Medical professionals have warned that a limited diet can have dire effects, following a case study in which a teenage boy from the United Kingdom lost his sight after eating nothing but fries, potato chips, and white bread.
The study, published by the University of Bristol, details the patient’s extremely limited diet: he reportedly told doctors that he only ate Pringles potato chips, fries, and processed ham sandwiches on white bread — and had done so since primary school. He also said that he avoided eating foods that had certain textures.
The patient first visited a doctor at the age of 14, claiming to be fatigued all the time. He had a fairly normal BMI, and exhibited no outward signs of malnutrition. He did, however, have low levels of vitamin B12, and was anemic. He was treated with injections of vitamin B12 and given dietary advice by his doctor.
A year later, he began to experience loss of hearing and problems with his vision, but doctors were unable to pinpoint the cause. By the time he reached the age of 17, his visual impairment had worsened, and he was totally blind. The case study reports that he was eventually diagnosed with nutritional optic neuropathy. This condition is most common in patients who suffer from a bowel illness, or who are taking medication which prevents the absorption of nutrients. In developing countries, it can also occur as a consequence of malnutrition.
In the patient’s case, the nutritional optic neuropathy was due to serious deficiencies in vitamin B12, copper and selenium, reduced levels of vitamin D, low bone density, and a high zinc level. While nutritional optic neuropathy is treatable if detected early enough, once blindness occurs, it is irreversible.
“Our vision has such an impact on quality of life, education, employment, social interactions, and mental health,” said study lead author Denize Atan, an ophthalmologist at Bristol Medical School and Bristol Eye Hospital. “This case highlights the impact of diet on visual and physical health, and the fact that calorie intake and BMI are not reliable indicators of nutritional status.”