You’re referring to the widely publicized case of a young man, now 19, who lost his sight and some of his hearing as a result of eating a diet for years which was limited to junk food. The physicians who treated him reported that he had a normal body mass index (BMI) and no visible signs of malnutrition. Speaking anonymously to the British newspaper The Guardian, the young man’s mother said her son became a fussy eater when he was about seven years old, consuming only French fries, potato chips, sausages, processed ham and white bread. The family first became aware of this when her son would come home from primary school with his packed lunch of sandwiches and fruit untouched.
Doctors first found that the teen was anemic and had low levels of vitamin B12. He was given injections of B12 and dietary advice, but a year later he had developed vision problems and hearing loss for which no cause could be found. By the time he turned 17, his vision had worsened, he had a vitamin B12 deficiency, low copper and selenium and vitamin D levels, a high zinc level, and low bone mineral density.
His junk food diet was believed responsible. He was diagnosed with a condition called “avoidant restrictive food intake disorder (Arfid), which sensitizes people to the taste, texture, smell and appearance of certain types of food, making them unappealing.
The eye problem the young man suffers from is nutritional optic neuropathy, a dysfunction of the optic nerve that can be reversed when caught early but results in permanent damage to the optic nerve and blindness if left untreated. In developed countries, the most common causes of this condition are bowel problems or medications that interfere with the absorption of various nutrients. Elsewhere in the world, poverty, war and drought linked to malnutrition can lead to higher rates of this condition.
Researchers at the Bristol Eye Hospital where the young man was treated suggested that his condition could become more prevalent “given the widespread consumption of junk food at the expense of more nutritious options, and the rising popularity of veganism if a vegan diet is not supplemented appropriately to prevent vitamin B12 deficiency.” They recommend that doctors take a dietary history as part of the routine physical exam, a step that might prevent missing a diagnosis of nutritional optic neuropathy soon enough to correct it. They note that deficiencies of vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B6 (pyridoxine), vitamin B9 (folate), vitamin B12 (cobalamin), iron, calcium, magnesium, and copper are all known to favor development of optic neuropathy.
Andrew Weil, M.D.
Denise Atan et al, “Blindness Caused by a Junk Food Diet,” Annals of Internal Medicine, September 3, 2019, doi: 10.7326/L19-0361