The study of iodine in Chinese total diets

Iodine and selenium: Dietary sources and nutritional status of the population of the Kurdistan Region in Northern Iraq

AIM

The primary aim of this study was to determine the selenium (Se) and iodine (I) food concentrations and dietary intake of the population living in the Kurdish controlled region of northern Iraq. We also assessed the extent to which iodised salt contributes to dietary iodine intake.

METHODOLOGY

Foods and samples of salt and drinking water were analysed, including 300 crops samples from 40 local farms. The results, supplemented by food composition data, were used to assess dietary Se and I intake for 410 volunteers using a semi-quantitative food questionnaire. To directly investigate the nutritional status of individuals, urine samples were also collected from participants.

RESULTS

Selenium intake was mainly supplied by protein and cereal sources. Calculated median dietary intake of Se was 62.7 µg d-1 (mean = 66.3 µg d-1) with c. 72 % of participants meeting or exceeding dietary reference intake recommendations for age. Median dietary intake of I, excluding salt consumption, was 94.6 µg d-1 (mean 100.2 µg d-1), increasing to 607.2 µg d-1 when salt (of which >90 % was iodized) was included. Salt intake was estimated to be c.13.5 g d-1 (5400 mg Na d-1) which greatly exceeds WHO recommended intake (< 2000 mg d-1 of Na). Urine iodine concentrations indicated that 98 % of school aged children had excessive iodine intake (≥300 µg L-1) and 80-90 % of all study participants had above average or excessive iodine intake (≥200 µg L-1).

CONCLUSIONS

Poultry and rice are the main sources of dietary Se to this population but around a third of children receive an inadequate Se intake. Fresh fruit and vegetables are the main sources of dietary I, but consumption of local foods cannot supply adequate I without iodised salt supplementation. Consumption of iodized salt well above recommended amounts is supplying this population with substantial iodine intake. Interventions to reduce salt intake would help to limit excessive iodine intake whilst also reducing cardio-vascular risks from Na consumption.

Role of different organic and inorganic amendments in the biofortification of iodine in Coriandrum sativum crop

Iodine deficiency disorder (IDDs) is one of the most prevailing and common health issues in mountainous communities. An effective way to control the prevalence and emergence of IDDs in remote areas is to use iodized salt. However, recent studies indicated that iodized salt is mostly lost during the cooking process. The current study of iodine biofortification differed from the previous studies in two main aspects: it involved exogenous organic iodine (OI), and inorganic iodine such as potassium iodide (KI), added in the amended soils, which previous studies did not consider. Moreover, the translocation, transformation, and distribution of iodine from soil to plants are poorly understood in amended soil. Thus, identifying an effective management option to enhance iodine (I) bioavailability in nutrient-deficient soils is currently a significant challenge. Therefore, a greenhouse study was conducted to investigate the effects of organic and inorganic soil amendments on the uptake of different iodine sources in coriander crops. Results showed that applying an inorganic iodine source significantly enhanced the iodine edible part of the crop compared to the control (p &lt; 0.05). The application of soil amendments relatively improved iodine uptake by the coriander crop compared to the control. The highest iodine was found in crop tissues grown in wood ash-amended soil supplemented with KI (291.97 μg kg−1). The KI uptake was significantly higher than the OI (p &lt; 0.05). Compared to OI, a higher translocation factor (0.96) and distribution coefficient (3.51) were found for plants treated with KI. Thus, this study indicates that a suitable soil amendment can be a better option for iodine biofortification and that it can serve as an alternative to iodized salt in preventing IDDs.

Iodide and iodate effects on the growth and fruit quality of strawberry

BACKGROUND

Iodine deficiency is an environmental health problem affecting one-third of the global population. An iodine biofortification hydroponic experiment was conducted to explore the iodide and iodate uptake characteristics of strawberry plants, to measure the dosage effects of iodine on plant growth and to evaluate the influence of I^- or IO₃^- application on fruit quality.

RESULTS

After biofortification, the iodine contents of the fresh strawberry fruits were 600-4000 µg kg^-1 , covering the WHO dietary iodine allowance of 150 µg · day^-1 for adults. The iodine uptake of the strawberry plants increased with increasing I^- or IO₃^- concentration of the culture solution. At the same iodine concentration, the iodate uptakes of various plant organs under I^- treatments were apparently more than those under IO₃^- treatments. Low-level exogenous iodine (I^- ≤ 0.25 mg L^-1 or IO₃^- ≤ 0.50 mg L^-1 ) not only promoted plant growth and increased biomass per plant, but also improved fruit quality by enhancing the vitamin C and soluble sugar contents of the strawberry fruits. Nevertheless, excessive exogenous iodine inhibited plant growth and reduced biomass per plant. IO₃^- uptake apparently increased the total acidity and nitrate content of the fruits, reducing the quality of the strawberry fruits. Conversely, I^- uptake obviously decreased the total acidity and nitrate content of the strawberry fruits, improving the fruit quality.

CONCLUSION

The strawberry can be used as a target crop for iodine biofortification. Furthermore, applying an appropriate dose of KI can improve the fruit quality of the strawberry plants. © 2016 Society of Chemical Industry.

Dietary supply of selenium for adolescents in three residential care orphanages in Southern Ghana

Adolescents require optimum dietary supply of the essential trace mineral selenium (Se); however the absence of reliable and accurate data on the dietary supply of selenium for the adolescent population in Ghanaian residential care orphanages have made it difficult for public health nutritionists to assess the adequacy of the dietary supply. The dietary supply of selenium for adolescents (12-15 years) in three residential care orphanages, (Osu, Tutu-Akwapim and Teshie), in Southern Ghana have been evaluated by sampling their 24-h duplicate diets (including water) for 7-consecutive days using the duplicate diet sampling technique. The mass fraction of selenium in the blended lyophilized homogenates of duplicate diets was determined by radiochemical neutron activation analysis (RNAA). The validity of the RNAA method for selenium determination was checked by analyses of NIST SRM 1548a (Typical diet). The chemical yield of the radiochemical separation was determined by spectrophotometry. The average mass fractions of selenium in the blended lyophilized 24-hour duplicate diets for Osu, Tutu-Akwapim and Teshie were; 165±61 [117.2-285.2], 203±68 [110.5-304.9] and 250±92 [128.8-408.0]ng Seg(-1) lyophilized matter respectively. The average dietary supply of Se were, 57.6±17.3 [42.2-88.4], 82.0±30.7 [44.3-136.2] and 91.7±44.2 [46.0-153.4]μg Se day(-1) for Osu, Tutu-Akwapim and Teshie orphanages respectively. The data generated will help public health nutritionists in the provision of dietary advice and nutritional support for the studied orphanages, as well as other orphanages. The data will also help in the planning of institutional diets.

Speciation of iodine in high iodine groundwater in china associated with goitre and hypothyroidism

Iodine intake affects the occurrence of disease in a population. Excessive iodine intake may be caused by a high iodine content of drinking water. Tap water in few locations in Europe contains up to 139 microg/L mostly bound to humic substances, probably leaching from marine sediments in the aquifers. Even higher iodine contents have been found in Chinese waters, previously shown to associate with goitre and hypothyroidism. The aims were to elucidate speciation of high iodine groundwater from deep wells in China and to compare with high iodine waters from Europe. Water was sampled from eight wells in five villages along Bohai Bay, China. Macro-molecules and low molecular weight (MW) substances were separated by size exclusion chromatography (high performance liquid chromatography, Superose 12 HR 10/30, buffer 0.1 M Tris, pH 7.0). Organic material was evaluated by A280 and iodine in fractions measured by the Ce/As method after alkaline incineration. Iodine content of well water varied from 135 to 880 microg/L (median 287 microg/L). The amount of organic material in water was low with A280, <1-5 mAU. The chromatographic traces were similar between samples: One peak of iodine eluted around K (AV) 0.65 corresponding to MW 5 kDa (humic substances) and one peak at V (total) (iodide/low MW substances). The fraction of iodine in macro-molecules, suggested to be humic substances, varied from 8% to 70% (median 27%). Iodine and peak absorbance were associated (p = 0.006). In conclusion, iodine in iodine-rich deep well water in northern China may have marine origin and may associate with humic substances, comparable to shallow well iodine-rich water in Europe. High iodine intake from iodine-rich water suggests the cause of endemic goitre and hypothyroidism in some areas in China being iodine.

Transfer of orally administrated iodine-131 into chicken eggs

Radioactive iodine-131 as both as free iodide (Na131I) and covalently bound to aniline (aniline-131I) was added to the drinking water of two Leghorn laying hens as a single dose and also as a cumulative dose over 1 week. The radioactivity of the principal parts of the eggs, i.e. shell, white, and yolk, was measured, and the radioactivity levels per gram material, and percent of the total radioactivity were calculated. The radioactivity measurements were continued for 1 month following the administration of 131I. In the case of the single dose administration, the results obtained showed that about 15% of the total radioactivity administered as Na131I was transported into the egg structure; compared to only about 1% for aniline-131I. After cumulative administration, about 15% of the total administered radioactivity was transported into the egg structure with both forms of 131I. This was probably because of metabolic cleavage of iodine bonds in the labeled aniline molecules during the longer period of exposure. These results also showed considerable accumulation of 131I in the egg yolks. In the case of the single dose administration, 131I can be detected in eggs up to about 20 days after administration, and up to about 30 days, in the case of the cumulative administration over 1 week.

Nutrient elements of commercial tea from Nigeria by an instrumental neutron activation analysis technique

A prototype miniature neutron source reactor (MNSR) with a thermal neutron flux of 3.0 x 10(11) n cm(-2) s(-1) has been used to determine the concentrations of some nutrient elements leading to short-lived activation products in commercial tea leaf samples from Nigeria. A total of eight elements Al, Ca, Cl, Cu, K, Mg, Mn and Na, that can be routinely used for quality control purposes, were analyzed in this study. Two biological reference materials, tomato leaves (NIST-1573) and citrus leaves (NIST-1572) were used as the standard and quality control materials, respectively. The analytical results show that the average concentrations of Al, Ca, Cl, Cu, K, Mg, Mn and Na in Nigerian tea are slightly higher when compared with a Chinese herbal tea analyzed in this study. The concentration ratios of K/Ca were found to be high in all the samples analyzed suggesting cultivation in potash-rich soils.