NUTRITION & DIGESTION Why Food is important Calorie: amount of energy to raise the temp. of 1g of water 1 degree Celsius usually provided by food 1 Calorie = 1000 calories for nutritionists Adults need roughly 1500 Calories/day depending on how active you are, kind of work you do, & your gender. Food supplies energy and building materials WATER (most important) –Water is a solvent, coolant, moistener, thinner –Water is constantly being used and lost within your bodies. –Replaced by drinking, eating certain foods, & in cellular respiration

FOOD & NUTRITION MINERALS (fig. 39-4) –Inorganic substances required by the body. –Lost in sweat, urine, and waste products, so they must be replaced. –Plants get the minerals from the ground, animals eat the plants, and we eat the plants and animals. –Replacement of Na, K, and Cl through dairy, salt, meat, & veggies CARBOHYDRATES: organic compounds –Bodies fuel composed of carbon, hydrogen, & oxygen –Simple sugars, glucose, frutcose, & galactose, are good sources of quick energy. –Disaccharides: Maltose, sucrose, lactose, two simple sugars linked together, enzymes must break the bonds to release the energy.

CARBOHYDRATES Polysaccharides: Complex carbohydrates made of stored sugars consisting of long chains of monosaccharides. (starch & cellulose) Starch: bread, corn, rice, potatoes Must be broken down first through cellular respiration. Cooked veggies easier to digest the starch. Cellulose: Part of the cell wall of plants. Indigestible for humans, but important because it gives us roughage, which stimulates digestion. Lettuce, celery, whole grain FATS Provide protection, keep skin from drying out, parts of the cell membrane, insulation from environmental changes

FATS The structure of fats Organic composed of oxygen, hydrogen, & carbon Saturated: single bonds w/maximum H atoms Solid at room temp.: butter, lard, animal fat Unsaturated: One or more double bonds, so fewer H atoms Liquid at room temp.: vegetable oils Polyunsaturated: Multiple double bonds, fewest H atoms Liquid at room temp.: vegetable oils Our diets should be limited in fats, especially saturated fats. Fats and Energy Provide twice the calories/gram than carbos. Stored for late use, deposited under the skin

PROTEINS Proteins: complex macromolecules that build & repair for growth Essential Amino Acids: The 8 of the roughly 20 your body can’t manufacture, must get from your diets. Meat and dairy contain all 8 amino acids: complete proteins Most plants lack one or more: incomplete proteins(vegetarians) Proteins & Energy Can be used but must be converted into carbos. first This is done in the liver through deamination in the liver as an amino group is removed. Produces ammonia which is converted to urea and removed from the body by the kidneys.

VITAMINS Vitamins are complex molecules needed is small amounts that usually cannot be synthesized by the body. (sunlight-Vitamin D) Vitamins are cofactors for enzyme-catalyzed chemical reactions Cofactors: Organic catalysts that assist enzymes in reactions See fig Needed in small amounts Fat soluble can be stored (A,D,E,K) water soluble can’t (C & B) Scurvy- bleeding gums, teeth loss, death Need vitamin C HEALTH AND A BALANCED DIET Five food groups (see fig ) Proportions is the key Fats, oils,& sugars used sparingly Keep calorie intake balanced no more than 30% from fats