For decades, parents around the world have encouraged children to eat their carrots in order to have healthy vision. If it were only that easy. If carrots could be to human eyes what spinach is to Popeye’s muscles, blindness wouldn’t exist, and we’d only wear glasses for cosmetic purposes. While there is some evidence that suggests eating carrots may help maintain current vision capabilities, there is no solid proof that eating carrots will improve eyesight.
Parents of picky eaters should not lose heart; carrots are high in beta-carotene (a pro-vitamin) which converts into Vitamin A. In terms of eyesight, Vitamin A plays an important role in maintaining healthy vision. When the body is deprived of Vitamin A there are risks of vision impairment and xerophthalmia — drying of the cornea. Blindness due to a lack of Vitamin A rarely occurs in the United States, however, it is a problem found in children from developing countries.
With too much Vitamin A there is some risk of toxic death, but carotenemia, a condition which turns skin orange or yellow, is more likely to occur. In either case, a healthy balance of Vitamin A can be attained by either increasing or decreasing the amount of carrots in your diet.
The United States Department of Agriculture (USDA) recommends a daily intake of 1,300 micrograms of Vitamin A. That means that eating an average sized carrot will give you more than 400% of the recommended daily intake. Because Vitamin A is found in many other foods like milk, eggs, and liver, eating carrots on a daily basis generally isn't necessary. (Neither is the apple, but that’s another topic).
A number of claims state that eating carrots will also improve eyesight at night. This is also a statement that deserves some reservation. The origin of eating carrots to improve eyesight in the dark may come from studies that show that once a carrot is consumed, Vitamin A is transformed at the eye’s retina into rhodopsin — a purple pigment needed for nighttime vision. Another source for the misinformation may come from associated risks for blindness, as challenges with nighttime vision are typically the first signs of a Vitamin A deficiency. As in the case for daytime vision, consumption of carrots may help maintain nighttime clarity, but will not necessarily improve eyesight.
Interestingly enough, scientists have found that certain amounts of chlorophyll derivatives, found in leafy green vegetables, may enhance eye sensitivity to red light, which improves nighttime vision. But don’t go betting on spinach and nighttime safety just yet. A safer bet would be on improved lighting; better than that is good medical care.