The Scoop - Winter 2019

Winter 2019
What’s the Scoop? Questions and Answers About Dietary Supplements

Vitamin and Mineral Upper Limits––What You Need To Know

More is better, right? Not when it comes to vitamins and minerals. Our bodies need these nutrients for many things, like breaking down the food we eat, making bones and DNA, helping muscles contract, and maintaining immunity. But there’s no reason to get more than you need, and some nutrients can be dangerous in large amounts.

Each vitamin and mineral has a recommended amount, which is what you should get each day for good health. Most of them also have what is called a “tolerable upper intake level” or UL. Getting more than the UL can cause health problems. Other vitamins and minerals appear to be safe at any dose, while a few have a UL only under certain circumstances.

Read the ODS fact sheets on vitamins and minerals for details about the recommended amounts and tolerable upper intake levels (ULs).

Which vitamins and minerals fall into which category? Here’s the breakdown:

Nutrients with ULs: calcium, choline, copper, fluoride, iodine, iron, manganese, molybdenum, nickel, phosphorus, selenium, vitamin B6, vitamin C, vitamin D, and zinc

Stay under the UL each day for these nutrients to avoid health problems unless your healthcare provider recommends more. For example, very high doses of vitamin B6 can cause severe nerve damage and too much iron can be fatal.

The ULs for these nutrients include what you get from food, beverages, fortified foods (including many breakfast cereals), and dietary supplements. But it’s unlikely you’ll go above the UL from food and beverages alone.

Nutrients with ULs, but only from dietary supplements and fortified foods: folate, magnesium, niacin, and vitamin E

These vitamins and minerals, as found naturally in food and beverages, won’t cause any health problems. But they can if you get amounts above the UL from supplements or fortified foods.

One nutrient with a UL, but only for certain forms: vitamin A

Vitamin A exists in two main forms: preformed vitamin A—such as retinol and retinyl palmitate—in animal products (including meat, poultry, fish, and dairy products); and beta-carotene (in fruits, vegetables, and other plant foods). Dietary supplements can contain both forms.

Only preformed vitamin A has a UL because high amounts can cause health problems, such as birth defects during pregnancy and liver damage. Beta-carotene has no UL because high amounts don’t cause these problems.

Nutrients with no ULs: biotin, chromium, pantothenic acid, riboflavin, thiamin, vitamin B12, and vitamin K

These nutrients have no identified safety concerns, even at high doses. But there’s no reason to get more than recommended amounts unless your healthcare provider recommends it.

What’s the bottom line?

Most vitamins and minerals have upper limits known as ULs, so there is a range of safe intake between the recommended amounts and the ULs. Check the labels of dietary supplements and fortified foods to see the amounts of vitamins and minerals they contain. Be careful about doubling-up on supplements or taking more than the serving size listed on product labels. And talk with your healthcare provider to determine which supplements, if any, might be valuable for you.

Read our vitamin and mineral fact sheets for more details about the recommended amounts and ULs.

Have More Questions?

The Office of Dietary Supplements (ODS) provides general information about dietary supplement ingredients in response to questions from consumers, health professionals, students, and others. While ODS cannot answer specific medical questions, make referrals, or give personal guidance on the use of dietary supplements, ODS’s registered dietitians on staff reply to each inquiry and give useful, scientific, and evidence-based information. Send your questions about dietary supplements to:

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About ODS
The Office of Dietary Supplements (ODS) is part of the National Institutes of Health (NIH), the nation’s medical research agency—supporting scientific studies that turn discovery into health.
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Office of Dietary Supplements
National Institutes of Health
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Bethesda, MD 20892-7517