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

Potassium-Enriched Salt Substitutes: A Review of Recommendations in Clinical Management Guidelines

Excess dietary sodium intake and insufficient dietary potassium intake are both well-established risk factors for hypertension. Despite some successful initiatives, efforts to control hypertension by improving dietary intake have largely failed because the changes required are mostly too hard to implement. Consistent recent data from randomized controlled trials show that potassium-enriched, sodium-reduced salt substitutes are an effective option for improving consumption levels and reducing blood pressure and the rates of cardiovascular events and deaths. Yet, salt substitutes are inconsistently recommended and rarely used. We sought to define the extent to which evidence about the likely benefits and harms of potassium-enriched salt substitutes has been incorporated into clinical management by systematically searching guidelines for the management of hypertension or chronic kidney disease. We found incomplete and inconsistent recommendations about the use of potassium-enriched salt substitutes in the 32 hypertension and 14 kidney guidelines that we reviewed. Discussion among the authors identified the possibility of updating clinical guidelines to provide consistent advice about the use of potassium-enriched salt for hypertension control. Draft wording was chosen to commence debate and progress consensus building: strong recommendation for patients with hypertension-potassium-enriched salt with a composition of 75% sodium chloride and 25% potassium chloride should be recommended to all patients with hypertension, unless they have advanced kidney disease, are using a potassium supplement, are using a potassium-sparing diuretic, or have another contraindication. We strongly encourage clinical guideline bodies to review their recommendations about the use of potassium-enriched salt substitutes at the earliest opportunity.

Estimation of dietary intake of sodium, potassium, phosphorus and protein in healthy Indian population and patients with chronic kidney disease

Introduction

Poor nutritious diet is a major risk element for non-communicable diseases (NCD), which are of considerable public health concern. Given the diverse dietary patterns in India, precise determination of nutrient consumption is crucial for disease management. The present study assessed the dietary intake of sodium, potassium, protein, and phosphorus among North Indians.

Methods

This cross-sectional study included healthy adults and adults with stage 2 to 4 chronic kidney disease (CKD). We analysed sodium, protein, potassium and phosphorus intakes using one-time 24-h urinary excretion. Dietary intake was also analysed in subgroups based on sex, body mass index, blood pressure and abdominal obesity. We evaluated the performance of various equations available to estimate sodium intake using a spot urine sample with respect to the sodium excretion measured in a 24-h urine sample. Descriptive statistics was used along with t-test for statistical significance.

Results

A total of 404 subjects (182 adult healthy subjects and 222 adults with CKD) with a mean age of 47.01 ± 11.46 years were studied. Mean dietary intakes of sodium, salt, potassium, protein and phosphorus were 2.94 ± 1.68 g/day, 7.42 ± 4.24 g/day, 1.43 ± 0.59 g/day, 47.67 ± 14.73 g/day and 0.86 ± 0.39 g/day, respectively. There were no differences in nutrient consumption between adults who were healthy and those with CKD. Consumption of sodium, salt, protein, potassium, and phosphorus among healthy population vs. those with CKD were 2.81 ± 1.60 vs. 3.05 ± 1.73 g/day (p = 0.152), 7.08 ± 4.04 vs. 7.70 ± 4.37 g/day (p = 0.143), 47.16 ± 14.59 vs. 48.08 ± 14.86 g/day (p = 0.532), 1.38 ± 0.59 vs. 1.48 ± 0.58 g/day (p = 0.087) and 0.86 ± 0.41 vs. 0.87 ± 0.37 g/day (p = 0.738), respectively. Men had higher consumption of these nutrients than women. Compared to non-hypertensives, hypertensive subjects had higher consumption of salt (8.23 ± 4.89 vs. 6.84 ± 3.59 g/day, p = 0.002) and potassium (1.51 ± 0.63 vs. 1.38 ± 0.55 g/day, p = 0.024), however, no difference were found in protein and phosphorus intakes. In terms of performance of equations used to estimate 24-h sodium intake from spot urinary sodium concentration against the measured 24-h urinary sodium excretion, INTERSALT 2 equation exhibited the least bias [1.08 (95% CI, -5.50 to 7.66)].

Conclusion

The study shows higher-than-recommended salt and lower-than-recommended potassium intake in the north Indian population compared to those recommended by guidelines. The dietary protein intake is below the recommended dietary allowance. These findings help the development of targeted policies for dietary modification to reduce the risk of the development and progression of CKD.

India's tryst with salt: Dandi march to low sodium salts

Salt plays a critical role in India's past as well as its present, from Dandi March to its role as a vehicle for micronutrient fortification. However, excess salt intake is a risk factor for high blood pressure and cardiovascular diseases (CVDs). Indians consume double the World Health Organization recommended daily salt (<5 g). India has committed to a 30 per cent reduction in sodium intake by 2025. Evidence based strategies for population sodium intake reduction require a moderate reduction in salt in - home cooked foods, packaged foods and outside-home foods. Reducing the sodium content in packaged food includes policy driven interventions such as front-of-package warning labels, food reformulation, marketing restrictions and taxation on high sodium foods. For foods outside of the home, setting standards for foods purchased and served by schemes like mid-day meals can have a moderate impact. For home cooked foods (the major source of sodium), strategies include advocacy for reducing salt intake. In addition to mass media campaigns for awareness generation, substituting regular salt with low sodium salt (LSS) has the potential to reduce salt intake even in the absence of a major shift in consumer behaviour. LSS substitution effectively lowers blood pressure and thus reduces the risk of CVDs. Further research is required on the effect of LSS substitutes on patients with chronic kidney disease. India needs an integrated approach to sodium reduction that uses evidence based strategies and can be implemented sustainably at scale. This will be possible only through scientific research, governmental leadership and a responsive evidence-to-action approach through a multi-stakeholder coalition.

Estimated Benefits and Risks of Using a Reduced-Sodium, Potassium-Enriched Salt Substitute in India: A Modeling Study

BACKGROUND

Salt substitution (ie, replacement of table and cooking salt with potassium-enriched salt substitutes) is a promising strategy to reduce blood pressure and prevent cardiovascular disease, particularly in countries like India where there is high sodium intake, mainly from discretionary salt, and low potassium intake. Life-threatening hyperkalemia from increased potassium intake is a postulated concern for individuals with chronic kidney disease.

METHODS

We used comparative risk assessment models to estimate the number of (1) cardiovascular deaths averted due to blood pressure reductions; (2) potential hyperkalemia-related deaths from increased potassium intake in individuals with advanced chronic kidney disease; and (3) net averted deaths from nationwide salt substitution in India. We evaluated a conservative scenario, based on a large, long-term pragmatic trial in rural China; and an optimistic scenario informed by our recent trial in India. Sensitivity analyses were conducted to assess the robustness of the findings.

RESULTS

In the conservative scenario, a nationwide salt substitution intervention was estimated to result in ≈214 000 (95% uncertainty interval, 92 764-353 054) averted deaths from blood pressure reduction in the total population and ≈52 000 (22 961-80 211) in 28 million individuals with advanced chronic kidney disease, while ≈22 000 (15 221-31 840) hyperkalemia-deaths might be caused by the intervention. The corresponding estimates for the optimistic scenario were ≈351 000 (130 470-546 255), ≈66 000 (24 925-105 851), and ≈9000 (4251-14 599). Net benefits were consistent across sensitivity analyses.

CONCLUSIONS

Modeling nationwide salt substitution in India consistently estimated substantial net benefits, preventing around 8% to 14% of annual cardiovascular deaths. Even allowing for potential hyperkalemia risks there were net benefits estimated for individuals with chronic kidney disease.

Performance of equations for estimation of 24-hour urinary sodium from morning fasting urine samples in a multisite study in India

Background Dietary salt intake is an important modifiable risk factor for cardiovascular diseases. Estimation of 24-hour salt intake using morning urine samples needs to be validated in the Indian context. We examined the performance of INTERSALT, Tanaka and Kawasaki equations for the estimation of 24-hour urinary sodium from morning fasting urine (MFU) samples. Methods We enrolled 486 adults aged 18-69 years from four regions of India with equal rural/urban and sex representation to provide 24-hour urine samples. The next day, a MFU sample was obtained. Based on the volume and sodium content of the 24-hour urine sample, 24-hour sodium excretion (reference method) was calculated. Sodium levels in the MFU samples were measured along with other parameters required, and the above equations were used to estimate 24-hour urinary sodium levels. Intraclass correlation coefficient (ICC) was used to assess the degree of agreement between the estimates from the reference method and the three equations. Bland-Altman (BA) plots were used to identify systematic bias and limits of agreement. A difference of 1 g of salt (0.39 g of sodium) between the mean salt intake by 24-hour urine and as estimated by equations was considered acceptable. Results A total of 346 participants provided both the samples. The mean (SD) daily salt intake estimated by the 24-hour urine sample method was 9.9 (5.8) g. ICC was low for all the three equations: highest for Kawasaki (0.16; 95% CI 0.05-0.26) and least for Tanaka (0.12; 0.02-0.22). Only Tanaka equation provided estimates within 1 g of measured 24-hour salt intake (-0.36 g). BA plots showed that as the mean values increased, all the three equations provided lower estimates of salt intake. Conclusion Tanaka equation provided acceptable values of 24-hour salt intake at the population level. However, poor performance of all the equations highlights the need to understand the reasons and develop better methods for the measurement of sodium intake at the population level.