According to the David Foreman, RPh., N.D. diet plays a large role in immune system support. One way to boost your immune system is to avoid sugar and other white foods like pasta, bread, cake, and honey. These type foods make your immune cells ineffective at fighting off disease for extended periods of time. Dairy should also be avoided because it thickens mucous, which can lead to infection.
Instead, a diet high in fruits, vegetables, legumes, nuts, seeds, fish and lean cuts of meats can help your immune system function properly.