We Asked: Beth Ricanati, M.D., YouBeauty's Wellness Advisor, physician and founding director of Lifestyle 180, a Cleveland Clinic lifestyle modification program.
The Answer: If your urine is bright yellow and you take vitamins and aren't dehydrated, there's a good chance that's exactly what's happening. It's probably a good thing. It indicates that you are getting enough vitamins to begin with and flushing out the excess. (If you don't take vitamins and notice a change in your urine, call your doctor; it could signal infection.)
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Your kidneys are a purification system for your body. They filter out the stuff you don't need and get rid of it through your pee. This includes extra vitamins. But not all vitamins are disposed of equally. Of the 13 essential vitamins your body needs to function, nine are water-soluble, which means that whatever your cells don't use right away is excreted in your urine. Examples include C, B and folate (aka folic acid).
Any surplus of the fat-soluble vitamins, A, D, E and K, however, gets stored in your fat cells, which makes it easy to overdose on them-and that can be dangerous. Too much vitamin A, for example, can cause nausea, vomiting, blurry vision, dry skin, headaches, fatigue, an enlarged liver and bone damage. Long-term buildup of E has been linked to internal bleeding.
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To be clear, OD'ing on water-soluble vitamins isn't risk-free. Too much vitamin C can tax your kidneys and build up into kidney stones. An overdose of B3 can cause nausea and hives, and B12 can stick around in your liver for years.
Put simply: More doesn't mean better. If you're eating a well-balanced diet, especially fruits and vegetables, you should be getting most of your vitamins and nutrients already, so you shouldn't really need supplements.
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There are a few exceptions: Many people are deficient in vitamin D, which we get from the sun, and pregnant women should take folate. But in general, supplements are meant to do just that: supplement! They're not food replacements. Stick to the recommended dosage on the bottle. If you follow the directions and still pee out a vivid vitamin-rich shade of yellow, be happy knowing your body got what it needed.
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