Racial disparities in preterm birth: an overview of the potential role of nutrient deficiencies.

OBJECTIVE To give an overview of the literature for evidence of nutrient deficiencies as contributors to the disparity in preterm birth (PTB) between African-American and Caucasian women. DESIGN Structured literature survey. METHODS We searched MEDLINE to identify observational and experimental studies that evaluated the relation between nutrient intake and/or supplementation and PTB. For nutrients for which studies supported an association, we searched MEDLINE for studies of the prevalence of deficiency in the USA by race. MAIN OUTCOME MEASURES Summarized findings on nutrients for which there is both evidence of a role in PTB and variability in the prevalence of deficiency by race. RESULTS Nutrient deficiencies for which there are varying levels of evidence for an association with PTB and a greater burden among African-American compared with Caucasian women include deficiencies of iron, folic acid, zinc, vitamin D, calcium and magnesium, and imbalance of ω-3 and ω-6 polyunsaturated fatty acids. There are inadequate high-quality studies that investigate the role of nutrient deficiencies in PTB, their potential interaction with other risks, the proportion of excess risk for which they account, and whether supplementation can reduce the risk of, and racial disparities in, PTB in US populations. CONCLUSION Deficiencies of several nutrients have varying levels of evidence of association with PTB and are of greater burden among African-American compared with Caucasian women. Although further research is needed, strategies that improve the nutritional status of African-American women may be a means of addressing a portion of the racial disparity in PTB.