Download The Trace Minerals

Chapter 13
The Trace Minerals
The Trace Minerals
• Essential nutrients found in the
human body in <5g.
• Needed in <20mg daily
• Food sources varies widely
• Nutrient interactions is very
common
Iron
• The most abundant mineral on earth
• The most abundant trace mineral in the
body
• An 130 pound woman has about 2300mg of
iron in her body about the size of a dime
• A 165 pound male will have about 4000mg
of iron in his body
• Key component of blood, highly valuable to
the body
• Once absorbed, very little leaves the body
• ~95% of iron in the body is recycled and
reused
• Most iron is lost due to bleeding
Iron
• Occurs in two forms:
– Heme – found in animal foods such as meat,
poultry, and fish
• Part of hemoglobin in red blood cells and myoglobin
in the muscle cells
• Easily absorbed by the body
– Non-heme – found mostly in plants foods such
as grains and vegetables
• Not easily absorbed as heme iron
• Compounds such as phytates in legumes rice, and
grains, and polypherols in tea and soy protein inhibits
absorption of non-heme iron
• In general, the body absorbs only 10
– 15% of the iron ingested
Iron
• You can enhance absorption of iron
by eating a food that’s high in vit C
along with iron rich foods
• As little as 25mg of vit C can double
the absorption of iron
• Eating non-heme iron with heme iron
can also ehnance absorption
• Too little or too much iron can be
harmful
Iron
Functions
• Hemoglobin and myoglobin transport
Oxygen in red blood cells
• Hemoglobin picks up carbon dioxide waste
to the lung to be exhaled from the body
• Needed for brain function, involved in the
synthesis of neurotransmitter in the brain
• Cofactor to enzymes
• Involve in making of amino acids,
collagens, and hormones
Iron
Factors that inhibit non-heme iron absorption;
• Phytates and Fibers (found in grains
and vegetables
• Oxalates ( spinach, beets, rhubarb)
• Calcium and phosphorus (milk)
• Food additives
• Tannic acid (found in tea and coffee)
Iron Deficiency
• Iron deficiency is the depletion of iron stores in
the body
• Iron deficiency anemia is the deletion of body’s
stored iron accompany by low hemoglobin and
hematocrit
• High risk for iron deficiency
– Women in their reproductive years
– pregnant women
– Infants and young children
– Teenagers
• Blood losses through bleeding
• Microcytic anemia – small pale red blood cells
• Iron deficency and pica
Iron
Deficiency – Iron deficiency is the most
common form of nutritional disorder in the
world
• Iron deficiency anemia:
–
–
–
–
–
Decrease in hemoglobin levels
Diminish delivery of oxygen through the body
weakness, fatigue, headaches
Weak immune system
Pre-menopausal women, pregnant women,
preterm and low birth weight children and
toddlers are all at risk
– Pica is craving for non nutrient substances like
chalk or ice, common among pregnant women
Iron
Toxicity from supplementation can
cause:
• Constipation, nausea, vomiting, diarrhea
• In the U.S. accidental consumption of
supplements containing iron is leading cause of
poisoning deaths in children under age 6
• Ingestion of as little as 2200mg as been shown to
be fatal
• The FDA requires warning label on iron
supplements that contain 30mg of iron or more
• Iron overload (hemochromatosis)– excessive
storing of iron over several years
Iron
• Food sources
– About half of Americans get their iron
from enriched bread and other grains
– Red meats, fish, poultry, shellfish, eggs
contributes about 12%
– Cooking food in iron skillet can increase
can increase non-heme iron content
Iron
• RDA
– Men: 8 mg/day
• Adult male consume over 16mg on average
– Women (19-50 years): 18 mg/day to cover
loss during menstruation
• Consume about 70% (13mg) of recommended intake
on average
– Women (51+ years): 8 mg/day
– Pregnant women: 27 mg/day
– Vegetarians require 1.8 time higher than non
vegetarians due to components in plan foods
that reduce absorption of iron
• Upper level for adults: 45 mg/day
Zinc
•
•
•
•
Zinc is found in every cell of the body
It is involved in more than 100 enzymes
Not considered essential until 1974
Roles
– Needed for DNA synthesis, and for growth and
development
– Helps keep immune system healthy
– Helps in wound healing by reducing
inflammation that usually accompanies wounds
– Helps fight age-related macular degeneration
(AMD) by working with enzymes needed to
produce active c=vitamin A in the eyes
Zinc
• Rate of absorption varies from 15 to
40%
• During digestion zinc is released in the
pancreas and travel to the small
intestine with dietary zinc
• Zinc is excreted primarily in feces
• Zinc is transported by albumin into the
bloodstream
• Large dose of zinc inhibit iron
absorption due to iron binding to
transferrin (protein that carries iron)
Zinc
• Deficiency symptoms
– Hair loss
– Loss of appetite
– Impaired taste of foods
– Delayed sexual maturation
– impotence
• Significant sources
– Protein-containing foods
– Red meats, shellfish
– Whole grains
Zinc
• RDA
–
–
–
–
Men: 11 mg/day
Women: 8 mg/day
Upper level for adults: 40 mg/day
Vegetarians can have as much as 50% higher
need for zinc
• Toxicity symptoms
–
–
–
–
Stomach pains
Nausea, vomiting, diarrhea
Can lower copper level in the body
More than 300mg can suppress the immune
system and lower HDL (good cholesterol)
Iodine
• Iodine is an essential mineral for the
thyroid glands
• The thyroid need iodine to make certain
hormones that regulate the majority of
the body’s cells
–
–
–
–
–
–
Regulate body temperature,
reproduction,
growth,
blood cell production,
nerve and muscle function
Influence the amount of energy released
during basal metabolism
Iodine
Deficiency
• Hypothyroidism – under activity
of the thyroid hormone
• Goiter – early sign of thyroid
deficiency
• Mental and physical retardation
in babies born to mothers with
iodine deficiency during
pregnancy (cretinism)
Iodine
• Toxicity
– overactive thyroid gland
– Reduce the synthesis and release of thyroid
hormones
• RDA for adults: 150 g/day
• Upper level: 1100 g/day
• Significant sources
–
–
–
–
Iodized salt,
seafood, bread,
dairy products,
plants grown in iodine-rich soil and animals fed
those plants
Copper
• Chief functions in the body
– Necessary for absorption and use of
iron in the formation of hemoglobin
– Part of several enzymes
• RDA for adults: 900 g/day
• Upper level for adults:
10,000 g/day (10 mg/day)
Copper
• Significant sources
– Seafood
– Nuts, whole grains, seeds, legumes
• Deficiency symptoms
– Anemia, bone abnormalities
• Toxicity symptoms
– Liver damage
Fluoride
Fluoride is the safe form of fluorine, a
poisonous gas
Functions
• Protect against tooth decay
• Helps repair the enamel of the tooth that
has already started to erode
• Interferes with the ability of the bacteria to
metabolize in carbohydrate, reducing the
amount of acid
Fluoride
• AI
– Men: 3.8 mg/day
– Women: 3.1 mg/day
• Upper level for adults: 10 mg/day
• Significant sources
– Drinking water (if fluoride containing
or fluoridated)
– Tea, seafood
Fluoride
• Deficiency symptoms
– tooth decay, especially with children
• Toxicity symptoms
– Fluorosis (pitting and discoloration of
teeth)
– Occurs when teeth are forming, only
infants and children up to age 8 are
at risk
– May occur from swallowing
toothpaste or excessive use of dental
products