Lisa,
Last time I looked, saliva contained enzymnes to break down starches -
salivary amylases.  This does not kick in in infants until around 6 months.
There are no significant proteolytic enzymnes in saliva - otherwise kissing
would be very hazardous!
        Nipple damage is much more likely to be due to friction - especially
from the infant's tongue - than from saliva.  Think of all the damage friction
does to surfaces such as car tires, hands (ropeburn), unlubricated engine
parts...makes much more sense.
Catherine Watson Genna, IBCLC  NYC  [log in to unmask]