Avitaminosis is any disease caused by chronic or long-term vitamin deficiency or caused by a defect in metabolic conversion, such as tryptophan to niacin. They are designated by the same letter as the vitamin.
Avitaminoses include
* vitamin A deficiency causes xerophthalmia or night blindness
* thiamine deficiency causes beriberi
* niacin deficiency causes pellagra
* vitamin B12 deficiency leads to megaloblastic anemia
* vitamin C deficiency leads to scurvy
* vitamin D deficiency causes rickets
* vitamin K deficiency causes impaired coagulation
If anyone know more about this then please comment on this topic.

I think I had vitamin deficiency growing up, usually it would be during winter, when less fresh fruit and vegetables were available. It did not get too severe in my case, thankfully.

It is a serious concern though. Most illnesses and diseases can be linked to vitamin or mineral deficiency in the body.

If you're a picky eater, I think you should be very careful about making sure that you get all the vitamins that you need. When I was growing up, my mom had to give me vitamins because I wouldn't eat the food that she was serving. I'm still a picky eater, so I'm stil trying to make sure that I get everything that my body needs.