Nutritional infusion for lupus sufferers ?

I was in the Co op the other day and happened to notice a drink for 'defence' - it said if you had been sick or suffering from a cold it could help. Someone else was also telling me the other day that ekenasia (natural alternative drops I think from a health food shop) can also help if you have a cold.

Does anyone know if there will be a whole lot of food you can eat to help the immune system and fight lupus?

Any ideas would be interesting.