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VITAMINS
Chapter 7
Learning Objectives



Explain the roles vitamins play in growth and good
health
List and describe the general functions and food
sources of fat-soluble vitamins and water-soluble
vitamins
List nutrients of concern that many Americans lack in
their diets and foods sources of these nutrients
Learning Objectives



Identify diseases caused by specific vitamin
deficiencies
Give tips to ensure that vitamin intake is sufficient
Identify cooking techniques that promote retention
of nutrients and those that cause nutrient loss from
foods
Vitamins


Essential for life and
health
Needs are small
 measured
in milligrams
(1/1000 of a gram) or
micrograms (1/1000
of a milligram)


Do not provide energy
Must be obtained
through food
Vitamins



All are organic compounds (contain carbon in their
structure)
Each vitamin has specific biological functions
Absence of each vitamin causes a specific deficiency
disease
Vitamins
13 are essential nutrients
 Must
come from food, not made in the body or
the body does not make enough
 Some
foods contain precursors that can be
converted in the body into vitamins
How the Body Uses Vitamins

Facilitate the processes by which other nutrients are:
 Digested
 Absorbed
 Metabolized
 Built

into body structures
Absence of a vitamin may cause a nutrient deficiency
(symptoms go away when vitamins are replenished
through diet)
Dangers of Excess Vitamins
Regular intake of high-dose supplements can be
dangerous, stressing liver and kidney
 Amounts
found in foods are safe
Fat-soluble vitamins are stored, toxicity possible
Supplements can interfere with meds/ alter lab tests
Two Types of Vitamins
1.) Fat Soluble
A, D, E, K
2.) Water Soluble
B vitamins -thiamin, riboflavin, niacin, folate, B12,
B6, Biotin, Pantothenic Acid
Vitamin C
Shortfall Nutrients – or Nutrients of Concern
Many people do not get adequate amounts of:
Vitamins
•
•
•
•
•
Minerals
Vitamin A
•
Vitamin C
•
Vitamin D*
•
Vitamin E
•
Vitamin K * Biggest nutrient gaps
Calcium*
Magnesium
Potassium *
Sodium*
Most diets also lacking dietary fiber
Most children and adults get too much sodium
FAT SOLUBLE VITAMINS
Fat Soluble Vitamins

Must be absorbed with fat

Stored in body fat and liver


Can build up to toxic levels, especially as
supplements in high doses
Vitamins A, D, E, K
Vitamin A
Antioxidant
Important roles in:
Vision
Bone and tooth growth
Reproduction
Cell functions
Immune system
Vitamin A

Retinol – active form
 liver,

egg yolks, dairy foods
Precursors include carotenoids – beta-carotene
which can be changed to active form in intestine
 bright

orange, yellow, green fruits and vegetables
Measured in retinol activity equivalents (RE)
 it
takes 12 mcg of beta-carotene to convert to 1 mcg retinol
Vitamin D
Some made in body with sunlight

Those who do not have skin exposed to sunlight need more
from diet
Acts like a hormone to help body absorb and regulate
calcium and phosphorus for strong bones, teeth and
muscle
Several forms:
 Calciferol
 D2
= ergocalciferol
 D3 = cholecalciferol
Vitamin D
Food sources
dairy and other fortified foods, egg yolks
butter, salmon, shrimp, mushrooms
100 IU in 1 cup milk
Deficiency
 fragile bones (osteoporosis)
soft bones (osteomalacia),
rickets
 increased cancer risk
depression, dementia
infections, gum disease
Vitamin D Requirements

Dietary Guidelines 2010
 600
IU children, most adults
 800 IU 70 and older
 1000 IU common supplementation recommendation

Up to 10,000 IU recommended to replenish for 1-2
weeks, then 1000 IU a day
Vitamin E - Tocopherol
Antioxidant in cell membranes
 especially lungs, brain, blood
Sources
Seeds, nuts, oils
fortified cereals, spinach
greens, pumpkin,
red bell peppers
Vitamin K - Phylloquinone

Intestines make about half of daily need


Needed to make the proteins involved in blood clotting


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Antibiotics reduce production
People who take meds to reduce blood clotting may need to adjust
intake of foods with vitamin K
Works with vitamin D to regulate blood calcium levels and
form bone
Food sources: green leafy veg (kale, greens, spinach, broccoli)
WATER SOLUBLE VITAMINS
Water Soluble Vitamins

Should be eaten daily

None or little stored

Excesses usually excreted through urine

Excess by supplements can cause increased
need
The B Vitamins
B Vitamins- General Functions
Metabolize Energy as Coenzymes(catalysts)
 release
calories from carbohydrates, protein and fats
Necessary to form red blood cells, heal wounds
Growth and development
Nerve functions
Proper digestion and appetite
B Vitamins Continued..



B vitamins found in most protein foods, leafy green
vegetables and grain (enriched) products
Enrichment- replaces thiamin, riboflavin, niacin
Generally little stored in the body
Oversupply or deficiency of one B vitamin can
effect need and use of others
Thiamin- B1


Critical role in energy
metabolism
Necessary for nerve
and heart function
Riboflavin- B2


Essential for metabolism of
carbohydrates to produce
energy
Milk, dairy and organ
meats are rich in riboflavin.
Light
destroys riboflavin.
Dairy should be in containers
that block light
Niacin- B3



Essential for metabolism of
carbohydrates to produce
energy
Body can make niacin by
converting tryptophan
(essential amino acid)
Niacin- high doses can
cause itching, flushing,
liver damage, high blood
sugar
Pantothenic Acid- B5
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Coenzyme in metabolic processes
Deficiencies Uncommon
No toxicities reported
Pyridoxine- B6
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Part of coenzyme necessary for metabolism of
carbohydrates, fat and protein
Necessary for nervous and immune system
Needed to convert tryptophan to niacin
Needed to make hemoglobin
Vitamin B12
Assists in bone-blood cell formation
 Pernicious anemia
Protects nerve fibers
Carbohydrate, protein, fat energy
metabolism
Needs intrinsic factor for absorption
Found in animal foods, fortified in
vegetarian.
Vegans should B12 supplement

Folate



Part of coenzymes
necessary to form DNA
Important for red blood
cell formation
Helps the body use
protein
Folate
 Food
Sources: legumes, oranges, green leafy
vegetables, enriched grains, asparagus, beets
 Some
lost in cooking
 Fortification-
adds folacin to grain foods.
 Folacin- more stable form
Critical in early pregnancy to prevent birth defects
 Part of coenzymes necessary to form DNA
 Women of child bearing age need supplemented
folate
Vitamin C – Functions

Helps make collagen (protein that stabilizes cell walls)

Helps keep gums and other tissues healthy

Aids in the healing of cuts and wounds

Helps the body absorb iron

Necessary to form thyroxin (hormone that regulates
metabolic rate)
Vitamin C
Shortfall nutrient because many Americans do not
eat enough fruits and vegetables

More needed by:
 Pregnant and lactating women
 Smokers
 Infections, fevers or wound healing
Food Issues Related to Vitamin C

Least stable nutrient. Destroyed by:
 Heat
 Leaching
into water while cooking
 Evaporation


Some juices and cereals fortified with Vitamin C
Supplements in high doses may cause gastrointestinal
symptoms
Vitamin C - Sources
Excellent sources include:
 Red bell peppers
 Oranges
 Grapefruit
 Broccoli
 Strawberries
 Papaya
 Brussels sprouts
 Fortified cereal or juices
 Tomatoes
Bioavailability is Influenced By:
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Nutritional status - if you are deficient your body
will absorb more
Other nutrients at the same meal- compete for
protein carriers needed for absorption
Nutrients in high dose supplements are not used as
well as nutrients in foods
Binders such as oxylates and phytates
Nutrient Bioavailability
Enhanced By:
The form of a nutrient;
•
vitamin D3 is absorbed better than D2
Fermentation processes
•
Ex. miso and tempeh, may improve iron bioavailability
Food preparation techniques
•
soaking and sprouting beans, grains and seeds, leavening
bread, can reduce binding of zinc by phytic acid and
increase zinc bioavailability
Organic acids
•
Ex. citric acid can enhance zinc absorption
Nutrient Bioavailability is Reduced By:
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Too much of one mineral can reduce the
absorption of another
Polyphenols in regular and herbal teas, coffee and
red wine bind some iron
Cooking softens cell walls of food so more nutrients
released
Nutrient Retention – Purchase Forms
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Canned: Canned foods are packed at their peak of
freshness and due to the absence of oxygen during
their storage period, canned fruits and vegetables
have a longer shelf life and remain relatively stable
up until opened.
Fresh: Fresh is best if consumed within a short time
after purchasing.
Frozen: Frozen products are packed at their peak of
nutrition and freshness. At least equal to fresh in
nutrients.
Nutrient Retention – In the Kitchen
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To retain nutrients: keep fresh produce chilled and
covered
Peel only when necessary. Peeling removes nutrients
and fiber of peel and under peel
Use pulp in citrus rather than straining it out
Purees and coulis increase nutrient availability by
breaking cell walls
Serve cooked vegetables immediately after
cooking – holding causes nutrient losses
Nutrient Retention – In the Kitchen
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Reserve liquids from cooked vegetables and add to
stocks, sauces, etc
Fry as little as possible. High heat destroys some
nutrients and creates free-radicals
Drain and rinse canned beans to reduce sodium
Drain brines from capers, pickles and other foods
packed in salted liquids
Chapter 7: Vitamins, Minerals and
Phytochemicals
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Discussion
Questions and Answers
Assignments