Can I take 400mg of vitamin E for Restless leg cramps in my legs? I have GERD will taking it increase acidity?

Vitamin E. I'm not sure of the strength of the clinical evidence showing effectiveness of Vitamin in RLS. However, regarding your question about Vitamin E and worsening of GERD, I have not been made adware of GERD exacerbation from 400 units per day of Vitamin E. That being said, being a fat soluble, vitamin E is best absorbed from the GI tract if taken with a meal containing some fat.