Chronic migraines, diarrhea, gas, bloating, and other unpleasant symptoms are sometimes the result of an inability to digest milk. Known as lactose intolerance, this condition is due to the lack of an enzyme in the digestive tract which is normally in charge of breaking down of milk sugar. While some with this enzyme deficiency can tolerate milk in small amounts, others have trouble with all foods containing lactose, including ice cream, many baked goods, and cream sauces.

Avoidance is the main "cure" for a food intolerance, although a lactose additive, which contains a does of the missing enzyme, is available, and may be helpful for some suffers. In addition, yogurt, aged cheese, buttermilk, and other dairy products whose sugars have been broken down by fermentation are often well tolerated by sensitive individuals.