Processing Nutrition:1. Digestive System: eat food that gets absorbed and

transformed into nutrients for cellular use.2. Respiratory System: require oxygen to use the

nutrients we eat.3. Cardiovascular System: blood circulates nutrients and

oxygen to cells.4. Urinary System: waste is discarded in blood and

filtered out in liquid form.

Ch. 6: Human Organism and the Importance of Nutrition

You Are What You Eat!• Food: substance to be ingested

sustaining life. Supplies body with nutrients.

• Nutrient: substance found in food that is used by the body for various purposes.

– 6 nutrients: • Carbohydrates • Fats/Lipids • Protein• Vitamins• Minerals • Water

• Energy: Is the ability to do work measured in joules (J).

• For food the common unit of measure for energy is dietary calorie.

• Calorie (Cal): 1 Cal is equal to 4000 J or 4 kJ.

*Adolescent girl: 1800 Cal (7200kJ)-2400 Cal (9600kJ)*Adolescent boy: 2200 Cal (8800kJ)-3200 Cal (12

800kJ)

*3 factors to measure calorie output: basal metabolic rate (BMR), physical activity, and the digestion of food.

Measuring Calorie Output:• BMR: is the amount of energy required by

the body to carry on its vital processes while at rest. Ex: respiration, circulation, cellular metabolism and maintaining body temperature.

• Physical activity: the energy required for physical activity is a function of the type of activity, the duration of the activity, and the size of the individual.

• Food digestion: the active process of breaking down, absorption, and assimilation of food.

Calorie Input and Output• Energy balance reflects the

relationship between incoming and outgoing calories.

• Three relationships are possible:– input = output; body weight

maintained– input > output; body weight

increase– input < output; body weight

decrease

– 4 sources of calories: protein, fat, carbohydrates, and alcohol.

– Fibre: is cellulose, comes from cell wall of plants. It can’t be digested by the human body.• It helps prevent constipation, helps to

absorb water, stimulates contraction of the intestine.

– Carbohydrates, fats, and proteins are complex molecules that need to be broken down into smaller molecules.

• Main function: provide energy for cells.• Cellular respiration: Glucose + Oxygen Energy + Carbon dioxide + Water

C6H12O6 + O2 ATP + CO2 + H2O

Carbohydrates

• consist mainly of sugars (polysaccharides, disaccharides or monosaccharides).– Are broken down into glucose.– Found in: fruits, breads, pasta, rice, some vegetables, honey,

juice, candy, grains, flour, legumes and tubers (beets, potatoes, turnips)

– Function: Provides main source of energy– Provides energy: 4 Cal/g (17 kJ/g). – Energy can be used rapidly

Fats/Lipids• Found in: oils from plants and animals Ex:

dairy products, eggs, margarine, nuts, meat, chips, fish

• Fat is broken down into fatty acids and glycerol.

• Function: – Energy usually stored by the body;

available over longer periods of time.– Building blocks of hormones, cell

membrane and protects organs, insulator.

• Source of energy; 9 cal/g (38 kJ/g)• Stored in fat (adipose) cells.

Proteins

• Large molecules consisting of long chains of amino acids.

• Found mainly in meat, poultry, fish, meat substitutes: nuts, legumes, eggs, tofu and milk products.

• Proteins are broken down into amino acids.• Function: Allows the body to build and repair

tissues (bones, muscle and skin)– Body’s last choice for energy.– Are the basic building blocks for cells

• Provides energy: 4 Cal/g (17 kJ/g).

• Vitamins, minerals and water are simple molecules that can be used directly by the cells (Don’t need to be broken down).

Vitamins• vital to all the body’s functions• 13 types including: A, B, C, D, E and K.• Found in:fruits, vegetables (esp. dark green and orange

veggies), eggs, meat substitutes, milk, grains, and nuts• Function: for proper growth and repair, regulation of

metabolism (regulate chemical reactions in the body), helps fight infections by strengthening immune system.

• Fat Soluble Vitamins: are absorbed through the intestinal tract with the help of lipids (fats). They are more likely to accumulate in the body. (A, D, E and K)

• Water Soluble Vitamins: dissolve easily in water, and in general, are readily excreted from the body. Consistent daily intake is important. Many types of water-soluble vitamins are synthesized by bacteria. (8 B vitamins and vitamin C).

Minerals• Are simple chemical elements• Include: calcium (Ca), potassium (K), sodium (Na),

phosphorus (P) and iron (Fe).• Found in: fruits, vegetables, legumes, meat, milk and

fish.• Only need a small amount of minerals.• Function: play a role in the makeup of various tissues

(cartilage, teeth, bones and nerves), regulation of metabolism and are essential to nervous system and muscle contractions, transport oxygen.

Water

• A pure substance that makes up about 70% of the human body.

• Found in most food; mostly in beverages, fruits and vegetables.

• Body needs ~2-3 L per day.• Function: Important in chemical reactions,

regulate body temperature, transports nutrients and waste products.