Politics means the world of government in general:
The vice-president has a long career in politics.
I hate discussing politics with my family because it always turns into an argument.
Sometimes people talk about "office politics" outside the context of government -this means the connections and actions that people inside a company take in order to gain power, forming relationships and manipulating situations to their advantage.
A policy is like a rule. Countries have policies (foreign policy, immigration policy, gun control policy) but schools and companies do, too:
Our policy is that customers can return an item and get a refund within 30 days of their purchase.
My school had strict policies regarding lateness - if you were late more than five times, you got suspended.
Food allergies are the abnormal response of the immune system to certain types of food that the body recognizes as harmful. In most cases, the reasons for food allergies are unknown. Food allergies that result in anaphylaxis are the worst kind and according to the