Hey,
I've found lots of articles that eatting specific fruits and veggies help to build stronger immune system... like deep green, yellow and orange vegetables (carrots, spinach, sweet potatoes, apricots, muskmelons, tomatoes, watermelons, etc)
My mom used to be a vegetarian, but started eatting meat and fish to help her with her low iron (instead of popin pills)
Thanks
H