A few months ago, a blood test showed that I have low Vitamin D (which I know is because I don't go out in the sun), and my doctor told me to start taking a supplement. I picked one up in my local pharmacy, on the bottle it says Vitamin D 1000IU (Cholecalciferol 25mcg). It also says to take it with food, so I always take it after breakfast but sometimes up to an hour after eating, not sure if that matters.
Initially I took 1 capsule each day for about 5 days. Prior to this point I had been doing quite well for a while and not suffering much from CFS symptoms. Over the next week however, I began experiencing low blood pressure-related symptoms (feeling very cold, extremely nauseous, dizzy and like I was about to pass out) particularly when waking up in the morning with an empty stomach. After about 5 days of taking the vitamin D I stopped taking it because I got a virus, and forgot to start taking it again when I got better. At the time I didn't connect my dizziness etc with taking the supplement.
However a few days ago my doctor reminded me to take vitamin D again so I started it again. And over the past few days I've had a recurrence of the symptoms described above. I skipped taking it today and felt much better.
It seems odd that a vitamin supplement would have this effect, so I'm wondering, has anyone else with CFS had strange reactions to vitamin D specifically? Or any particular brand or dosage of vitamins?