Vitamin A deficiency is surprisingly common today. An interesting story about Eduard Schwarz, an early doctor/researcher (plus much about vitamin A) is at: ht

Vitamin A deficiency is surprisingly common today. An interesting story about Eduard Schwarz, an early doctor/researcher (plus much about vitamin A) is at: http://www.westonaprice.org/health-topics/abcs-of-nutrition/vitamin-a-saga/ http://www.westonaprice.org/health-topics/abcs-of-nutrition/... An Excerpt: "Eduard Schwarz (1831-1862), a ship’s doctor on an Austrian frigate that was sent around the world on a scientific exploration. Before his departure from Vienna, several physicians had asked Schwartz to test the old folk remedy of boiled ox liver against night blindness. On the voyage, 75 of the 352 men developed the condition. Every evening when dusk came, they lost their vision and had to be led about like the blind. Schwartz fed them ox or pork liver and found that the night vision in all of the afflicted was restored." More about Schwarz: http://www.sciencedirect.com/science/article/pii/S0899900797002037 http://www.sciencedirect.com/science/article/pii/S0899900797... Should you want to test yourself, a teaspoon of cod liver oil should do the trick. Animal-based versions of vitamin A seem to be more efficacious than their vegetable analogs. Meanwhile eat your liver(mmmm!), fish, carrots and blueberries.