@livingparadox, interesting. So it would seem that a vitamin supplement on it own is potentially useless (depending on which vitamin it is) if it wasn’t mixed with healthy fats to aid absorption.
My doctor responded to my email with the article on supplementation. It would seem they perhaps didn’t read through to the conclusion that gives a nice summary. The summary agrees with @Tordenskjold that if you are already consuming a healthy diet, the excess just gets pissed away. Other vitamins in excess do harm, such as Vitamin A.
The article is from uptodate.com and she copy and pasted the info into an email. Here is the URL.
Vitamin supplementation in disease prevention
Kathleen M Fairfield, MD, DrPH
Timothy O Lipman, MD
Lee Park, MD,
SUMMARY AND RECOMMENDATIONS — In general, vitamin supplementation is not necessary for most adults who eat a balanced diet and get regular sun exposure or drink vitamin D–fortified dairy products. However, many people take multivitamins, and common formulations, generally containing 0.5- to 1.5-times the daily reference intakes of individual vitamins, are likely safe in nearly all people. Because some vitamins in larger doses can be harmful in some people, high-dose vitamin recommendations should be tailored to individual patients:
●A balanced diet with fruits and vegetables promotes health not only by providing known vitamins, but also because it contains fiber and other less well-defined nutrients and replaces meat and animal fat. People on restricted or special diets, or those living in regions of the world with widespread malnutrition, may have additional needs for vitamin supplementation. (See ‘Special diets’ above.)
●For adults with a balanced diet, there is no convincing evidence that taking multivitamins in the usual doses of 50 to 200 percent of the recommended daily allowance (RDA) is either helpful or harmful. If the multivitamin includes vitamins E and/or A, these should be in low doses (eg, no more than 30 units of vitamin E; no more than 2500 international units of vitamin A).
Physicians should strongly recommend vitamin supplements in the doses and clinical situations in which they are known to be beneficial (see below) and against vitamin supplements in doses or clinical situations in which they are harmful (see below).
For people on balanced developed-world diets (ie, those eating a variety of fruits, vegetables, grains, and proteins), we suggest not taking multivitamin supplements (Grade 2B). Clinicians can tell patients that such supplements are unnecessary, but should understand that many patients want to take vitamins based on their own belief systems and not struggle against that practice as long as it is harmless. (See ‘Multivitamins’ above.)
●Patients are at increased risk of vitamin deficiency in some clinical situations (table 2). Classical vitamin deficiency syndromes such as scurvy, beriberi, and pellagra do exist in special clinical populations and more generally in resource-poor regions of the world. (See ‘Vitamin deficiency’ above.)
●Testing for vitamin blood levels is not indicated in healthy adults and should be undertaken only if there is clinical suspicion of vitamin deficiency, such as measurement of B12 and/or methylmalonic acid levels in patients with macrocytic anemia and vitamin D levels in the evaluation of established osteoporosis. (See ‘Testing’ above.)
●Vitamin supplementation is known to be effective in some specific clinical situations:
•In women who could become pregnant, we recommend supplementation with folic acid (Grade 1A). (See “Folic acid supplementation in pregnancy”.)
•In most older adults, particularly those at increased risk of falls, we suggest supplementation with vitamin D (Grade 2B). We administer 1000 units of vitamin D daily, depending on dietary intake. Other experts, including other authors for UpToDate, use somewhat lower daily doses of vitamin D. (See ‘Falls’ above and “Vitamin D deficiency in adults: Definition, clinical manifestations, and treatment”.)
In children in developing countries, vitamin A supplementation reduces mortality, presumably by strengthening the immune system against common infections.
●High doses of vitamins, especially fat-soluble vitamins, are toxic and some may be risky even at doses short of toxicity.
Vitamin A supplementation is known to have harms, particularly in certain populations:
•In women in the first trimester of pregnancy, vitamin A at doses >10,000 international units increases the risk of birth defects. (See ‘Birth defects’ above.)
•In unselected adults, vitamin A supplementation may increase the risk of osteoporosis, especially in women at increased risk or in people with a high dietary intake of vitamin A. (See ‘Fractures’ above.)
•High-dose vitamin A may increase cardiovascular mortality. (See ‘Cardiovascular disease’ above.)
•Beta-carotene apparently increases the risk of lung cancer in adults at increased risk because of smoking or asbestos exposure. (See ‘Cancer’ above.)
High-dose vitamin C apparently increases the risk of kidney stones. (See ‘Kidney stones’ above.)
●A large and growing research literature suggests many other harms and benefits of vitamins, but so far without high enough quality evidence to change clinical decision-making, except as noted above. Specifically, the possibility raised by observational studies that folic acid, vitamin B12 and vitamin B6 supplementation might prevent cardiovascular disease by lowering homocysteine has not been consistently supported by results of randomized trials. Similarly, the hypothesis that antioxidants prevent cardiovascular disease and cancer has also not been borne out by results of randomized trials. Also, in adults in developed countries, vitamin D supplementation appears to have little or no effect on bone mineral density in the short term. (See ‘Antioxidant vitamins’ above and ‘Osteoporosis’ above and “Overview of homocysteine”, section on ‘Supplementation in the general population’.)
●Genetic factors may affect how vitamins are metabolized and the consequences of supplementation in various clinical situations and doses. Not enough is yet known to use genetic information to guide clinical decisions about vitamin dose and deficiencies, but that information is likely to become available. (See ‘Introduction’ above.)