Megavitamin therapy is the use of large doses of vitamins, often many times greater than the recommended dietary allowance (RDA) in the attempt to prevent or treat diseases. It is typically used in complementary and alternative medicine by practitioners who call their approach "orthomolecular medicine", but also used in mainstream medicine for "exceedingly rare" genetic conditions which respond to megadoses of vitamins.^[1] In 2002, a review of these conditions identified about 50 which respond to "high-dose vitamin therapy".^[2] Further understanding of these conditions is expected to play a part in the emerging field of nutrigenomics.^[3]

Nutrients may be useful in preventing and treating some illnesses,^[4] but the conclusions of medical research are that the broad claims of disease treatment by advocates of megavitamin therapy are unsubstantiated by the available evidence.^[4][5][6] Critics have described some aspects of orthomolecular medicine as food faddism or even quackery.^[7][8][9] Research on nutrient supplementation in general suggests that some nutritional supplements might be beneficial, and that others might be harmful;^[10][11][12] several specific nutritional therapies are associated with an increased likelihood of the condition they are meant to prevent.^[13]

[edit] Multivitamin vs megavitamin

Megavitamin therapy must be distinguished from the usual 'vitamin supplementation' approach of traditional multivitamin pills. Megavitamin doses are far higher, orders of magnitude higher than the levels of vitamins ordinarily available through western diets. Multivitamin supplementation has been demonstrated to have negligable effect in treating cancer. A study of 161,000 individuals (post-menopausal women) provided, in the words of the authors, "convincing evidence that multivitamin use has little or no influence on the risk of common cancers, cardiovascular disease, or total mortality in postmenopausal women".^[14] However, this evidence against use of multivitamin does not appear to have any implication for megavitamin dose therapy.

[edit] History

In the 1930s and 1940s, some scientific and clinical evidence suggested that there might be beneficial uses of vitamins C, E and B₃ in large doses. Beginning in the 1930s, the Shutes in Canada developed a megadose vitamin E therapy for cardiovascular and circulatory complaints, naming it the "Shute protocol".^[15] Tentative experiments in the 1930s^[16] with larger doses of vitamin C were superseded by Fred R. Klenner's development of megadose intravenous vitamin C treatments in the 1940s.^[17] William Kaufman published articles in the 1940s that detailed his treatment of arthritis with frequent, high doses of niacinamide.^[18]

In 1954, R. Altschul and Abram Hoffer applied large doses of the immediate release form of niacin (Vitamin B-3) to treat hypercholesterolemia (high cholesterol).^[19] The 1956 publication of Roger J. Williams Biochemical Individuality introduced concepts for individualized megavitamins and nutrients.^[20] In the 1960s, biochemist Irwin Stone, author of The Healing Factor, observed that vitamin C's utility in the megadose treatments of human disease parallels the amounts of vitamin C physiologically produced in most animals and postulated humans' evolutionary loss of this capability. Megavitamin therapies were also publicly advocated by Linus Pauling in the late 1960s.^[21]

Several orthomolecular megavitamin protocols have been publicized.^[22] While formal medical recognition of niacin therapy for hypercholesterolemia followed confirmation by William Parsons of the Mayo Clinic (1956) and the Canner study (1986), the success of several popular books since the 1980s has made the public more aware of niacin's role in combination with other medications, for dyslipidemias (abnormal lipid levels in the blood).^[23] Pauling's advocacy of megadoses of vitamin C for colds, beginning in the 1960s, and later for cancer, made millions aware of the concept of megavitamin treatment in disease. Pauling's vitamin C recommendations are lower than some modern recommendations.^[24]

Other treatments include orthomolecular oral dosing schedules for an early treatment of colds,^[25] and for bowel tolerance for more established colds.^[26]

[edit] Usage of therapy

An American cottage industry in the late 20th century, the evolving megavitamin therapy are integrated with orthomolecular and naturopathic medicine. Although megavitamin therapy still largely remains outside of the structure of evidence-based medicine, they are increasingly used by patients, with or without the approval of their treating physicians.^[27] In the 21st century, proposed megavitamin therapies with vitamin C are being evaluated for their possible use in cancer. Clinical results from one trial evaluating use of vitamins not in the megavitamin dose range have shown no effect on treating or reducing the risk of cancer.^[28] However analysis of historical data has indicated suprisingly promising results when using megavitamin doses, when combining a variety of vitamins, but with improved outcomes frequent even when supplementing only vitamin C. [1]

In 2008 researchers established that higher vitamin C intake reduces serum uric acid levels, and is associated with lower incidence of gout. The effect is more pronounced as intake increases into the megavitamin range ^[29]

[edit] Criticism

The proposed efficacy of various megavitamin therapies has been contradicted by results of some clinical trials, but since this study was not a megavitamin regime, the relevance seems lacking.^[28] For example, a review of clinical trials in the treatment of colds with small and large doses of Vitamin C has established that there is no evidence for its efficacy.^[30]

Toxic effects of high doses of vitamin A,^[31] and vitamin D^[31] are well-established. Some vitamins such as vitamin B₁₂ have no recommended maximum dosage, or tolerable upper intake level. A 1986 article argued that although "it is not known whether maintaining a prolonged high level of vitamin B₁₂ is harmful", megadoses of vitamin B₁₂ should not be used in dialysis patients because there are no "demonstrable benefits" and a possible risk of toxicity based on epidemiological and animal evidence.^[32] In 1998 the group which set the U.S. Dietary Reference Intakes stated that "there appear to be no risks associated with intakes of supplemental B₁₂ that are more than two orders of magnitude higher than the ninety-fifth percentile of intake".^[33]

[edit] See also

• Codex Alimentarius
• Essential nutrient
• Health freedom movement
• Life extension
• Multivitamin
• Naturopathic medicine
• Orthomolecular medicine
• Vitamin C megadosage

[edit] References

[edit] External links

• Orthomolecular Therapy