Vitamin A
(includes Provitamin A carotenoids that are dietary precursors of Retinol)
Functions:
Required for normal vision, gene expression, reproduction, embryonic development and immune function.
Selected Food Sources:
Liver, greens, carrots, apricots, sweet potatoes, dairy products, fish.
Adverse Effects Of Severe Deficiency:
Skin lesions, night blindness, dry eyes.
Potential Therapeutic Uses:
Gastric ulcer.
Toxic Effects Of Excess:
Specific birth defects, liver toxicity, hip fractures. Note: Toxic effects are observed with excess supplemental intake of preformed Vitamin A (Retinol) only. Adverse effects are not associated with supplemental intake of Provitamin A carotenoids. Individuals particularly susceptible to adverse effects of high intake of preformed Vitamin A include pregnant women, individuals with high alcohol intake, preexisting liver disease, hyperlipidemia, severe protein malnutrition, or women taking oral contraceptives.
Vitamin D (Calciferol)
Functions:
Maintains serum calcium and phosphorous concentrations.
Selected Food Sources:
Fish e.g. sardines, salmon, tuna, shrimp), sunflower seeds, liver, eggs, fortified milk products.
Adverse Effects Of Severe Deficiency:
Rickets characterized by malformation of the skeleton in children, and osteomalacia in adults.
Potential Therapeutic Uses:
Psoriasis, mood regulation during the winter, additional Vitamin D may be needed by patients on glucocorticoid therapy.
Toxic Effects Of Excess:
Hypercalcemia (high calcium in the blood), fatigue, headache, nausea, vomiting.
Vitamin E (alpha-tocopherol)
Functions:
Major function appears to be as a non-specific chain-breaking antioxidant.
Selected Food Sources:
Vegetable oils, unprocessed cereal grains, nuts (e.g. sunflower seeds, almonds), fruits, vegetables, meats, wheat germ, spinach, oatmeal, bran.
Adverse Effects Of Severe Deficiency:
Symptoms nonspecific and rare.
Potential Therapeutic Uses:
Myocardial infarction, intermittent claudication, premenstrual syndrome, dysmenorrhea, epilepsy, osteoarthritis. Note: A growing amount of evidence suggests that a Vitamin E supplement in a dose of 400 IU is likely to be beneficial to middle-aged and older individuals who are at increased risk of coronary disease (Willett & Stampfer, 2001).
Toxic Effects Of Excess:
Increases anticoagulant activity and may cause hemorrhagic toxicity. Note: Patients on anticoagulant therapy should be monitored when taking Vitamin E supplements. Also Vitamine E may be associated with increased blood pressure in individuals with hypertension.
Vitamin K
Functions:
Coenzyme during the synthesis of many proteins involved in blood clotting and bone metabolism.
Selected Food Sources:
Greens (e.g. broccoli, lettuce, spinach), cabbage, liver, cheese, butter.
Adverse Effects Of Severe Deficiency:
Rare but can occur in newborns causing easy bruisability.
Potential Therapeutic Uses:
Osteoporosis.
Toxic Effects Of Excess:
None known to date. Note: May affect clotting. Patients on anticoagulant therapy should be monitored when taking Vitamin K supplements.
References
Bland, J., Costarella, L., Levin, B., Liska, D., Lukaczer, D., Schiltz, B., & Schmidt, M. (1999). Clinical Nutrition: A Functional Approach. Gig Harbor, Washington: The Institute for Functional Medicine.
Gaby, A., & Wright, J. (2001). Nutrient Therapeutics : Nutrition Seminars.
Galland, L., & Buchman, D. D. (1988). Superimmunity for Kids. New York: Dell Publishing.
Mertz, W. (2000). Three Decades of Dietary Recommendations. Nutrition Reviews, 58(10), 324-331.
Willett, W., & Stampfer, M. (2001). What vitamins should I be taking, Doctor? New England Journal of Medicine, 345(25), 1819-1824.
Additional references were used for selected food sources (Bland et al., 1999; Galland & Buchman, 1988), potential therapeutic uses (Gaby & Wright, 2001), and toxic effects (Bland et al., 1999; Willett & Stampfer, 2001). Unless otherwise indicated, therapeutic uses are preliminary findings from one or more randomized, controlled, and/or double-blind studies. For more information regarding appropriate therapeutic doses for your condition, please arrange a consultation.
Read more > Table of Water Soluble Vitamins