At winter and early spring I begin to feel malaise, caused by vitamins deficiency. Because it is impossible to get them all from food, when you live in the city and buy vegetables and fruit from supermarkets. Then I resort to using supplements, which contains synthetic vitamins. For me, it was interesting to know, can synthetic vitamins be harmful and what is it at all? Some answers on the questions I tried to find in this post: http://icexp.com/are-synthetic-vitamins-good-or-bad/.
So, if this topic is interesting for you too – welcome!