MENU
ConsumerLab.com Answers

Question:
How can the Recommended Daily Allowance (RDA) for magnesium be higher than the Upper Tolerable Intake Level (UL)? That is, how can an amount which is healthful also put you at risk for harm?

Answer:
It is true that, at first glance, there seems to be a contradiction. For example, the UL for magnesium (above which the risk of adverse effects increases) is 350 mg per day for adults and children over age 8, but the RDA (the amount one needs) can be as high as 420 mg for many people within this group depending on gender and stage of life.  However, the magnesium one consumes from food does not count toward the UL; only magnesium from supplements and medicine can cause adverse effects and counts toward this limit. So, as long as you're not getting more than 350 mg of magnesium per day from supplements and/or medicine and are getting some magnesium from foods (like whole grains, nuts, beans, and green leafy vegetables) you can satisfy the RDA without exceeding the UL.

For more about this, see the "What to Consider When Using" section of the Magnesium Supplements Review.

The ULs established for niacin and folate also only apply to the amounts consumed from supplements and fortified foods and not from foods naturally containing these vitamins. For vitamin E, the upper limit is higher for the natural form than the synthetic form.

See these related CL Answers:

Is there a danger of getting too much calcium from Tums? I take them frequently for heartburn. >>

Which is the best form of magnesium to take - one that contains the most magnesium and is best absorbed? >>

Some websites are highly critical of magnesium stearate, which is in many supplements. Is this substance toxic and should I avoid it? >>

I was surprised when my doctor told me to stop taking supplements because my kidney function was low. But after stopping the supplements, my kidney function returned to normal. Can taking a lot of supplements really damage the kidneys? >>


See other recent and popular questions >>
Comments
Add Comment
Be the first to add a comment...

This CL Answer initially posted on 7/14/2015. Last updated 8/3/2017.

Add Comment...

Share your thoughts and comments about this topic in the space below. Please abide by the following rules:
  • If you make a statement of fact, such as whether a type of treatment does or does not work, state your basis -- such as personal experience or a published study.
  • If you make a positive or negative comment about a product, note whether or not you have a financial interest in the product or in a competing product.
  • Please be respectful in your tone.
  • Please do not submit any type of HTML markup or scripting as it will not be accepted.
Comment:

Add Comment...

Share your thoughts and comments about this topic in the space below. Please abide by the following rules:
  • If you make a statement of fact, such as whether a type of treatment does or does not work, state your basis -- such as personal experience or a published study.
  • If you make a positive or negative comment about a product, note whether or not you have a financial interest in the product or in a competing product.
  • Please be respectful in your tone.
  • Please do not submit any type of HTML markup or scripting as it will not be accepted.
Comment:

Edit Comment...

You can modify your comment below. Please be aware the comment will have to approve the changes before they will be shown:
Comment: