Transcript The Micronutrients and Water

The Micronutrients and Water
Chapter 2 Part 1
Micronutrients
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Micronutrients include vitamins and
minerals.
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They do not provide energy.
They are needed in small quantities.
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“micro”
Deficiencies and excesses of the
micronutrients can affect health.
Vitamins
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Vital amines (false name)
13 known specific nutrients
Involved in almost every metabolic
process
Body cannot make (indispensible)
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Except vit D
Fat soluble
Water soluble
Vitamins
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Vitamins are organic substances.
Plants manufacture vitamins during
photosynthesis.
Vitamins have no particular chemical
structure in common.
Provitamins are inactive precursors to
vitamins.
Roles of Vitamins
Roles of Vitamins
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Serve as essential links and regulators
in numerous metabolic reactions that
release energy from food
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Regulate metabolism
Control process of tissue synthesis
Protect the cells’ plasma membrane
Classifications of Vitamins
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Fat-soluble
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Vitamins A, D, E, and K
Water-soluble
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Vitamin C
B-complex
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Thiamine (B1), riboflavin (B2), pyridoxine (B6),
niacin (nicotinic acid), pantothenic acid,
biotin, folic acid, and cobalamin (B12)
Fat-Soluble Vitamins
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Dissolve and stored in the body’s fatty
tissues
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A, D in liver (K)
E in fatty tissues
Dietary lipids are a source of fatsoluble vitamins.
Should not be consumed in excess
without medical supervision
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Are not excreted easily from the body
Water-Soluble Vitamins
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Act largely as coenzymes
Disperse readily in the body fluids
Excess intake is voided in the urine.
Marginal deficiencies could develop
within about 4 weeks of inadequate
intake.
•
With well-balanced diet, little chance of
long-term vitamin deficiency.
Coenzymes
The Vitamins
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The B Vitamins

Coenzymes
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Thiamin
• Other names: Vitamin B1
• 1998 RDA
– men: 1.2 mg/day
– women: 1.1 mg/day
• Chief functions in the body
– Part of coenzyme TPP (thiamin
pyrophosphate) used in energy metabolism
(pyruvate to acetyl CoA conversion)
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Thiamin
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Deficiency disease
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Beriberi ( I can’t, I can’t); when they
polished the rice
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Deficiency symptoms
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Wet: with edema (due to heart failure)
Dry: with muscle wasting (nervous sys damage)
Enlarged heart, cardiac failure
Muscular weakness
Apathy, poor short-term memory,
confusion, irritability
Anorexia, weight loss
Toxicity symptoms: none reported
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Thiamin
Sources
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Riboflavin
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Riboflavin
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
Other names: Vitamin B2
1998 RDA
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Men: 1.3 mg/day
Women: 1.1 mg/day
Chief functions in the body

Part of coenzymes FMN (flavin
mononucleotide) and FAD (flavin
adenine dinucleotide) used in energy
metabolism.
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Riboflavin
Sources
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Niacin
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Other names
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Precursor: dietary tryptophan
1998 RDA
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Nicotinic acid
Nicotinamide
Niacinamide
Vitamin B3
Men: 16 mg NE/day
Women: 14 mg NE/day
Upper level for adults: 35 mg/day
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Niacin
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Chief functions in the body
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Part of coenzymes NAD
(nicotinamide adenine dinucleotide)
and NADP (its phosphate form) used
in energy metabolism
Deficiency disease: pellagra
Deficiency symptoms
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Diarrhea, abdominal pain, vomiting
Depression, apathy, fatigue, loss of
memory, headache
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Niacin
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Toxicity symptoms
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Painful flush, hives, and rash (“niacin
flush”)
Excessive sweating
Blurred vision
Liver damage, impaired glucose
tolerance
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Niacin
Sources
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Biotin
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1998 adequate intake (AI)
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Adults: 30 g/day
Chief functions in the body
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Part of a coenzyme used in energy
metabolism (pyruvate to oxaloacetate), fat
synthesis, amino acid metabolism, and
glycogen synthesis
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Pantothenic Acid
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1998 adequate intake (AI)

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Adults: 5 mg/day
Chief functions in the body

Part of coenzyme A, used in energy
metabolism
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Vitamin B6
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Other names
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1998 RDA
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Pyridoxine
Pyridoxal
Pyridoxamine
Adults (19-50 years): 1.3 mg/day
Upper level for adults: 100
mg/day
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Vitamin B6
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Chief functions in the body
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Part of coenzymes PLP (pyridoxal
phosphate) and PMP (pyridoxamine
phosphate) used in amino acid and
fatty acid metabolism
Helps to convert tryptophan to niacin
and to serotonin
Helps to make red blood cells
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Vitamin
B6
Sources
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Folate
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Neural tube defects
 Spina bifida
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Folate: In Summary
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Chief functions in the body
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Part of coenzymes THF
(tetrahydrofolate) and DHF
(dihydrofolate) used in DNA
synthesis and therefore important in
new cell formation
Significant sources
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Fortified grains
Leafy green vegetables, legumes,
seeds
Liver
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Folate
Sources
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Vitamin B12
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Activation
 Folate
Absorption
 HCl: with pepsin, helps
“release” B12
 Intrinsic factor: binds to B12,
which helps small intestinal
receptors to “recognize” B12
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Vitamin B12
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Deficiency of folate or B12
produces pernicious anemia
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Vitamin B12: In Summary
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Other names: cobalamin (and
related forms)
1998 RDA
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Adults: 2.4 g/day
Chief functions in the body
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Part of coenzymes methylcobalamin
and deoxyadenosylcobalamin used in
new cell synthesis
Helps to maintain nerve cells
Reforms folate coenzyme
Helps to break down some fatty
acids and amino acids
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Vitamin B12: In Summary
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Significant sources
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Animal products (meat, fish, poultry,
shellfish, milk, cheese, eggs)
Fortified cereals
Easily destroyed by microwave
cooking
Deficiency disease: pernicious
anemia
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Vitamin C
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Other name: ascorbic
acid
2000 RDA
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Men: 90 mg/day
Women: 75 mg/day
Smokers: + 35 mg/day
Upper level for adults:
2000 mg/day
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Vitamin C
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Chief functions in the body
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Collagen synthesis
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Strengthens blood vessel walls, forms
scar tissue, provides matrix for bone
growth
Antioxidant
Thyroxin synthesis
Amino acid metabolism
Strengthens resistance to infection
Helps in absorption of iron
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Vitamin C
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Deficiency disease: scurvy
Deficiency symptoms
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Anemia (small-cell type)
Atherosclerotic plaques
Pinpoint hemorrhages, bone fragility,
joint pain
Poor wound healing, frequent
infections, bleeding gums, loosened
teeth
Muscle degeneration and pain,
hysteria, depression, rough skin,
blotchy bruises
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Vitamin C
Sources
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Vitamin A And
Beta-Carotene
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Retinoids and carotenoids
 Vitamin A activity
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Vitamin A And
Beta-Carotene
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Vitamin A And
Beta-Carotene
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Retinol-binding protein (RBP)
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Picks up Vit. A from liver and
transports it via the blood to the
cells of the body
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Vitamin A And
Beta-Carotene
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Roles in the body
 Vitamin A in vision
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
Roles in the body
 Vitamin A in protein synthesis
and cell differentiation
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Vitamin A And
Beta-Carotene
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Roles in the body
 Vitamin A in reproduction and
growth
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Retinol: sperm production; in
women: fetal development
Beta-carotene as an antioxidant
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In Summary
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Other names
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Retinol
Retinal
Retinoic acid
Precursors are carotenoids such
as beta-carotene
2001 RDA
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Men: 900 g RAE/day
Women: 700 g RAE/day
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In Summary
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Significant sources
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Retinol: fortified milk, cheese,
cream, butter, fortified
margarine, eggs, liver
Beta-carotene: spinach and
other dark leafy greens;
broccoli, deep orange fruits
(apricots, cantaloupe) and
vegetables (squash, carrots,
sweet potatoes, pumpkin)
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Vitamin D
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Other names
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Calciferol
1,25-dihyroxy vitamin D
(calcitriol)
Animal version: vitamin D3 or
cholecalciferol
Plant version: vitamin D2 or
ergocalciferol
Precursor is the body’s own
cholesterol
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Vitamin D
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1997 adequate intake (AI)
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19-50 years: 5 g/day
51-70 years: 10 g/day
more than 70 years: 15 g/day
Upper level for adults: 50
g/day
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Vitamin D
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Chief functions in the body
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Mineralization of bones (raises
blood calcium and phosphorus
by increasing absorption from
digestive tract, withdrawing
calcium from bones, stimulating
retention by kidneys)
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Vitamin D
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Significant sources
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Synthesized in the body with
the help of sunlight
Fortified milk, margarine,
butter, cereals, and chocolate
mixes
Veal, beef, egg yolks, liver, fatty
fish (herring, salmon, sardines)
and their oils
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Vitamin D
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Deficiency
diseases
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Rickets
Osteomalaci
a
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Vitamin E
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Other name: alpha-tocopherol
2000 RDA
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Adults: 15 mg/day
Upper level for adults: 1000
mg/day
Chief function in the body
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Antioxidant (stabilization of cell
membranes, regulation of
oxidation reactions, protection
of polyunsaturated fatty acids
and vitamin A)
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Vitamin E
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Vitamin E
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Significant sources
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Polyunsaturated
plant oils
(margarine, salad
dressings,
shortenings)
Leafy green
vegetables, wheat
germ, whole
grains, liver, egg
yolks, nuts, seeds
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Vitamin E
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Easily destroyed by heat and
oxygen
Deficiency symptoms
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Red blood cell breakage
Nerve damage
Toxicity symptoms
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Augments the effects of
anticlotting medication
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Vitamin K
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Other names
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Phylloquinone
Manaquinone
Menadione
Naphthoquinone
2001 AI
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Men: 120 g/day
Women: 90 g/day
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Vitamin K
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Chief functions in the body
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Synthesis of blood-clotting
proteins and bone proteins that
regulate blood calcium
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Vitamin K
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Significant
sources
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Bacterial
synthesis in the
digestive tract
Liver
Leafy green
vegetables,
cabbage-type
vegetables
Milk
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Vitamin K
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Deficiency symptoms
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Hemorrhaging
Toxicity symptoms
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None known
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