In the sixth grade, we spent a large portion of health class talking about nutrition. We learned about the food pyramid, cholesterol, and the mechanics of the digestive system. We also spent an inordinate amount of time discussing nutrition-related diseases like rickets, scurvy, and beriberi.
I’m not sure why our teachers thought that a group of well-fed children from Ohio were at risk of developing such archaic diseases of malnutrition, yet we spent more time learning about the poor dietary habits of seventeenth-century pirates than we did learning about the consequences of real-life nutritional deficiencies or about the actual nutritional benefits of vitamins.
As Americans during a time of relative plenty, we don’t have to worry about some of the most destructive forms of malnutrition, but a lopsided diet that deprives the body of vitamins and minerals can still take a big toll on our health.
It’s not true that eating carrots can make your eyesight better, but not ingesting vitamin A can have disastrous consequences. Also called retinol, it’s required to produce a photoreceptor pigment in the retina, as well as maintain skin health. Due to a rice-based diet, vitamin A deficiency is still rampant in Asia, where it’s the most common cause of childhood blindness. In adults, it cripples the immune system, causes skin problems, and destroys the eyes. The first symptom is usually night blindness, followed by the failure of the eye to lubricate itself by producing tears. Eventually, patches of dead skin and other secretions can build up on the conjunctiva, and lesions develop on the cornea.
Vitamin A deficiencies can also cause the skin to harden and crack, including the mucous membranes in the lungs, digestive system, and urinary tracts. To prevent it, eat plenty of dark, leafy-green vegetables such as spinach and kale, as well as bright-colored fruits like papayas and mangoes. Egg yolk, liver, and fish oil can also be helpful. Vitamin A is a fat-soluble vitamin, so eating it with some kind of dietary fat increases the amount of the vitamin that the liver can absorb.