Our yeast-free, complete vitamin B complex is the ideal supplement for the whole family to enjoy, especially those with yeast intolerance's. PLEASE NOTE: This supplement is not suitable for Vegans or Vegetarians. What Is Vitamin B Vitamin B plays a critical role in the body’s normal functioning. Essentially, Vitamin B complex – as the eight B vitamins are often referred to – helps the body to turn digested food into usable energy.