Yes we do get enough "supplements" in our normal diet providing of course we do not have a medical condition which prevents us from absorbing these supplements or losing them.
In hot weather, you lose WATER.....not supplements, so drink plenty of water. At extreme times you may.....just may lose salt, but WATER is what you need.
How do you know that you are losing salt in hot weather?
Lick your forearm and if you are losing salt which needs replacing, then you will taste it.