A British teen has been left blind and partially deaf after living off a diet of chips, sausages and crisps.
The boy’s diet was so bad he suffered from a condition normally only seen in malnourished third world children.
It is believed to be the first case of its kind in the UK.
The 17 year-old only ate chips, Pringles, sausages, processed ham and white bread – for up to a decade.
He told doctors he did not like the “texture” of fruit and vegetables.
Corresponding author Dr Denize Atan, of University Hospitals Bristol NHS Foundation Trust, said: “He had a daily portion of fries from the local fish and chip shop and snacked on Pringles (Kellogg), white bread, processed ham slices and sausage.”
The shocking lack of vitamins damaged his optic nerve – which connects the eye to the brain.
He was found to have a condition called nutritional optic neuropathy (NON) – usually only seen in Africa and other undeveloped countries.
Dr Atan said the youngster’s blindness was caused by junk food. He was suffering from a rare eating illness known as ARFID (avoidant-restrictive food intake disorder).
It’s ‘picky eating’ taken to extremes. Sufferers become sensitive to the taste, texture, smell or appearance of certain types of food. Some can only eat them at a certain temperature.
The unnamed patient, from the West Country, also developed hearing loss and bone weakness. Eating too much sugar and carbohydrates in processed food can damage the ears.
Dr Atan said: “The conditions remained undiagnosed for several years.”
The boy was blind by the time he reached 17. Experts at Bristol Eye Hospital were mystified.
NON can run in families but there were no hereditary signs. But he was deficient in vitamin B12 found in offal, milk, fish and eggs – prompting further investigation into his diet.
He said he didn’t drink, smoke or take drugs – which can all cause NON. He was not overweight. His height was average and his BMI (body mass index) of 22 was normal.
Dr Atan said: “However, the patient confessed that, since elementary school, he would not eat certain textures of food.”
He had first been taken to his GP three years earlier, when he was 14, complaining of tiredness.
Aside from being labelled a “fussy eater”, he was otherwise well and took no medications.
Blood tests showed he was anaemic, due to low B12 that causes fatigue. He was treated with vitamin injections and advised about his diet.
But at 15 his hearing began deteriorating – and his sight soon afterwards. MRI scans found no structural damage to the ears.
Following two years of progressive loss his visual sharpness was just 20/200. He was diagnosed with NON.
The boy had lost nerve fibres in the retina. The tiny organ at the back of the eye sends light signals to the brain where they are converted into images.
His central visual field had been ruined, said Dr Atan.
She said his vitamin B12 injections had lapsed. He also had low copper and vitamin D levels – and poor bone mineral density.
Dr Atan said: “He was prescribed nutritional supplements that corrected his deficiencies and was referred to mental health services for his eating disorder.”
Normal vision is 20/20, which means you can read an eye chart at 20 feet. To be considered legally blind, it needs to be 20/200 or worse.
This means you can read an eye chart at 20 feet about as well as someone with normal vision could read it at 200 feet.
The little sight he had left stabilised – but “did not improve”, said Dr Atan.
Purely dietary causes of NON are rare in the Western world.
His lack of vitamin B and copper “likely contributed to the patient’s vision and hearing loss”, said Dr Atan.
The vital nutrients are found in liver, seafood, poultry, dairy produce, vegetables, nuts and seeds.
His bone weakness was probably caused by not consuming oily fish, cheese and eggs – which contain vitamin D.
Dr Atan said: “Junk foods are nutritionally poor but energy-dense and cheap.
“Hence, high-energy diets correlate with high BMI, low socioeconomic status and poor health.
“‘Fussy eating’ that is restricted to junk foods and causes multiple nutritional deficiencies is an eating disorder.
“Avoidant-restrictive food intake disorder (ARFID) is a relatively new diagnostic entity, but unlike anorexia nervosa, it is not driven by weight or shape concerns.
“Onset is in middle childhood, with lack of interest in food, heightened sensitivity to food textures, and fear of the consequences of eating.
“As in this patient, BMI is often normal.”
Her team warned NON should be considered in any patient with unexplained vision symptoms and poor diet, regardless of BMI.
It is potentially reversible if caught early. But if left untreated, it leads to permanent blindness.
Reporting the case in Annals of Internal Medicine, they said it is well known junk food increases the risk of poor cardiovascular health, obesity and cancer.
But poor nutrition can also permanently damage the nervous system – particularly eyesight.
Doctors need to be aware of the “visual complications of a diet restricted to junk food,” they said.