Over-Supplementation of Vitamin D

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Q: After following your guidelines, I calculated that I'm taking 450 percent of the daily Vitamin D requirement through my multivitamins. If I eliminate any multi-vitamin, I lose the other vitamins in it. What is your advice? 

R. F., Newtonville, Massachusetts 

A: First of all, we are so glad that you found one of our previous responses to be so helpful. Supplementation can have many benefits, but levels known as tolerable upper limits (ULs) exist to protect consumers from the negative side effects of over-supplementing. There is such a thing as too many vitamins, especially when you are taking them in a pill form.

Here are a few options for you to consider:

  1. Go shopping for a new multi-vitamin. There are many multi-vitamins that contain only 100 percent of each vitamin. Check the labels before purchasing. We know it is tempting to look for the labels with the highest percentages, but because you are looking for the well-rounded benefits of a multi, you do not need to be over-supplementing on any single vitamin or mineral.
  2. Then consider a new Calcium+Vitamin D supplement that, when combined with your multi, contains only up to 800–1,000 IU of vitamin D and 500-600 mg of calcium. We believe that to be the level of supplementation per day that is usually safe and may help prevent deficiency and provide the important benefits for bone health. Calcium is also not fully absorbed in dosages larger than that, at one time, so you are paying for benefits that your body isn't getting. Your body needs the Vitamin D to absorb calcium, which is why the supplements are often paired together. However both have set ULs that you shouldn't exceed. According to the Office of Dietary Supplements, the UL for Vitamin D is 4,000 IU per day for adults. Ask your dietitian or doctor what your personal Vitamin D recommendation is and follow this guidance as to how much is the "right amount" for you. You may request a blood test to determine your Vitamin D supplementation needs. The Office of Dietary Supplements states that the UL for calcium is 2,500 mg per day for men and women aged 19-50 years, and 2,000 mg per day for adults over 50.
  3. Take your calcium and multivitamin supplements at separate times for maximum absorption of nutrients. Calcium is a large mineral that competes for absorption with other minerals. Nothing bad will happen but if you take these two together, you likely won’t be getting all you can out of your multivitamin.

Remember, the best sources for vitamins and minerals are from whole, non-processed food sources in your diet. To reach your 1,200 mg of calcium per day, consider getting the other 600 mg or so from foods. If this is not feasible or your doctor recommends you take 1,000-1,200 mg of calcium supplements daily, take the 500-600 mg supplement twice a day instead of the full dose all at once for best absorption.

Examples of calcium-rich foods:

  • 1 cup non-fat milk: 300 mg
  • 1 cup low-fat, plain yogurt: 300 mg
  • 1.5 ounces shredded cheese: 306 mg
  • 1 cup raw broccoli: 90 mg
  • 1 cup raw kale: 90 mg

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