Some people have an intolerance to the alcohol itself, according to Bassett. They can "feel sick" or even experience a migraine.
Those of Irish and Scottish descent -- about 1 percent of the population -- are prone to celiac disease, an allergy to gluten in wheat, barley and rye. They may find whisky and bourbon intolerable.
"Most sake is fine," said Bassett. "That's made from rice."
Ethnicity can make a difference. Asians, particularly those of Chinese, Japanese or Korean descent, can experience a "flush syndrome" when drinking alcohol because of troubles with digestion, according to Bassett.
Bassett said those who have difficulty with alcohol should work with an allergist to minimize risk.
"Nonalcoholic beer is safer for the holidays," said Bassett. "Nonalcoholic drinks can be made to accommodate and keep people healthy and happy at the same time."
As for Kristen Brown, she has had to give up alcohol almost entirely.
Now, if she even tries liquor, "all hell breaks loose," said Brown. "I can't even drink the tiniest little bit or I get sick right away."
Oddly, she can't drink hard spirits, but has no problem with a bottle of Guinness beer. "Once a year, at least one friend brings me a six-pack of Guinness for my birthday."