The American Academy of Pediatrics recommends that all breastfed infants receive 400 IU of vitamin D, the “sunshine vitamin,” a day. Vitamin D, along with calcium and phosphorous, is one of the key vitamins babies need to develop strong bones. Without it, babies have a hard time absorbing calcium and phosphorous, which can lead to scary symptoms like pain, fragile bones, a misshapen skull, poor growth, and rickets. Symptoms of rickets may take several months to show up. In adults, a vitamin D deficiency can lead to similar symptoms and, left unchecked, can ultimately contribute to osteomyelitis and osteoporosis. Our bodies also need sufficient vitamin D to reduce inflammation, help with cell growth, and aid in neuromuscular and immune function.
Vitamin D plays a role in maintaining healthy teeth since tooth enamel, the hard substance on the surface of our teeth, is made mostly of the mineral, calcium phosphate. Research suggests that infants of mothers who were deficient in vitamin D during pregnancy are more likely to have enamel defects and higher cavity rates than infants of mothers who had sufficient levels of vitamin D during pregnancy.
If mother’s milk otherwise has all the nutrients a baby needs, why the need for vitamin D supplementation? We naturally produce vitamin D for our bodies by exposing our skin to sunlight, specifically UVB rays, which are the same ones that cause sunburn and can lead to skin cancers, including the deadly malignant melanoma. It only takes 10-15 minutes of exposure to the sun for your body to get the vitamin D it needs. We’re told, however, to keep new babies out of the sun because their delicate skin is so much more susceptible to burning, which raises their risk of skin cancer. Infant sunscreen is only recommended for infants 6 months and older, so until my son was that age, I kept him inside as much as possible and always covered him with a hat and long sleeves. If we follow the common advice to keep our babies out of the sun, they don’t get the vitamin D that they need naturally.
Even if your baby spends time outside, those who live in far northern climates and those with darker skin are at a higher risk for having vitamin D deficiency. In fact, the Canadian Pediatric Society notes that vitamin D deficiency and rickets are more common in infants who live in the high northern aboriginal coastal communities. One of the problems with balancing our need for skin exposure for the sake of getting enough vitamin D while also trying to minimize our risk of skin cancer is that our bodies don’t have a special timer that tells us when we have absorbed the ideal amount of sun. To add to the confusion, the amount of sun we need depends upon where in the world we are, what time of day we are exposed to the sun, and how long we are in the sun.
Formula-fed and formula-supplemented babies have different vitamin D requirements because most infant formula is already supplemented with vitamin D. Your exclusively formula-fed infant may need some vitamin D supplementation if he or she drinks less than a liter, or 32 ounces, of formula a day. It’s always wise to consult your pediatrician about your child’s particular needs.