Transcript Chapter 10: Water and Minerals: The Ocean Within

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.
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
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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, highfiber 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