You’re probably aware of the tragic story about a teen who apparently lost his vision because of a lousy diet. Here’s the opening to an article from CNN:
Eating a diet of french fries, Pringles and white bread was enough to make one teenage boy lose his sight, according to a case study published in a medical journal. Scientists from the University of Bristol examined the case of a young patient whose extremely picky eating led to blindness, and have warned of the dangers of a poor diet.
The unidentified patient told doctors he had only eaten fries from the fish and chip shop, Pringles potato chips, white bread, slices of processed ham and sausage since elementary school, and he avoided foods with certain textures. He first visited a doctor at age 14, complaining of tiredness, according to a case report published in the Annals of Internal Medicine on Monday.
He wasn’t taking any medication, had a normal BMI and height, and showed no visible signs of malnutrition.
Doctors discovered low vitamin B12 levels and anemia, treating the patient with vitamin B12 injections and offering dietary advice. One year later there were signs of hearing loss and vision symptoms, but doctors did not find the cause.
His vision had worsened to the point of blindness by 17 years of age, and doctors identified vitamin B12 deficiency, low copper and selenium levels, a high zinc level, reduced vitamin D level and bone level density, according to a statement from the University of Bristol. By this stage, vision damage was permanent.
That’s horrible. As I read the article, I was expecting someone to point out what seems obvious to me: when your diet is refined carbs, more refined carbs, and even more refined carbs, your blood sugar is probably sky-high most of the time. Chronically high blood sugar damages nerves and other tissues. That’s why diabetics go blind or have their limbs amputated.
But the CNN article mostly blamed the tragic results on malnutrition:
Researchers from Bristol Medical School and the Bristol Eye Hospital examined the case and concluded that the patient suffered nutritional optic neuropathy, a dysfunction of the optic nerve.
The researchers say that poor diet and reduced intake of minerals caused vision loss in this case, and warn that nutritional optic neuropathy could become more common due to the consumption of junk food. They also warned vegans to make sure to supplement for vitamin B12 to avoid deficiency.
Yeah, okay, the kid probably wasn’t getting sufficient vitamins and minerals on that lousy diet. Maybe that figured into it. But again: WHAT ABOUT CHRONICALLY HIGH BLOOD SUGAR? Did anyone even check what his glucose levels were on a diet of fries, Pringles and white bread?
An article on the NPR news site did mention the dangers of too many refined carbs, but boy, it took them a long time to get there – and of course, they had to take a swipe at red meat and high-fat dairy foods along the way, as if that somehow explains what happened to the kid.
“It’s intriguing,” say Allen Taylor, the director of the Nutrition and Vision Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts. “But it’s important to remember it’s a study of only one case with very limited information in it,” Taylor says.
“There is, absolutely, a link between poor diet and vision loss,” Taylor explains. But, he says, usually people don’t develop symptoms until much later in life.
He points to a study he and his collaborators published back in 2014, which found that poor-quality diets can increase the risk of age-related macular degeneration. This can lead to blurry vision and can make reading more difficult. It usually occurs after age 60.
Oh, boy, here we go … I looked up Dr. Taylor’s study. It’s yet another observational study based on those oh-so-reliable food questionnaires. Dr. Taylor divided people into two groups: those who followed what he labeled an “oriental” diet pattern and those who followed a “western” dietary pattern. The NPR article recounts the results:
People in Taylor’s study who consumed plenty of vegetables, legumes, fruits, whole grains, tomatoes and seafood had a lower risk of developing AMD. On the other hand, people who consumed a diet rich in red meat, processed meat, high-fat dairy products, French fries and refined grains had a higher risk of developing the condition.
Head. Bang. On. Desk. Do we see the problem here? Fries and refined grains have nothing to do with red meat and high-fat dairy products. Refined carbs jack up your blood sugar. Meat and butter don’t. Lumping red meat and high-fat dairy foods together with fries and refined carbs because they’re all “western” foods is like lumping gin, vodka and water together because they’re all “clear liquid foods.”
Speaking of lumping foods together, we need to add fruitsvegetableswholegrains! to our dictionary of terms like arterycloggingsaturatedfat! and hearthealthywholegrains! Poke a dietician or health reporter in her sleep, and she’ll mutter fruitsvegetableswholegrains! fruitsvegetableswholegrains! fruitsvegetableswholegrains!
The kid who lived on fries, white bread and Pringles didn’t go blind because he failed to consume enough fruitsvegetableswholegrains! If he did, we can expect carnivores like Dr. Shawn Baker, Amber Hearn and Jordan Peterson to start having vision problems any day now. But I suspect that won’t happen.
Waaay deep into the NPR article, we finally get a possible explanation other than the lack of fruitsvegetableswholegrains!
Consuming a lot of refined carbohydrates, including foods such as white bread, chips, crackers and sweets, is linked to a higher risk of developing AMD and some forms of cataracts. Taylor and his collaborators are trying to understand how refined carbohydrates may inflict damage on the cells within our eyes and bodies.
“If you look at the chemistry behind what’s going on in the cells, you can actually see the vestiges of the carbohydrates in the cells,” Taylor says.
“The carbohydrates end up damaging the proteins within the cells of the eyes,” he says, so the proteins are no longer as functional as they might have been.
Yes. Now we’re getting somewhere. The refined carbohydrates lead to high levels of glucose, which end up damaging the proteins within the cells. Not the meat. Not the high-fat dairy foods. And all the fruitsvegetableswholegrains! in the world won’t prevent a diet of fries, Pringles and white bread from jacking up your glucose.
But as usual, the experts and the people who quote them are blinded by their own biases.