There are eight B-group vitamins, which are essential for body functions such as cell regeneration and producing red blood cells. However, these water-soluble vitamins are easily destroyed while cooking or processing food. They contribute to healthy hair, skin and eyes and play an important role in health and development of foetus. Because B vitamins are water-soluble, your body uses them but cannot store them. This means you need to consistently replenish your body with foods or supplements rich in B vitamins. Deficiency of certain B vitamins can cause anemia, tiredness, loss of appetite, abdominal pain, depression, numbness and tingling in the arms and legs, muscle cramps, respiratory infections, hair loss, eczema, poor growth in children, and birth defects. If planning a pregnancy, women should consider taking folic acid (folate or B9) supplements to reduce the risk of conditions such as spina bifida in the baby.