Photos: Pond5. Referred to as vitamin B complex, the eight B vitamins — B1, B2, B3, B5, B6, B7, B9, B12 — play an important role in keeping our bodies running like well-oiled machines. These essential nutrients help convert our food into fuel, allowing us to stay energized throughout the day.long with fellow B vitamins 12 and 9, B6 helps regulate levels of the amino acid homocysteine (associated with heart disease). Pyridoxine is a major player in mood and sleep patterns because it helps the body produce serotonin, melatonin and norepinephrine, a stress hormone.