Vitamin D is one of the best strategies for avoiding the common cold, the flu, H1N1, and other seasonal viruses.  Vitamin D increases the production of cathelicidin in the cells, which helps your immune system fight off invading pathogens.  The best way to get vitamin D is to be out in the sun for at least 15 minutes for around 3 times a week.  Studies show that most Americans a deficient in vitamin D.

Vitamin C is commonly used in white blood cells.  White blood cells fight off and invaders and vitamin C helps protects the cells from being damaged in this process.  Vitamin C is not naturally produced in the body and must  come from food, but it is highly unlikely that you consume a sufficient amount of vitamin C a day so supplementation is recommended.
 
Probiotics are friendly bacteria in your bowels that is important to your immune system.  Bad bacteria  produces metabolites which are harmful waste products that circle throughout your body.  These metabolites circle around your body putting a strain on your immune system.  The healthy probiotic bacteria helps neutralize these metabolites and produce B vitamins and vitamin K, which are powerful antioxidants to help defend your body.

Selenium is a trace mineral that incorporates protein into selenoproteins, which are some of the strongest antioxidants that prevent cell damage from free radicals.  A few years ago, scientists working with animals noticed animals with selenium deficiency had the flu virus mutate much quicker.  For example, with an animal with normal levels of selium would have a mild case of pneumonia, animals with selenium deficiencies would face a life-threatening severe case of pneumonia 

These are just a few things that you can include in your diet to improve your immune system.  The best practice is supplementation to make sure you receive all of the vitamins and nutrients necessary to boost your immune system.  Biometics suggests the Daily Health Pack which is a program that includes Bio Fuel, Bio Immune, and Cell Care.  This package will give you and your loved ones the tools to remain healthy throughout the holiday season.