Consider: if your body is healthy but your mind is filled with negativity, stress or toxic thoughts, you cannot function optimally. This can result in dis-ease or  disease. If your mind is positive, quick and bright but your body is ill, you are incapable of giving your all. This can result in dis-ease or disease. If your mind and body are quite healthy but your spirit is in pain from loss, or trauma it is difficult to live wholly, openly and with trust. This can result in dis-ease or disease.
To calm and control the mind, we learn that meditation and the practice of positive thinking are highly effective tools to stop the 'monkey mind’ – or the ‘mind chatter'. Again, developing a steady meditation practice for a short time every day will change your life. Taking charge of a runaway negative mind by replacing negative thoughts with positive ones is a way to re-train the mind to serve us in a healthy way.
Without this control, the mind tends to control us causing depression and anxiety, or anger and fear-based behaviors. The use of visualization is also very helpful in boosting our mental immunity.
The practice of meditation  is an organic, holistic, immune system "booster" that provides us with natural ways to reduce the effects of not only physical, but also mental, emotional, and spiritual pollution. Meditation helps us realize that not only the physical toxins that we encounter day to day in our environment affect us, but also by the pollutants to our mind, our spirit, our energy and our divine nature. There are countless studies that show that both yoga and meditation  improve immune functioning in all layers of our being and it is actually working to benefit us from the genetic level all the way through the spiritual level.
Meditation aids in mental focus helping to purify the body, mind and spirit, moving us towards enlightenment and encourages more mindful and healthy behaviors to aid us on this path.
With a steady and regular meditation  practice, we have a much greater sense of inner  awareness which enables us to detect sooner when something is not right. By being more in touch with ourselves we're able to administer self care more quickly and efficiently by adjusting our asana or breathing practice to a more gentler one, spending more time in meditation, eating more mindfully, and resting when necessary.
It is so important to understand how you can direct your meditation intentionally, in order to heal yourself and keep yourself balanced and healthy. Whenever you feel like you're coming down with a cold or flu, if you're dealing with a diagnosed illness, or you feel that something is wrong and you don't know what it is- use meditation to let help you let go of fear and surround yourself with healing light.
Please feel free to listen to my healing meditation.