Food vitamins and minerals can lead to diseases that can have far-reaching effects on health. For instance, 30% of the world's population either has, or is at risk for developing, iodine deficiency. It is estimated that at least 3 million children are blind due to vitamin A deficiency. Vitamin C deficiency results in scurvy. Calcium, Vitamin D, and phosphorus are inter-related; the consumption of each may affect the absorption of the others. Kwashiorkor and marasmus are childhood disorders caused by lack of dietary protein. Many individuals limit what foods they eat for reasons of morality, or other habit. For instance, vegetarians
Scurvy with many dying as a result. During the Age of Exploration (between 1500 and 1800), it has been estimated that scurvy killed at least two million sailors. Jonathan Lamb wrote: "In 1499, Vasco da Gama lost 116 of his crew of 170; In 1520, Magellan lost 208 out of 230;...all mainly to scurvy." In 1579, the Spanish friar and physician Agustin Farfán published a book in which he recommended oranges and lemons for scurvy, a remedy that was already known in the Spanish Navy. In 1593, Admiral Sir Richard Hawkins advocated drinking orange and lemon juice as a means of