Simplify the following text for a Grade 13 native English-speaking person.
Original: However , two B vitamins , niacin and riboflavin , bind with adenine to form the essential cofactors nicotinamide adenine dinucleotide ( NAD ) and flavin adenine dinucleotide ( FAD ) , respectively .
Simplified: However , two B vitamins , niacin and riboflavin , bind with adenine to form the essential cofactors NAD and FAD respectively .