Even so, if you suffer with migraines your doctor may advise you to read food labels closely and to steer away from any product containing this MSG.

While many foods have natural chemicals already in them, it doesn't always make them a reliable food. Salicylates are one such chemical and aspirin is a compound of salicylate. If you cannot tolerate aspirin, you may have trouble eating certain fruits, vegetables or nuts. You might also discover intolerance to coffee, wine and beer.

Seeking a doctor's advice is always important even though there is no real test for food intolerance. Your doctor might advise you to keep a food diary, or pay close attention to what you eat on a daily basis. Foods eaten every day or eaten in large quantity will trigger symptoms of food intolerance.

If you are lactose intolerant, but have cream in your coffee in the morning or a simple glass of milk, you may not experience any side effects. However, if you are a heavy coffee drinker who uses cream regularly or you are used to having several glasses of milk daily, you will most likely experience the uncomfortable side effects if you are lactose intolerant.