People with a balanced diet do not need to take any vitamins or minerals. However some like Vitamin D, C, A are necessary to maintain your health especially during long winter nights where your body is luckuin from the contact with the Sun. People who train in the gym do need to replenish themselves with minerals and vitamins after a heavy workout session. Vitamin D is helping to regulate phosphate and calcium in the body which is important for your bones and nervous system. Deficiency of the vitamin D can lead to hair loss, depression and low mood, tiredness and fatigue and decrease your immune system. If you are worried about catching a virus then grab your vitamin D as soon as you can.