Digestive 
Blood
Cardiovascular
Dermatology
Genitourinary,
Hormones
Infections
Oncology and
Musculo-skeletal
Mental health and
Parasites
Respiratory
Senses
Various
Vitamins work by converting food into energy, regulating the chemical reactions necessary for life.
There are two different types of vitamins.
Fat soluble:
Vitamin A (retinol), Vitamin D (calciferol), Vitamin E (tocopherol) and Vitamin K (antihemorrhagic). These vitamins dissolve in fats and oils; they are stored in the liver and in the fatty tissue. If consumed in excess, they can cause toxicity.
Water soluble:
Vitamin C and the Vitamin B Complex: B1, B2, B3, B5, B6, B7, B9 and B12. These vitamins dissolve in water and are not stored in the body, so they must be administered regularly and we can only go without them for a few days.
