none actually. common colds are caused by bacteria and viruses. your diet has little to do with it. however they are more prominent in cold because bacts and viruses thrive better in cold. steaming, using saline drops and doing nose frida helps. Vicks is not recommended for younger kids however you can apply baby rub. just be very careful of not applying too much of it in nosestils. it's should not block the passage completely

in your diet avoid curd & citrus fruits. May be due to climate also. Apply Vicks on feet of baby in night. Don't give head bath daily for few days.