Allergic reactions to vitamin B12 are rare, but real. The reason may sound strange, but it's true - an allergy to cobalt.

Picking out a snack is easy for most people, but for those living with severe food allergies, it can cause severe anxiety.

Aches and pains. Pain (think: body aches and a sore throat) is also a tip off that you’re dealing with a virus like a cold.