has role independent continuant water-soluble vitamin (role) organonitrogen compound organooxygen compound nutraceutical B vitamin B vitamins B-group vitamins Any member of the group of eight water-soluble vitamins originally thought to be a single compound (vitamin B) that play important roles in cell metabolism. The group comprises of vitamin B<small>₁</small>, B<small>₂</small>, B<small>₃</small>, B<small>₅</small>, B<small>₆</small>, B<small>₇</small>, B<small>₉</small>, and B<small>₁₂</small> (Around 20 other compounds were once thought to be B vitamins but are no longer classified as such). B-group vitamin vitamin B