Determination of Iron Bioavailability in the Diets of Pregnant Adolescents in East Tennessee

Determination of dietary iron intake and estimation of iron bioavailability in the diets of pregnant adolescents (ages 13 to 18 years) in East Tennessee (N=100) was performed to assess iron nutriture adequacy. Using a combination of two 24-hour recalls and 2-day diet records, results indicated daily total iron intake (14.8 ± 8.9 mg) was below the recommended Dietary Allowance (RDA) of 30.0 md/d for pregnancy. Mean intakes of protein and ascorbic acid were ≥ 150% of the RDA for these nutrients. Using the Monsen and Balintfy model to estimate overall iron bioavailability, the 8.996 ± 1.2% was less than the 10% absorption level assumed by the National Research Council. Breakfast, lunch, and evening meals provided 23%, 31%, and 36% of the daily energy intake, respectively. Breakfast contained significantly more (p ≤ .05) ascorbic acid than either lunch or evening meals. Consumption of meat, fish, and poultry (MFP) was significantly more (p ≤ .05) in the evening meal than breakfast and lunch meals. This resulted in MFP contributing to total enhancing factors (EF) and making total iron bioavailability significantly higher for the evening meal (p ≤ .05) than for breakfast and lunch. Snacks contributed a moderate amount to overall iron nutriture; mean total iron intake was 2.6 me, 1.7 mg, and 1.7 mg for morning, afternoon, and evening snack periods, respectively. Iron bioavailability between snacks was not significant (p ≤ .05). It was concluded that dietary iron status in pregnant adolescents in East Tennessee is less than the recommended standard. Dietary intervention and nutrition counseling should focus on total iron intake, food combinations, and preparation techniques to improve bioavailability.