It relaxes the sphinctor muscle between the esophagus and stomach allowing for more reflux.
Other common triggers include anything
with caffeine (soda, coffee, tea and chocolate), spicy foods (hot spicy or just a lot of herbs), eating too close to bed time (allow a minimum of two hours after eating before liing down 4 hours is best), over eating. Eggs and cheese are also common triggers. You may also want to elevate the head of your bed 6 inches.