Compiled by Reed Mangels, PhD, RD, FADA
A recent study (1) on orofacial clefts—more commonly known as cleft lip and cleft palate—seems to implicate a vegetarian diet, but on closer examination is a weak piece of evidence.
Cleft lip and palate are birth defects. They occur when an infant’s lip or mouth doesn’t form properly. The lip and palate are formed early in the first trimester of pregnancy—between the 4th and 9th week (2).
The causes aren’t known although there sometimes appears to be a genetic factor. Cigarette smoking, diabetes, and exposure to certain medicines during pregnancy all appear to increase the risk (2).
In the recent study, researchers in India compared infants who had cleft lip and/or cleft palate (cases) with infants who did not (controls) (1). They wanted to see if there were differences in the mothers’ diets, exposure to toxins, and other factors.
A total of 785 infants were studied–157 cases and 628 controls. Most families were quite poor and very few of the mothers took prenatal vitamins.
Not surprisingly, there was a higher rate of cleft lip/palate in infants from families where other family members had this condition. Somewhat surprisingly, there was a markedly higher rate—4.47 times higher (95% CI: 1.83- 10.98)—of cleft lip/palate in infants whose mothers reported following a vegetarian diet.
But it wasn’t clear what the researchers meant by a “vegetarian” diet. They described it as an “exclusive” vegetarian diet, which suggests no animal products—however, a traditional vegetarian diet in India typically includes dairy products. The authors note that some subjects classified as non-vegetarians may have generally followed a vegetarian diet and this could have affected the results.
Information wasn’t provided about specific foods eaten, and although the researchers speculate that low intakes of vitamin B12 or folate could have increased the risk of having an infant with cleft lip/palate, we don’t actually know if there were any differences in intakes.
While intriguing, this was a cross-sectional study measuring a wide range of variables, which is of limited value in providing evidence of causation. A prospective study designed to test vegetarian diets and incidence of orofacial clefts would provide more reliable information.
