How will South Africa's mandatory salt reduction policy affect its salt iodisation programme? A cross-sectional analysis from the WHO-SAGE Wave 2 Salt & Tobacco study

Comparing a range of potassium-enriched low sodium salt substitutes to common salt: Results of taste and visual tests in South African adults

BACKGROUND AND AIMS

Potassium-enriched low sodium salt substitutes (LSSS), which replace a proportion of sodium chloride (NaCl) with potassium chloride (KCl), have been shown to reduce blood pressure and offer a potential solution to address the high burden of hypertension in South Africa. However, it is unknown which proportions of KCl in LSSS are acceptable. We compared the taste and visual acceptability of various LSSS in South African adults.

METHODS AND RESULTS

Fifty-six adults underwent double-blind taste and visual tests of four LSSS (35%KCl/65%NaCl; 50%KCl/50%NaCl; 66%KCl/34%NaCl; 100%KCl) in comparison to 100%NaCl (common salt). Participants scored each product by taste ranking, taste perception and likeliness to use. Participants then visually inspected the five products and attempted to identify which was which. Almost half (45 %) of participants ranked the taste of 50%KCl/50 %NaCl as fantastic or really good. Furthermore, 62 % of participants liked and would be happy to use the 50 %KCl/50 %NaCl or felt this tasted like common salt. Only 12 % rated the 100%KCl highly for taste, and over half reported being unlikely to use this. Most participants (57.3 % and 36.4 %) were able to visually identify 100%NaCl and 100%KCl, while identification of other blends was generally poor. Responses were similar for 35%KCl/65%NaCl and 66%KCl/34%NaCl throughout.

CONCLUSION

Our findings suggest that the taste of the 50%KCl salt substitute would be well tolerated by South African adults, most of which could not visually differentiate between this salt substitute and common salt.

Switching the World's Salt Supply-Learning from Iodization to Achieve Potassium Enrichment

Sodium is an essential dietary component, but excess sodium intake can lead to high blood pressure and an increased risk of cardiovascular disease. Many national and international bodies, including the World Health Organization, have advocated for population-wide sodium reduction interventions. Most have been unsuccessful due to inadequate sodium reduction by food industry and difficulties in persuading consumers to add less salt to food. Recent research highlights potassium-enriched salt as a new, feasible, acceptable, and scalable approach to reducing the harms caused by excess sodium and inadequate potassium consumption. Modeling shows that a global switch from regular salt to potassium-enriched salt has the potential to avert millions of strokes, heart attacks, and premature deaths worldwide each year. There will be many challenges in switching the world's salt supply to potassium-enriched salt, but the success of universal salt iodization shows that making a global change to the manufacture and use of salt is a tractable proposition. This in-depth review of universal salt iodization identified the importance of a multisectoral effort with strong global leadership, the support of multilateral organizations, engagement with the salt industry, empowered incountry teams, strong participation of national governments, understanding the salt supply chain, and a strategic advocacy and communication plan. Key challenges to the implementation of the iodization program were costs to government, industry, and consumers, industry concerns about consumer acceptability, variance in the size and capabilities of salt producers, inconsistent quality control, ineffective regulation, and trade-related regulatory issues. Many of the opportunities and challenges to universal salt iodization will likely also be applicable to switching the global salt supply to iodized and potassium-enriched salt.

Health systems performance for hypertension control using a cascade of care approach in South Africa, 2011-2017

Hypertension is a major contributor to global morbidity and mortality. In South Africa, the government has employed a whole systems approach to address the growing burden of non-communicable diseases. We used a novel incident care cascade approach to measure changes in the South African health system's ability to manage hypertension between 2011 and 2017. We used data from Waves 1-5 of the National Income Dynamics Study (NIDS) to estimate trends in the hypertension care cascade and unmet treatment need across four successive cohorts with incident hypertension. We used a negative binomial regression to identify factors that may predict higher rates of hypertension control, controlling for socio-demographic and healthcare factors. In 2011, 19.6% (95%CI 14.2, 26.2) of individuals with incident hypertension were diagnosed, 15.4% (95%CI 10.8, 21.4) were on treatment and 7.1% had controlled blood pressure. By 2017, the proportion of individuals with diagnosed incident hypertension had increased to 24.4% (95%CI 15.9, 35.4). Increases in treatment (23.3%, 95%CI 15.0, 34.3) and control (22.1%, 95%CI 14.1, 33.0) were also observed, translating to a decrease in unmet need for hypertension care from 92.9% in 2011 to 77.9% in 2017. Multivariable regression showed that participants with incident hypertension in 2017 were 3.01 (95%CI 1.77, 5.13) times more likely to have a controlled blood pressure compared to those in 2011. Our data show that while substantial improvements in the hypertension care cascade occurred between 2011 and 2017, a large burden of unmet need remains. The greatest losses in the incident hypertension care cascades came before diagnosis. Nevertheless, whole system programming will be needed to sufficiently address significant morbidity and mortality related to having an elevated blood pressure.

Global nutritional challenges of reformulated food: A review

Food reformulation, the process of redesigning processed food products to make them healthier, is considered a crucial step in the fight against noncommunicable diseases. The reasons for reformulating food vary, with a common focus on reducing the levels of harmful substances, such as fats, sugars, and salts. Although this topic is broad, this review aims to shed light on the current challenges faced in the reformulation of food and to explore different approaches that can be taken to overcome these challenges. The review highlights the perception of consumer risk, the reasons for reformulating food, and the challenges involved. The review also emphasizes the importance of fortifying artisanal food processing and modifying microbial fermentation in order to meet the nutrient requirements of people in developing countries. The literature suggests that while the traditional reductionist approach remains relevant and yields quicker results, the food matrix approach, which involves engineering food microstructure, is a more complex process that may take longer to implement in developing economies. The findings of the review indicate that food reformulation policies are more likely to succeed if the private sector collaborates with or responds to the government regulatory process, and further research is conducted to establish newly developed reformulation concepts from different countries. In conclusion, food reformulation holds great promise in reducing the burden of noncommunicable diseases and improving the health of people around the world.

The perspective of hypertension and salt intake in Chinese population

Salt intake is too high nowadays. It has been widely recognized that there is a close relationship between hypertension (HTN) and dietary salt intake. Investigations reveal that long-term high salt intake, mainly sodium intake, induces a relevant increase in blood pressure in hypertensive and normotensive individuals. According to most scientific evidence, a diet with high salt intake in public increases cardiovascular risk, salted-related HTN, and other HTN-associated outcomes. Given the clinical importance, this review aims to present the prevalence of HTN and trends in salt intake in the Chinese population and will comprehensively discuss the risk factors, causes, and mechanisms of the association between salt intake and HTN. The review also highlights the education of Chinese people regarding salt intake and the cost-effectiveness of salt reduction from a global perspective. Finally, the review will emphasize the need to customize the unique Chinese practices to reduce salt intake and how awareness changes people's eating lifestyle and helps adopt diet salt reduction strategies.

The Healthy Aging Adult South Africa report card: a systematic review of the evidence between 2013 and 2020 for middle-aged South African men and women

Due to the increasing non-communicable disease burden in Africa, several strategies that target the major lifestyle and physiological risk factors have been implemented to combat such diseases. The Healthy Aging Adult South Africa report card systematically reviews national and regional prevalence data of middle-aged South African adults (45-65 years) published between 2013 and 2020 on diet, physical activity, tobacco use and alcohol consumption, obesity, hypertension, dyslipidaemia and diabetes mellitus. Each indicator was assigned two grades, (1) based on the availability of prevalence data, and (2) based on whether policies have been proposed and implemented for the respective indicators. Alcohol consumption, obesity, hypertension and diabetes received an A grade for the availability of prevalence data. Tobacco use and diet received an A grade for policy and implementation. Gaps have been identified that need to be filled by future research focusing on continued surveillance of all indicators in order to inform and implement effective policies.

The effect of sodium restriction on iodine prophylaxis: a review

PURPOSE

Sodium is essential to life. However, its dietary excess is detrimental to the cardiovascular system, and sodium restriction is a crucial step in cardiovascular prevention. Iodine deficiency has been fought worldwide for decades, and substantial success has been achieved introducing the use of iodine-enriched salt. Nevertheless, areas of iodine deficiency persist around the world, both in developing and industrialized countries, and a major concern affecting dietary sodium reduction programs is represented by a possible iodine intake deficiency. There are substantial differences in the source of alimentary iodine among countries, such as iodized salt added, household tap water, seafood, or salt employed in packaged food. It is clear that a sodium-restricted diet can induce differences in terms of iodine intake, depending on the country considered. Moreover, iodine status has undergone relevant changes in many countries in the last years.

METHODS

Systematic review of literature evidence about the possible effects of sodium restriction on population iodine status.

RESULTS

To date, the available results are conflicting, depending on country, salt iodization policy, as well as time frame of data collection. However, to ensure an optimal iodine supply by salt fortification, without exceeding the current recommendation by World Health Organization for salt intake, seems to be an achievable goal.

CONCLUSION

A balanced approach may be obtained by an adequate iodine concentration in fortified salt and by promoting the availability of iodized salt for household consumption and food industry use. In this scenario, updated prospective studies are strongly needed.

The Role of Multiply-Fortified Table Salt and Bouillon in Food Systems Transformation

Our global food system lacks the critically needed micronutrients to meet the daily requirements of the most at-risk populations. Diets also continue to shift toward unhealthy foods, including the increased intake of salt. While most countries exceed the WHO’s recommended levels, sodium does play an essential physiological role. Table salt and other salt-containing condiments, such as bouillon, also have cultural importance, as they are used to enhance the flavor of foods cooked at home. Given their universal consumption across income classes and both urban and rural populations, these condiments are an integral part of the food system and should, therefore, be part of its transformation. Fortification of salt and salt-containing condiments can play a catalytic role in the delivery of population-wide nutritional and health benefits. With relatively consistent levels of intake across the population, these condiments hold high potential for delivering micronutrients beyond iodine while also reducing concerns related to high micronutrient intake, particularly so in countries where the industries are relatively consolidated. As a flexible and complementary strategy to an evolving food system, fortification levels can also be adjusted over time to ensure micronutrient delivery targets continue to be achieved as the system improves, whether through lower intakes of sodium in line with WHO recommendations, enhanced consumption of nutrient-dense foods, and/or broader adoption of biofortified crops. Future areas of innovation are required to realize this vision, including developing affordable salt substitutes to meet cost requirements of consumers in low-and middle-income countries, improving the stability and bioavailability of the micronutrients in condiments so that delivery targets can be reached without affecting sensory attributes, and the development of efficient systems for monitoring population intake and micronutrient status to inform fortification program design and management. Rather than being considered antithetical to the transformation, multiply-fortified salt and bouillon can strengthen our ability to meet the cultural, sensory, nutritional, and health needs of an evolving food system.

Seasonal effects on urinary iodine concentrations in women of reproductive age: An observational study in Tanzania and South Africa

BACKGROUND

Iodine intake in populations is usually assessed by measuring urinary iodine concentrations (UICs) in spot samples. Hot climate conditions may reduce urine volume, thus leading to overestimations of UIC and thereby masking inadequate iodine intake.

OBJECTIVES

We investigated the effects of season on UICs in 2 populations exposed to high-temperature climates.

METHODS

In this observational study, we examined women (18-49 years) in Tanzania (ncold = 206; nhot = 179) and South Africa (ncold = 157; nhot = 126) during cold and hot seasons. From each woman in both seasons, we obtained two 24-hour urine collections and 2 spot urine samples, as well as salt, water, and cow's milk samples. We measured the urine volume, UIC, and urinary creatinine concentration (UCC). The 24-hour urinary iodine excretion (UIE) was calculated and used to estimate the iodine intake. We used linear mixed-effects models to test for differences between seasons.

RESULTS

In Tanzanian women, we observed no seasonal effect on the urine volume, 24-hour UIE, 24-hour UIC, spot UIC, spot UIC:UCC ratio, or salt iodine concentration. In South African women, the median 24-hour urine volume was 1.40 L (IQR, 0.96-2.05 L) in the winter and 15% lower in the summer (P < 0.001). The median 24-hour UIE was 184 µg/day (IQR, 109-267 µg/day) in the winter and 34% lower in the summer (P < 0.001), indicating a lower iodine intake. As a result, UICs did not significantly differ between seasons in 24-hour collections and spot samples, whereas the spot UIC:UCC ratio differed by 21% (P < 0.001) and reflected the lower iodine intake. In both study populations, the within- and between-person variabilities in urine volume, 24-hour UICs, and spot UICs were higher than the variability between seasons.

CONCLUSIONS

Spot UIC may slightly overestimate the iodine intake in hot temperatures due to concentrated urine, and methods to correct for urine volume may be considered. Local seasonal differences in iodine intakes may also occur in some populations. This trial was registered at http://www.clinicaltrials.gov as NCT03215680.

Population-level interventions targeting risk factors of diabetes and hypertension in South Africa: a document review

BACKGROUND

South Africa bears an increasing burden of non-communicable diseases (NCDs), particularly diabetes, cardiovascular diseases, and cancer. The objective of this study was to identify which population-level interventions, implemented at the level of governmental or political jurisdictions only, targeting risk factors of diabetes and hypertension were included in policies in South Africa. We also looked at whether these have been implemented or not.

METHODS

A review of relevant reports, journal articles, and policy documents was conducted. Documentation from government reports that contains information regarding the planning, implementation and evaluation of population-level interventions targeting diabetes and hypertension were considered, and various databases were searched. The identified population-level interventions were categorized as supportive policies, supportive programs and enabling environments according to the major risk factors of NCDs i.e., tobacco use, harmful consumption of alcohol, unhealthy diet/nutrition and physical inactivity, in accordance with the WHO 'Best buys'. A content document analysis was conducted.

RESULTS

The source documents reviewed included Acts and laws, regulations, policy documents, strategic plans, case studies, government reports and editorials. South Africa has a plethora of policies and regulations targeting major risk factors for diabetes and hypertension implemented in line with WHO 'Best buys' since 1990. A total of 28 policies, legislations, strategic plans, and regulations were identified - 8 on tobacco use; 7 on harmful consumption of alcohol; 8 on unhealthy diet and 5 on physical inactivity - as well as 12 case studies, government reports and editorials. There is good progress in policy formulation in line with the 'Best buys'. However, there are some gaps in the implementation of these policies and programs.

CONCLUSION

Curbing the rising burden of NCDs requires comprehensive strategies which include population-level interventions targeting risk factors for diabetes and hypertension and effective implementation with robust evaluation to identify successes and ways to overcome challenges.

Iodine status of pregnant women living in urban Johannesburg, South Africa

Adequate intake of iodine is important during pregnancy because of its essential role in foetal growth and neurodevelopment. Data on iodine status of South African pregnant women are scarce, and the salt reduction policy implemented in 2016 may decrease iodine intake of South Africans. This cross-sectional study assessed the iodine status of pregnant women residing in urban Johannesburg, South Africa. A total of 250 pregnant women were enrolled into the 'Nutrition during Pregnancy and Early Development' (NuPED) study and 312 pregnant women into the 'Assessment of dried blood spot thyroglobulin in pregnant women to redefine the range of median urinary iodine concentration that indicates adequate iodine intake, South Africa' (STRIPE-SA) study and were included in this analysis. Urinary iodine concentration (UIC) was analysed in a spot urine sample. Thyroglobulin (Tg) was measured in serum, and thyroid-stimulating hormone (TSH) and total thyroxine (tT4) were measured in dried blood spots. The median [interquartile range (IQR)] UIC of pregnant women was 144 (84-234) μg/L. Women in the first (n = 99), second (n = 262) and third (n = 174) trimester had a median UIC of 133 (81-316), 145 (84-236) and 156 (89-245) μg/L, respectively (p = 0.419). Median TSH, tT4 and Tg were 2.7 (2.3-3.2) mU/L, 202 (163-236) nmol/L and 9.2 (5.4-17.9) μg/L, respectively. Based on the median UIC, pregnant women residing in urban Johannesburg may be borderline iodine deficient. These findings highlight the need for ongoing monitoring of iodine status among vulnerable pregnant women, especially considering the recently introduced salt reduction policy in South Africa.

Salt-reduction strategies may compromise salt iodization programs: Learnings from South Africa and Ghana

OBJECTIVES

Universal salt iodization has been adopted by many countries to address iodine deficiency. More recently, salt-reduction strategies have been widely implemented to meet global salt intake targets of <5 g/d. Compatibility of the two policies has yet to be demonstrated. This study compares urinary iodine excretion (UIE) according to 24-h urinary sodium excretion, between South Africa (SA) and Ghana; both countries have implemented universal salt iodization, but in Ghana no salt-reduction legislation has been implemented.

METHODS

Participants from the World Health Organization's Study on Global Ageing and Adult Health Wave 3, with survey and valid 24-h urinary data (Ghana, n = 495; SA, n = 707), comprised the sample. Median 24-h UIE was compared across salt intake categories of <5, 5-9 and >9 g/d.

RESULTS

In Ghana, median sodium excretion indicated a salt intake of 10.7 g/d (interquartile range [IQR] = 7.6), and median UIE was 182.4 µg/L (IQR = 162.5). In SA, both values were lower: median salt = 5.6 g/d (IQR = 5.0), median UIE = 100.2 µg/L (IQR = 129.6). UIE differed significantly across salt intake categories (P < 0.001) in both countries, with positive correlations observed in both-Ghana: r = 0.1501, P < 0.0011; South Africa: r = 0.4050, P < 0.0001. Participants with salt intakes <9 g/d in SA did not meet the World Health Organization's recommended iodine intake of 150 µg/d, but this was not the case in Ghana.

CONCLUSIONS

Monitoring and surveillance of iodine status is recommended in countries that have introduced salt-reduction strategies, in order to prevent reemergence of iodine deficiency.

Dietary Sodium Intake and Health Indicators: A Systematic Review of Published Literature between January 2015 and December 2019

As the science surrounding population sodium reduction evolves, monitoring and evaluating new studies on intake and health can help increase our understanding of the associated benefits and risks. Here we describe a systematic review of recent studies on sodium intake and health, examine the risk of bias (ROB) of selected studies, and provide direction for future research. Seven online databases were searched monthly from January 2015 to December 2019. We selected human studies that met specified population, intervention, comparison, outcome, time, setting/study design (PICOTS) criteria and abstracted attributes related to the study population, design, intervention, exposure, and outcomes, and evaluated ROB for the subset of studies on sodium intake and cardiovascular disease risks or indicators. Of 41,601 abstracts reviewed, 231 studies were identified that met the PICOTS criteria and ROB was assessed for 54 studies. One hundred and fifty-seven (68%) studies were observational and 161 (70%) focused on the general population. Five types of sodium interventions and a variety of urinary and dietary measurement methods were used to establish and quantify sodium intake. Five observational studies used multiple 24-h urine collections to assess sodium intake. Evidence mainly focused on cardiovascular-related indicators (48%) but encompassed an assortment of outcomes. Studies varied in ROB domains and 87% of studies evaluated were missing information on ≥1 domains. Two or more studies on each of 12 outcomes (e.g., cognition) not previously included in systematic reviews and 9 new studies at low ROB suggest the need for ongoing or updated systematic reviews of evidence on sodium intake and health. Summarizing evidence from assessments on sodium and health outcomes was limited by the various methods used to measure sodium intake and outcomes, as well as lack of details related to study design and conduct. In line with research recommendations identified by the National Academies of Science, future research is needed to identify and standardize methods for measuring sodium intake.

Curtis C, Frieden TR, Cobb LK. Priority Actions to Advance Population Sodium Reduction

High sodium intake is estimated to cause approximately 3 million deaths per year worldwide. The estimated average sodium intake of 3.95 g/day far exceeds the recommended intake. Population sodium reduction should be a global priority, while simultaneously ensuring universal salt iodization. This article identifies high priority strategies that address major sources of sodium: added to packaged food, added to food consumed outside the home, and added in the home. To be included, strategies needed to be scalable and sustainable, have large benefit, and applicable to one of four measures of effectiveness: (1) Rigorously evaluated with demonstrated success in reducing sodium; (2) suggestive evidence from lower quality evaluations or modeling; (3) rigorous evaluations of similar interventions not specifically for sodium reduction; or (4) an innovative approach for sources of sodium that are not sufficiently addressed by an existing strategy. We identified seven priority interventions. Four target packaged food: front-of-pack labeling, packaged food reformulation targets, regulating food marketing to children, and taxes on high sodium foods. One targets food consumed outside the home: food procurement policies for public institutions. Two target sodium added at home: mass media campaigns and population uptake of low-sodium salt. In conclusion, governments have many tools to save lives by reducing population sodium intake.

Monitoring and implementation of salt reduction initiatives in Africa: A systematic review

This systematic review aims to document salt consumption patterns and the implementation status and potential impact of salt reduction initiatives in Africa, from studies published between January 2009 and November 2019. Studies were sourced using MEDLINE, Embase, Cochrane Library electronic databases, and gray literature. Of the 887 records retrieved, 38 studies conducted in 18 African countries were included. Twelve studies measured population salt intake, 11 examined salt level in foods, 11 assessed consumer knowledge, attitudes, and behaviors, 1 study evaluated a behavior change intervention, and 3 studies modeled potential health gains and cost savings of salt reduction interventions. The population salt intake studies determined by 24‐hour urine collections showed that the mean (SD) salt intake in African adults ranged from 6.8 (2.2) g to 11.3 (5.4) g/d. Salt levels in foods were generally high, and consumer knowledge was fairly high but did not seem to translate into salt lowering behaviors. Modeling studies showed that interventions for reducing dietary sodium would generate large health gains and cost savings for the health system. Despite this evidence, adoption of population salt reduction strategies in Africa has been slow, and dietary consumption of sodium remains high. Only South Africa adopted legislation in 2016 to reduce population salt intake, but success of this intervention has not yet been fully evaluated. Thus, rigorous evaluation of the salt reduction legislation in South Africa and initiation of salt reduction programs in other African countries will be vital to achieving the targeted 30% reduction in salt intake by 2025.

Impact of water fortification with calcium on calcium intake in different countries: a simulation study

Objective:

To simulate the impact – effectiveness and safety – of water fortification with different concentrations of Ca using the Intake Modelling, Assessment and Planning Program.

Design:

This is a secondary analysis of national or sub-national dietary intake databases.

Setting and Participants:

Uganda, Lao People’s Democratic Republic (PDR), Bangladesh, Zambia, Argentina, USA and Italy.

Results:

We found that for dietary databases assessed from low- and middle-income countries (LMIC), the strategy of fortifying water with 500 mg of Ca/l would decrease the prevalence of low Ca intake in all age groups. We also found that this strategy would be safe as no group would present a percentage of individuals exceeding the upper limit in >2 %, except women aged 19–31 years in Lao PDR, where 6·6 % of women in this group would exceed the upper limit of Ca intake. The same strategy would lead to some groups exceeding the upper limit in USA and Italy.

Conclusions:

We found that for most LMIC countries, water fortified with Ca could decrease the prevalence of Ca intake inadequacy without exceeding the upper levels of Ca intake.

Regulatory and Policy-Related Aspects of Calcium Fortification of Foods. Implications for Implementing National Strategies of Calcium Fortification

Daily calcium intake is well below current recommendations in most low- and middle-income countries (LMICs). Calcium intake is usually related to bone health, however an adequate calcium intake has also been shown to reduce hypertensive disorders of pregnancy, lower blood pressure and cholesterol values, and to prevent recurrent colorectal adenomas. Fortification of foods has been identified as a cost-effective strategy to overcome micronutrient gaps in public health. This review summarizes regulatory aspects of fortification of commonly consumed foods with micronutrients, with an emphasis on calcium. We selected a convenient sample of 15 countries from different WHO regions and described the regulatory framework related to calcium fortification of staple foods. We assessed the relevant policies in electronic databases including the WHO Global database on the Implementation of Nutrition Action (GINA) for fortification policies and the Global Fortification Data Exchange Database, a fortification database developed and maintained by Food Fortification Initiative (FFI), Global Alliance for Improved Nutrition (GAIN), Iodine Global Network (IGN), and Micronutrient Forum. Food fortification with micronutrients is widely used in many of the selected countries. Most countries had national legislation for the addition of micronutrients to staple foods, especially wheat flour. These national legislations, that includes regulations and standards, can provide the framework to consider the implementation of adding calcium to the fortification strategies, including the selection of the adequate food vehicle to reach the targeted population at risk safely. The strategy to include calcium in the fortification mix in fortified staple foods seems promising in these countries. However, potential undesired changes on the organoleptic characteristics of fortified foods and products thereof, and operational feasibility at the manufacturing site should be evaluated by the stakeholders during the planning stage. Codex Alimentarius standards should be considered by regulators in order to assure adherence to international standards. While the selected countries already have established national regulations and/or standards for fortification of key staple food vehicles, and there are experiences in the implementation of fortification of some staple foods, national food intake surveys can help plan, design, and modify existing fortification programs as well as monitor food and nutrient consumption to assess risk and benefits.

Potassium Intake in India: Opportunity for Mitigating Risks of High-Sodium Diets

INTRODUCTION

Most Indians are vegetarian or eat very little meat, which could imply high potassium intake. Because a high-potassium diet could counterbalance the adverse health effects of high-sodium intake, this study aimed to describe potassium relative to sodium intake and investigate the relationship between blood pressure and potassium intake relative to sodium intake in rural and urban India.

METHODS

Investigators collected 24-hour urines from 1,445 participants in a subset of 2 population-based surveys in North India in 2012-2013. Standardized questionnaires were used to collect information on demography, behaviors (tobacco, alcohol consumption, physical activity, and diet [food frequency and 24-hour recall]), and medical history. After evaluating expected versus measured creatinine excretion, the authors calculated median urine potassium excretion and sodium/potassium ratio, according to sex and urban or rural residence, and estimated least square means for the urine measures by participant demographics and comorbidities, after accounting for caloric intake. Two-year blood pressure follow-up data were available in the urban study, and ANCOVA regression was used to determine the association with urine measures. All the statistical analyses of the data were done in January 2019.

RESULTS

Acceptable 24-hour urine collections were available in 1,397 participants (rural, n=730). Median urine potassium excretions were 1,492 (IQR=1,012-2,063) and 975 (615-1,497) mg/day; sodium/potassium ratios met the recommended target of <1 in 2.9% rural and 6.6% urban participants. Rural participants did not have higher potassium or lower (better) sodium/potassium ratios when diagnosed with hypertension or other cardiovascular conditions. Higher potassium excretion was associated with lower blood pressure during follow-up among the urban participants (mean systolic blood pressure, 129 vs 133 mm Hg in highest vs lowest potassium excretion tertiles; p=0.029).

CONCLUSIONS

Low potassium intake in India warrants dietary policies promoting intake of potassium-rich foods to improve heart health. This approach may be more acceptable than programs focused on sodium reduction alone.

Impact of Moderate Sodium Restriction and Hydrochlorothiazide on Iodine Excretion in Diabetic Kidney Disease: Data from a Randomized Cross-Over Trial

Sodium restriction may potentially reduce iodine intake. This study aimed to determine the effect of sodium restriction (dietary counseling) on 24-h urinary iodine excretion. Diuretics provide an alternative to sodium restriction and are frequently added to sodium restriction, so the effects of hydrochlorothiazide (50 mg daily) and combined therapy were also studied. We performed a post-hoc analysis of a Dutch multi-center, randomized cross-over trial in 45 patients with diabetic kidney disease with a mean age of 65 ± 9 years, mean eGFR of 65 ± 27 mL/min/1.73 m², median albuminuria of 648 [230–2008] mg/24 h and 84% were male. During regular sodium intake with placebo, mean 24 h urinary sodium and iodine excretion were 224 ± 76 mmol/24 h and 252 ± 94 ug/24 h, respectively (r = 0.52, p < 0.001). Mean iodine excretion did not change significantly if sodium restriction and hydrochlorothiazide were applied separately; mean difference −8 ug/day (95% CI −38, 22; p = 0.6) and 14 ug/day (95% CI −24, 52; p = 0.5), respectively. Combined therapy induced a significant decrease in mean iodine excretion (−37 ug/day; 95% CI −67, −7; p = 0.02), yet this was not seen to a clinically meaningful level. The number of patients with an estimated intake below recommended daily allowances did not differ significantly between the four treatment periods (p = 0.3). These findings show that sodium restriction is not a risk factor for iodine deficiency.

Dietary Sources of Salt in Low- and Middle-Income Countries: A Systematic Literature Review

Rapid urbanization in low- and middle-income countries (LMICs) is transforming dietary patterns from reliance on traditional staples to increased consumption of energy-dense foods high in saturated fats, trans fats, sugars, and salt. A systematic literature review was conducted to determine major food sources of salt in LMICs that could be targeted in strategies to lower population salt intake. Articles were sourced using Medline, Web of Science, Scopus, and grey literature. Inclusion criteria were: reported dietary intake of Na/salt using dietary assessment methods and food composition tables and/or laboratory analysis of salt content of specific foods in populations in countries defined as low or middle income (LMIC) according to World Bank criteria. Of the 3207 records retrieved, 15 studies conducted in 12 LMICs from diverse geographical regions met the eligibility criteria. The major sources of dietary salt were breads, meat and meat products, bakery products, instant noodles, salted preserved foods, milk and dairy products, and condiments. Identification of foods that contribute to salt intake in LMICs allows for development of multi-faceted approaches to salt reduction that include consumer education, accompanied by product reformulation.

Low-Salt Intake Suggestions in Hypertensive Patients Do not Jeopardize Urinary Iodine Excretion

A low-sodium diet is an essential part of the treatment of hypertension. However, some concerns have been raised with regard to the possible reduction of iodine intake during salt restriction. We obtained 24-h urine collections for the evaluation of iodine (UIE) and sodium excretion (UNaV) from 136 hypertensive patients, before and after 9 ± 1 weeks of a simple low-sodium diet. Body mass index (BMI), blood pressure (BP), and drug consumption (DDD) were recorded. Data are average ± SEM. Age was 63.6 ± 1.09 year. BMI was 25.86 ± 0.40 kg/m² before the diet and 25.38 ± 0.37 kg/m² after the diet (p < 0.05). UNaV decreased from 150.3 ± 4.01 mEq/24-h to 122.8 ± 3.92 mEq/24-h (p < 0.001); UIE decreased from 186.1 ± 7.95 µg/24-h to 175.0 ± 7.74 µg/24-h (p = NS); both systolic and diastolic BP values decreased (by 6.15 ± 1.32 mmHg and by 3.75 ± 0.84 mmHg, respectively, p < 0.001); DDD decreased (ΔDDD 0.29 ± 0.06, p < 0.05). UNaV and UIE were related both before (r = 0.246, p = 0.0040) and after the diet (r = 0.238, p = 0.0050). UNaV and UIE were significantly associated both before and after the diet (p < 0.0001 for both). After salt restriction UIE showed a non-significant decrease remaining in an adequate range. Our dietary suggestions were aimed at avoiding preserved foods, whereas the cautious use of table salt was permitted, an approach which seems safe in terms of iodine intake.

The catalytic role of iodine excess in loss of homeostasis in autoimmune thyroiditis

PURPOSE OF REVIEW

To review the latest developments concerning the role of iodine in the pathophysiology of autoimmune thyroiditis.

RECENT FINDINGS

Recent studies have provided evidence that in areas with excess iodine intake, increased incidence of autoimmune thyroiditis marked by high titers of thyroid peroxidase and thyroglobulin antibodies has occurred. Investigations in the NOD.H2h4 mouse, a strain prone to AIT, showed that they are better adapted to the Wolff-Chaikoff effect.

SUMMARY

To provide an overview of the studies conducted during the last few years implicating iodine in the development and manifestation of autoimmune thyroiditis.