Dietary phytate intake inhibits the bioavailability of iron and calcium in the diets of pregnant women in rural Bangladesh: a cross-sectional study

Abstract

Background: Phytate, a potent inhibitor of calcium, iron, and zinc absorption, may hamper the bioavailability of these micronutrients at the time of pregnancy. This study assessed dietary phytate intake and its inhibitory effect on the bioavailability of calcium, iron, and zinc from the diets of pregnant women in rural Bangladesh. The study also explored significant determinants that predicted the absorption of these minerals from the diet. Methods: A multiple pass recall (MPR) approach was used for this study, with in-depth probing interview covering 24-h dietary recall conducted among 717 pregnant women who were in either their second or third trimester. Results: The mean daily phytate, calcium, iron and zinc intake of the pregnant women were found to be 695.1, 192.2, 5.1, and 5.7 mg respectively. The mean molar ratios of phytate to calcium, iron, zinc and (phytate x calcium)/zinc were 0.27, 12.8, 11.2, and 54.8 respectively. All the molar ratios were found to be significantly higher in a group with the highest phytate intake compared to other intake groups. Phytate inhibited iron absorption from the diet of all the pregnant women sampled, and inhibited calcium absorption among 52 % of the women while inhibition of zinc absorption was not found in a notable number (12 %) of the pregnant women. When using multivariate models, phytate intake, inadequate micronutrient intake, gestational age, and energy intake significantly predicted the variance in phytate to mineral molar ratios. The predicting models calculated about 92 %, 88 %, and 89 % variance in phytate to calcium, iron, and zinc molar ratios respectively. Phytate to calcium, iron, and zinc molar ratios would be expected to be respectively 0.05, 2.48, and 1.96 points higher for every 100 mg increment in daily phytate intake. Conclusions: Phytate intake was found to inhibit the bioavailability of iron and calcium from the diets of pregnant women. Moreover, phytate was one of the strongest inhibitory predictors of calcium, iron and zinc bioavailability.

Phytic acid content may affect starch digestibility and glycemic index value of rice (Oryza sativa L.)

“…Most notably, Fe and Zn deficiencies occur due to high phytate intake. Negative effects of PA (mainly low mineral bioavailability) have a significant impact on infants and pregnant and lactating women if their diet contains ample amounts of cereal‐based food . PA is also reported to have some beneficial roles as plant antioxidant and protector of seeds during oxidative stress .…”

Phytochemical components of beverages from African star apple (Chrysophyllum albidum) tissue fractions under ambient storage

“…The slight decrease of phytate levels from 6 weeks of storage is probably related to the capacity of endogenous phytates to be metabolized on incubation. Al Hassan et al (2016) in their study of phytate in diets of pregnant women concluded that phytate is the strongest inhibitory predictor of mineral bioavailability as it is significantly associated with bioavailability of calcium, iron and zinc from diet.…”

High-phytate/low-calcium diet is a risk factor for crystal nephropathies, renal phosphate wasting, and bone loss

“…High-phytate diets cause stronger adverse effects on Ca 2+ , iron, and zinc levels among infants, young children, and pregnant and lactating women when cereal-based foods represent a large percentage of the diet (Al Hasan et al, 2016; Chan et al, 2007). Prior studies of dogs demonstrate that increasing the levels of phytate reduces the intestinal absorption of Ca 2+ and causes nutritional rickets (Harrison and Mellanby, 1939; Mellanby, 1949).…”