There is an old cliche among scientists who study nutrition: "Americans have the most expensive urine in the world." This refers to the large excess of water soluble vitamins that we purchase as supplements in this country.
That said, there is a lot of variation among individuals in the optimal intakes of each vitamin. For the vast majority of Americans, these requirements can be met by wise selection of food. For many people, certain combinations of chosen diets and specific physiological states (infancy, pregnancy, lactation, illness, previous deficiencies, etc.) can result in deficiencies. So, sometimes, adding vitamins by supplementation or ceasing the use of supplemental vitamins may be necessary to maintain or restore health.
Excess doses of anything (including water) can be dangerous. Fortunately we humans can tolerate substantial excesses of the B vitamins, and vitamins C, E and K without too many problems (see wisecrack about expensive urine). But it is possible, if one has the money, and bad information to get sick on those usually benign supplements.
The most common problems with vitamin overdose occur with vitamins A and D. Temporary therapeutic needs for A can exceed doses that would be toxic if maintained for an extended period. And actual vitamin A is more to...
There is an old cliche among scientists who study nutrition: "Americans have the most expensive urine in the world." This refers to the large excess of water soluble vitamins that we purchase as supplements in this country.
That said, there is a lot of variation among individuals in the optimal intakes of each vitamin. For the vast majority of Americans, these requirements can be met by wise selection of food. For many people, certain combinations of chosen diets and specific physiological states (infancy, pregnancy, lactation, illness, previous deficiencies, etc.) can result in deficiencies. So, sometimes, adding vitamins by supplementation or ceasing the use of supplemental vitamins may be necessary to maintain or restore health.
Excess doses of anything (including water) can be dangerous. Fortunately we humans can tolerate substantial excesses of the B vitamins, and vitamins C, E and K without too many problems (see wisecrack about expensive urine). But it is possible, if one has the money, and bad information to get sick on those usually benign supplements.
The most common problems with vitamin overdose occur with vitamins A and D. Temporary therapeutic needs for A can exceed doses that would be toxic if maintained for an extended period. And actual vitamin A is more toxic than natural precursors such as carotene. The toxic dose of A is close enough to the required dose to warrant caution in deciding how much to take.
Vitamin D can be a similar threat, but is more complicated since in addition to diet and physiological state, one has to consider the body's ability to make its own vitamin D in the presence of sunlight on the skin, skin color, etc. in figuring out individual requirements. So the optimum dose for one person could cause deficiency in another or toxicity for someone else.
Vitamins are not BS. But the vast majority of the population does not need to take vitamin supplements.
(more)