What is rickets?
Rickets is an abnormal bone formation in children resulting from inadequate calcium in their bones. This lack of calcium can result from inadequate dietary calcium, inadequate exposure to sunshine (needed to make vitamin D), or from not eating enough vitamin D - a nutrient needed for calcium absorption. Vitamin D is found in animal foods, such as egg yolks
and dairy products.
Vitamin D is made by the body when it is exposed to ultraviolet light (sunlight). Vitamin D is also added to milk, milk products, and multi-vitamin pills. Some people who do not get enough sun exposure, milk products, or green vegetables may also develop the disease, but that rarely happens anymore. Hereditary rickets, is caused by an inherited disease that interferes with the resorption of renal tubular phosphate in the kidney. Rickets can also be caused by certain liver diseases. A similar disorder can occur in adults, and is called osteomalacia. Then, it is caused by the inability of bone cells to calcify, or harden. Less frequently, nutritional shortage of calcium or phosphorus may produce rickets.
Rickets is a failure to mineralize bone. This softens bone (producing osteomalacia) and permits marked bending and distortion of bones. Up through the first third of the 20th century, rickets was largely due to lack of direct exposure to sunlight or lack of vitamin D. Sunlight provides the necessary ultraviolet rays. These rays do not pass through ordinary window glass. Once the role of vitamin D in rickets was discovered, cod liver oil (which is rich in vitamin D) became a favored, if not too tasty, remedy. Thanks to such supplements of vitamin D, nutritional rickets has become relatively rare in industrialized nations. It still occurs, for example, in breast-fed babies whose mothers are underexposed to sunlight and in dark-skinned babies who are not given vitamin D supplements. And in unindustrialized countries, vitamin D deficiency rickets continues to be a problem.
Rickets most commonly affects children, who may have low vitamin D levels due to poor diet or a condition (such as celiac disease) that makes it difficult for the body to absorb vitamin D and calcium. Rickets is most likely to occur during periods of rapid growth, when the body demands high levels of calcium and phosphate.