Transcript Chapter 7

Chapter 7:
Minerals
Minerals
 Minerals
 Solid, crystalline substances
 Do not contain carbon
 Are not broken down by chemical processes like
digestion
 Able to carry an electrical charge*
 Major (macro) or trace (micro)
Major Minerals
 Major minerals
 Required in larger amounts
 At least 100 mg/day are needed
 Total amount in the body is at least 5 grams
Calcium
Sodium
Potassium
Phosphorus
Magnesium
Sulfur
Chloride
Trace Minerals
 Trace minerals
 Required in smaller amounts
 Less than 100 mg/day are needed
 Total amount in the body is less than 5 grams
Iron
Zinc
Copper
Selenium
Iodine
Fluoride
Chromium
Manganese
Molybdenum
Minerals in the Human Body
1400
1200
Ca
Major Minerals
Trace Minerals
Grams
1000
800
P
600
400
200
K
S
Na
0
Cl
Mg
Fe
Mn
Cu
I
Major/Macro Minerals
Need >100 mg/day
Nutrients Involved in
Bone Health
Calcium, Phosphorus, Magnesium
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Bone Health
 Bone structure
 Provides strength to support the body
 Composed of about 65% minerals, providing the hardness
of bone
 Allows for flexibility
 Collagen fibers–fibrous protein in bone tissue providing
structure, strength, durability, and flexibility
 Protect vulnerable tissues/organs
 Examples?
 Most blood cells formed inside bones
Bone Health
 Two types of bone tissue
 Cortical bone (compact bone)–very dense tissue
making up 80% of the skeleton
 Outside of skeleton; small bones of wrists, hands, feet
 Trabecular bone (spongy bone)– "scaffolding" on the
inside of bones; supports cortical bone and makes up
20% of the skeleton
 Ends of long bones; inside spinal vertebrae, flat bones, pelvis
Bone Health
Bone Health
 Bone density
 Refers to the compactness and strength of bones
 Peak bone density is reached by the age of 30.
 Density begins to decrease after age 40 because
breakdown exceeds new bone formation.
Bone Health
 Bone mass is regularly recycled by a process of
remodeling.
 Breakdown–surface of bones is broken down by
osteoclasts
 Osteoclasts are cells that erode the surface of bones.
 C = crunching or cutting
 Formation of new bone by osteoblasts
 Osteoblasts produce the collagen-containing component of
bone.
 Control deposition of minerals on the collagen
 B = building
Bone Health
Calcium
 Calcium:
 is the most abundant major mineral in the body (1.5% of
body weight)
1. is required to form and maintain bones and teeth
2. is critical for nerve impulse transmission and muscle
contraction
3. assists with blood clotting
Calcium and Bone Health
 99% found in bones and teeth
 Hydroxyapatite
 Must have vitamin D to get calcium to bone
 1% in the blood
 Body will pull from bones to put into the blood
Osteoporosis
 Osteoporosis is a disease characterized by:
 low bone mass
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 deterioration of bone tissue
fragile bones leading to bone fractures
compaction of bone; decreased height
shortening and hunching of the spine
1 in 3 women and 1 in 5 men
Osteoporosis
Kyphosis
Osteoporosis
 Factors influencing the risk of osteoporosis include:
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Age
Gender
Genetics: Caucasian and Asian women
Nutrition
Physical activity
Osteoporosis
 Age is a factor for osteoporosis because:
 bone mass decreases with age
 age-related hormonal changes influence bone density
 older adults are less able to metabolize vitamin D
Osteoporosis
 Gender is a risk factor for
osteoporosis.
 80% of Americans with
osteoporosis are women.
 Women have lower bone
density than men.
 Estrogen loss in postmenopausal women causes
increased bone loss.
Osteoporosis
Osteoporosis
 Nutritional factors may affect the risk for osteoporosis.
 High caffeine intakes/alcohol abuse may increase bone
loss.
 Calcium and vitamin D are important for proper bone
development and maintenance of bone density.
 Need adequate intakes of energy, protein, Mg, vitamins C
&K
Osteoporosis
 Physical activity influences the risk for osteoporosis.
 Regular exercise causes stress to bones, leading to
increased bone mass.
 Weight-bearing activities (walking, jogging, weight
training) are especially helpful in increasing bone mass.
Osteoporosis
 There is no cure for osteoporosis.
 For prevention or to slow the progression:
 adequate calcium, vitamin D/K intake
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 Spread it out
regular weight-bearing exercise
don’t smoke, or quit if you do
Maintain adequate weight (estrogen)
*medications to slow or stop bone breakdown
Calcium Needs
 Recommended intake
 AI values vary with age and gender (1000 – 1300mg).
 Intake is limited by bioavailability–the amount that can
be absorbed.
 We only absorb ~30% of what is consumed
 Spread calcium intake throughout day
 No more than 500 mg at one time
B
D
L
Calcium Needs
 Main determinants of how much is absorbed:
 Dose of calcium
 Levels of phytate and oxalate
 Phytates found in whole grains, soy isolates
 Oxalates found in spinach, Swiss chard, beet greens, rhubarb
 Have a mixed diet
 Need vitamin D
Calcium
 Sources of calcium
 Skim milk, low-fat cheese, nonfat yogurt, green leafy
vegetables
 Highly absorbable calcium sources include:
 Kale
 Collard greens
 Broccoli
 Bok choy
 Watercress
 Dairy (including fortified plant milks, not cottage cheese)
 Fortified OJ
Food Sources of Calcium
Calcium
 What if you consume too much calcium?
 Excess calcium is excreted from the body.
 Calcium supplements can lead to mineral imbalances.
 What if you don't consume enough calcium?
 Long-term consequence of inadequate calcium is
osteoporosis.
Phosphorus
 Phosphorus is:
 2nd most abundant mineral
 as phosphate
 critical for proper bone
formation (85% here)
 found in ATP
 a major component of the
cell membrane
 phospholipids
 lipoproteins
Phosphorus
Phosphorus
 Recommended intake
 RDA for phosphorus is 700 mg/day.
 Sources of phosphorus
 Widespread in many foods, including processed
 Found in high amounts in foods that contain protein (e.g.,
meat, milk, eggs, legumes)
 Found in colas (phosphoric acid)
Food Sources of Phosphorus
Phosphorus
 What if you consume too much phosphorus?
 Causes muscle spasms, convulsions
 What if you don't consume enough phosphorus?
 Deficiencies of phosphorus are rare.
 Can occur with alcohol abuse, premature babies, or in
elderly people with poor diets
Magnesium
 Magnesium:
 50%-60% in bones
 Works with vitamin D;
regulates calcium
absorption
 coenzyme for over 300
enzyme systems
 is required for ATP, DNA, and
RNA
 necessary for protein
synthesis/repair
 supports muscle relaxation
and blood clotting
Mg
Magnesium
 Recommended intake
 RDA varies based on age and gender.
 320 mg/day for women age 19–30
 400 mg/day for men age 19–30
 Sources of magnesium
 Green leafy vegetables, whole grains, seeds, nuts,
seafood, beans, chocolate
 Unprocessed, whole foods best source!
 More fiber = more magnesium
Food Sources of Magnesium
Magnesium
 What if you consume too much magnesium?
 No toxicity from magnesium in food
 Magnesium supplements can cause diarrhea, nausea,
cramps, dehydration, cardiac arrest
 What if you don't consume enough magnesium?
 Low magnesium can result in low blood calcium and
osteoporosis; seizures, muscle cramps, nausea,
weakness, confusion
 Alcohol abuse, kidney disease, chronic diarrhea
Trace/Micro Minerals
Need <100 mg per day
Nutrients Involved in
Blood Health
Iron, Zinc, Copper
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Iron
 Iron is:
 a component of the protein hemoglobin that carries
oxygen in red blood cells
 a component of myoglobin that carries oxygen in muscle
cells
 a coenzyme involved in energy metabolism of
carbohydrates, fats, and proteins
 can be an antioxidant or pro-oxidant
Iron
Iron
Transport
Storage
 Transferrin
 Ferritin
Iron
 Two types of iron are found in foods.
 Heme iron: found in animal-based foods and more
absorbable
 Non-heme iron: plant and animal foods; not as easily
absorbed
 Non-heme iron is more easily absorbed:
 from meat, poultry, and fish (MFP factor)
 in combination with vitamin C
 cooking with a cast-iron pan
 Iron inhibitors: phytates, polyphenols, calcium
Iron
 Recommended intake
 RDA varies based on age, gender, and other factors.
 1.8 times higher for vegetarians
 Higher for young women than for men
 18 mg versus 8 mg/day
 Higher for pregnant women
 27 mg/day
 Sources of iron
 Meat, poultry, fish, clams, oysters, enriched cereals and
breads, legumes, dried fruit
Food Sources of Iron
Iron
 What if you consume too much iron?
 Iron overdose is the most common cause of poisoning
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deaths in children.
Hemochromatosis
Toxicity symptoms: nausea, vomiting, diarrhea, dizziness,
confusion
 UL is 45 mg/day
Delayed treatment of iron toxicity can result in severe
damage to the heart, central nervous system, liver,
kidneys.
Constipation
Iron
 What if you don't consume enough iron?
 Iron deficiency is the most common nutrient deficiency in
the world.
 Iron-deficiency anemia: red blood cells do not contain
enough hemoglobin
 High-risk people include infants, young children,
preadolescent girls, menstruating women, and pregnant
women.
 Measure blood hemoglobin and hematocrit (%RBCs)
Iron/Anemia
Normal vs. Anemic RBCs
Hematocrit
Zinc
 Zinc is:
 Helps 200 different enzymes
 Alcohol metabolism; insulin function; DNA
 A coenzyme for hemoglobin production and for other
proteins
 Required for proper development and function of the
immune system
 Required for normal growth
 Including sexual maturation
Zinc
 Recommended intake
 The need for zinc is small, but the amount of absorption is
variable.
 More protein in body = more zinc
 Men = 11 mg/d; women = 8 mg/d
 Sources of zinc
 Red meats, some seafood, legumes, whole grains,
enriched grains and cereals
Food Sources of Zinc
Zinc
 What if you consume too much zinc?
 Toxicity can occur from supplements.
 UL is 40 mg/d
 May reduce copper absorption
 Symptoms are intestinal pain, cramps, nausea, vomiting,
loss of appetite.
 What if you don't consume enough zinc?
 Deficiencies are uncommon in the United States.
 Symptoms are severe growth retardation, diarrhea,
delayed sexual maturation, hair loss, lowered immunity
Copper
 Copper:
 Also a cofactor for many enzymes
 As a component of ceruloplasmin, it is required for iron
transport and metabolism
 Contributes to blood tissue, collagen, and tissues
surrounding nerves
 Is involved in neurotransmitters required for brain function
 Necessary for ATP synthesis
Copper
 Recommended intake
 RDA for adults is 900 mcg/day.
 Competes with zinc for absorption
 Sources of copper
 Organ meats, seafood, nuts, seeds, whole grain foods,
chocolate, legumes
 Water from copper pipes
Copper
 What if you consume too much copper?
 Toxicity is not well studied in humans.
 What if you don't consume enough copper?
 Copper deficiency is rare.
 High intakes of iron or zinc can reduce absorption
Antioxidant Nutrient
Selenium
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Selenium
 Selenium is:
 Necessary for making thyroid hormones
 An antioxidant to spare vitamin E and protect cell
membranes
 Glutathione peroxidase
 Found especially in fish, organ meats, wheat, and nuts
(Brazil nuts, especially)
 major sources in American diet are: breads, grains, meat,
poultry, fish, eggs
 depends on selenium content of soil
 Needed daily at 55 mcg
Food Sources of Selenium
Nutrients Involved in
Energy Metabolism
Iodine
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Iodine
 Iodine is:
 Critical for making thyroid hormones
 Found in saltwater fish
 Added to table salt (iodized salt)
 some breads, milk/dairy
 takes ½ teaspoon salt to meet RDA
 150 mcg/day
 Both iodine deficiency and toxicity can result in
hypothyroidism and goiter.
 Low in pregnancy = cretinism in children
Iodine: Goiter
Other Trace Nutrients
Fluoride, Chromium
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Fluoride
 99% of the body's fluoride is stored in teeth and bones.
 Fluoride:
 Is required for proper development and maintenance of
teeth and bones
 Combines with calcium and phosphorus to protect teeth
from bacteria
 Incorporated into the crystal structure of bones
Fluoride
 Recommended intake
 RDA varies by gender and increases with age during
childhood.
 3 mg/day for women
 4 mg/day for men
 Sources of fluoride
 Fluoridated dental products
 Fluoridated water
 Tea
Fluoride
 What if you consume too much fluoride?
 Fluorosis (excess fluoride) creates porous tooth enamel;
teeth become stained and pitted.
 What if you don't consume enough fluoride?
 Dental caries (cavities)
 Possible lower bone density
Chromium
 Improves insulin function
 Only an issue when chromium is lacking
 Does not appear to increase muscle mass or decrease
fat mass
 Women need 25 mcg/day; men need 35 mcg/day
 Found in nuts, whole grains, cheese, brewer’s yeast
Nutrients Involved in
Fluid Balance
Water, Sodium, Potassium
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Water
Water
 The body fluid composition
varies by:
 Tissue type
 Lean tissues have higher
fluid content than fat
tissues
 Gender
 Males have more lean
tissue and therefore more
body fluid than females
 Age
 Lean tissue is lost with
age, and body fluid with it
Functions of Water
 Water dissolves and
transports substances
 Water accounts for blood
volume
 Lower/higher blood volume =
decreased/increased blood
pressure
Functions of Water
 Water helps maintain body
temperature**
 Sweating
 Heat is evaporated
 High % water content of
body
 Takes a high temp and long
exposure to raise body temp
Functions of Water
 Fluids protect and lubricate body tissues.
 Brain, spinal column, fetus
 Lubricant for joints
 Digestive secretions allow for easy passage of material
Water Balance
Maintaining Water Balance
 Any water lost through urine, feces, sweat,
evaporation, and exhalation must be replaced.
 Most water is lost through urine.
 The kidneys control how much water is reabsorbed.
Excess water is processed by the kidneys and
excreted as urine.
 Some water is lost through the skin
(sweat/evaporation) or through the lungs during
exhalation.
Maintaining Water Balance
 Within the hypothalamus =
thirst mechanism.
 prompts us to feel thirsty
when it detects either:
 increased sodium
concentration in the
blood
 decreased blood volume
and blood pressure
 Water is gained through
beverages, food, and
metabolic reactions.
 Most water enters the body
through beverages.
 Some foods have very high
water content.
Water Intakes
 Recommended Intake:
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1 to 1.5 mL/kcal
Men = 13 cups/day
Women = 9 cups/day
Pregnancy = 10 cups/day
Breastfeeding = 13 cups/d
 Activity level, temps,
diuretics, and diets are
considerations
 Water is best at hydrating*
Maintaining Water Balance
 What if you don't drink
enough water?
 Dehydration
 Table 7.5
 Infants and the elderly are
especially vulnerable.
 Heatstroke can occur in hot,
humid environments when
the body can't release
enough heat to keep body
temperature in a safe range
Maintaining Water Balance
 Water intoxication (overhydration) is rare
 Can occur in endurance athletes and kidney disease
 Can result in a dilution of sodium (hyponatremia)
Are You Properly Hydrated?
 Urine should look like diluted lemonade
 Weight check = each pound of body weight lost = 2
cups of water
Electrolytes
 Body fluid is composed of:
 Water
 Electrolytes: minerals dissolved in water that become
charged, including:
 Sodium
 Potassium
 Chloride
Electrolytes
 Electrolytes have many different functions in the body.
 Carry electrical charges
 “Spark” nerve transmissions
 Maintain fluid balance because they:
 keep cells from becoming too swollen or dehydrated
 strongly attract water
 do not move easily across cell membranes (water does move
easily)
Fluid Balance
Electrolytes: Sodium
 Functions of sodium
 Fluid and electrolyte balance
 The primary electrolyte outside of cells
 Associated with blood pressure
 Required for nerve impulse transmission
 Assists with transport of certain nutrients (e.g., glucose)
into body cells
Na+
Na+
Na+
Na+
Na+
Na+
Electrolytes: Sodium
 Recommended intake
 AI is 1500 mg/day (a little more than 1/2 a teaspoon).
 Sources of sodium
 Natural foods (eggs, milk, celery, artichokes)
 Table salt (Na+Cl-)
 Processed foods are high in sodium.
 Prepackaged, canned, lunch meats, snack/fast foods,
breads, cheeses, chips, nuts
Electrolytes: Potassium
 Functions of potassium
 The primary electrolyte inside of cells
 Balances sodium and fluids
 Very important in muscle contractions and transmission of
nerve impulses
 High potassium intake helps maintain a lower blood
pressure.
K+
K+
K+
K+
K+
K+
K+
Electrolytes: Potassium
 Recommended intake
 AI for adults is 4.7 g/day.
 Sources of potassium
 Processed foods are usually low in potassium.
 But higher in what??
 Fresh fruit, vegetables, and whole grains are good
sources of potassium.
Food Sources of Potassium
Potassium
 Potassium toxicity is rare in healthy people because
the kidneys excrete the excess.
 Potassium deficiency is also rare but can occur in
patients with kidney disease or diabetes.
 Can lead to deadly heart rate changes
Hypertension
 Hypertension
 High blood pressure
 Healthy BP is <120/80 mmHg
Systolic
Diastolic
Hypertension and Sodium
 Not necessarily caused by sodium, but hypertension is
more common in people who consume more sodium.
 DASH diet ("Dietary Approaches to Stop Hypertension")
can significantly reduce blood pressure.
 8 to 10 servings of fruit/veggie per day
 Low in saturated fat
 Lots of potassium! (and magnesium, calcium)