbed by plants or eaten by animals.

The human body requires substantial amounts of minerals on a daily basis to ensure proper functioning of the organs, bones, tissue and immune system.

Minerals

• Macro-minerals

• Trace Minerals

MineralsMineral What the mineral does Food sources

Sodium Fluid and electrolyte balance, supports muscle contraction and nerve impulse transmissions

salt, soy sauce, bread, milk, meats

Chloride Maintains fluid and electrolyte balance, aids in digestion

salt, soy sauce, milk, eggs, meats

Potassium Maintains fluid and electrolyte balance, cell integrity, muscle contractions and nerve impulse transmission

potatoes, vegetables, banana, strawberries, cod, milk

Calcium Formation of bones and teeth, supports blood clotting

milk, yogurt, cheddar cheese, Swiss cheese, tofu, sardines, green beans, spinach, broccoli

Phosphorus Formation of cells, bones and teeth, maintains acid-base balance

all animal foods (meats, fish, poultry, eggs, milk)

Magnesium Supports bone mineralization, protein building, muscular contraction, nerve impulse transmission, immunity

Green vegetables, tomato juice, beans, cashews, halibut

Iron Part of the protein hemoglobin (carries oxygen throughout body's cells)

spinach, broccoli, green beans, tomato juice, beef liver

MineralsMineral Function Food sources

Zinc Enzymes production of genetic material/proteins, vitamin A transport, wound healing, sperm production and the normal development of the fetus

Green vegetables, tomato juice ,lentils, oysters, shrimp, crab, meats yoghurt, cheese

Selenium Antioxidant, works with vitamin E to protect body from oxidation

seafood, meats and grains

Iodine Thyroid hormones regulate growth, development and metabolic rate

salt, seafood, bread, milk, cheese

Copper Absorption/utilization of iron, formation of hemoglobin , enzymes

meats, water

Manganese Facilitates many cell processes widespread in foods

Fluoride formation of bones and teeth, helps to make teeth resistant to decay

fluoridated drinking water, tea, seafood

Chromium Associated with insulin and is required for the release of energy from glucose

vegetable oils, liver, whole grains, cheese, nuts

Molybdenum Facilitates many cell processes legumes, organ meats76

Vitamin Characteristics

• Each vitamin has one or more specific purposes.

• Vitamins are essential to life processes. • Vitamins are generally used by the body with

very minimal changes• Vitamins are usually required in only small

amounts • Most vitamins cannot be synthesized by the

body directly

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Important VitaminsVitaminVitamin FunctionFunction SourceSource

A A RetinolRetinol

Supports vision, skin, bone and Supports vision, skin, bone and tooth growth, immunity and tooth growth, immunity and reproductionreproduction

mango, broccoli, butternut mango, broccoli, butternut squash, carrots, tomato squash, carrots, tomato juice, sweet potatoes, juice, sweet potatoes, pumpkin, beef liverpumpkin, beef liver

C C Ascorbic AcidAscorbic Acid

Collagen synthesis, amino acid Collagen synthesis, amino acid metabolism, helps iron metabolism, helps iron absorption, antioxidantabsorption, antioxidant

Fruits and vegetablesFruits and vegetables

DD Promotes bone mineralizationPromotes bone mineralization Self-synthesis milk, egg Self-synthesis milk, egg yolk, liver, fatty fishyolk, liver, fatty fish

B12B12 New cell synthesis, Breaking New cell synthesis, Breaking down fatty acids / amino acids, down fatty acids / amino acids, nerve cell maintenancenerve cell maintenance

Meats, poultry, fish, Meats, poultry, fish, shellfish, milk, eggsshellfish, milk, eggs

EE Antioxidant, regulation of Antioxidant, regulation of oxidation reactions, supports cell oxidation reactions, supports cell membrane stabilizationmembrane stabilization

Shrimp, codShrimp, cod, , wheat wheat germ, tofu, germ, tofu, polyunsaturated polyunsaturated vegetable oils, sweet vegetable oils, sweet potatoes, potatoes,

KK Synthesis of blood-clotting Synthesis of blood-clotting proteins, regulates blood calciumproteins, regulates blood calcium

Liver, leafy green vegetables, Liver, leafy green vegetables, spinach, broccoli, cabbage, spinach, broccoli, cabbage, 78

Vitamin C Sources• Vitamin C is found in many

fresh fruits and vegetables. • . Cooking vegetables in water

tends to leach the vitamin from the food.

• Cooked foods also contain less vitamin C, since it is also easily oxidized and hence destroyed in the cooking process.

• Aid in healing wounds and helping to prevent bacterial infections

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Vitamin C Deficiencies

• Scurvy or Scorbutus.

• Symptoms include 1. swollen legs,

2. rotting gums,

3. and bloody lesions. • Common among sailors in

the 18th and 19th centuries who spent a long time at sea without fresh fruits and vegetables

80

Vitamin A Sources• Commonly found in cod liver oil, green vegetables,

and fruit. • Carrots indirectly serve as a source of vitamin A

since they contain carotene which the body readily converts to vitamin A

81

Vitamin A Functions• Vitamin A is fat soluble.• It is not readily broken down by cooking.•  Role in aiding in night vision.

82

Vitamin A Deficiencies• A deficiency in vitamin

A results in night blindness.

• The most serious deficiency results in a condition known as Xeropthalmia, a severe form of conjunctivitius or blindness.

83

Vitamin D - Sources • Vitamin D is commonly found in fish liver oil as

well as egg yokes. • Unlike other vitamins, the body synthesizes

vitamin D in the skin through the action of ultraviolet light

Vitamin D Functions • Vitamin D is an important regulator of

calcium metabolism. • It is involved in the uptake of calcium and

phosphate ions from food into the body. • It is necessary for the proper formation of

bone structures and teeth.

Nutrional DeficienciesNutrional deficiencies diseases in children often result from a lack of protein

MarasmusMarasmus

KwashiorkorKwashiorkor

KwashiorkorKwashiorkor is a specific wasting away often occurring in infants at weaning. It results from a lack of protein in the diet

MarasmusMarasmus is a wasting away of the body tissues from the lack of calories as well as protein in the diet. The child is fretful rather than apathetic and is skinny rather than swollen with edema.

The Ugly Face The Ugly Face of “Hidden of “Hidden Hunger”Hunger”

Zinc Deficiency

Vitamin A Deficiency Iodine Deficiency

Iron Deficiency

Ca DeficiencyRickets

(Map from USAID)

Global Micronutrient Global Micronutrient DeficienciesDeficiencies

> 3 billion people afflicted

> 200 million children affected

Map from WHO

Prevalence of Vitamin A DeficiencyPrevalence of Vitamin A Deficiency