Re: lack of vitamin d
It really depends on how low your vitamin D levels are. If you suspect you have low vitamin D levels, you need to have those and other vitamins tested because sometimes various vitamin deficienies can mimic each other. I had all my vitamins checked and it turned out my vitamin D levels were only 12ng (very low). I felt very exhausted and fatigued all the time. My levels are up to 29ng now after two months of taking 1000IU of vitamin D a day plus eating salmon three times a week in addition to increasing my intake of fortified dairy products.