Just A Spoonful of Sugar...

...can harm your eyesight!

Yesterday in class, my teacher was describing some differences she notices in herself when she eats too much sugar. One thing that caught my attention: the day after a sugar “binge”, she notices her eyesight is cloudier. She said there is a definite link between high sugar diets and quality of eyesight.

This was particularly interesting to me because of what happened at my last eye appointment. I know that I have always eaten too much sugar, but in the past six months I have cut back significantly. When I went to my annual eye appointment in December, the vision in my right eye had actually improved! I didn’t think much of it until now. I wonder if it is because I have decreased sugar in my diet?

Another interesting observation: I had better-than-perfect eyesight all the way until my sophomore year of college, when suddenly I needed glasses to see even the white board in class. Let’s piece this puzzle together: ages 0-18 I was living at home, playing sports, and eating my mom’s home-cooked meals that always included fresh, high-quality foods. Then at age 18, I move to Milwaukee, WI, the Beer Capital of the World, and live in a dorm nicknamed “The Beer Can”. I was partying a lot (excessive alcohol intake causes high blood sugar), but also working and studying hard, so I drank too much coffee (usually with a sugary syrup) and ate poorly. And to top it off, I was not getting as much exercise as I got in high school. I think I was walking evidence that high-sugar diets and poor eyesight are linked!

Besides our brains, our eyes need more oxygen and nutrients than any other part of our bodies. When we eat excess sugar, the sugar molecules attach to hemoglobin in our blood. This, in turn, makes it more difficult for our blood to deliver oxygen throughout the body. Oxygen is needed to power most metabolic processes and is vital to the proper functioning of many things in our bodies.

A high sugar diet causes blood sugar to spike and dip very quickly. When our blood sugar fluctuates, our tiny blood vessels are shocked and they weaken and become very narrow. This reduces blood flow throughout the body, including oxygen transport to the eyes.

There are other studies I found that link nearsightedness, or myopia, in children to their high-sugar and high-carbohydrate diets. When blood sugar is high, insulin levels elevate. And when the insulin levels go up, the body does not produce as much of a certain protein that is used to shape eyeballs and lenses for clear vision.

In older people, cataracts are a common problem. Cataracts form when sugar molecules attach to the proteins in the lens of the eye. This causes the lens to twist and fold, which leads to cloudy vision. Many older people with cataracts have eaten too much sugar throughout their lives.

Sugary foods include the obvious cakes, pastries, candy and ice cream, but also other simple carbohydrates such as white bread, processed cereals and white pasta.

And now for the good news…

All of these processes can be controlled or reversed through nutrition! Don’t you just love nutrition?!

When you eat carbohydrates, try to stick with only complex carbs such as whole grains, fresh fruits and vegetables, and legumes. And be sure to buy the highest quality you can afford of these items (think Whole Foods freshly baked whole grain bread, not Oroweat 7-grain bread). In addition, making sure you get plenty of antioxidant nutrients like vitamins A, C and E will help prevent or repair poor eyesight. These are found primarily in fresh fruits and vegetables. Controlling alcohol intake will also benefit eyesight (and countless other things) throughout our lives.

So, if you’re like me, you may have taken a little hit in college (but it was oh so worth it… college was so great!), but it is never too late to improve our diets and reverse or prevent the many diseases that are associated with high sugar intake.


  1. I've known for a while that I eat too much sugar, but was just hard pressed to convince myself to do anything about it. This blurry vision insight hits home -- and since my vision is one thing I don't want to mess with - I think this may just be the kick I need to watch my sugar intake a lot more closely! Keep up the good work!!!

  2. I can't believe that I found this post when I did. I just came off of a big sugar binge a.k.a. the holidays, and so far this month, I find myself having to lean a little closer in to see certain words on my computer. It could be that I need glasses, but I did NOT have this problem last month.

  3. Rahim - That is so interesting! Especially because I had a friend tell me the same thing yesterday: She ate a lot of simple carbs (mac & cheese, white bread, etc. - all things that turn to sugar immediately inside our bodies) and the next day she was trying to write something, and her vision was all off and she had brain fog. I think the effects can be that immediate, but things like this can also be reversed if we eliminate sugars for a couple weeks to cleanse our systems.

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