Vitamins: great for your body, bad for your water supply. While a well-balanced diet should provide the body with the nutrients it needs, it’s also no secret why we take multivitamins. For vegetarians, they can give you the vital B12 your body craves; for those with an iron deficiency, they can help you regulate your anemia. However, it’s also a well-known fact that whatever the body doesn’t end up using, it releases through urine. Read more.