1. Nutrition and Digestion
SBI 3U

2. BIG IDEA
Animals obtain and process nutrients for energy and growth from the food they eat!

3. It All Starts With a Healthy Diet …
Nutrients: the chemicals in the food you eat that help your body perform all its functions.
Six types in food:
Carbohydrates
Proteins Macronutrients
Fats
Water
Vitamins Micronutrients
Minerals

4. Processing Molecules Digestive system disassembles food we eat
Body uses these as source of energy or assembles them into more complex molecules
Uses them to build and maintain cell structure and function

5. 1. Carbohydrates Main source of energy for the body
Composed of C, H, O atoms
Three main types:
- monosaccharides – one sugar (ex. glucose)
- disaccharides – two sugars joined (ex. sucrose)
- polysaccharides – many sugars joined
(ex. cellulose)

6. GLUCOSE STARCH Main fuel supply for cells
Cells break it down and extract stored energy
Extra glucose stored as fat
STARCH
Whole grain cereals, bread, rice and potatoes
Complex carb
Broken down into simple sugars and absorbed into blood
Excess blood sugar converted into GLYCOGEN
Glycogen stored in liver and muscle and fat cells
When body needs it, glycogen broken down into glucose

7. CELLULOSE Fruits, veggies, whole grain breads, bran, wheat germ
Often called FIBRE
Human digestive system can’t break it down
Helps move food and wastes through digestive system
Helps reduce heart disease?

8. 2. Proteins
Complex molecule constructed from 20 kinds of smaller molecules called AMINO ACIDS
8 essential amino acids – cells cannot make so must get in diet
Meat, milk, eggs and cheese provide 8 essential
Protein functions
Control of chemical reactions
Muscle movement
Transporting oxygen
Structure
Hormones
Defense
Last source of energy

9. 3. Fats Also called LIPIDS
Molecules formed from 3 fatty acids and a glycerol molecule
Store energy in body
Help absorb fat soluble vitamins
Provide insulation
Fatty acid chains
Glycerol

10. SATURATED FATS
Carbon atoms have max number of hydrogens bonded to them
Solid at room temp
Most animal fats (butter, lard)
Bad fats
Can build up within walls of blood vessels and block blood flow

11. UNSATURATED FATS TRANS Fruits, veggies, fish, olive oil
At least one double bond with Carbons so missing Hydrogens
Liquid at room temp
Better for you then saturated fats
TRANS
Man made to accept more hydrogens
Solid at room temp
Margarines, fying fast food
AVOID!!!!!

12. 4. Vitamins organic molecules body requires in small amounts
regulate cell functions, growth, and development
Carbs, proteins and fats are building blocks; vitamins are tools that help put them together
fat soluble (will dissolve in fats)
A,D,E,K
Can be stored in fatty tissue for future use
water soluble (will dissolve in water)
C and B
Cant be stored so must be attained in diet

13. 5. Minerals Inorganic nutrients; don’t contain carbon
Calcium, iron, phosphorous, copper, sodium, zinc
Need to consume these to replace what you lose in sweat, urine and digestive wastes

14. 6. Water Our bodies are 55 – 60 % water
needed for chemical reactions, to digest food, and to eliminate waste products.
also necessary to maintain your blood volume, to regulate body temperature, and to keep your skin moist.
We need about 2L of water per day

15. Food As Fuel
In cells, glucose makes cellular energy by reacting with oxygen during cellular respiration
40% of energy from food goes to performing cell functions
Other 60% converted to thermal energy (heat)
100-watt light bulb?

16. Calories
The amount of energy required to raise the temperature of 1g of water by 1°C
needed to provide energy so the body functions properly.
number of calories in a food depends on the amount of energy the food provides.
Fuel
Calories Per Gram
Fat 9
Carbohydrate 4
Protein
Alcohol 7

17. Energy Requirements
Metabolism: set of chemical reactions that occur in living organisms that are necessary to maintain life
Catabolism: metabolic reactions that break down larger molecules into smaller ones
Anabolism: the metabolic reactions that use energy to produce larger molecules from smaller subunits
Metabolic Rate: the rate at which the body converts stored energy into working energy.
Generally five trends (see p397)

18. number of calories a person needs depends on age, height, weight, gender, and activity level.

19. Read Before You Eat

20. Fighting Disease
Nutraceutical – a substance that is purified from foods and taken like a medicine to provide health benefits
Omega-3 fish oil pill taken as a supplement
Functional Food – food that has health benefits beyond the normal nutritional benefit of the food
OJ enriched with calcium
Eggs enriched with omega-3
Milk enriched with vit D
Designer food industry
Probiotic yogurt

21. Canada’s Food Guide

22. Please Complete Mini Investigation in textbook p398
Explain why your body must process food in order for you to use it.
What is the difference between glucose and glycogen?
Why do you need to eat a variety of foods each day?
Why is it important to ensure your diet has the right amount of vitamins and minerals?
Have you changed your eating habits based on diets and nutritional claims presented in the media? Why or why not?