A case study in a medical journal illustrates the hazards of extremely picking eating. A young patient in the UK says in elementary school he began subsisting on a narrow range of food—potato chips (mostly Pringles), french fries, white bread, and sliced ham and sausage, reports CNN. The result after several years: blindness, according to University of Bristol researchers writing in the Annals of Internal Medicine. After the boy went to the doctor at 14 because he was tired all the time, doctors diagnosed him with anemia and a B12 deficiency. He got a shot and dietary advice but didn’t change his ways. Hearing loss and vision trouble showed up the following year, per Live Science, though doctors weren’t sure of the cause. The teen’s vision worsened to 20/200—legally blind—over the next two years; tests finally revealed damage to his optic nerve.
The diagnosis? Nutritional optic neuropathy, which can be reversed if caught early enough. In this case, it wasn’t. In developed countries, the disease is typically caused by bowel issues or drugs that prevent the body from absorbing nutrients. This time, though, the teen appears to have caused it through years of “junk food” consumption, per the researchers. It was particularly hard to detect because the teen had a normal body-mass index. “Although it is an extreme example, it highlights the importance of having a wide and varied diet,” says a professor of nutrition at Imperial College London who was not involved in the study. For the record, another expert at King’s College London is skeptical because the case study relied on the patient’s own reporting of his diet. He wonders about a genetic cause. (Something similar happened to a boy in Canada.)