NUTRITION FUNCTION OF NUTRIENTS

WATER Essential nutrient 55 – 65% of body weight Water loss through evaporation, excretion, and respiration

CARBOHYDRATES Main source of energy Excess carbs converted to fat Calorie Unit measuring amount of energy contained within the chemical bonds of different foods Empty calories – foods like candy with no nutritional value Roughage – indigestible part of carbs (cellulose)

LIPIDS (FATS) Source of energy – twice as many calories as same amount of carb or protein Body fat cushions internal organs, insulates against cold Fats carry fat-soluble vitamins Cholesterol Animal fat found in meat, cheese, eggs Excess can build up in artery walls causing atherosclerosis Recommended blood level under 200 mg/dl HDL – High density lipoprotein – “good”, removes excess cholesterol from cells to carry back to liver to be broken down and eliminated LDL – Low density lipoprotein – carry fat to cells

PROTEINS Many functions: Amino acids are building blocks of proteins Enzymes Source of energy Muscles, hormones, clotting, antibodies all depend on proteins Amino acids are building blocks of proteins Complete proteins contain all amino acids – milk, eggs, cheese Incomplete proteins – do not contain ALL amino acids – vegetables, beans, wheat Body can’t store amino acids Adults in US eat too many proteins, putting extra burden on kidneys and liver to excrete

MINERALS Inorganic compound needed for human growth and maintenance Most important: Sodium Potassium Calcium Iron Trace elements – present in small amounts, toxic levels close to healthy levels Most minerals present in average adult diet Fluorine – in drinking water, for bones and teeth Iodine – in fish, shellfish, iodized salt, needed to make thyroid hormones Iron – liver, lean meats, needed to make hemoglobin

VITAMINS Biologically active organic compound Function as coenzyme for normal health and growth, some behave like hormones A, D, E and K – fat soluble, can be stored in the body B vitamins and Vitamin C are water soluble, can’t be stored, excess excreted through urine

FIBER Found in plant foods like whole grain breads, cereals, beans, peas, other vegetables and fruit Important for proper bowel functioning, may lower risk of heart disease and some cancers