A friend of mine recently asked a very good question about a concern he had over taking more than the RDA (Recommended Daily Allowance) of vitamins in a multivitamin. I decided to share his concern with you because I think the same reasoning may be shared by many others.
Here is an excerpt from his email to me:

The very first sentence of this question illustrates the confusion most have about the RDA. The RDA does NOT vary depending on a person’s age and health. It is basically the same no matter whether the person is male, female, old, young, pregnant, sick, healthy, stressed, or non-stressed. What he really meant to say in this sentence was that he realized that the necessity of any vitamin can vary depending on a person’s age and health. Please let me get two points through to you:

1. The RDA has absolutely NOTHING to do with the appropriate amount of any vitamin or mineral needed for health. It only gives information about the MINIMUM amount needed to stave off deficiency diseases like scurvy, beriberi, or pellagra.
2. The RDA has absolutely NOTHING to do with the safety of any vitamin or mineral. Let me say it again…the RDA has absolutely NOTHING to do with the safety of any vitamin or mineral!

For some reason doctors and the general public are convinced that the RDA is a guide for the appropriate amount to be used of any vitamin or mineral and for their safety. How many times have you heard a doctor say to never take more than the RDA? Or, taking more than the RDA may be dangerous. If you agree with these statments, you are wrong and you cannot support your position. I can support my position with NUMEROUS studies showing that many times the RDA for most vitamins and minerals is nowhere near dangerous and is much more appropriate for almost everyone. This is especially true for vitamin B12.

(Listen to the Vitamin Answer Book for more detailed information about the RDA and how to evaluate multivitamin quality.)

So, what about taking 8,000% or even 16,000% of the RDA for vitamin B12? Is the OrthoMolecular Company out of its mind? First, let me ask you what evidence can you come up with to show that this amount of vitamin B12 is unsafe? I assume your next question is what evidence I have that it is safe. The answer, again, is found in the numerous studies using far higher levels than this over long periods of time. I quote from the Monograph of Methylcobalamin (B12) which is the scientific evaluation for this vitamin. (Email me if you would like a copy.)

"The dosage for clinical effect is 1,500 - 6,000 mcg per day. Methylcobalamin has excellent tolerability and no known toxicity."

This dosage is 25,000% to 100,000% the RDA! Wow! If the RDA gives information about safety, they are only off by 100,000%. As I stated earlier, the RDA gives no information about vitamin or mineral safety. Next time you hear someone saying this you will immediately know that they are not well versed in the use of vitamins or minerals. Don’t ask for their opinion regarding supplementation.

O.K. if the RDA gives no meaningful information about the amount to take of any vitamin or mineral, how much should you take of any given nutrient? There is no good answer for this question. The amount you may need for your unique bag of chemistry will most likely be different from anyone else. If you want guidance consider making an appointment for a nutritional consult with me. You have two choices in doing so. The first if you live near Indianapolis, Indiana is to come to the clinic. The second is through a phone consult. I consult via telephone all over the United States. You can get more information by going to the Nutritional Counseling section of www.ZimmerNutrition.com.