This study analyzed cases of rickets in infants and toddlers, which occurred in at one hospital in Texas between 1997 and 1998. They came up with the following observations:
Because of these results, the researchers recommend that all dark-skinned, breastfed babies receive vitamin D supplements, even in warmer climates such as that in Texas.
Rickets, a condition in which a deficiency in vitamin D in childhood leads to abnormal bone formation, can result in bow legs, knock knees and spinal curvature. A deficiency of vitamin D in adults can lead to a condition called osteomalacia, in which the bones become soft.
Vitamin D is an important nutrient, involved in the metabolism of calcium and phosphorus for bone and tooth formation, that can be obtained either from sunlight exposure or from the diet. Fish is the best natural dietary source, but it is also added to most milk.
The researchers suggest that melanin, the pigment that darkens skin, may act as a natural sunscreen and reduce the amount of vitamin D the body produces from sunlight exposure.
Texas Medicine 2000;96:64-68.
Vitamin D is the only vitamin that breast feeding moms need to supplement their children with, unless they are exposed to regular sunshine, as the skin will convert sunshine to vitamin D. The recommendations made in the above study don't take into account those children, of all skin colors, who live in colder climates and get almost no sunlight exposure during the winter months. Also, another possible idea would be to supplement the breastfeeding mothers, so that the vitamin D could be passed on in the milk.
Certain drugs can also interfere with the absorption and metabolism of vitamin D. Some of the known examples are Dilantin, cholestyramine, and phenobarbital. Additionally, because vitamin D is a fat-soluble vitamin, any drug or substance that interferes with fat absorption may cause problems, as may a low-fat diet.
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