Household salt iodine content estimation with the use of rapid test kits and iodometric titration methods

Field-friendly MUNNG® optima simple test kit for quick qualitative assessment of iodine and iron presence in double-fortified salt

Background

Data from several efficacy studies and a long-term effectiveness study have encouraged the governments to adopt a policy of providing double-fortified salt (DFS) in the Mid-Day Meal (MDM) programs in government schools across India. These envisaged food security events are likely to boost the manufacturing of DFS in a big way. Thus, it becomes pertinent to come up with a robust monitoring system involving community and field workers for quality checks. It is imperative to equip these field workers with simple testing kits (STKs) capable of qualitative detection of iron and iodine in DFS. As the consumer acceptance of foods is based on several factors including sensory characteristics, performance, convenience, cost, nutrition, and product image, a variety of iron compounds are in use for fortification. However, it becomes challenging to provide a kit that can overcome the chemical masking of iodine detection by iron compounds.

Objectives

We aimed at (1) the development of a field-friendly STK for quick qualitative assessment of iodine and various forms of iron present in DFS, (2) to check its validity under field conditions.

Methods

We put in place reagents combined using known chemical reactions and balanced use of oxidants to overcome the problems of encapsulation and to maximize the use, by enabling reagent combination to react with all forms of iron.

Results

The kit reagents successfully detect iodine as well as three commonly used iron fortificants in DFS. Published field trials confirmed the specificity and sensitivity of the developed kit. The simplicity and use of the kit by a field worker can be seen in the enclosed video.

Conclusion

The combination of improvised kit reagents allows early detection of iron and iodine in DFS. Iron is detected in a variety of iron-containing fortifications. The provision of diluted H2O2 ensures the presence of oxygen-free radicals that enhances iodine release captured by concentrated KI making iodine detection an easy task.

Probabilistic Health Risk Assessment of Iodine Exposure in Bangladesh

In this study, the concentrations of iodine in household salt samples (n = 690) were determined by following the iodometric titration method, and the health risks of Bangladeshi people were assessed based on the semi-probabilistic approach and the US Environmental Protection Agency (USEPA) deterministic model. After adjusting 20% of cooking losses, the iodine concentration (mean, range) in salt samples of Phultala, Dighalia, Terokhada, Rupsha, Batiaghata, Dumuria, Paikgacha, Koyra, Dacope, and KCC was (29.68 ± 8.67, 14.39-48.26), (31.05 ± 6.68, 15.24-43.18), (26.94 ± 5.57, 16.09-45.72), (24.33 ± 5.61, 12.70-37.26), (26.69 ± 6.73, 10.16-44.87), (27.20 ± 8.44, 9.31-53.34), (27.71 ± 8.09, 8.46-47.42), (28.39 ± 7.80, 11.01-46.57), (28.20 ± 7.97, 3.38-49.10), and (29.21 ± 6.62, 18.62-40.64) mg/kg, respectively. The iodine contents in 97.25% of samples were within the standard fortification level of Bangladesh (15-50 mg/kg), while 2.61% of samples were below this limit. The semi-probabilistic risk assessment studies showed that 80.14% of samples at a low ingestion rate could provide optimal nutrition (150-299 μg/day) to the whole population. Contrarily, at medium, moderate-high, and high consumption rates 34.93%, 65.22%, and 85.94% of samples, respectively, belonged to above the requirements to excessive exposure categories (300-1100 μg/day), which might cause iodine-induced diseases. The target hazard quotient (THQ) values for the adults in most of the samples were within the threshold risk limit (THQ < 1.0), whereas THQ values in 6.82% to 85.97% of samples for the children at low to high ingestion rates, respectively exceeded this limit, which revealed that the adults were almost safe, but the children might face non-carcinogenic health effects. Therefore, regular monitoring of iodine concentration in iodized salts should be done to prevent iodine deficiency or iodine-induced disorders.

Availability of adequately iodized salt at household level in Dessie and Combolcha Towns, South Wollo, Ethiopia

Background

Iodine deficiency disorder is the leading cause of mental retardation and poor economic performance in developing countries. Worldwide, universal salt iodization has been implemented to eliminate iodine deficiency. However, the adequacy of iodine in salts needs close monitoring to meet its intended goal and this study was aimed at investigating the adequacy of iodine in dietary salt at household level in Dessie and Combolcha Towns.

Methods

A community-based cross-sectional study was employed at household level in Dessie and Combolcha towns from January to February, 2017. Data were collected from 753 households using systematic sampling technique. The adequacy of iodine in salt was analyzed using rapid testing kit. Socio-demographic and economic, dietary sources, labeling, packaging, storage and cooking methods of household’s characteristics were collected via questionnaire developed using open data kit tool and STATA version 12 was used for further statistical analysis. Ordinal Logistic regression was performed to assess associations between explanatory variables and the response variable.

Results

Nearly one-thrid (31.2%) of the households used inadequate iodized salt, which was below the World Health Organization recommendation level (≥15 ppm at the household level). Most of the respondents from Combolcha town (64.6%) were affected by inadequate use of iodized salt as compared to Dessie Town residents (22.2%). Being Dessie resident (OR = 2.53; 95% CI: 1.31–4.90), households with better socioeconomic status (OR = 2.54; 95% CI:1.10–5.87), site of labeling and packing (salt from open market (OR = 0.10; 95% CI: 0.04–0.23) and no exposure to sunlight (OR = 2.54; 95% CI:1.31–4.91) were the predictors of adequacy of iodized salt at household level.

Conclusions

Availability of adequately iodized salt at the household level in the study area was low. There should be regular quality control and regulatory enforcement of salt iodization at production, labeling and packaging sites of small scale industries and at household level.

Breast Milk Iodine Concentration Rather than Maternal Urinary Iodine Is a Reliable Indicator for Monitoring Iodine Status of Breastfed Neonates

There is no scientific consensus on whether breast milk iodine concentration (BMIC) accurately reflects iodine status in lactating mothers and breastfed infants. This study aimed to compare BMIC and maternal urinary iodine concentration (UIC) as indicators of iodine status in breastfed neonates. In this cross-sectional study, 147 lactating mothers and their neonates (3-5 days postpartum) were randomly selected from health care centers. Breast milk and urine samples were collected from each mother and neonate, and a heel-prick blood sample was taken from all neonates as part of a congenital hypothyroidism screening program. According to the World Health Organization criteria, median urinary iodine concentration (UIC) ≥ 100 μg/L in lactating mothers and neonates indicates iodine sufficiency. In areas of iodine sufficiency, median BMIC ≥ 100 μg/L is considered an adequate level. Overall, 129 (89.0%) and 16 (11.0%) mothers had BMICs ≥ 100 and ˂ 100 μg/L, respectively. Median (interquartile range [IQR]) maternal UIC was 70 μg/L (42-144 μg/L) and 37 μg/L (25-100 μg/L) in mothers with breast milk iodine levels ≥ 100 and ˂ 100 μg/L, respectively (P = 0.047); values for UIC of neonates born to mothers with BMICs ≥ 100 and ˂ 100 μg/L were 230 μg/L (114-310 μg/L) and 76 μg/L (41-140 μg/L), respectively (P < 0.001). In the linear regression model, neonate UIC was positively associated with BMIC in both unadjusted (β = 0.558, P < 0.001) and adjusted analysis (β = 0.541, P < 0.001). A similar result was found in logistic regression analysis, indicating that neonates born to mothers with BMIC ≥ 100 μg/L were more likely to have UIC ≥ 100 μg/L compared to those whose mothers had BMIC < 100 μg/L in both unadjusted (OR = 7.93, P < 0.001) and adjusted analysis (OR = 7.29, P = 0.001). The present findings indicate that BMIC is a more sensitive indicator than maternal UIC for assessment of iodine status in breastfed neonates. To address low levels of maternal UIC, further studies on the prescription of supplements containing 150 μg/day iodine during lactation period are warranted.

Low Urinary Iodine Concentration among Mothers and Children in Cambodia

A 2014 national assessment of salt iodization coverage in Cambodia found that 62% of samples were non-iodized, suggesting a significant decline in daily iodine intakes. The Cambodian Micronutrient Survey conducted in 2014 (CMNS-2014) permitted obtaining national data on urinary iodine concentrations (UIC) to assess iodine status and whether iodized salt use had an impact. Urine samples were collected from mothers (n = 736) and children (n = 950). The median UIC was 63 µg/L and 72 µg/L in mothers and children respectively. More than 60% of mothers and their children had a UIC < 100 µg/L, thereby indicating a serious public health problem. Iodine status was significantly lower among mothers and children living in rural areas, belonging to the poorest socioeconomic category, or living in a household not using iodized salt. The limited enforcement of the legislation for iodized salt has resulted in a major decrease in the prevalence of iodized salt, which in turn has compromised iodine status in Cambodia. It is essential for the government to enhance enforcement of the iodized salt legislation, and implement short term strategies, such as iodine supplementation, to prevent an increase of severe complications due to iodine deficiency in the Cambodian population.