Sodium is just one.
https://en.wikipedia.org/wiki/Electrolyte#Physiological_impo...
The average intake for people in the US for magnesium, potassium, and calcium is well below DRI.
https://www.nature.com/articles/1001955
More support/info:
https://ods.od.nih.gov/factsheets/Potassium-HealthProfession...
Track your food (myfitnesspal/cronometer/etc) with a cheap gram scale and ensure you are meeting the daily recommended requirements for vitamins and minerals. Plain potatoes are a great source of magnesium and potassium, and are pretty low calorie/healthy if you don't put junk on them, but there are plenty of other foods as well.