Despite huge leaps in modern medicine throughout the 20th century, certain ailments have only gotten more common-- About one in five Americans now has some kind of allergy, ranging from seasonal hay fever to life-threatening food sensitivities.
Roughly one in 13 has an autoimmune disease-- a disorder in which the immune system tasked with our protection instead attacks our own body -- such as Crohn’s, lupus, and ulcerative colitis.
These diseases are twice--possibly three times-- more common in recent decades. Why-- and what’s to be done?