A higher ratio of wastes to water turns urine a bright yellow color, which explains why the first urine in the morning is often quite a deep yellow.
If your urine is a very faint yellow, it generally means you’re well hydrated. If your urine is dark, you’re probably dehydrated.
Eating different types of food can also give your urine different shades of yellow. If you take vitamins, your pee might turn into a bright yellow. No need to worry, this is perfectly normal. The same thing might happen if you drink lots of milk. The exact cause of this is the bi-products when we metabolize Vitamin B.
If your pee is ever a strange color, it would be wise to see a doctor, as it might indicate problems other than just being dehydrated. The science of what we eat and drink is quite simple, our bodies either absorbs it, or it comes out eventually. Kinda like a black hole, but not.