If you think your immune system is just a simple thing that only helps you fight off colds and flus, think again. It is, in fact, a highly complex, protective, and intelligent system that can bolster health and healing from head to toe. A number of factors--from your diet, lifestyle, and the illnesses you've had to the medications you take or the toxins and people you interact with on a daily basis--can throw your immune system off balance, resulting in excessive inflammation that worsens allergies and pain and can even lead to serious health conditions.

Don't panic: You can feed,...