Good health is often a balancing act. Too much sun exposure can cause unwanted sunburn in babies, but too little sun exposure can lead to vitamin D deficient rickets.
Breast milk does not necessarily contain much vitamin D. Neither does cow’s milk, nor most baby foods. Theoretically, mothers and babies can produce their own when their skin is exposed to sunlight. However, the optimal amount of sunlight for each baby is different and difficult to determine. Exposure to direct sunlight in young babies also carries the potential increased risk for burns and eventual development of skin cancer.
Babies who do not get enough or produce enough vitamin D can develop rickets, the failure of developing bones to form properly. In the absence of adequate amounts of vitamin D, the body steals calcium from the bones to keep the blood levels of calcium high enough for life.
Breast-fed babies whose mothers do not get adequate time in the sun can develop rickets. This is especially true in colder climates and in darker-skinned individuals. Window panes, sunscreen, (and sometimes smog or haze) are able to block the sun’s rays needed to create vitamin D.
Today’s infant formulas are supplemented with plenty of vitamin D.
Low birth weight babies and kids with underlying conditions, such as celiac disease or cystic fibrosis, are more susceptible to rickets. Medications such as steroids and anti-seizure drugs can also increase the risk.
Several metabolic, liver, and kidney diseases can interrupt the normal functioning of the calcium/vitamin D system and lead to rickets.
In rickets, the bones do not form properly. Often the first noticeable instance of this is the thin, pliable skull. Pressing on it can feel like pressing on a ping-pong ball. The head shape may be abnormal.
Teething may be delayed and the teeth may be poorly formed. Severe cavities are common.
The wrists and ankles may appear swollen. The tips of the rib bones can enlarge creating a string of lumps called the rachitic rosary. Bowed legs, knock-knees, or fractures are common.
Kids with rickets tend to sweat more than average.
Rickets is suspected by the history and the physical examination. The diagnosis is confirmed by lab tests and x-rays.
For children with nutritional rickets, giving vitamin D will begin reversing the problem. Rickets may be caused by other underlying problems which may require additional treatment.
Babies need an average of 400 IU of vitamin D per day to prevent vitamin D deficient rickets. Because getting the right amount of sun exposure is unreliable and because of the potential risks of direct sunlight to young babies, the American Academy of Pediatrics does not recommend sun exposure as a strategy for preventing rickets. Instead, they recommend that all babies who are exclusively breastfed receive vitamin D supplementation. Babies who are taking less than 32 ounces of vitamin D fortified formula or vitamin D fortified cow’s milk also need vitamin D supplements.
More information on the AAP recommendations may be found here.
Vitamin D Deficient Rickets, The rachitic rosary.