Occurrence of deoxynivalenol and nivalenol in Spanish corn-based food products

The aim of the present work was to evaluate the occurrence of trichothecenes toxins, deoxynivalenol (DON) and nivalenol (NIV) in samples of corn-based foods (breakfast cereals and snacks) consumed by the Spanish population. A total of 175 commercially available samples were randomly collected during 2005. Trichothecenes were determined by a gas chromatography–electron capture detector. The estimated limit of quantification was 25.4 μg/kg for DON and 15.9 μg/kg for NIV. DON was detected in 22 of the 55 samples of breakfast cereals, in 13 of the 57 samples of baked corn snacks and in 12 of the 63 samples of fried corn snacks. NIV was detected in 6 samples of breakfast cereals and 1 sample of snacks. The median concentrations of DON and NIV found in all samples were 53.9 and 60.2 μg/kg, respectively. The influence of different factors, such as the presence of additional ingredients and the type of commercial brand, on the toxin incidence and content levels were also studied. The values of both mycotoxin intake found in this study are lower than the proposed tolerable daily intake for the respective toxin (1 and 0.7 μg/kg bw/day for DON and NIV, respectively).     

Carotenoid and retinol composition of South Asian foods commonly consumed in the UK

The main aim of this study was to provide new and reliable food composition data on carotenoids and retinol in South Asian Foods for the United Kingdom's national database. A total of 38 commonly consumed foods were analysed using HPLC and accredited methods of analyses. Palak paneer (spinach and soft Indian cheese) contained the highest levels of β-carotene (4066 μg/100 g) followed by gajjeralla (carrot based sweet, 2324 μg/100 g) and saag (mixed green leafy vegetables), which contained 1514 μg/100 g, whilst retinol was present in only a few foods, with ghee being the major source (968 μg/100 g). Meat dishes contained higher amounts of lycopene (up to 1140 μg/100 g in chicken balti) than vegetable or dhal dishes (highest in palak paneer 317 μg/100 g), because of larger quantities of tomatoes used in meat curries. A variety of ethnic vegetables (green leafy vegetables and other coloured vegetables), namely legumes/dhal, tomatoes and coriander, were identified to be the major ingredients containing carotenoids. These new data can be used in future diet and nutrition surveys, as well as to identify carotenoid-rich foods for dietary programs.     

Determination of acrylamide in starch-based foods by ion-exclusion liquid chromatography

A simple and rapid method using liquid chromatography coupled with diode array detection (LC–DAD) was developed for the determination of acrylamide in starch-based foods. The method entails extraction of acrylamide with 75% (v/v) methanol in water, concentration, and cleanup with an Oasis HLB solid-phase extraction (SPE) cartridge. The chromatographic separations were performed on an HC-75H⁺ column with 5 mM sulfuric acid as the mobile phase, and acrylamide was well resolved from co-extractives in the shape of a protonated cation. The final extract was analyzed by LC–DAD for quantification and the limit of detection was estimated to be 30 μg/kg based on the signal-to-noise ratio of 3 recorded at 200 nm. The method was applied for the determination of acrylamide in spiked food samples without native acrylamide yielding recoveries between 92.5% and 104.0%. Finally, commercial samples of potato chips, cookies, and some Chinese fried foods were analyzed to assess applicability of the method to acrylamide, giving results similar with those reported in the literature.     

Acrylamide in crisps: Effect of blanching studied on long-term stored potato clones

Acrylamide, a probable carcinogen, is formed via the Maillard reaction between reducing sugars and the amino acid asparagine during heating of carbohydrate-rich foods. Potatoes contain high levels of these precursors, and thus potato crisps can contain high levels of acrylamide. In this study, the effect of blanching on the concentration of precursors and acrylamide content was studied in three potato clones stored at 4 °C or 8 °C. After 6, 12 and 18 weeks of storage, potatoes were sliced and blanched for 3 min in water at 80 °C and deep-fat fried for 3 min at an initial frying temperature of 180 °C and a final frying temperature of 160 °C. Blanching reduced the acrylamide content by 51–73%. Interestingly, blanching affected the levels of the precursor sugars and asparagine, but not the acrylamide content to the same extent. The reduction of precursors was 17–66%. This may be due to restriction of the transport of precursors to the surface, as the availability of precursors for reactions is crucial for acrylamide formation. In conclusion, blanching was an efficient way to reduce acrylamide content in potato crisps, in addition to using potatoes low in asparagine and reducing sugars.     

Testing of folate conjugase from chicken pancreas vs. commercial enzyme and studying the effect of cooking on folate retention in Thai foods

Crude enzyme from chicken pancreas as a source of folate conjugase was prepared in a lyophilised form. Homogeneity, stability and activities were checked against a commercial enzyme. Subsequently, the prepared crude enzyme was used to investigate the process of folate extraction in various food matrices and study the effect of cooking on folate retention in several Thai foods. The lyophilised enzyme was homogeneous and contained 4 μg endogenous folate per g of prepared lyophilised crude enzyme. The stability of the lyophilised enzyme and the diluted enzyme, kept at 4 °C, was at least 12 months and 3 days, respectively. The activity of the prepared lyophilised folate conjugase, used at the level of 20 mg/g sample, was evaluated by a microbiological assay of total folate in brown rice, egg, whole milk powder, soybeans and asparagus. It showed comparable results to that of the commercial enzyme. Single-enzyme treatment (folate conjugase alone) was sufficient for the determination of folate content in brown rice, soybeans and asparagus. However, for egg and whole milk powder, it was necessary to apply tri-enzyme treatment as this showed a significantly higher level (at P < 0.05) of total folate than that obtained using only single- or di-enzyme (protease + folate conjugase) treatments. Among the representative foods studied, the levels of total folate ranked in order of concentration, were soybeans > egg > asparagus > brown rice > steamed-mackerel (common form sold) (305, 117, 95, 41 and 24 μg/100 g wet weight basis, respectively). After cooking, the true retention of total folate in the cooked foods ranged from 60% in brown rice (cooked in an electric rice cooker) up to 82% in boiled asparagus. On a wet weight basis, the total folate content in boiled soybeans, boiled asparagus, boiled egg, fried mackerel and cooked brown rice was 100, 84, 72, 22 and 12 μg/100 g, respectively. One boiled egg (50 g) contributes 36 μg folate, which is equal to 18% of the Thai Recommended Daily Intake (RDI), and thus it can be considered as a good source of folate based on one serving size. A serving of boiled soybeans (70 g) or boiled asparagus (80 g) is an excellent source of folate, each contributing about 35% of the Thai RDI.     

Variations in the carotenoid and anthocyanin contents of Korean cultural varieties and home-processed sweet potatoes

The sweet potato is an important industrial crop and a source of food that contains useful dietary fiber and vitamins. Recently, orange- and purple-fleshed varieties have come under the spotlight due to their healthful components, carotenoids and anthocyanins, respectively. In this study, an HPLC-DAD method was applied to determine the carotenoid composition and content in nine Korean cultural varieties of sweet potato. Changes in carotenoid contents and composition were also observed during home-processing of an orange-fleshed cultivar with high carotenoid content (530 ± 60 μg/g of dry weight, DW as all-trans-β-carotene). A loss of the carotenoids was observed for all of the home-processing methods examined; the baked or boiled or steamed sweet potatoes had higher amounts of all-trans-β-carotene (246 ± 34, 253 ± 29 and 240 ± 21 μg/g DW, respectively) than pressure-cooked, sautéed and fried ones (194 ± 21, 201 ± 28 and 111 ± 19 μg/g DW, respectively). Interestingly, cis-isomer of the all-trans-β-carotene, 13Z-β-carotene was found in elevated amounts in all of the processed samples, particularly in baked, pressure-cooked and steamed sweet potatoes compared to control. Variations in anthocyanin content in the nine cultural varieties and home-processed sweet potatoes were also determined by an HPLC-DAD method.     

Seasonal variations in antioxidant components of cherry tomatoes (Lycopersicon esculentum cv. Naomi F1)

To evaluate seasonal variations in antioxidant components of greenhouse cherry tomatoes, the compositional profile of fruits (“Pomodoro di Pachino”, cv. Naomi F1) harvested at six different times of the year was compared. Among tomato antioxidants, phenolic compounds (naringenin content ranged from 1.84 to 9.04 mg/100 g, rutin from 1.79 to 6.61 mg/100 g) and α-tocopherol (40–1160 μg/100 g) showed the greatest variability. Ascorbic acid (31–71 mg/100 g), carotenoids (8350–15119 μg/100 g), phenolics and α-tocopherol concentration did not show definite seasonal trends, nor correlation with solar radiation or average temperature. Nevertheless, tomatoes harvested in mid-summer were characterized by lowered lycopene levels. Greenhouse growing conditions induced the accumulation of relatively high level of antioxidants for most of the year: one serving of raw tomatoes (100 g) could provide from 50% to 120% of the recommended daily intake of vitamin C, from 13% to 27% of that of vitamin A, from 0.4% to 12% of that of vitamin E, and from 15% to 35% of the flavonoid daily intake estimated for an Italian diet.     

HPLC determination of carotenoids in Bulgarian berries

Carotenoids are bioactive substances in foods with powerful antioxidant activity. Based on the health benefits from berries, more information on the content of bioactive substances such as carotenoids is required. The aim of the present study was to determine lutein, zeaxanthin, lycopene, β-cryptoxanthin, α-carotene and β-carotene content in berries, which form part of the Bulgarian diet. Study covered six different berry species: strawberry, raspberry, blackberry, blueberry, black currant and red currant. For each berry five individual samples were analyzed. An HPLC gradient elution system with monomeric C₁₈ column and UV detection at 450 nm were used for separation and quantification of the carotenoids. Lycopene was not detected in any of these fruits. Blackberry had the highest levels of carotenoids. Strawberry had the lowest carotenoid content. Lutein was present in raspberry in higher levels (317.0 μg/100 g), followed by blackberry (270.1 μg/100 g). The highest zeaxanthin levels were found in blackberry (29.0 μg/100 g), followed by blueberry (14.0 μg/100 g). Blackberry has the highest value of β-cryptoxanthin (30.1 μg/100 g). α-Carotene was present in highest levels in raspberry (23.7 μg/100 g). Blackberry had the highest β-carotene content (101.4 μg/100 g), followed by black currant (61.6 μg/100 g). Our data will be included in the Bulgarian National Food Composition Database.     

Determination of nitrofuran metabolites in seafood by ultra high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry

A new analytical method has been developed for the simultaneous determination of 4 nitrofuran metabolites in seafood by ultra-high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (UHPLC–QqQ-MS/MS). The extraction procedure was based on a simultaneous acidic hydrolysis and derivatization using 2-nitrobenzaldehyde (2-NBA), followed by a solid-phase extraction (SPE). Recovery was studied by spiking blank samples at two concentration levels (1 and 10 μg/kg) and recoveries ranged from 73 to 100% and 79 to 103%, respectively. Precision values, expressed as relative standard deviation (RSD) were ≤19% and ≤23% for intra-day and inter-day precision, respectively. Linearity was studied in the range 1–50 μg/kg and the obtained determination coefficients (R²) were ≥0.9900 for all compounds. Limits of detection (LODs) for the derivatized nitrofuran metabolites were 0.5–0.8 μg/kg and limits of quantification (LOQs) were established at 1 μg/kg, whereas decision limit (CC_α) and detection capability (CC_β) ranged from 1.5 to 2.6 μg/kg and 1.6 to 3.1 μg/kg, respectively. Finally, the method was applied to real food samples, but nitrofurans were not found.     

Selenium content of Thai foods

Information on selenium content of foods in different countries, particularly among Asian countries, including Thailand, is limited. In this study, the fluorometric method for selenium determination was tested for accuracy and reliability prior to applying for analysis of selenium in various Thai foods. Common food commodities, i.e., cereals, meat, poultry, seafood, fish, milk, eggs, fruits and vegetables were purchased from 10 representative markets in Bangkok which symbolized the outlets of the commodities from various regions in Thailand. A wide range of selenium content was found among the various food groups. High levels were found in seafood and fish, and eggs with mean±s.d. of 45.0±20.8 and 40.2±14.1 μg/100 g, respectively. Moderate levels of selenium were found in meat and poultry, and pulses with mean±s.d. of 18.2±5.8 μg/100 g and 13.1±13.4 μg/100 g, respectively. Cow's milk and cereals contained low concentrations of selenium (6.4±2.4 μg/100 g and 5.0±1.1 μg/100 g, respectively). Selenium content in vegetables and fruits (1.2±2.0 μg/100 g and 0.6±0.5 μg/100 g, respectively) was lower than the reported values from other countries.     

Food content of ubiquinol-10 and ubiquinone-10 in the Japanese diet

Seventy food items (8 types of meat, 16 types of fish and shellfish, 21 vegetables, 7 fruits, 6 pulses, 3 potatoes, 3 dairy products and 6 others) were analyzed using a simple and reliable method that can detect the reduced form of coenzyme Q₁₀ (ubiquinol-10) and the oxidized form of coenzyme Q₁₀ (ubiquinone-10) simultaneously. This method employed direct 2-propanol extraction and high performance liquid chromatography (HPLC) equipped with a reduction column and an electrochemical detector (ECD). Ubiquinol-10 was found in 63 out of 70 food items, while ubiquinone-10 was found in 66 of the 70 food items. In the food items in which ubiquinol-10 was found, its content ranged from 2.63 to 84.8 μg/g in meat, 0.38 to 23.8 μg/g in fish and shellfish, 0.17 to 5.91 μg/g in vegetables, 0.22 to 3.14 μg/g in fruits, 0.68 to 1.82 μg/g in potatoes, 0.72 to 4.3 μg/g in pulses and 0.18 to 33.3 μg/g in other food items including seeds, eggs, dairy products, soybean oil and miso (fermented soybean paste). Pork (shoulder), bovine liver, chicken heart, horse mackerel, young yellowtail and soybean oil showed a high ubiquinol-10 content of more than 20 μg/g. On the other hand, total coenzyme Q₁₀ content ranged from 13.8 to 192 μg/g in meat, 1.25 to 130 μg/g in fish and shellfish, 0.08 to 7.47 μg/g in vegetables, 0.51 to 9.48 μg/g in fruits, 1.05 to 3.01 μg/g in potatoes, 2.31 to 6.82 μg/g in pulses and 0.26 to 53.8 μg/g in other food items. The estimated average daily intakes of ubiquinol-10 and total coenzyme Q₁₀ calculated from our results and data on Japanese daily food consumption were 2.07 and 4.48 mg, respectively. Thus, intake of ubiquinol-10 accounted for 46% of the total coenzyme Q₁₀ intake.     

Carcinogenic and neurotoxic risks of acrylamide and heavy metals from potato and corn chips consumed by the Lebanese population

The present study aims to quantify acrylamide and metals in potato and corn chips and to determine their carcinogenic and neurotoxic risks. Gas chromatography mass spectrometry analysis revealed that the average acrylamide level in potato and corn chips (1756 μg/kg) was 3500-fold higher than the permissible limit for acrylamide in drinking water (0.5 μg/kg). Potato-based chips and baked chips were found to contain 23% and 18% more acrylamide than corn-based chips and fried chips, respectively. The daily consumption of acrylamide from potato and corn chips was found to be 7–40-fold higher than the risk intake for carcinogenesis set by World Health Organization (WHO) but was below the neurotoxic risk threshold. Energy dispersive X-ray fluorescence and thermal atomic absorption analysis revealed that the mean concentrations of zinc, lead and cadmium in corn chips were approximately 1.5-, 1.7- and 2.4-fold higher than the permissible limits set by Food and Agriculture Organization/WHO, respectively. However, the daily intake of these metals was lower than the oral reference dose and the upper tolerable daily intake set by the US Food and Drug Administration. The cancer risk for the Lebanese population from acrylamide exposure estimations appears to be significant, highlighting the need to conduct further epidemiological studies and ensure monitoring of acrylamide levels in food products.     

Blood lead levels in a representative sample of the Spanish adult population: The BIOAMBIENT.ES project

This paper provides the first baseline information on a national scale regarding lead exposure in the Spanish adult population. Blood lead levels were measured in a representative sample of the Spanish working population (1880 subjects aged 18–65 years) in order to help establish reference levels, follow temporal trends, identify high-exposure groups and to enable comparisons with other countries. All participants completed an epidemiological questionnaire including gender, age, occupational sector, geographic area, and dietary and lifestyle information. We found that the geometric mean of blood lead levels in the study population was 24.0 μg/L (95% CI: 23.0–25.1 μg/L), with women having significantly lower levels than men, 19.5 μg/L (18.5–20.5 μg/L) compared to 28.3 μg/L (26.7–30.0 μg/L), respectively. Mean blood lead levels were higher in elder groups in both genders. Women of a childbearing age had blood levels of 18.0 μg/L (GM). Reference values (95%) for lead in blood in the studied population was 56.80 μg/L, with −64.00 μg/L, 44.80 μg/L and 36.00 μg/L for man, women and women of childbearing age, respectively. Workers from the service sector had lower blood lead levels than those from the construction, agricultural and industry sectors. Small, although significant, geographical differences had been found.In an European comparison, the Spanish population studied herein had lead levels similar to populations in countries such as France and Belgium, and slightly lower levels than Italian, Czech, German or UK populations.     

Carotenoid and vitamin content of Micronesian atoll foods: Pandanus (Pandanus tectorius) and garlic pear (Crataeva speciosa) fruit

The fruit of pandanus (Pandanus tectorius) and garlic pear (Crataeva speciosa) are important indigenous Micronesian atoll foods, but are increasingly neglected due to dietary and lifestyle changes. Previous studies have shown considerable differences in carotenoid concentrations in some pandanus cultivars. There are many Micronesian pandanus cultivars, most of which have not been assessed. Carotenoid-rich foods protect against vitamin A deficiency, anemia, and chronic disease, including cancer, heart disease and diabetes, which are serious problems in Micronesia. Eleven pandanus cultivars of Mwoakilloa and Kapingamarangi Atolls, Pohnpei, Federated States of Micronesia (FSM) (assessed for the first time), dried pandanus paste of the Marshall Islands, and garlic pear of Mortlock Atolls, Chuuk, FSM, were analyzed for carotenoids (β- and α-carotene, β-cryptoxanthin, lutein, zeaxanthin, and lycopene). Pandanus paste was assessed for 11 vitamins. The pandanus cultivars contained substantial concentrations of provitamin A carotenoids (110–370 μg β-carotene/100 g) and total carotenoids (990–5200 μg/100 g). Pandanus paste contained 1400 μg β-carotene/100 g, 5620 μg total carotenoids/100 g, and 10 vitamins (including 10.8 mg/100 g vitamin C). Garlic pear contained 1070 μg β-carotene/100 g and 1460 μg total carotenoids/100 g. These cultivars and foods should be promoted in Micronesia and possibly elsewhere in the Pacific and other contexts in order to reduce vitamin A deficiency and provide further health benefits and enjoyment.     

Phytonutrient content of Solanum sisymbriifolium Lam. berries

Solanum sisymbriifolium Lam. (Litchi tomato) is grown ornamentally, and in Europe it is used as a trap crop for management of the potato cyst nematode (PCN). Its berries are edible, but little is known about their nutritional content. If more was known about their nutritional value this could provide incentive to grow it as a food crop. Phytonutrient content was characterized in berries from four varieties and four synthetic breeding lines developed to have reduced spininess. Litchi tomatoes contained 6.8–10.4 mg of total phenolics per g dry weight. Antioxidants measured by FRAP ranged from 148 to 242 μmol TE/g DW. HPLC analysis showed chlorogenic acid (1856–4385 μg/g DW) was the most abundant phenylpropanoid. Ascorbic acid ranged from 2042 to 4511 μg/g DW. The yellow/orange flesh color was due to carotenoids, with β-carotene the most abundant (204–633 μg/g DW). Soluble protein in Litchi tomato ranged from 86.9 to 120.9 mg/g. Of the cultivated Litchi tomato varieties analyzed, SS91 had the highest amount of antioxidant activity, ascorbic acid, chlorogenic acid and β-carotene. These results suggest that Litchi tomato fruits can be a good source of phytonutrients, expanding the plant's functionality beyond its use as a PCN trap crop.     

Vitamin D levels in fish and shellfish determined by liquid chromatography with ultraviolet detection and mass spectrometry

Vitamin D₃ (cholecalciferol) levels were determined in finfish and shellfish using UV detection at 265 nm (combined with auxiliary full scan UV detection) and selected ion monitoring (SIM) mass spectrometry (MS), using vitamin D₂ (ergocalciferol) as an internal standard. Analysis of standard reference material (SRM) NIST 1849 (Infant/Adult Nutritional Formula) was included to validate the method. Three-point calibration curves were employed, allowing values to be determined over a range of species, from those having little or no detectable vitamin D₃ (e.g., pollock, shrimp) to those with high levels (e.g., salmon with up to 33.23 μg/100 g). The limit of detection (LOD) and limit of quantitation (LOQ) calculated from the uncertainty and intercept of the calibration curves were 1.22 μg/100 g and 5.30 μg/100 g, respectively, based on all analyses (n = 27 sequences). Use of response factors (RF) allowed quantitation at lower levels of vitamin D₃, with an LOQ of <0.20 μg/100 g. The values obtained using the validated methodology agreed well with literature and tabulated database results for most species. However, much lower average vitamin D₃ concentrations were found for oysters (0.05 μg/100 g, raw) and clams (0.18 μg/100 g, cooked) compared to other reports for these products.     

Nutritive value and display-life attributes of selenium-enriched beef-muscle foods

Our objective was to assess the nutritive value and display-life attributes of selenium-enriched beef-muscle foods. Samples of foreshank and short-loin subprimals were excised from chilled carcasses (n=20) of beef steers that were individually finished (120 days) on either supranutritional selenium (selenium-enriched; 68.1 μg Se/kg body weight/day; n=9) or adequate selenium (non-enriched; 9.1 μg Se/kg body weight/day; n=11) diets. High-selenium wheat grain was included in the diet of supranutritional selenium-fed steers to achieve selenium-enrichment. Selenium-enriched foreshank had 3.8 times more (1085 vs. 283 ng/g wet weight, P<0.01) selenium and 1.3 times more (P<0.01) glutathione peroxidase activity than non-enriched foreshank samples. Selenium-enrichment did not influence foreshank (P=0.16–0.89) moisture, ash, crude protein, and lipid contents, and expressible moisture, or short-loin (P=0.11–0.41) drip-loss percentage or color change throughout the display-life evaluation. The results indicate that, compared to non-enriched, selenium-enriched beef-muscle foods have a much higher amount of selenium and similar display-life attributes.     

Environmental implication of iodine in water,milk and other foods used in Saharawi refugees camps in Tindouf,Algeria

A cross-sectional survey among Saharawi refugees in four camps carried out in 2007 revealed enlarged thyroid volume and high urinary iodine concentration in women and school children. The purpose of this paper is to describe the content of iodine in food and water and explore whether any sources in the environment can explain the situation. Samples of water (n = 143), milk (n = 19) and salt (n = 89) were collected. Different wells supplied the camps with water and the median iodine concentration was 108 μg/L (range 55–545 μg/L) and significantly higher in two of the camps (El Aiune and Ausserd; 300 μg/L (range 55–545 μg/L)), compared to the two other camps (Smara; 87 μg/L (55–127 μg/L) and Dakla; 70 μg/L (55–96 μg/L)). In local goat milk the median iodine concentration was 370 μg/L (70–13,070 μg/L). The median content of iodine in salt was 6 μg/g (0–51 μg/g). Water and local milk were the most important sources of iodine for women. High levels of iodine in water seem to be one of the main sources of iodine that affects humans as well as animals.     

Antioxidant capacity of Brazilian fruit,vegetables and commercially-frozen fruit pulps

Several epidemiological and research studies suggest that a high intake of foods rich in natural antioxidants increases the antioxidant capacity of the plasma and reduces the risk of some kinds of cancers, heart diseases, and stroke. These health benefits are attributed to a variety of constituents, including vitamins, minerals, fiber, and numerous phytochemicals, such as flavonoids. Thus, in addition to measuring the composition of the usual macronutrients and micronutrients, it seems important to also measure the antioxidant capacity of foods. For this purpose, 28 foods including fruits, vegetables and commercially-frozen fruit pulps were analyzed for antioxidant capacity. The antioxidant capacity of the foods varied from 0.73 to 19.8 μmol BHT equiv/g. The highest values were observed for wild mulberries (19.8 μmol BHT equiv/g), acaí fruit pulp (18.2 μmol BHT equiv/g) and watercress (9.6 μmol BHT equiv/g). The antioxidant capacities are only indicative of the potential of the bioactive compounds; however, these data are important to explore and understand the role of fruit, vegetables and other foods in health promotion.     

Interaction between cadmium (Cd), selenium (Se) and oxidative stress biomarkers in healthy mothers and its impact on birth anthropometric measures

To our knowledge, this study may be the first to examine the antagonistic role of selenium (Se) on oxidative stress induced by cadmium (Cd) and its impact on birth measures. Cd and Se levels were measured in umbilical-cord blood and the placentas of a subsample of 250 healthy mothers who participated between 2005 and 2006 in the project “Prenatal Exposure to Pollutants”. The median Cd levels in cord and maternal blood and placental tissue were 0.78 μg/l, 0.976 μg/l and 0.037 μg/g dry wt., respectively. The median levels of Se in cord serum and placental tissue were 65.68 μg/l and 1.052 μg/g dry wt., respectively. Se was more than 100-fold in molar excess over Cd in both cord serum and placental tissue. The median molar Cd/Se ratios in cord serum and placental tissue were 0.008 and 0.024, respectively, which were much lower than unity. This study suggests that both Cd and Se play a role in the mechanism of oxidative stress, but, the process underlying this mechanism remains unclear. Nevertheless, three biomarkers of oxidative stress had inconsistent relationships with Cd and/or Se in various matrices, perhaps due to potential untested confounders. Our results generally support an association between low in utero exposure to Cd and the anthropometric development of the fetus. Adjusted regression models indicated a negative association of cord blood Cd levels ≥0.78 μg/l with Apgar 5-min scores and birth height. Maternal Cd levels ≥0.976 μg/l were associated with a 5.94-fold increased risk of small-for-gestational-age births, which increased to 7.48-fold after excluding preterm births. Placenta weight decreased with increasing placental Cd levels ≥0.037 μg/g dry wt. (p = 0.045), an association that became stronger after excluding preterm births or adjusting for birth weight. Cord Se levels ≥65.68 μg/l were positively associated with placenta weight (p = 0.041) and thickness (p = 0.031), an association that remained unchanged after excluding preterm births. Cord Se levels, however, were negatively associated with cephalization index, but only after excluding preterm births (p = 0.017). Each birth measure was again modeled as a function of the Cd/Se ratios in cord blood and placenta tissue. Interestingly cord ratios ≥0.008 were negatively associated with Apgar-5 min score (p = 0.047), birth weight (p = 0.034) and placenta thickness (p = 0.022). After excluding preterm births, only the association with placenta thickness remained significant (p = 0.021), while birth weight (p = 0.053) was marginally significant. In contrast, cephalization index increased with Cd/Se ratios ≥0.008 (p = 0.033), an association that became marginally significant after excluding preterm births (p = 0.058). For placental Cd/Se ratios ≥0.024, only placenta weight was reduced with (p = 0.037) and without (p = 0.009) the inclusion of preterm births. These findings do not support an antagonistic mechanism between Cd and Se. The role of oxidative mechanisms either induced by Cd exposure or alleviated by Se on these birth anthropometric measures was examined by principal component analysis. Se did not have a clear protective role against Cd-induced adverse effects despite its substantial excess over Cd, and its role in alleviating oxidative stress by reducing malondialdehyde levels. The results may suggest that the extent of the Se beneficial effects is not governed only by its concentration but also by the chemical forms of Se that interact with various proteins. Consequently, the speciation of Se in such studies is essential for understanding and predicting Se availability for absorption.