Nutrition

Food as Fuel Cells need energy to function. Nutrients from food are digested and circulated throughout the body. A nutrient is any substance that has a useful function in the body. Calorie: heat required to raise temperature of 1g of H2O by 1°C

Classification of Food Organic or Inorganic. Macronutrients or Micronutrients.

Organic vs. Inorganic Organic: Produced by living organisms. Carbohydrates, protein, fats and vitamins. Inorganic: From rocks, soil and seas. Water and minerals.

Macronutrients vs. Micronutrients Macronutrients - Needed in large amounts. Carbohydrates, proteins and fats. Micronutrients - Needed in small amounts. Vitamins and minerals.

Carbohydrates Composed of carbon, hydrogen & oxygen. Major source of energy. Starches, etc. Made up of sugars Ready source of glucose Excess stored as glycogen or as fat. Cellulose (fibre) indigestible but important.

Fats Concentrated source of energy 2x the energy of carbs Also made of C, H and O but in different ratio Also used for insulation, forms cell membranes, protects vital organs & increases nerve transmission.

Fats Unsaturated fats: Liquid at room temperature. Easier for body to digest e.g., olive oil, canola oil Saturated fats: Solid at room temperature. Harder for the body to digest e.g., butter, lard

Which Fat is Healthier?

Proteins Most abundant compound in body Used throughout the body Structure for skin, organs, bones, etc. Also enzymes and hormones Made of 20 amino acids 8 are essential - get from diet Meat, eggs, milk, fish, etc.

Micronutrients Not an energy source Consumed in small amounts Vitamins – Growth & muscle function. - Often act as coenzymes. Minerals – e.g., iron (blood), calcium (bones), etc.

Water Most abundant substance in body. 90% of blood plasma. Transports all nutrients. Forms extracellular fluid between cells. Regulates body temperature