Otherwise known as ascorbic acid, vitamin C is a powerful immune booster that boosts white blood cell function and antibody production. The immune system will struggle to cope with low vitamin C levels. Supplementing on vitamin C while experiencing the flu and common cold may decrease the severity and duration of illness. Our bodies need vitamin C for growth, development and repair of all body tissues. This is why taking vitamin C is vital for wound healing. Gum bleeding may also occur when vitamin C is deficient. Vitamin C can also lower blood pressure.