Low intake of iodized salt and iodine containing supplements among pregnant women with apparently insufficient iodine status - time to change policy?

BACKGROUND: Iodine is an essential nutrient for human health throughout the life cycle, especially during early stages of intrauterine life and infancy, to ensure adequate neurocognitive development. The growing global reliance on desalinated iodine-diluted water raises the specter of increased iodine deficiency in several regions. The case of Israel may be instructive for exploring the link between iodine status and habitual iodine intake in the setting of extensive national reliance on desalinated water. The aim of this study was to explore the relationship between iodine intake, including iodized salt and iodine-containing supplements intake, and iodine status among pregnant women residing in a sub-district of Israel that is highly reliant on desalinated iodine-diluted water. METHODS: A total of 134 consecutive pregnant women were recruited on a voluntary basis from the obstetrics department of the Barzilai University Medical Center during 2018. Blood was drawn from participants to determine levels of serum thyrotropin (TSH), thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TgAb) and thyroglobulin (Tg). An iodine food frequency questionnaire (sIFFQ) was used to assess iodine intake from food, IS and ICS. A questionnaire was used to collect data on demographic and health characteristics. RESULTS: A total of 105 pregnant women without known or reported thyroid disease were included in the study. Elevated Tg values (≥ 13 µg/L), were found among 67% of participants, indicating insufficient iodine status. The estimated iodine intake (median, mean ± SD 189, 187 ± 106 µg/d by sIFFQ) was lower than the levels recommended by the World Health Organization and the Institute of Medicine (250 vs. 220 µg/day respectively). The prevalence of iodized salt intake and iodine containing supplement intake were 4 and 52% (respectively). Values of Tg > 13 µg/L were inversely associated with compliance with World Health Organization and Institute of Medicine recommendations. CONCLUSIONS: While the Israeli Ministry of Health has recommended the intake of iodized salt and iodine containing supplements, this is apparently insufficient for achieving optimal iodine status among Israeli pregnant women. The evidence of highly prevalent probable iodine deficiency in a sample of pregnant women suggests an urgent need for a national policy of iodized salt regulation, as well as guidelines to promote iodine containing supplements and adherence to them by caregivers. In addition, studies similar to this one should be undertaken in additional countries reliant on desalinated iodine-diluted water to further assess the impact of desalinization on maternal iodine status.

Dietary advice to cardiovascular patients. A brief update for physicians.

It is important, in our opinion, to provide physicians with a brief update of scientifically-sound evidence in preventive nutrition, to be employed in their everyday practice, since the latest scientific and clinical advances in this area are generally not well known. Here, we review the most recent evidence in support of an optimal cardio-protective diet, and we identify the need to focus mainly on protective food which should be part of such diet, rather than on nutrients with negative effects to be limited (salt, saturated fats, simple sugars). We conclude that, to favor patient compliance, it is also necessary to underscore indications on the topics for which there is convincing and coherent literature, leaving other less-explored aspects to individual preferences.

The responses of the inflammatory marker, pentraxin 3, to dietary sodium and potassium interventions.

Pentraxin-3 is a sensitive marker of inflammation that plays dual roles, pathogenic and cardioprotective, in the progression of cardiovascular diseases. Inflammation is intimately involved in salt-induced hypertension. We investigated the responses of pentraxin-3 to sodium and potassium supplementation to elucidate the potential role of pentraxin-3 in salt-induced hypertension. A total of 48 participants from northwest China were enrolled. All participants were maintained on a 3-day normal diet, which was sequentially followed by a 7-day low-sodium diet, a 7-day high-sodium diet, and a 7-day high-sodium plus potassium diet. Plasma concentrations of pentraxin-3 were assessed using ELISA. Plasma pentraxin-3 decreased significantly during the low-salt period compared to baseline (0.57 ± 0.19 ng/mL vs 0.72 ± 0.33 ng/mL, P = .012) and increased during the high-salt period (0.68 ± 0.26 ng/mL vs 0.57 ± 0.19 ng/mL, P = .037). Potassium supplementation inhibited salt-induced increase in pentraxin-3 (0.56 ± 0.21 ng/mL vs 0.68 ± 0.26 ng/mL, P = .015). Ln-transformed pentraxin-3 at baseline was inversely correlated with BMI (r = -.349, P = .02), DBP (r = -.414, P = .005), MAP (r = -.360, P = .017). We found a positive correlation between the ln-transformed concentrations of pentraxin-3 and 24-hour urinary sodium during low and high Na+ periods (r = .269, P = .012) and a negative relationship with 24 hours urinary potassium excretion during high-salt and high-salt plus potassium periods (r = -.246, P = .02). These correlations remained significant after adjusting for confounders. Pentraxin-3 responses were more prominent in salt-sensitive individuals than salt-resistant individuals. Dietary salt and potassium interventions significantly altered circulating pentraxin-3.

Iodine Prophylaxis in the Lights of the Last Recommendation of WHO on Reduction of Daily Salt Intake.

BACKGROUND: In 1994, International Organizations: WHO, UNICEF and ICCIDD indicat ed salt Natrium Chloride as the main carrier of iodine in the prophilaxis systems in the iodine deficient areas over the world. Following this recommendation, 24 European countries introduced the model of iodine p rop hylaxis based on the salt iodization. However in 7 European countries only - among tchem in Poland - salt iodization is mandatory as the most effective mode lon the population level. OBJECTIVE: Presenting the method for the reduction of the consumption of iodized salt and supplement ation of iodine by other iodine carriers. METHODS: Concentration of iodine in the salt has been calculated according to the daily salt consumption and WHO recommendation on the daily dose of iodine that should be supplied in different groups of age and in pregnant and breast feeding women. No relevant recent patents were available for this WHO report. RESULTS: Consumption of salt in European countries is from 8 to 11g/day/person. In Poland, it is very high 11.5g/day/person. WHO in 1996 introduced recommendation on reducing daily salt intake to 5g/day/person as Natrium is a risk factor of hypertension and some neoplastic processes. CONCLUSION: When iodized salt is the main carrier of iodine in the prophylaxis systems, additional carriers of iodine should be introduced in the food market for instant -iodized mineral water. A very important factor is the proper information and education on the population level. This action is under control of the Polish Council for Control of Iodine Deficiency Disorders [PCCIDD] established in 1991 following the example of the International Council for Control of Iodine Deficiency Disorders [ICCIDD].

Stirring the Pot: Can Dietary Modification Alleviate the Burden of CKD?

Diet is one of the largest modifiable risk factors for chronic kidney disease (CKD)-related death and disability. CKD is largely a progressive disease; however, it is increasingly appreciated that hallmarks of chronic kidney disease such as albuminuria can regress over time. The factors driving albuminuria resolution remain elusive. Since albuminuria is a strong risk factor for GFR loss, modifiable lifestyle factors that lead to an improvement in albuminuria would likely reduce the burden of CKD in high-risk individuals, such as patients with diabetes. Dietary therapy such as protein and sodium restriction has historically been used in the management of CKD. Evidence is emerging to indicate that other nutrients may influence kidney health, either through metabolic or haemodynamic pathways or via the modification of gut homeostasis. This review focuses on the role of diet in the pathogenesis and progression of CKD and discusses the latest findings related to the mechanisms of diet-induced kidney disease. It is possible that optimizing diet quality or restricting dietary intake could be harnessed as an adjunct therapy for CKD prevention or progression in susceptible individuals, thereby reducing the burden of CKD.

Impact of Salt Intake on the Pathogenesis and Treatment of Hypertension.

Excessive dietary salt (sodium chloride) intake is associated with an increased risk for hypertension, which in turn is especially a major risk factor for stroke and other cardiovascular pathologies, but also kidney diseases. Besides, high salt intake or preference for salty food is discussed to be positive associated with stomach cancer, and according to recent studies probably also obesity risk. On the other hand a reduction of dietary salt intake leads to a considerable reduction in blood pressure, especially in hypertensive patients but to a lesser extent also in normotensives as several meta-analyses of interventional studies have shown. Various mechanisms for salt-dependent hypertension have been put forward including volume expansion, modified renal functions and disorders in sodium balance, impaired reaction of the renin-angiotensin-aldosterone-system and the associated receptors, central stimulation of the activity of the sympathetic nervous system, and possibly also inflammatory processes.Not every person reacts to changes in dietary salt intake with alterations in blood pressure, dividing people in salt sensitive and insensitive groups. It is estimated that about 50-60 % of hypertensives are salt sensitive. In addition to genetic polymorphisms, salt sensitivity is increased in aging, in black people, and in persons with metabolic syndrome or obesity. However, although mechanisms of salt-dependent hypertensive effects are increasingly known, more research on measurement, storage and kinetics of sodium, on physiological properties, and genetic determinants of salt sensitivity are necessary to harden the basis for salt reduction recommendations.Currently estimated dietary intake of salt is about 9-12 g per day in most countries of the world. These amounts are significantly above the WHO recommended level of less than 5 g salt per day. According to recent research results a moderate reduction of daily salt intake from current intakes to 5-6 g can reduce morbidity rates. Potential risks of salt reduction, like suboptimal iodine supply, are limited and manageable. Concomitant to salt reduction, potassium intake by higher intake of fruits and vegetables should be optimised, since several studies have provided evidence that potassium rich diets or interventions with potassium can lower blood pressure, especially in hypertensives.In addition to dietary assessment the gold standard for measuring salt intake is the analysis of sodium excretion in the 24 h urine. Spot urine samples are appropriate alternatives for monitoring sodium intake. A weakness of dietary evaluations is that the salt content of many foods is not precisely known and information in nutrient databases are limited. A certain limitation of the urine assessment is that dietary sources contributing to salt intake cannot be identified.Salt reduction strategies include nutritional education, improving environmental conditions (by product reformulation and optimization of communal catering) up to mandatory nutrition labeling and regulated nutrition/health claims, as well as legislated changes in the form of taxation.Regarding dietary interventions for the reduction of blood pressure the Dietary Approaches to Stop Hypertension (DASH) diet can be recommended. In addition, body weight should be normalized in overweight and obese people (BMI less than 25 kg/m2), salt intake should not exceed 5 g/day according to WHO recommendations (<2 g sodium/day), no more than 1.5 g sodium/d in blacks, middle- and older-aged persons, and individuals with hypertension, diabetes, or chronic kidney disease, intake of potassium (~4.7 g/day) should be increased and alcohol consumption limited. In addition, regular physical activity (endurance, dynamic resistance, and isometric resistance training) is very important.

Salt in the diet in patients with heart failure: what to recommend.

PURPOSE OF REVIEW: Recognizing the relevance of sodium balance in heart failure, it has been presumed that patients with heart failure benefit from a low-sodium diet, though its efficacy and safety are unclear. The purpose of this review is to provide insight into the currently available evidence base for the effects of dietary sodium restriction in patients with chronic heart failure. RECENT FINDINGS: There has been an increasing body of evidence on the effects of sodium restriction in heart failure; however, both observational and experimental studies have shown mixed results. Recent randomized controlled trial data has even suggested that sodium restriction may have detrimental effects in patients with heart failure. Only a few randomized controlled trials have included clinical outcomes as a primary endpoint. These have been either unpowered to test the association between reduced sodium intake and outcomes, or conducted in the context of an aggressive diuretic treatment and fluid restriction. SUMMARY: The effects of a low-sodium diet on clinical outcomes in patients with heart failure remain unclear. Ongoing research into the effects of lowering sodium for patients with chronic or acute heart failure will shed light on the importance of holistic self-care and dietary strategies in heart failure.

Impact of a program of Tai Chi plus behaviorally based dietary weight loss on physical functioning and coronary heart disease risk factors: a community-based study in obese older women.

This study employed a quasi-experimental design in a community-based study translating the results of our recent findings on the combined effects of Tai Chi and weight loss on physical function and coronary heart disease (CHD) risk factors. A 16-week intervention was conducted to assess the impact of Tai Chi plus a behavioral weight loss program (TCWL, n = 29) on obese (body mass index [BMI] = 35.4 ± 0.8 kg/m²) older (68.2 ± 1.5 yr.) women compared to a control group (CON, n = 9, BMI = 38.0 ± 1.5 kg/m², 65.6 ± 2.7 yr.), which was asked to maintain their normal lifestyle. The TCWL group lost weight (1.6 ± 2.9 kg, P = 0.006) while the CON group did not (1.2 ± 1.9 kg, P = 0.106). Physical functioning as measured by the short physical performance battery improved in TCWL when compared to the CON group (ß = 1.94, 95% Confidence Interval [CI]: 1.12, 2.76, P < 0.001). TCWL also improved in sit-and-reach flexibility (ß = -2.27, 95% CI: -4.09, -0.46, P = 0.016), body fat mass (BMI, ß = -0.65, 95% CI: -1.03, -0.26, P = 0.002), waist circumference (ß = -1.78, 95% CI: -2.83, -0.72, P = 0.002), systolic blood pressure (ß = -16.41, 95% CI: -21.35, -11.48, P < 0.001), and diastolic blood pressure (ß = -9.52, 95% CI: -12.65, -6.39, P < 0.001). Thus, TCWL intervention may represent an effective strategy to improve physical function and ameliorate CHD risk in the older adult population.

A lowered salt intake does not compromise iodine status in Cape Town, South Africa, where salt iodization is mandatory.

OBJECTIVE: Universal salt iodization is an effective strategy to optimize population-level iodine. At the same time as salt-lowering initiatives are encouraged globally, there is concern about compromised iodine intakes. This study investigated whether salt intakes at recommended levels resulted in a suboptimal iodine status in a country where salt is the vehicle for iodine fortification. METHODS: Three 24-h urine samples were collected for the assessment of urinary sodium and one sample was taken for urinary iodine concentrations (UICs) in a convenience sample of 262 adult men and women in Cape Town, South Africa. Median UIC was compared across categories of sodium excretion equivalent to salt intakes lower than 5, 5 to 9, and greater than or equal to 9 g/d. RESULTS: The median UIC was 120 µg/L (interquartile range 75.3-196.3), indicating iodine sufficiency. Less one-fourth (23.2%) of subjects had urinary sodium excretion values within the desirable range (salt <5 g/d), 50.7% had high values (5-9 g/d), and 22.8% had very high values (≥9 g/d). No association between urinary iodine and mean 3 × 24-h urinary sodium concentration was found (r = 0.087, P = 0.198) and UIC status did not differ according to urinary sodium categories (P = 0.804). CONCLUSION: In a country with mandatory universal salt iodization, consumers with salt intakes within the recommended range (<5 g/d) are iodine replete, and median UIC does not differ across categories of salt intake. This indicates that much of the dietary salt is provided from non-iodinated sources, presumably added to processed foods.

Reduction of salt: will iodine intake remain adequate in The Netherlands?

Salt is the main vehicle for iodine fortification in The Netherlands. A reduction in salt intake may reduce the supply of iodine. Our aim was to quantify the effect of salt reduction on the habitual iodine intake of the Dutch population and the risk of inadequate iodine intake. We used data of the Dutch National Food Consumption Survey (1997-8) and an update of the food composition database to estimate habitual salt and iodine intake. To take into account uncertainty about the use of iodised salt (industrial and discretionary) and food supplements, a simulation model was used. Habitual iodine and salt intakes were simulated for scenarios of salt reduction and compared with no salt reduction. With 12, 25 and 50 % salt reduction in industrially processed foods, the iodine intake remained adequate for a large part of the Dutch population. For the extreme scenario of a 50 % reduction in both industrially and discretionary added salt, iodine intake might become inadequate for part of the Dutch population (up to 10 %). An increment of the proportion of industrially processed foods using iodised salt or a small increase in iodine salt content will solve this. Nevertheless, 8-35 % of 1- to 3-year-old children might have iodine intakes below the corresponding estimated average requirement (EAR), depending on the salt intake scenario. This points out the need to review the EAR value for this age group or to suggest the addition of iodine to industrially manufactured complementary foods.

Effect of sodium alterations on hepatic cytochrome P450 3A2 and 2C11 and renal function in rats.

Numerous dietary supplements are known to modulate cytochrome P450 (CYP)-mediated metabolism and subsequently alter drug toxicity or efficacy in animals and humans. In the present study we investigated the effect of varying amounts of sodium intake on renal function and the metabolic activity of the hepatic CYP3A2 and CYP2C11 isoforms. Rats were maintained on standard rodent chow or a low-salt rice diet. Within each of these groups rats received either a single intraperitoneal injection of furosemide to initiate salt depletion, or saline. Additional groups included salt supplementation of 500 mg/300 g body weight/day and 1.25 g/300 g body weight/day of sodium chloride solution. Rats receiving the low-salt diet, both with and without a concomitant furosemide administration, had a significant reduction in creatinine clearance without changes in serum creatinine. In addition, urine flow rate was markedly reduced in rats maintained on the low-salt diet. Western blot analysis indicated that neither sodium supplementation nor deprivation altered hepatic microsomal CYP3A2 levels; however, hepatic CYP2C11 levels significantly increased in rats receiving the largest sodium supplement. In vitro metabolic activity of CYP3A2 was unchanged as compared with controls. Activity of CYP2C11 was significantly reduced in both rat groups receiving additional sodium supplements. Acute manipulation of daily sodium intake does alter renal function and specific hepatic CYP isoforms and should be considered when using these rat models.

Salt iodination as a effective method of iodine supplementation.

BACKGROUND: In January 1997 a new approach to preventing iodine deficiency was introduced in Poland. The goal of the present study was to determine whether the mandatory iodization of kitchen salt (30 mg KI/kg) has had any impact on ioduria. MATERIAL/METHODS: The study was performed on 29 healthy volunteers, aged 22-29 (average age 23.93 +/- 1.14), examined in 1996 and retested after 36 months of iodine supplementation in 1999. Each person underwent a physical examination and thyroid ultrasonography. The iodine level was determined using morning urine samples. RESULTS: For the duration of the study thyroid volume remained unchanged, ranging from 11.48 I3.89 ml in 1996 to 12.11 +/- 3.85 ml in 1998. The echostructure was normal in all subjects both in 1996 and in 1999. In 1996 the iodine concentration in urine (ICU) in the study group averaged 100.4 +/- 41.5 mg/L (range from 43.3 to 175.6 microg/L). Seventeen persons had an iodine concentration below 100 microg/L. In 1999 the average ICU was 140.7 +/- 78.87 microg/L. Three subjects had a lower ICU in 1999 (53.93 +/- 24.65 microg/L) than in 1996 (104.1 +/- 24.6 microg/L). These persons claimed to have completely eliminated the use of added salt in their diet. CONCLUSIONS: We conclude that mandatory iodine supplementation method is sufficiently effective when salt is used in the diet. In the case of restrictions on salt consumption the use of preparations containing iodine should be recommended.

Metabolic effects of strict salt restriction in essential hypertensive patients.

OBJECTIVE: Some observations suggest that a strict low-salt diet may induce unfavourable metabolic side-effects. The main aim of this study was to analyse the possible consequences of severe salt restriction in mildly hypertensive patients. DESIGN: The study was carried out through a randomized double-blind protocol. SUBJECTS: Forty-seven ambulatory patients proceeding from the hypertension unit were initially admitted: 17 were lost, and 30 non-diabetic mildly hypertensives (DBP 90-104 mmHg) with normal renal function completed the protocol. INTERVENTION: After a wash-out period, patients were maintained on a low-salt intake (2.8 +/- 1.0 g day-1 of NaCl) and placebo for 2 weeks, and the same diet and salt supplements (11.7 +/- 2.5 g day-1 of NaCl) for another 2 weeks, separated by a second wash-out period. MEASURES: At the end of each dietary period, blood pressure (BP) and body weight were measured, and a blood sample was taken for determination of routine serum chemistries, plasma lipid and apolipoprotein concentrations, immunoreactive insulin (IRI), and plasma renin activity (PRA). Urinary 24 h excretion of sodium and potassium were measured. RESULTS: During the salt restriction period BP did not change, weight lowered, and PRA raised. There was a significant increase in serum level of creatinine, uric acid, IRI, total cholesterol and apo B, and a decrease in HDL cholesterol and apo A-I. CONCLUSION: As previously suggested, these observations seem to indicate that strict salt restriction may cause, at least in the short-term, adverse metabolic changes in hypertensive patients.

Salt substitutes and medicinal potassium sources: risks and benefits.

The purpose of this investigation was to gather and summarize currently available product information on salt substitutes, low-sodium products, and medicinal potassium supplements. A review of the literature identified both risks (e.g., hyperkalemia) and benefits (e.g., changing sodium:potassium ratios, and low-cost substitutes for medicinal potassium replacement) resulting from the use of salt substitutes. Risks and benefits are related to individual patient conditions and treatment plans. Nutritionists and physicians must be aware of the medicinal and dietary potassium sources and be able to educate patients in the proper use of the products. Lists of medicinal and dietary sources of potassium are provided to aid health professionals in determining appropriate potassium equivalents. Case reports from the literature of patients developing hyperkalemia secondary to the use of salt substitutes are summarized. Regular monitoring of serum potassium levels is necessary to achieve and maintain normal values.

Iodide excretion in a salt-restriction trial.

Twenty-four hour urinary iodide excretion was measured twice, with a four month interval, in 133 individuals who were in a 12-month salt-restriction study in an area where iodine-deficiency goitre was once common and where most household salt is iodised. Half the subjects were salt restricted; their mean 24 h sodium excretion after eight months was 89 mmol for men and 73 mmol for women. Iodide excretion correlated with sodium excretion in the whole group on each occasion. After eight months mean 24 h iodide excretion in the salt-restricted group (men 1.3 SD 0.6 mumol, women 1.1 SD 0.4 mumol) was lower (p less than 0.01) than that in the control group (men 1.8 SD 0.8 mumol, women 1.7 SD 0.8 mumol), but was reasonable in terms of recommended dietary allowances (1.2 mumol, 150 mg). Mean iodide content of local milk was 1.3 mumol/l. Any salt that is used in the home should continue to be iodised. However, it has become unnecessary in this population to use salt (ie, iodised salt) simply in order to avoid iodine deficiency, so long as other foodstuffs continue to contain iodine as at present. As the other sources of iodine may be subject to change, the adequacy of intake of iodine from these sources should be monitored from time to time in samples of the population.