You need to be infected by the cold virus before you can build immunity to it. Food, vitamins or minerals are not going to do it for you.
Boosting the immune system is meaningless statement anyway. The immune system is just that; a system. It’s not a single entity but an extremely complex series of interactions on many levels. It's made up of special cells, proteins, tissues, and organs, and is not something you can just ‘boost’.
In any case, boosting would be bad – for example if you have a cold the symptoms are due to your immune response to the virus. Would you really want to boost that response and get increased fever, mucus, congestion and sneezing? Or produce an inflammatory response which can lead to things like heart attacks?
Your goal should be to keep your immune function operating at it's optimal baseline, you can't do better than that. Maintain a healthy diet and lifestyle, get plenty of exercise and rest, don't smoke and go easy on the alcohol and coffee.
Avoid crowds and sick people, wash your hands frequently and get your flu shot.