ABC | Volume 114, Nº3, March 2020

Original Article Arantes et al. Added salt and blood pressure Arq Bras Cardiol. 2020; 114(3):554-561 These governmental measures are crucial for preventing many diseases related to excessive salt intake. Lowering salt intake to up to 2,300mg per day could prevent 11 million cases of systemic arterial hypertension and save billions of dollars in health care costs. 24 A meta-analysis showed that a drastic reduction in salt intake (up to 3g/day) was effective in preventing CVD. A major part of this prevention is explained by reductions of BP that occur in both hypertensive and prehypertensive individuals. 18 Another interesting strategy may be the replacement of conventional salt with low-sodium salt. A randomized trial with patients with uncontrolled hypertension showed reductions in BP and urinary sodium in the group of individuals that received 3 grams of light salt compared with the group that received regular salt. 25 All these strategies are important, but ineffective if used alone. Our results reinforce the need to sharply reduce the amount of salt intake, especially through packaged foods that usually contain great amounts of sodium. Processed foods are very present in post-modern society and the main sources of salt in the diet. 26 It is also important the use of clear and objective information about salt content in packaged foods, so that consumers can deliberately change or make adaptations in their habitual diet. 27 Also, although quantification of urinary sodium is the gold standard method to estimate sodium intake, it has a sensitivity of 86% in detecting urinary sodium excretion. Considering that interventions towards lowering added salt affect only 15% of total salt intake, the sensitivity of the method to detect changes in sodium excretion in these interventions is probably low, as may have occurred in our study. Besides, adherence to interventions like this varies between individuals and may be low. In our sample, we did not detect significant reductions in urinary sodium excretion in any of participants. Another factor to be considered is that we cannot assure that the 24-hour urinary excretion test was performed correctly, since we did not verify how urine sample was collected and stored. However, this method has been used by different researchers in Brazil 28 and in the world. 29,30 The meta-analysis of trials with a modest reduction in salt intake and duration of four weeks to three years evaluating the effects on 24-hour urinary sodium excretion and BP showed that a reduction of 4.4g per day of salt was associated with a fall in SBP of 5.4 mmHg in normotensive individuals. Therefore, a moderate reduction in salt intake for longer periods was effective in reducing BP levels. 18 One of the limitations of our study was the difficulty in ensuring that participants had at least four main meals at home per week and that the salt added during food preparation was only that received during the study. Out-of-home meals were not controlled also. The strategy used was to involve the whole family in lowering the amounts of added salt and to emphasize the importance of identifying high-sodium foods in restaurant and of choosing low-sodium foods. Conclusions The intervention proposed, to gradually reduce the amount of added salt from 6 grams to 4 grams per day for 13 weeks, did not show significant reductions in the 24-hour urinary sodium excretion. However, the amount of sodium excretion showed a positive, moderate correlation with CBP and casual DBP in the HG. Author contributions Conception and design of the research: Arantes AC, Sousa ALL, Jardim PVBV, Jardim TSV, Rodrigues RB, Souza WKSB. Acquisition of data: Arantes AC, Rodrigues RB, Souza WKSB. Analysis and interpretation of the data: Arantes AC, Sousa ALL, Vitorino PVO, Rezende JM, Rodrigues RB, Souza WKSB. Statistical analysis: Arantes AC, Vitorino PVO, Rezende JM, Lelis ES, Souza WKSB. Obtaining financing: Arantes AC, Sousa ALL. Writing of the manuscript: Arantes AC, Sousa ALL, Vitorino PVO, Rezende JM, Souza WKSB. Critical revision of the manuscript for intellectual content: Arantes AC, Vitorino PVO, Jardim PVBV, Jardim TSV, Rezende JM, Coca A, Souza WKSB. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding This study was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico. Study Association This article is part of the thesis of Master submitted by Ana Carolina Arantes, from Universidade Federal de Goiás. Ethics approval and consent to participate This study was approved by the Ethics Committee of the Hospital das Clínicas da Universidade Federal de Goiás CAEE: 00790712.3.0000. 5078. All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study. 559