I used to get horrible week long headaches before I went low carb.
The fix was to drink lots of V8, like a 64 oz can in 2 days
so 2 cups twice a day!

Vegetable juice has tons of sodium and most importantly potassium.
Now that I'm low carbing, I drink much less, just a glass for dinner.

But if you think you need salt you probably also need posassium and Magnesium, V8 is the only way to get a significant amount potassium

too bad it has 10 carbs and like 8g of sugar