Is it true that beer can boost the breastmilk?

Yes: Studies indicate that the prolactin level is raised. This hormone triggers the production of milk. The barley and hops in beer increase milk production simply because they are galactogogues (increase milk production).The alcohol in beer allows a mother to relax and increase "let down". That being said...drink non-alcoholic beer to prevent the negative effects of alcohol on the baby.

Once thought true: In older studies it was found to have some effect in increasing prolactin.However, it is now known to have a potent inhibitory effect on oxytocin, the let down hormone and eventually reduces the amount of milk delivered to the infant.The alcohol, though small in amount, hasa toxic effect on the developing brain.Best avoid it. (MEDICATIONS IN MOTHERS MILK:2012:15ed,T Hale.)