Low-impedance headphones are in the range 16 to 32 ohms and high-impedance headphones are about 100-600 ohms. As the impedance of a pair of headphones increases, more voltage (at a given current) is required to drive it, and the loudness of the headphones for a given voltage decreases.
Yes, taking to much Vitamin D can cause some people to get diarrhea. Some others may experience constipation from to much Vitamin D.
Vitamin D is a fat-soluble vitamin stored in the liver. Excess vitamin D, which usually occurs from taking too many supplements, can cause poor appetite, nausea and vomiting; elevated calcium in the blood; and impaired growth. Mega doses of vitamin D are not associated with elevated liver enzymes.