Transcript Trace Minerals - 35-206-202

TRACE MINERALS
CHAPTER 15
LEARNING OUTCOMES
• Describe the important food sources, major
functions, deficiency and toxicities of each trace
mineral discussed in class
• Understand trace mineral absorption,
transportation, storage and excretion.
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OVERVIEW OF TRACE MINERALS
• Inorganic substances needed by the body in small
quantities
• Includes iron, zinc, copper, maganese, iodine,
selenium, chromium, fluoride, and molybdenum
• Typically difficult to measure in the body and in
food
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IRON
• Foods
• Heme iron: iron part of hemoglobin and
myoglobin in animal flesh
• Nonheme iron: vegetables, grains, and
supplements
• Needs
• RDA 18 mg/day adult women, 8 mg/day adult
men
• After menopause drops to 8 mg/day
• Most common trace mineral deficiency worldwide
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IRON
• Absorption, Transportation and Excretion
• Ferritin: iron binding protein in small intestine
• Storage form of iron, made in response to iron stores
• Also acts as “mucosal block”
• Transferrin: protein that binds iron and transports it
through body (needs copper)
• Absorption and storage is tightly regulated in the body
because the body has limited ability to excrete
absorbed iron
• Most iron is recycled, only 10% is excreted
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Mucosal
“block”
Non heme must be in Fe2+ form to
be absorbed
Muscle (Myogl)
Bone marrow
RBC (Hgb)
Liver
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IRON
• Functions
• Component of
proteins
• Hemoglobin-protein in
red blood cells that
carries oxygen in body
• Myoglobin- protein in
muscle that carries
oxygen to muscles and
heart
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IRON
• Functions
• Component of
enzymes or act as
coenzyme
• Needed for energy
metabolism
• Needed for drug and
alcohol metabolism in the
liver
• Needed for
neurotransmitter synthesis
• Needed for immune
system
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IRON
Deficiency
• Iron deficiency anemia
• At risk: premature infants, children, females of child bearing
age, vegetarians
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IRON DEFICIENCY
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Pale skin, fatigue and weakness.
In severe cases, trouble breathing
Pica for ice is a very specific symptom
Lightheadedness
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IRON
• UL
• 45 mg/day
• Nausea, vomiting, diarrhea, constipation, interfere
with absorption of other minerals
• Who?
• Supplements (especially kids)
• Hemochromatosis- genetic disorder that can cause liver
disease and heart failure
• Frequent blood transfusions
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CASE STUDY
Betsy just got diagnosed with iron deficiency
anemia. What would be a good breakfast?
• Iron fortified cereal with milk and coffee
• Spinach and cheese omelet
• Steak and eggs
• Ham, egg, and cheese on whole grain bread
with OJ
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ZINC
• Foods
• Protein rich meat and
seafood, whole grains
• Needs
• RDA 8-11 mg, most in US
get adequate zinc
• Absorption,
Transportation and
Excretion
• Has a mucosal block
similar to iron
(metallothionein)
• Not stored, but is
recycled
• Can be excreted in
feces, so less toxic than
iron
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ZN ABSORPTION
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ZINC
• Function
• At least 300 different enzymes require zinc
• DNA synthesis, immune function, growth and development,
home synthesis, antioxidant
• Deficiency
• Overt deficiency common in poverty
• Low appetite, impaired growth, decreased taste, immune
dysfunction
• North America-marginal deficiencies if absorptive diseases,
dialysis, vegetarians
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ZINC
• UL
• 40 mg/day-usually people who take
supplements
• Low appetite, nausea, vomiting, GI upset
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COPPER
• Foods
• Liver, shellfish, nuts, seeds, mushrooms, soy and
dark chocolate
• Needs
• RDA 900 micrograms daily
• Deficiency rare
• Absorption, Transportation and Excretion
• Little is stored, excreted in feces
• Binds to metallothione in intestine
• Copper balance controlled by copper absorption
and influenced by iron and zinc status
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COPPER
• Function
• Iron metabolism
• In family of enzymes
that act as
antioxidants
• Deficiency rare
• Menkes disease
• UL
• Toxicity is also rare
• Wilson’s disease
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IS CHOCOLATE GOOD FOR YOU?
• One study reported that men who ate the most
chocolate had a 47 percent lower mortality rate
over 15 years than a similar group that
consumed little chocolate.
• Another study that showed a small amount of
chocolate slowed platelet clumping.
• A new chocolate called CocoaVia got a lift
from the Journal of the American Dietetic
Association, which reported that two (small) bars
a day lowered LDL cholesterol in a highcholesterol subject group by 6.7 percent
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MATCH THE DEFICIENCY WITH THE ANEMIA
• Vitamin E
• Folate
• Vitamin B12
• Iron
• Copper
• Megaloblastic
• Microcytic
• Hemolytic
*** See page 548 in book for summary
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MANGANESE
• Foods
• Whole-grain cereals, nuts, legumes and tea
• Needs
• AI 1.8-2.3 mg/daily
• Deficiency rare
• Absorbed in small intestine, transported
with protein carriers, excreted in bile
• Only ~10% is absorbed, unless need is high
• Absorbed better if iron status is good
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MANGANESE
• Function
• Shares functional similarities with Zinc and
Copper (cofactor for enzymes, energy
metabolism)
• Deficiency
• Rare
• UL
• 11 mg/day
• Inhalation of car emissions
• Causes nerve damage
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IODINE
• Foods
• Saltwater seafood, seaweed, iodized salt,
molasses and dairy products
• Needs
• RDA is 150 micrograms daily
• ½ teaspoon of iodized salt meets RDA requirement
• Absorbed efficiently and stored in thyroid
gland, excreted in urine
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IODINE
• Function
• Component of
thyroid hormone so
needed for normal
metabolism
• Deficiency
• Goiter (enlarged
thyroid) and cretinism
(poor growth)
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IODINE
• UL
• 110 micrograms/day
• Enlarged thyroid gland, increased risk
of thyroid cancer
• Japan- high intake of seaweed
• Chile- high levels in soil
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SELENIUM
• Foods
• Seafood, meats, cereal grains and nuts
• Soil dependent
• Needs
• RDA 55 micrograms adults
• Intake typically above the RDA
• Easily absorbed, excess is excreted in urine
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SELENIUM
• Function
• Anti-oxidant defense network (similar to vitamin E,
protects cell membranes from oxidation)
• Synthesis of thyroid hormone
• May decrease risk of cancer (especially prostrate and
lung)
• Deficiency
• No specific disease but deficiency can cause Keshan
disease
• UL
• 400 micrograms daily
• Nausea, diarrhea, fatigue, hair loss, change in nails,
and skin rashes
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SELENIUM AND CANCER
• 1) Epidemiology studies show that where selenium levels in
the soil are high, death rates from cancer are significantly
lower.
• 2) Clinical trial studies
• 32,000 men
• Researchers gave the men either selenium, vitamin E, or
a combination of selenium and vitamin E to learn
whether either would lower the risk of prostate cancer.
• This study was suspended early because analysis found
no benefit to taking selenium for an average of more
than 5 years.
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CHROMIUM
• Foods
• Nutrient databases inadequate
• In many foods including broccoli, processed
meats, liver, eggs, whole grain products
• Needs
• AI 25-35 micrograms
• Uncommon deficiency and no UL
• Functions
• May improve insulin function and help normalize
blood sugar, although supplements have not been
shown to be beneficial
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FLUORIDE
• Foods
• Fluoridated water, tea, seafood and seaweed
• Non food sources are toothpaste and mouthwash
• Needs
• AI 3-4 mg/daily
• Easily absorbed and stored in teeth and bones
• Function
• Promotes bone and dental health
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FLUORIDE
• Deficiency
• Associated with an
increase in dental
caries
• UL
• .1 mg/kg body
weight daily up to 8
years old
• Most risk is 8 yo or
younger
• Mottling or fluorosis
with chronic intake
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MYTHS
• I drink bottled water, am I missing out on the
benefits of Fluoride?
• Do I need to drink fluoridated water if I brush my
teeth?
• What are other health effects of too much fluoride?
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ULTRA TRACE MINERALS
Needed in very small amounts but essential for many
enzymes
• Molybdenum
• Boron
• Nickel
• Silicon
• Arsenic
• Vanadium
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