danb,
i know you weren’t replying to me but i just wanted to add a little more. your attitude to supplementation is so similar to a typical patient’s response–hey, it works for me so leave me alone. which is perfectly fine too. if i was your doctor i wouldn’t stop you just so you wouldn’t think i was a prick and never come back to my clinic. but again, if i was your doctor, i do have the responsibility to tell you that to the best of my knowledge what you’re doing is not gonna do jack-shit. for too long, medicine has been bogged down by treatments that by logic ought to work but when finally tested do not. there is no longer a place in medicine for anecdotal evidence because it can be dangerous (what if years from now research comes out that vit. c megadosing causes cancer, or impotence, or zits, etc?) and because useless treatments take money away from more worthwhile endeavors–i.e. if the marketing money used on you to convince you to buy vit. c was used to subsidize your healthcare instead then you wouldn’t be bitching about exorbitant MD fees.
Kim
P.S. i don’t know about the american curriculum, but admittedly there is a lack of training in med school here in the Philippines with regards to the endurance athlete subpopulation. it is a very small and insiginificant population, especially when you consider more pressing concerns such as infectious disease, cancer, malnutrition, etc. and, even if someone were so inclined (as I am) to learn more regarding the special needs of athletes, there is precious little material to find out there. so, personally, i take the view that athletes (who are already so much healthier than the population at large) just need to eat more to meet caloric and nutrient requirments. In my 7 years of triathlon, I have never had symptoms of a vitamin deficiency.
finally found what i was looking for–warning this is looong!
Routine Vitamin Supplementation to Prevent Cancer and Cardiovascular Disease
The U.S. Preventive Services Task Force concludes the evidence is insufficient to recommend for or against the use of vitamin supplements A, C, or E; multivitamins with folic acid; or antioxidant combinations for the prevention of cancer or heart disease. (I recommendation.)
The Task Force found poor evidence to determine whether supplementation with these vitamins reduces the risk for heart disease or cancer. The available evidence from randomized trials is either inadequate or conflicting, and the influence of confounding variables on observed outcomes in observational studies cannot be determined. As a result, the Task Force could not determine the balance of benefits and harms of routine use of vitamin supplements A, C or E; multivitamins with folic acid; or antioxidant combinations for the prevention of cancer or heart disease.
The Task Force recommends against the use of beta-carotene supplements, either alone or in combination, for the prevention of cancer or heart disease. (D recommendation.)
The Task Force found good evidence that beta-carotene supplementation provides no benefit in the prevention of cancer or heart disease in middle-aged and older adults. In 2 trials restricted to heavy smokers, beta-carotene supplementation was associated with higher incidence of lung cancer and higher all-cause mortality. The Task Force concludes that beta-carotene supplements are unlikely to provide important benefits and might cause harm in some groups.
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The Task Force did not review evidence regarding vitamin supplementation for patients with known or potential nutritional deficiencies, including pregnant and lactating women, children, the elderly, and people with chronic illnesses. Dietary supplements may be appropriate for people whose diet does not provide the recommended dietary intake of specific vitamins. Individuals may wish to consult a health care provider to discuss whether dietary supplements are appropriate.
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With the exception of vitamins for which there is compelling evidence of net harm, there is little reason to discourage people from taking vitamin supplements. Patients should be reminded that taking vitamins does not replace the need to eat a healthy diet. All patients should receive information about the benefits of a diet high in fruits and vegetables, as well as information on other foods and nutrients that should be emphasized or avoided in their diet.
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Patients who choose to take vitamins should be encouraged to adhere to the dosages recommended in the Dietary Reference Intakes of the Institute of Medicine. Some vitamins, such as A and D, may be harmful in higher doses; therefore, doses greatly exceeding the Recommended Dietary Allowance or Adequate Intake should be taken with care while considering whether potential harms outweigh potential benefits. Vitamins and minerals sold in the United States are classified as “dietary supplements,” and there is a degree of quality control over content if they have a U.S. Pharmacopeia (USP) seal. Nevertheless, imprecision in the content and concentration of ingredients could pose a theoretical risk not reflected in clinical trials using calibrated compounds.
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The adverse effects of beta-carotene on smokers have been observed primarily in those taking large supplemental doses. There is no evidence to suggest that beta-carotene is harmful to smokers at levels occurring naturally in foods.
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The Task Force did not review evidence supporting folic acid supplementation among pregnant women to reduce neural tube defects.
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Clinicians and patients should discuss the possible need for vitamin supplementation when taking certain medications.
For more information, please visit http://www.ahrq.gov/clinic/3rduspstf/vitamins/vitrrpda.htm