8333% of RDA

[my3labs]

Question:
If a person takes a vitamin/supplement that has over the RDA of a particular ingredient, what happens to the "overage"? ie: do you absorb it, and if so, could that be a bad thing? Or, does your body purge out the excess in the urine?

Example:
I recently started taking a B12 supplement (because of my fear of anemia and the low blood pressure). The supplement I'm taking has either 833% or 8333% (I'm too lazy to go look at the bottle) of the RDA and I'm wondering if that's dangerous or wasteful?

Another question:
Because it has over the RDA, do I only need to take it periodically (ie: weekly, monthly, etc).

[Bowwowmeow]

The RDA (Recommended Dietary Allowance) is the minimum amount of any known nutrient needed to avoid the deficiency disease caused by not getting enough. Water soluble vitamins will be used by the body as needed, and excreted. B vitamins are water soluble, and there are almost no known problems with taking excessive amounts, except for niacin, which may harm the liver if taken in excess. The excess B vitamins not used by the body are what color the urine bright yellow. If you need lots of certain vitamins, lower amounts taken several times a day is a better way than taking one pill or tablet with higher quantities of the nutrients you need. Unless you get a time-release version. The body can only use so much at one time, and if you have a problem that needs vitamin therapy to solve, you should take smaller amounts more frequently.

People's systems are all different, and some folks may need more of a certain nutrient than others. That's what makes RDAs insufficient for optimal health. You want to do more than just barely avoid scurvy, pellagra, or B12 induced anemia. You want to thrive, and as long as you learn what levels of nutrients cause damaging side effects you'll be fine. Most of the worst side effects of vitamin overdose are caused in clinical tests, involving much larger amounts than most of us would ever be able to afford to take, and the symptoms disappear when the vitamin is discontinued. The vitamins to really worry about overdosing are A, D, and niacin. Vitamin C causes diarrhea when the optimal dose is exceeded, but the diarrhea stops when Vitamin C is reduced, and many people figure out for themselves how much to take by taking it in increasing amounts until diarrhea occurs. Often, when you are ill, your tolerance for vitamin C increases, and you can take much more than usual before diarrhea occurs. Too much beta carotene will make your skin orange. I can't remember what happens in A or D toxicity, but they are more serious than diarrhea or skin discoloration.

Minerals are different. Its very important to become aware of how much is too much if you are taking a mineral supplement. Even calcium, which the dairy industry tries to frighten people into believing that they need so much of, is toxic in excess, but its even more important to make sure you are not supplementing potassium, iron, or copper without advice from a health care professional (not necessarily a doctor!).

[1vegan]

Question:

Example:
I recently started taking a B12 supplement (because of my fear of anemia and the low blood pressure). The supplement I'm taking has either 833% or 8333% (I'm too lazy to go look at the bottle) of the RDA and I'm wondering if that's dangerous or wasteful?

Another question:
Because it has over the RDA, do I only need to take it periodically (ie: weekly, monthly, etc).

Some vitamins, i.e. the B-type, are mostly peed out, Vitamin A gets stored and high doses can do damage afaik (esp. to unborn childs)


With B-12, you can just take whatever you want, the excess is partly absorbed and stored in your body.
afaik, B-12 does not help for anemia, you need iron for that, like green leavy vegetables, or figs, something like that.

800% of b-12 RDA isn't that high, I take solgar 1000 ug, which is 10,000% of RDA according to the bottle :)

A part of the excess b12 is not aborbed, but it's said that if you take B-12 only once a week, you should take 2000 ug or microgram to make sure you get enough for the whole week.

See this article (http://www.veggieboards.com/boards/showthread.php?t=9309) (which is mostly about homocysteine, but includes some info on B12)

If I had your brand of B12, I'd take it at least twice a week :)

[Bowwowmeow]

afaik, B-12 does not help for anemia, you need iron for that, like green leavy vegetables, or figs, something like that.
Yes, B12 deficiency does cause anemia, but its not the same as iron deficiency anemia. Its called pernicious anemia, and people who get it actually need B12 injections, because the disease impairs the ability of intrinsic factor to utilize dietary B12.

[dreamer]

I know that you're supposed to "pee-out" excess B vitamins, but when I took a megadose--I think about 5000%--it gave me a headache. Now I try not to take more than 1000%, as it doesn't seem to bother me then. As BWM points out, it depends on the vitamin or mineral in how dangerous overages are...as well as the person as we do each require different amounts than the RDA.

[Bowwowmeow]

Sometimes they add choline to B complex supplements. Choline is a muscle toner, and too much can cause headaches due to tightening of the face muscles.

[thevegantwins]

I don't take extra B12 supplements, just the 100mg or so that is in my multi plus I eat a little nutritional yeast almost daily. My homocysteine levels (blood test to determine if you are B12 deficient) are always fine. I'm having my next blood test next Tuesday. :crossfingers:

[Gliondrach]

If the tablet contains more of something than you want you can break it in half or a quarter.

[dreamer]

TVT, I always thought homocysteine levels were an accurate way to tell if you're B12 deficient, but as I read about nutrition, I realized that it wasn't. Apparently folic acid and B12 together impact homocysteine levels, so if you have enough of one, it can sometimes mask not having enough of the other. I'm hoping this year I can get my doctor to test specifically for B12--I think maybe MMA levels tell more?--as part of my physical, though apparently it's expensive to have that test done:confused:

[thevegantwins]

I've been taking at least 400mcg of folic acid daily for years so I'm guessing I don't have any issues with folic acid deficiency.

[dreamer]

Right, I don't think most vegans do. That's the point...that sometimes homocysteine levels are fine in vegans when they are actually deficient in B12 because their higher levels of folic acid compensate. (Necrotarians could be the opposite, with their homocysteine levels measuring fine yet they might be folic acid deficient.)

[thevegantwins]

Ohhhh. Too late, I already had my bloodwork done this morning. I'm going to ask them to fax the results so I can read the invidual results.

[Bowwowmeow]

Example:
I recently started taking a B12 supplement (because of my fear of anemia and the low blood pressure). The supplement I'm taking has either 833% or 8333% (I'm too lazy to go look at the bottle) of the RDA and I'm wondering if that's dangerous or wasteful? I forgot that B12 does get stored in the liver, so I think that once your liver reached full capapcity, you probably would start peeing out the excess. Since there's no way I know of to test your liver's concentration, you won't know when your liver is filled up, and you start wasting the excess. But, since B12 is a crucial nutrient, and I've never read of harm coming from megadoses, I wouldn't worry about wasting the percentage you don't absorb. Your body is in a state of constant flux, and there may be times when you use all the B12 you ingest, and times you don't. If there is room in your liver, the extra will be stored, and if there isn't, you will lose it through urine, and since its not very expensive, take what you think you need.

[dreamer]

Sometimes they add choline to B complex supplements. Choline is a muscle toner, and too much can cause headaches due to tightening of the face muscles.
I checked the label and there's no choline.