This is the theory. Like increases like. You feel cold and have a cold, then eating and drinking cold will increase the cold.
Ice cream in Winter is not a good decision. It will cause congestion and lower your digestive capacity and basically set you up for allergies in the Spring.
When a bug is trying to leave the system it needs to be flushed out via the circulatory system into the digestive system/elimination system. If you impair this function by FREEZING it then the cold will just stick around.
If you want to treat yourself or your kids, then look for warm desserts.