Water: Crucial to Life –45–75% BW –Intracellular –Extracellular Electrolytes and water –Balanced inside and outside cells Cation Anions Osmosis

Intake Recommendations Intake: How much is enough? –Men = 3.7 l/d –Women = 2.7 l/d –Pregnancy and lactation = 3.0–3.8 l/d –Increased needs for activity and sweating Sources –Drinking water –Beverages –Water in food –Metabolic reactions

Water Balance Hormonal effects –Antidiuretic hormone (ADH) –Aldosterone Thirst Alcohol, caffeine, and common medications affect fluid balance

Regulation of Water Balance Dehydration Water intoxication –First causes headaches and seizures

Understanding Minerals Minerals –Inorganic elements –Not destroyed by heat, light, acidity, or alkalinity –Micronutrients –Major minerals and trace minerals –Involved in body structure and regulation –Found in plant and animal foods –Absorption limited by several factors

Minerals in Foods Both plants and animal sources Bioavailability –Body adjusts mineral absorption to our needs –Megadosing can alter absorption of other minerals –Fiber affects absorption

Major Minerals and Health Hypertension: high blood pressure –Increases risk for heart disease, stroke, and kidney disease –Risk factors for hypertension: Obesity High sodium intake Lack of physical activity Excess alcohol intake Race Age Family history

Major Minerals and Health Sodium (Na + ) and hypertension –Reducing Na + intake lowers BP Other dietary factors –DASH diet helps to reduce hypertension Dietary Approach to Stop Hypertension

Calcium Functions –Bone structure Hydroxyapatite Bone cells –Osteoblasts –Osteoclasts Reserve of calcium and phosphorus

Major Minerals and Health Osteoporosis –Decreased bone mineral density –Develops gradually with age Peak bone mass ~ 30 years old

Risk Factors You Cannot Change Gender. Women have less bone tissue and lose bone faster than men because of the changes that happen with menopause.menopause Age. The older you are, the greater your risk of osteoporosis. Your bones become thinner and weaker as you age. Body size. Small, thin-boned women are at greater risk for developing osteoporosis than larger women. Ethnicity. Caucasian and Asian women are at the highest risk of developing the disease. African-American and Hispanic women have a lower, but still significant, risk. Family history. Your risk for fractures may be due, in part, to heredity. People whose parents have a history of fractures also seem to have reduced bone mass and may be at risk for fractures themselves.

Risk Factors You Can Change Sex hormones. Abnormal absence of menstrual periods (amenorrhea), low estrogen levels (menopause), and low testosterone levels in men. Anorexia nervosa. Characterized by an irrational fear of weight gain, this eating disorder increases your risk for osteoporosis. Calcium and vitamin D intake. A lifetime diet low in calcium and vitamin D makes you more prone to bone loss. Medication use. Long-term use of glucocorticoids and some anticonvulsants can lead to loss of bone density. Lifestyle. An inactive lifestyle or extended bed rest weakens bone. Cigarette smoking. Cigarettes are bad for the bones as well as the heart and lungs. Alcohol intake. Excessive consumption of alcohol increases the risk of bone loss and fractures.

Sodium Dietary recommendations –Daily intake less than 2,300 mg/d –Daily intake less than 1,500 mg/d for persons 51 and older –Limit consumption of foods that contain refined grains, especially those that contain solid fats, added sugars, and sodium

Trace Minerals Cofactors for enzymes Components of hormones Participate in many chemical reactions Essential for growth Essential to the immune system

Iron Functions –Oxygen transport as part of hemoglobin and myoglobin –Cofactor for enzymes, immune function, and normal brain function Photo © PhotoDisc

Iron Regulation of iron in the body –Iron absorption Effect of iron status –Absorption varies Effect of GI function –Depends on stomach acid Effect of the amount and form of iron in food –Conserve iron Heme iron Non-heme iron

Iron Iron absorption –Enhance iron absorption Vitamin C –Inhibit iron absorption Phytate, polyphenols, oxalates, high- fiber foods, calcium, and zinc –Transport and storage Transferrin

Iron Iron absorption –Turnover and losses Rapid growth and blood expansion Blood loss Digestive disorder Food sources –Red meat, clam, oyster, liver, poultry, fish, pork, lamb, tofu, legumes, enriched and whole grains, fortified cereal

Iron Deficiency –Iron-deficiency anemia Toxicity –Poisoning in children –Hereditary hemochromatosis

Iron Toxicity Iron is important for good nutrition because it is used in blood and muscle tissue. However, it is also very poisonous if too much is taken. Each year, there are over 3,500 iron poisonings in children under the age of 6 years. It is also one of the most frequent causes of poisoning death in children.

Hereditary hemochromatosis is a genetic disease and is the most common autosomal recessive disease among Caucasians with about 8 to12% carring one abnormal gene. Men develop hemochromatosis at an earlier age than women (30 to 50 years average age for men vs 50 years of age for women). Mutations in the HFE gene (located on human chromosome 6) are responsible for most cases of hemochromatosis.

If you have hereditary hemochromatosis, you can do some things to help: Don't take iron supplements, not even vitamins with iron in them. Don't take vitamin C supplements. Don't eat very much red meat. Don't drink very much alcohol. Too much iron plus alcohol can make liver disease worse. Chronic liver disease Blood transfusions and kidney dialysis.

Zinc Functions –Cofactor for enzymes –Gene regulation, immune health Enzymes –Helps provide structural integrity or activate catalytic ability Gene regulation –Absorption –Transport, distribution, excretion Immune system

Zinc Regulation of zinc in the body –Absorption Similar to iron Phytate inhibit absorption –Transport, distribution, and excretion Circulates bound to protein Food sources –Red meats, seafood

Zinc Deficiency - Uncommon, but may occur in people with illness that impair absorption Slowing of growth and development Delayed sexual maturation, Skin rashes Chronic and severe diarrhea Immune system deficiencies Impaired wound healing Diminished appetite Impaired taste sensation

Intakes of 150–450 mg zinc/d have been associated with: Low copper status Altered iron function Reduced immune function Reduced HDL Treatment for Wilson’s disease