Maternal iron kinetics and maternal-fetal iron transfer in normal-weight and overweight pregnancy.

BACKGROUND: Inflammation during pregnancy may aggravate iron deficiency (ID) by increasing serum hepcidin and reducing iron absorption. This could restrict iron transfer to the fetus, increasing risk of infant ID and its adverse effects. OBJECTIVES: We aimed to assess whether iron bioavailability and/or iron transfer to the fetus is impaired in overweight/obese (OW) pregnant women with adiposity-related inflammation, compared with normal-weight (NW) pregnant women. METHODS: In this prospective study, we followed NW (n = 43) and OW (n = 40) pregnant women who were receiving iron supplements from the 14th week of gestation to term and followed their infants to age 6 mo. We administered 57Fe and 58Fe in test meals mid-second and mid-third trimester, and measured tracer kinetics throughout pregnancy and infancy. RESULTS: In total, 38 NW and 36 OW women completed the study to pregnancy week 36, whereas 30 NW and 27 OW mother-infant pairs completed the study to 6 mo postpartum. Both groups had comparable iron status, hemoglobin, and serum hepcidin throughout pregnancy. Compared with the NW, the OW pregnant women had 1) 43% lower fractional iron absorption (FIA) in the third trimester (P = 0.033) with median [IQR] FIA of 23.9% [11.4%-35.7%] and 13.5% [10.8%-19.5%], respectively; and 2) 17% lower maternal-fetal iron transfer from the first tracer (P = 0.051) with median [IQR] maternal-fetal iron transfer of 4.8% [4.2%-5.4%] and 4.0% [3.6%-4.6%], respectively. Compared with the infants born to NW women, infants born to OW women had lower body iron stores (BIS) with median [IQR] 7.7 [6.3-8.8] and 6.6 [4.6-9.2] mg/kg body weight at age 6 mo, respectively (P = 0.024). Prepregnancy BMI was a negative predictor of maternal-fetal iron transfer (ß = -0.339, SE = 0.144, P = 0.025) and infant BIS (ß = -0.237, SE = 0.026, P = 0.001). CONCLUSIONS: Compared with NW, OW pregnant women failed to upregulate iron absorption in late pregnancy, transferred less iron to their fetus, and their infants had lower BIS. These impairments were associated with inflammation independently of serum hepcidin.This trial was registered at clinicaltrials.gov as NCT02747316.

Traceability of potential enterotoxigenic Bacillus cereus in bee-pollen samples from Argentina throughout the production process.

Bee-pollen is a functional food sold for human and animal consumption but also is a favorable microhabitat for many spore-forming bacteria. Among them, Bacillus cereus can produce several toxins and other virulence factors, causing an emetic or diarrheal syndrome after ingestion. The study involved 36 bee-pollen samples obtained from different sampling points throughout the production process (collecting, freezing, drying, and cleaning) in Argentina. Fifty isolates of B. cereus yielded 24 different fingerprint patterns with BOX and ERIC primers. Only three fingerprint patterns were maintained throughout the production process. In contrast, others were lost or incorporated during the different steps, suggesting that cross-contamination occurred as shown by differences in fingerprint patterns after freezing, drying, and cleaning steps compared to the initial collection step. Genes encoding for cereulide (ces), cytotoxin K (cytK), sphingomyelinase (sph), the components of hemolysin BL (hblA, hblB, hblC, hblD) and non-hemolytic complex (nheAB) were studied. All the isolates displayed one or more enterotoxin genes. The most frequent virulence genes detected belong to the HBL complex, being the most abundant hblA (98%), followed by hblD (64%), hblB (54%), and hblC (32%), respectively. Ten strains (20%), present at all sampling points, carried all the subunits of the HBL complex. The non-hemolytic enterotoxic complex (nheAB) was found in 48 strains (96%), while seven strains (14%) present at all sampling points showed the amplification product for sphingomyelinase (sph). One cereulide-producer was isolated at the cleaning step; this strain contained all the components for the hemolytic enterotoxin complex HBL, the NHE complex, and cytotoxin K related to the foodborne diarrhoeal syndrome. In total, 11 different virulence patterns were observed, and also a correlation between rep-fingerprint and virulence patterns. The results suggest that bee-pollen can be contaminated at any point in the production process with potential enterotoxic B. cereus strains, emphasizing the importance of hygienic processing.

In overweight and obese women, dietary iron absorption is reduced and the enhancement of iron absorption by ascorbic acid is one-half that in normal-weight women.

BACKGROUND: Iron deficiency is common in overweight and obese individuals. This deficiency may be due to adiposity-related inflammation that increases serum hepcidin and decreases dietary iron absorption. Because hepcidin reduces iron efflux from the basolateral enterocyte, it is uncertain whether luminal enhancers of dietary iron absorption such as ascorbic acid can be effective in overweight and obese individuals. OBJECTIVE: In this study, we compared iron absorption from a meal with ascorbic acid (+AA) and a meal without ascorbic acid (-AA) in women in a normal-weight group (NW) with those in overweight and obese groups combined (OW/OB). DESIGN: Healthy, nonanemic women [n = 62; BMI (in kg/m(2)): 18.5-39.9] consumed a stable-isotope-labeled wheat-based test meal -AA and a wheat-based test meal +AA (31.4 mg ascorbic acid). We measured iron absorption and body composition with the use of dual-energy X-ray absorptiometry, blood volume with the use of a carbon monoxide (CO)-rebreathing method, iron status, inflammation, and serum hepcidin. RESULTS: Inflammatory biomarkers (all P < 0.05) and hepcidin (P = 0.08) were lower in the NW than in the OW/OB. Geometric mean (95% CI) iron absorptions in the NW and OW/OB were 19.0% (15.2%, 23.5%) and 12.9% (9.7%, 16.9%) (P = 0.049), respectively, from -AA meals and 29.5% (23.3%, 38.2%) and 16.6% (12.8%, 21.7%) (P = 0.004), respectively, from +AA meals. Median percentage increases in iron absorption for -AA to +AA meals were 56% in the NW (P < 0.001) and 28% in OW/OB (P = 0.006). Serum ferritin [R(2) = 0.22; ß = -0.17 (95% CI: -0.25, -0.09)], transferrin receptor [R(2) = 0.23; ß = 2.79 (95% CI: 1.47, 4.11)], and hepcidin [R(2) = 0.13; ß = -0.85 (95% CI: -1.41, -0.28)] were significant predictors of iron absorption. CONCLUSIONS: In overweight and obese women, iron absorption is two-thirds that in normal-weight women, and the enhancing effect of ascorbic acid on iron absorption is one-half of that in normal-weight women. Recommending higher intakes of ascorbic acid (or other luminal enhancers of iron absorption) in obese individuals to improve iron status may have a limited effect. This trial was registered at clinicaltrials.gov as NCT01884506.