Your first line of defense is to choose a healthy lifestyle. Following general good-health guidelines is the single best step you can take toward naturally keeping your immune system strong and healthy. Every part of your body, including your immune system, functions better when protected from environmental assaults and bolstered by healthy-living strategies such as these:
Eat a diet high in fruits and vegetables.
Maintain a healthy weight.
If you drink alcohol, drink only in moderation.
Get adequate sleep.
Take steps to avoid infection, such as washing your hands frequently and cooking meats thoroughly.
Try to minimize stress.