Molar ratios of dietary phytate to minerals and iron status of female residential students in University of Dhaka, Bangladesh

Phytate-iron molar ratio and bioavailability of iron in Bangladesh

OBJECTIVE

Phytate, an important component of plant origin foods, works as a chelator for mineral nutrients such as iron. Estimating the phytate-iron molar ratio is a traditional method to assess the bioavailability of dietary iron, and a ratio >1 is suggestive of poor absorption of iron through the intestinal mucosa. In Bangladesh, the ratio is considerably higher; nonetheless, the haemoglobin and ferritin status are satisfactory. Hence, we appraised phytate-iron molar ratios and concomitant haemoglobin and ferritin status.

METHODS

Dietary intake of iron and phytate was estimated in non-pregnant non-lactating women and school-age children from a nationally representative survey. The phytate-iron molar ratios were estimated. Linear regressions on haemoglobin for the phytate-iron molar ratios and on molar ratios predicting inflammation-adjusted ferritin were performed.

RESULTS

The median ratios were 6.12 in women and 5.47 in children, with corresponding haemoglobin concentrations of 12.6 and 12.5 g/dl. Hypothetical lowering of the ratios by ~50% revealed a nominal increment of haemoglobin and ferritin.

CONCLUSION

The standard cut-off phytate-iron molar ratio of >1 is inconsistent with the iron and haemoglobin status of the Bangladeshi population. One plausible explanation for the inconsistency is a non-dietary environmental factor-groundwater iron. Isotope studies incorporating the iron from dietary and the drinking groundwater sources are needed to establish a ratio which might better explain iron bioavailability.

Plant-based Diet and Iron Deficiency Anemia in Sundanese Adolescent Girls at Islamic Boarding Schools in Indonesia

BACKGROUND

Adolescent girls are at risk for iron deficiency anemia (IDA) due to the higher demand of iron for growth and the loss of blood during menstruation. Consumption of foods containing iron that have higher bioavailability can reduce the risk of IDA although diets that are largely plant-based, like those consumed by many Sundanese people, may not contain sufficient bioavailable iron. Here, we investigated the correlation between plant-based diets and IDA in adolescent Sundanese girls who were students at Islamic boarding schools in Indonesia.

METHODS

A total of 176 girls from seven Islamic boarding schools in Tasikmalaya were recruited. Nutritional intake data were obtained using 24-hr dietary recall. Blood samples were analyzed with a Sysmex-XNL instrument to measure several parameters including hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC).

RESULTS

The prevalence of IDA in the study population was 22.2%. Iron intake was 6.59 mg/day, which was lower than the recommended amount. The molar ratio of phytic acid to iron and vitamin C to iron was 8.72 and 0.03, respectively. There was a correlation between heme iron and both hemoglobin (p=0.009) and hematocrit (p=0.018). Iron from meat, fish, and poultry was correlated with hemoglobin (p=0.009) and hematocrit (p=0.011).

CONCLUSION

The Sundanese plant-based diet did not affect the IDA status. Instead, IDA was associated with consumption of less animal-based foods that have iron with higher bioavailability. Increased access to an animal-based menu at the school cafeteria could be an approach to prevent IDA in students at Islamic boarding schools in Indonesia.