Rickets, a bone disorder caused by vitamin D deficiency, appears to be on the rise in infants and toddlers who are exclusively breastfed, particularly African Americans.

Because of this, the American Academy of Pediatrics (AAP), will likely issue new recommendations that all breast fed infants receive vitamin D supplements, in the near future.

Although breastfed infants are more at risk for a vitamin D deficiency, experts caution that breast milk is still the best food source for infants.

Thirty cases of severe rickets have been seen in the past 10 years in North Carolina, but 60% of those cases occurred in the last 18 months, according to one report. All the cases occurred in African-American babies who were exclusively breast fed, and the cases were so severe the infants sometimes had obvious bone abnormalities or even seizures.

In Georgia, the CDC found six cases of severe rickets occurred in youngsters 7-21 months of age between January 1997 and June 1999. The children were breast-fed for at least 7 to 19 months and in one instance, a child drank an unfortified milk substitute after being weaned.

Although most diagnosed cases are especially severe, doctors suspect there may be many more mild cases of the illness that go undiagnosed.

"Any time there's a case report of a clinically apparent deficiency disease it's likely there were more children that were deficient that we weren't able to pick up," said Dr. Susan Baker, chair of the AAP's Committee on Nutrition.

The vitamin D deficiency in rickets is a "failure of the bony matrix to mineralize," Dr. Baker said. Bones become soft and weak, and typically the legs bow outwards due to the weight of the body. The condition can lead to skeletal abnormalities, and in severe cases, seizures. While 50% of children under the age of five had the condition in the late 1800s, the condition was thought to be relatively rare now in the US.

One reason for the recent increase may be the trend towards protecting babies from sunshine, the primary source of vitamin D. The risk is especially great for darker skinned infants, who have higher levels of skin pigment, which limits the amount of vitamin D production triggered by the sun.

"Human milk unfortunately has very little vitamin D," Dr. Baker said. According to the AAP, the answer may be to provide breast-fed infants, regardless of race, vitamin D supplements.

In addition, adequate vitamin D levels are important for older children and adults as well. Dr. Baker states that if fortified milk is not a part of someone's diet, they should not rely on alternative products such as soy milk or rice beverages, which are not always fortified with vitamin D.

All commercially available infant formulas are fortified with vitamin D, and formula-fed infants should not be given vitamin D supplements, according to the experts, since too much vitamin D can be toxic.

Meeting of the American Academy of Pediatrics October, 2000 Chicago, Illinois