I have Labrador Retrievers who get itchy from late spring until late fall

I have Labrador Retrievers who get itchy from late spring until late fall. I have used Apoquel which has worked, but I am opposed to suppressing an animals immune system on a long-term basis. I am looking for some natural remedy, whether it’s food or supplements that actually work. I have tried several with not either a little improvement or none at all. Please give me some ideas of foods or supplements that might minimize the discomfort. Thank you.