The vitamin that helps in boosting the white blood cells is vitamin C, according to SFGate. Vitamin A and vitamin D also boost the white blood cells.
Aside from facilitating the production of the white blood cells, vitamin C activates the white blood cells to function efficiently in the body, explains SFGate. While men need 90 milligrams or more of vitamin C per day, women need to consume a minimum of 75 milligrams of this vitamin daily.
The sources of vitamin C include citrus fruits, red bell peppers and broccoli, as stated by Healthline. Vegetables such as spinach also contain vitamin C.