Bioavailability: refers to the rate and extent a nutrient is absorbed and used and is effected by

• digestion / GI transit time
• nutritional status
• what foods are consumed at the same time
• preparation: cooked, raw, etc...
• source: naturally occurring, fortified, synthetic

Precursors: substances that precede others - ie: provitamins are inactive forms of vitamins in some food (which become active in the body after ingestion)

Stability: some vitamins can be easily destroyed if overcooked or exposed to excessive oxygen

Solubility:  determines classification

• Water soluble (hydrophilic): B vitamins and vitamin C
  • found in watery compartments of food
  • moves directly into the blood after being absorbed
  • can travel freely in the blood
  • freely circulate in watery compartments of the body's cells
  • regulated and excreted when in excess by the liver easily
• Fat soluble (hydrophobic): Vitamins A, D, E, and K
  • found in fats and oils of food
  • carried through the lymph to the blood
  • many times require proteins for transport in the blood
  • trapped in cells associated with fat
  • less readily excreted - tend to stay in fat storage sites

Toxicity: when consumed in excess amounts, toxic levels of some (mostly fat soluble) vitamins can cause adverse side effects - sometimes life-threatening  [TOP]

Fat Soluble

Forms / Names
Beta-carotene or Retinol

Functions
Vision, reproduction, growth, tissue repair, bone formation, hormone synthesis, antioxidant (in beta-carotene form).

Deficiencies
Night blindness, impaired bone growth, susceptibility to infection, rough skin

Toxicity of Retinol
Red Blood Cell damage, abdominal cramps, blurred vision, irritability, bone pain, loss of appetite, diarrhea, nosebleeds, growth retardation, hair loss, skin rashes, dry skin, liver disease, nausea, vomiting, headache and increased cerebrospinal pressure.

Recommended Intakes
RDAs:
1000 µg Retinol Equivalents (RE)/day for adult males
800 µg RE for adult females
1300 µg RE and 1200 µg RE for adult females during the 1st and 2nd six months of lactation
375 µg RE for infants
400 µg RE for children ages 1-3
500 µg RE for children ages 4-6
700 µg RE for children ages 7-10

Food Sources
Fortified foods (mostly dairy), liver, eggs, green leafy vegetables, oranges and red fruits and vegetables. [TOP]
 

Type
Fat Soluble

Forms / Names
Cholecalciferol, Ergocalciferol

Functions
Calcium and phosphorus metabolism, bone formation, calcium absorption.

Deficiencies
Rickets in children, osteomalacia in adults, abnormal growth, joint pain, soft bones, muscle weakness, bony deformities, neuromuscular irritability.

Toxicity
Raised blood calcium, constipation, weight loss, irritability, weakness, nausea, kidney stones, mental retardation, physical retardation, hypercalcemia, hypercalciuria, soft tissue calcifications.

Recommended Intakes
RDAs: (with daily sunlight exposure)
200 IU for adults (5 µg) / day
300 IU for infants birth to 6 months / 7.5 µg
400 IU for children ages 1-24 / 10 µg

Food Sources
Fortified milk/dairy, fish, liver, eggs.

Non-Food Sources
Sunlight. [TOP]
 

Type
Fat Soluble

Forms / Names
Tocopherols and Tocotrienols

Functions
Antioxidant, cellular membrane stability, red blood cell protection.

Deficiencies
Muscle wasting, red blood cell damage, hemolytic anemia, hemorrhaging, reproductive failure, neurological abnormalities.

Toxicity
Rare.  Possible general discomfort.

Recommended Intakes

New DRIs:
15 mg/day for all adults

Old RDAs:
10 mg/day for adult males
8 mg/day  for adult females

Food Sources
Vegetable and seed oils, nuts, whole grains, wheat germ, green leafy vegetables. [TOP]
 

Type
Fat Soluble

Functions
Blood clotting, protein synthesis, blood calcium regulation

Deficiencies
Hemorrhaging

Toxicity
Jaundice

Recommended Intakes
RDAs:
70-80 µg /day for adult males
60-65 µg /day for adult females
55 µg /day for children ages 15-18
45 µg /day for children ages 11-14
30  µg /day children ages 7-10
20 µg /day children ages4-6
15 µg /day children ages1-3
10 µg /day infants ages six months - one year
5  µg /day infants from birth - six months
 

Food Sources
Dark green vegetables, liver, cabbage-type vegetables, spinach, broccoli, kale

Non-Food Sources
Intestinal flora - bacterial synthesis in the digestive tract  [TOP]
 

Type
Water Soluble

Forms / Names
Ascorbic Acid

Functions
Antioxidant, collagen synthesis, wound healing, infection resistance, iron absorption

Deficiencies
Anemia, scurvy, depression, infections, bleeding gums, muscle degeneration, poor wound healing, atherosclerotic plaques, capillary hemorrhaging

Toxicity
Nausea, diarrhea, red blood cell damage, nosebleeds, abdominal cramps

Recommended Intakes

NEW DRIs:
75 mg for adult women
90 mg for adult men

Old RDAs:
60 mg for adults
75-95 mg for pregnant and lactating women
35-40 mg/day in children, ages 1-3
The requirement in smokers may be increased to 100 mg/day.
 

Food Sources
Citrus fruits, berries, , papayas, melons, tomatoes, potatoes, green peppers and leafy gree [TOP]
 

Type
Water Soluble

Forms / Names
Vitamin B1

Type
Water Soluble

Forms / Names
Vitamin B2

Type
Water Soluble

Forms / Names
Nicotinic acid, Nicotinamide

Functions
Participates in enzymatic energy release of energy nutrients; promotes health of nerves, skin and digestive system

Deficiencies
Pellagra, dermatitis on body parts exposed to sun, diarrhea, dementia, loss of appetite, weakness, mental confusion, irritability, fatigue

Toxicity
Low blood pressure, skin flushing, headaches, ulcer irritation,  hepatic/liver abnormalities, nausea

Recommended Intakes
RDAs:   NE =  niacin equivalents
13-19 NE/day for adults
additional 2 NE/day during pregnancy
additional 5 NE/day during lactation
5-6 NE/day for infants
9-13 NE/day for children, ages 1-10

Food Sources
Yeast, meats, eggs, poultry, liver, cereal, legumes, seeds, milk, green leafy vegetables, fish, nuts [TOP]
 

Type
Water Soluble

Forms / Names
Pyridoxine, pyridoxine hydrochloride, pyridoxal and pyridoxamine

Functions
Fat and protein metabolism, antibody formation, red blood cell formation, involved in converting tryptophan to niacin

Deficiencies
Central nervous system disorders, seizures, dermatitis, angular stomatitis, anemia, muscle weakness, kidney stones

Toxicity
Depression, fatigue. irritability, headaches, can be neurotoxic

Recommended Intakes
RDAs:
2.0  mg/d for adult males, ages 15+
1.6  mg/d for adult females, ages 15+
2.2 mg/d during pregnancy
2.1 mg/d during lactation
1.7 mg/d for male children, ages 11-14
1.4 mg/d for female children, ages 11-14
1.4 mg/d for children, ages 7-10
1.1 mg/d for children, ages 4-6
1.0 mg/d for children, ages 1-3
0.6 mg/d for infants six months to one year
0.3 mg/d for infants birth to six months
 

Food Sources
Meats, fish, green leafy vegetables, legumes, bananas, whole grains [TOP]
 

Type
Water Soluble

Forms / Names
Folic acid,  folacin

Functions
Red blood cell formation, new cell division, protein metabolism

Deficiencies
Anemia, diarrhea, smooth tongue, depression, heartburn

Toxicity
Insomnia, irritability, diarrhea, may mask B12 deficiency

Recommended Intakes
RDA:
400 µg/day for adults
400 µg/d for adult females of childbearing age *see here
600 µg/d during pregnancy
500 µg/d during lactation
150 µg/d for children ages 11-14 years
100 µg/d for children ages 7-10 years
75 µg/d for children 4-6 years
50 µg/d for children 1-3 years
35 µg/d for children six months to 1 year
25 µg/d for infants birth to six months

Food Sources
Green leafy vegetables, liver, legumes, seeds, and enriched breads, cereals, rice, and pasta. [TOP]
 

Type
Water Soluble

Forms / Names
Vitamin B12, Cobalamin

Functions
Red blood cell formation, nervous system maintenance

Deficiencies
Anemia, nerve degeneration, paralysis, smooth tongue, fatigue, dementia, depression

Toxicity
None known

Recommended Intakes
RDAs:
(Strict vegetarians should consult a physician or RD for B12 supplements)
2.0 µg/day for adolescents and adults
2.2 µg/d during pregnancy
2.6 µg/d during lactation
1.4 µg/d for children, ages 7-10
1.0 µg/d for children, ages 4-6
1.0 µg/d for children, ages 1-3
0.5 µg/d for infants six months to one year
0.3 µg/d for infants birth to six months

Food Sources
Found almost exclusively in animal products.
Meats, fish, poultry, milk, eggs, yeast, cheese [TOP]
 

Type
Water Soluble

Functions
Coenzyme in energy metabolism

Deficiencies
Rare. Nausea, fatigue, difficulty sleeping

Toxicity
Possible diarrhea

Recommended Intakes
Estimated Safe and Adequate Intake:
4-7 mg/day for adults
4-7 mg/d for children ages 11+ years
4-5 mg/d for children 7-10 years
3-4 mg/d for children 4-6 years
3 mg/d for children six months to 3 years
2 mg/d for infants birth to six months

Food Sources
Widespread in foods [TOP]
 

Type
Water Soluble

Forms / Names
Vitamin H and Coenzyme R

Functions
Coenzyme in energy metabolism, glycogen and fat synthesis

Deficiencies
Loss of appetite, nausea, depression, muscle pain, hair thinning, weakness, fatigue, rash, loss of hair, hallucinations

Toxicity
None known

Recommended Intakes
Estimated Safe and Adequate Intake:
30-100 µg/day for adults
30 µg/d for children ages 7-10 years
25 µg/d for children 4-6 years
20 µg/d for children 1-3 years
15 µg/d for children six months to 1 year
10 µg/d for infants birth to six months

Food Sources
Widespread in foods [TOP]