Vitamins. Vitamins and minerals are vital for us. Even deficient in vitamin B12 may cause impaired cell division to slow down. When this slow impaired cell division occurs, red blood cells are enlarged and are more likely to be destroyed by the immune system. Hence, even vitamin B12 deficiency can cause hallucination apart from gastrointestinal problems as well as neurological problems.
Digestion. Also could be poor digestion.
Possible. You could have a yeast growth on the tongue which is called thrush. This can be caused by a variety of problems such as poor nutrition, diabetes and others.
Why do you ask? Nowadays, vitamin deficiency is only a rare cause of hair loss. If you make this assumption based on a charlatan's website, you'll end up buying something that won't work, and if you complain, you'll be told it was your fault. Biotin deficiency sufficient to cause hair loss is hard to get. Get with a competent physician if hair loss is a concern.
Many. Night blindness is one of the first signs of vitamin a deficiency. Vitamin B12 deficiency can cause permanent damage to nervous tissue if left untreated longer than 6 months.[scurvy is a disease resulting from a deficiency of vitamin c. Vitamin d deficiency has been associated with rickets, a disease in which the bone tissue doesn't properly mineralize. Sorry, there is not room for more.