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Updated December 28, 2020
Swallowing that extra vitamin may seem like an innocuous way to ensure you’re fulfilling your body’s required daily nutritional intake. But as with anything you put into your body, moderation is key. In some cases, you can get too much of a good thing.
Can you overdose on vitamins? Here’s the answer to that question, plus an overview of all the acronyms the vitamin industry uses to describe daily values, recommended dietary allowances and more measures for how much to take in a given day.
How to track your vitamin doses
In the world of vitamins, moderation is measured through various figures that represent the amount your body requires.
Daily Value (DV)
The most common of the terms measuring vitamin dosages is the DV, or Daily Value. DV is a single figure, making it compact enough to fit on most labels. This is the amount of a specific vitamin required for a person on a 2,000 calorie diet.
Recommended Dietary Allowance (RDA)
The RDA is the ideal amount your age group and gender requires of a particular vitamin. The DV is the same as the RDA as long as you’re on a 2,000 calorie diet.
Tolerable Upper Intake Level (UL)
There’s also the UL (Tolerable Upper Intake Level), the maximum dose of daily vitamins you can ingest safely without risk of serious side effects or an overdose. The number and seriousness of every vitamin’s UL is different for every person. What does that mean? While the average person can take 50 times the RDA of Vitamin B6 without experiencing any adverse side effects, others might develop nerve pain from high levels of B6.
When a vitamin’s RDA is already near its UL, it’s especially easy to take too much. A man taking more than three times the RDA of Vitamin A, for instance, would be taking more than the UL, which can result in a toxic buildup.
Here’s a quick list of daily ULs for major vitamins.
- Vitamin A: 10,000 IU
- Vitamin C: 2,000 mg
- Vitamin B6: 100mg
- Vitamin E: 1,000mg
On top of all those acronyms is this kicker: many vitamins don’t even have these guidelines. The government reviews only a fraction of vitamins for their ideal and maximum dosages. This brings us to the question on everyone’s mind. Can you actually overdose on vitamins?
Can you overdose on vitamins?
While many common multivitamins have a wide margin between the RDA and UL, most food is fortified with vitamins. Hypothetically, you could be taking proper dosages through your vitamins, but also getting enough of that vitamin in your food to send you into more dangerous territory.
The signs that you’re receiving too much of a vitamin can be subtle. However, common symptoms include edginess in temper, difficulty sleeping or concentrating, and nerve problems like numbness or tingling. Diarrhea, fatigue, hair loss and mild nerve damage can also be side effects of mega-dosing on a variety of other vitamins.
But here’s the bottom line: the typical person on the street isn’t at risk of overdosing on vitamins. Whether symptoms are long-term or reversible, they’re usually caused by repeatedly exceeding the UL—typically with the addition of too many vitamins to an already fortified diet.
What vitamins can you take too much of?
There are three vitamins in particular to ensure you regulate properly: Vitamin D, calcium and folic acid. These are by far the most serious vitamins when it comes to exceeding their UL; they are also the most commonly found vitamins in fortified food and drinks. Adults regularly exceeding the UL for Vitamin D could end up with a buildup of calcium in the blood, which in turn can cause weakness, frequent urination and other serious issues like calcium stones. Excess Vitamin D rarely, if ever, comes from too much sun, instead stemming from supplements. Meanwhile, too much folic acid can conceal a lack of B12, which can result in permanent nerve damage over time.
That’s a lot of information, and it can be overwhelming to track your DVs, RDAs and ULs. However, vitamin overdosing isn’t common, and it doesn’t happen overnight, according to Dr. Andrew Shao, PhD, senior vice president of scientific and regulatory affairs for the Council for Responsible Nutrition, a trade group for the supplements industry. According to the doctor, “Most multivitamins have such a wide margin of safety that even when you’re combining them with fortified foods, it’s still not going to cause you to keel over.”
Go ahead, breathe a sigh of relief.
How many vitamins can you take a day?
There might be many figures to track, but there’s also plenty of help to demystify your own personal RDAs. An easy-to-read breakdown of all the RDAs and ULs is available for individuals 19 years old and over. It’s also comforting to know that for some nutrients, like magnesium or niacin, there’s no UL if the vitamin is derived from natural foods. For these nutrients, it’s only in synthetic forms that there’s a specific amount not to exceed.
As with anything else, vitamins should be taken in moderation and in recommended doses. As one doctor tells WebMD, it’s crucial to check the labels of both your foods and vitamins. And if you’re curious about which supplements your body truly needs, it’s best to have a nutritionist provide you a customized plan.
But in the meantime, there’s no need to worry too much about vitamin overdosing. Except in rare cases and with the three vitamins we mentioned earlier, taking too many vitamins won’t cause serious health issues.