Until very recently, the true causes of most diseases have been a mystery, and that is still largely the case today. We know, of course, that infectious diseases begin when a virus, bacteria, or some other parasite invades our bodies, and in many of these cases researchers have developed vaccines, antibiotics, or other forms of treatment. We know that exposure to toxins can disrupt mechanisms in our cells and poison us or cause cancer. We also know that our diet, our lifestyle, or other aspects of our interaction with the environment can cause serious health problems such as obesity, diabetes, and cardiovascular disease. Genetic factors also play a role: the unique set of DNA that we inherit from our parents can cause illness or make us more likely to develop Alzheimer’s and a wide range of other diseases. But exactly how all of these factors disrupt our molecules, cells, and tissues and eventually kill us – even in normal processes such as aging – remain largely a mystery.
Russ Hodge, science writer at the Max Delbrück Center for Molecular Medicine, answered this question.