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Chapter 3
The Micronutrients of Balanced
Meals: Vitamins, Minerals, and
Phytochemicals
Introduction
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Vitamins, minerals, and phytochemicals,
as found in foods, are necessary to help
the body function in a variety of ways.
Supplements have been available since
the early 20th century, but much remains
to be known about when supplements are
helpful and harmful.
A well-balanced diet can provide all
needed nutrients, although supplements,
used wisely, can serve a vital role.
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Plants Produce Vitamins
Through Their Genetic Makeup
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Vitamins are organic and can be broken
down
Vitamins are grouped based on their ability
to dissolve in fat or water
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Fat-soluble vitamins—A, D, E, K (stored in the
body; require dietary fat intake for absorption)
Water-soluble vitamins—Bs, C (not stored in
the body; needed on a daily basis)
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Medical Causes of Vitamin
Deficiency
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Fat-soluble vitamins (A, D, E, K)
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Fat-malabsorption due to:
• Cystic fibrosis
• Surgical removal of the ileum (lowest portion of the small
intestine)
• Medications/fat substitutes (Olestra) that inhibit absorption
of fat
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Water-soluble vitamins (B vitamins, vitamin C)
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Medications such as proton pump inhibitors and
anti-epileptic medications
Excess urination due to diuretic treatment or excess
fluid intake
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Vitamin A and Beta Carotene
Two types of vitamin A:
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Precursor—carotene (deep orange color as found in
carrots, sweet potatoes, cantaloupe; also found in dark
green, leafy vegetables); the liver uses the precursor form to
make vitamin A
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Oranges are the exception to the color rule
Because the precursor form allows production of vitamin A, it is
simply referred to as vitamin A
Preformed—retinol/retinol palmitate (liver, supplements);
also found in water-soluble forms (the most toxic and form
typically used in food fortification)
Carotene—harmless but can turn skin to orange color;
avoidance of carotene allows return to normal color
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Functions of Vitamin A
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Vitamin A is needed for:
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Retinal health and night vision
Promoting good immunity
Maintaining skin health (epithelial tissue)
Promoting bone growth
Reproduction
Preventing a form of iron deficiency
(Kelleher and Lonnerdal, 2005)
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Vitamin D:
“Sunshine Vitamin”
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Dietary intake is either from fortified foods (milk) or as
naturally found in fish liver (cod liver oil or whole fish [with
liver])
 Cod liver oil advised by doctors to prevent rickets in
children in the early 20th century
Sun allows conversion in the skin of cholesterol into vitamin D
 Melanin interferes with sun’s ability to produce vitamin D
Compromise message of sun exposure to prevent skin cancer
while meeting vitamin D needs
 20 minutes of sun exposure without sunscreen lotion
Latitudes north of Philadelphia: the sun is too weak to make
vitamin D in the skin from September through March
 Increased intakes of at least 800 IU advised in Northern
climates; may be as many as 2000 IU needed
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Functions of Vitamin D
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Allows calcium absorption for strong bones
and teeth and allows the body’s use of calcium
Needed for a strong and healthy immune
system
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Helps prevent autoimmune diseases (type 1
diabetes, multiple sclerosis [MS]—Olympic skiers
have the highest rate of MS)
May help prevent “winter blues,” or seasonal
affective disorder (SAD)
Helps regulate blood pressure and acts as a
tumor suppressant to help prevent cancer
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Vitamin D Deficiency
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Can cause bone loss, rickets, and secondary
hyperparathyroidism
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Breastfed infants are advised to take vitamin D supplements to
help prevent rickets
 Screening of vitamin D status advised for high-risk groups,
including those treated for epilepsy (Nettekoven et al., 2008)
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Other associations with deficiency:
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Impaired neuromuscular function with muscle pain
Tuberculosis and/or impaired immunity
Rheumatoid arthritis
Multiple sclerosis (MS)
Inflammatory bowel disease
Hypertension
 Diabetes
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Vitamin E: Tocopherol
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Originally discovered as necessary for rat
reproduction
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Appears necessary for fetal growth
An antioxidant vitamin—helps prevent
cellular damage caused by oxidation
Helps regulate cell signaling and gene
expression
Sources—nuts and peanut butter,
vegetable oils, wheat germ
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FYI
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Vitamin E during pregnancy may reduce
risk of childhood asthma (Seaton, 2008)
Vitamin E inadequacy during pregnancy
may be linked with low birth-weight and
smaller head circumference (Masters et al., 2007)
Excess or deficiency of vitamin E appears
linked to inflammation (Wagner et al., 2008; Gianello et al.,
2007)
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Vitamin K: Phylloquinone
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Allows for clotting of blood
Involved in vascular function and bone metabolism
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Evidence it supports bone growth
Found in green leafy vegetables, green tea, cauliflower,
butter, soybean oil, legumes
Intestinal bacteria produce vitamin K
Only concern is usually related to Coumadin (an anticlotting
medication), which necessitates stable intake of vitamin K;
antibiotics used to treat gram-negative bacteria can cause
vitamin K deficiency, with potential for increased effect of
Coumadin
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Deficiency Concerns of Vitamin K
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Newborn infants generally require injection at birth
because of lack of intestinal bacteria
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Intracranial hemorrhage (ICH) at 1 to 2 months of age;
signs and symptoms: vomiting, absence of pupil
reaction, fontanel bulging, convulsions, irritability with
coma
Vitamin K supplement needed for infants with
antibiotic treatment, diarrhea, liver problems, or
breastfeeding
With long-term use of antibiotics for gramnegative bacteria for children and adults,
supplementation is advised
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Water-Soluble Vitamins
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Water-soluble vitamins
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B vitamins
B1: thiamin
B8: biotin*
B2: riboflavin
B9: folate*
B3: niacin
B12: cobalamin
B5: pantothenic acid*
choline
B6: pyridoxine and related substances
*not generally referred to numerically
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Vitamin C (ascorbic acid)
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B Vitamins
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Easily destroyed with cooking
Serve as cofactors to allow cellular
metabolism; needed for energy production
in the mitochondria
Most B vitamins found in whole grains and
legumes
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B2 found mainly in milk, eggs, peanuts, organ
meats
B3 requirement met, in part, by production from
the amino acid tryptophan
B12 found in animal products only
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Hyperhomocysteinemia
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A condition related to deficiency of B vitamins
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Linked with neurodegenerative diseases and
dementia (Hermann et al., 2007)
An increased intake of the B vitamins
(especially folate, B6, and B12) may improve
brain function
Other conditions that may benefit with
increased intake of B vitamins include
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Parkinson’s disease with L-dopa medication
Multiple sclerosis
Epilepsy and Acid-Reflux due to medications
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Folate: Names for “Foliage”
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May be referred to as vitamin B9
Named for a chief source of folate: foliage or dark-green,
leafy vegetables
Active form: folic acid, formed with vitamin C
Aids in metabolism of DNA, promotes chromosomal health,
red blood cell formation
Helps prevent spina bifida if consumed in first few days after
conception
Women of childbearing years advised to consume 400 mcg
folate daily
Processed white-grain products are fortified with folate to
lower the risk of infants born with spina bifida (a form of
neural tube defect)
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Vitamin B12: Cobalamin
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Important in DNA synthesis and may affect bone
formation (Tucker et al., 2005)
Found in animal-based foods only; contains the mineral
cobalt (hence the name cobalamin)
Deficiency causes irreversible nerve damage,
megaloblastic anemia
Vitamin B12 supplementation may not be adequate;
intramuscular B12 injections commonly provided for the
elder population or persons with malabsorption (e.g.,
after gastric bypass surgery)
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Vitamin C (Ascorbic Acid): WaterSoluble Derivative of Glucose
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First vitamin identified from experience of “limeys” (British
sailors)—scurvy avoided by eating lemons (then called
limes)
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Scurvy = severe deficiency; mild deficiency related to bleeding
gums and/or loose teeth, easy bruising, pedal edema,
arthralgias (joint pain), and joint swelling
Acts as “glue” to hold body cells together
Promotes immunity and wound healing
Promotes bone growth, collagen, and growth of all body
tissues
Serves as an antioxidant to reduce levels of free radicals
(reactive oxygen species) for reduced risk of cellular
damage
Found in fruits and vegetables only (e.g., leafy greens,
citrus, melons, potato, green peppers, berries, tomatoes)
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General Functions of Minerals
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Serve as building materials and found in
all body constituents
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Bone and teeth (calcium, phosphorus)
Hair, nails, and skin (sulfur)
Blood (iron in hemoglobin)
Serve as regulators of body metabolism
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Muscle contraction and relaxation (calcium,
potassium)
Blood clotting (calcium)
Coenzymes (zinc, magnesium, potassium)
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Calcium
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Chief mineral in bones and teeth
Allows for muscle contraction and function of
nervous system and blood coagulation
Found in high amounts in milk, soybeans, bones
(i.e., bones of salmon/anchovies), some leafy
greens: collards, seaweed, hard water
Chief age for bone mineralization <35 years
Osteoporosis risk factors—low calcium and/or
vitamin D intake, Caucasian or Asian heritage,
low body weight, rheumatoid arthritis, steroids,
smokers, alcohol abusers and alcoholics
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Magnesium: Part of the
Chlorophyll Molecule
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Involved in strong bone formation
Critical to 300 metabolic enzymes
Regulates heartbeat, helps transport potassium
and calcium, helps with muscle contractions,
lowers inflammation
Involved in energy metabolism
Can serve as a calcium channel blocker (used to
control hypertension and migraines)
Bound with chlorophyll (green leafy vegetables)
and also found in milk, legumes, fish, eggs
Can be lost with diuretics and excess urination (as
found with uncontrolled diabetes)
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Phosphorus
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Helps enzymes act in energy metabolism
Only second to calcium in body content
Primarily found in bones
A ratio of 1.5 calcium to 1.0 phosphorus
intake advised in early infancy to prevent
tetany
Widely found in foods; added to
carbonated beverages
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Potassium
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Promotes regular heartbeat; altered levels
contribute to irregular heart beat
A key “electrolyte” (related to electric flow)
Critical for intracellular enzyme functioning
Found in all foods; easy to obtain; very
high amounts in green leafy vegetables,
whole grains, milk, citrus fruits, bananas,
potatoes, tomatoes
Excess avoided with kidney disease or use
of ACE inhibitor Rx (avoid potassium
chloride [KCl] in salt substitutes)
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High Potassium Foods >500 mg
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1 banana
1 cup tomato or orange juice
12 oz milk
1½ cups leafy green vegetables
1½ cups melon
1 cup beets
1 medium potato
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Sodium
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Serves as an essential electrolyte
Found in salt as sodium chloride (Na+Cl-), minor
amounts found in leafy green vegetables, milk, eggs,
meat; very low amounts in fruits and unprocessed
grains
1 teaspoon salt contains 2400 mg Na+
The Upper Limit (UL) of safety set at 2300 mg
The DASH diet (Dietary Approaches to Stop
Hypertension) advocates restriction of 1500 mg
“No added salt” diet defined as less than 4000 mg
Na+
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Chloride
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Found in extracellular fluids and serves as
an electrolyte
Found in gastric juice as part of
hydrochloric acid
Deficiency found in conjunction with
sodium depletion
Excess levels due to dehydration
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Fluorine
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Found in fluoride tablets and fluoridated
water as used to promote strong teeth
formation in children
Also found in fish, tea, and gelatin
Can be toxic and lead to mottling of teeth
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Iodine
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Found in thyroid hormones and involved in
general metabolism
Has an antioxidant function
Sea fish and seaweed naturally high in iodine;
iodized salt is an important alternative source
Deficiency states: hypothyroidism, goiter (see
slide)—linked with reduced IQ, and cretinism, a
form of mental retardation, of infants born to
women with iodine deficiency (now rare because
of iodized salt use)
Excess intake leads to hyperthyroidism
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Goiter: Caused By Iodine Deficiency
Goiter. (From Swartz MH: Textbook of physical diagnosis: history and
examination, ed 5, Philadelphia, 2006, Saunders.)
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Iron
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Carries oxygen in red blood cells
Prevents iron-deficiency anemia
Heme—animal sources: especially liver,
red meat; heme form readily absorbed
Nonheme—plant; need vitamin C source
to convert to heme form for enhanced
absorption
Iron frying pans are a source of iron, with
long duration of cooking and acidic foods
leading to highest iron absorption
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Iron Supplementation
or Fortified Foods
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Advised for those with iron-deficiency anemia as
determined with iron studies:
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Percent iron saturation
TIBC (total iron-binding capacity)
Transferrin levels (a protein that transports iron)
Ferritin (storage form of iron)
With high-risk populations: pregnancy, growing
children, women with menstrual cycle—related
imbalances, malabsorptive conditions
Excess can cause hemochromatosis and lead to
diabetes, liver, and heart damage; dx: transferrin
index >1.0 (serum iron/transferrin)
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Selenium
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An antioxidant mineral; helps prevent skin damage
from sun exposure
Found in high amounts in Brazil nuts
Deficiency related to cardiomyopathy (a form of heart
disease), loss of muscle strength (Beck et al., 2007), and
found with a form of anemia (Semba et al., 2007)
Toxicity found with hair loss, defects of fingernails
and toenails, anorexia, dermatitis, depression, organ
damage, and central nervous system problems,
including ataxia and respiratory disturbances
(Kaprara and Krassas, 2006)
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Zinc
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Critical for protein synthesis and cell division and
function; part of 300 proteins; promotes stable
DNA
Needed for bone growth, wound healing,
immunity, sexual development, smell acuity, taste
perception, promotes normal vitamin A levels
Part of 50 metabolic enzymes
Found in whole grains (germ), oysters, crabmeat,
organ meats, brewer’s yeast
As a trace mineral, toxicity is possible; can lead to
severe anemia due to low serum copper levels
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Phytochemicals: “Chemicals of Life”
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Vitamin-like substances recognized since
the 1990s
Includes lutein (found in green leafy
vegetables)
Lutein: essential to prevent macular
degeneration
Includes lycopene (found in tomatoes)
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Lycopene controls prostate tumors
Estimated 100 phytochemicals yet to be
identified
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Food Preparation Strategies to
Preserve Vitamin and Mineral
Content
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Store fresh produce to avoid wilting and/or drying out
Cook foods in whole pieces, as possible, to decrease
surface area for leaching of minerals into cooking
water
Steam or microwave to reduce leaching of minerals
Cover open containers of juice to preserve vitamin C
Avoid excessive stirring while cooking to minimize
exposure of vitamin C to air
Keep milk out of light to preserve vitamin B2 content
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Fortification Versus Enrichment
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Fortify—make stronger (e.g., iron-fortified
cereal)
Enrich—replace after removal by
processing (e.g., enriched white bread with
vitamins B1, B2, B3)
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