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 It was mainly by scurvy that George Anson, in his celebrated voyage of 1740–1744, lost nearly two-thirds of his crew (1,300 out of 2,000) within the first 10 months of the voyage. The Royal Navy enlisted 184,899 sailors during the Seven Years' War; 133,708 of these were "missing" or died from disease, and scurvy was the leading cause. Although throughout this period sailors and naval surgeons were increasingly convinced that citrus fruits could cure scurvy, the classically trained physicians who ran the medical establishment dismissed this evidence as mere anecdote which did not conform to current theories of disease. Literature