The contribution of high sodium intake to hypertension and to the severity of immune-mediated diseases is still being heatedly debated in medical literature and in the lay media. This review aims to demonstrate two conflicting views on the topic, with the first part citing the detrimental effects of excessive salt consumption. Sodium plays a central role in volume and blood pressure homeostasis, and the positive correlation between sodium intake and blood pressure has been extensively researched. Despite the fact that the average of global daily salt consumption exceeds recommendations of international associations, health damage from excessive salt intake is still controversial. Individual differences in salt sensitivity are in great part attributed to this contradiction. Patients suffering from certain diseases as well as other vulnerable groups—either minors or individuals of full age—exhibit more pronounced blood pressure reduction when consuming a low-sodium diet. Furthermore, findings from the last two decades give insight into the concept of extrarenal sodium storage; however, the long-term consequences of this phenomenon are lesser known. Evidence of the relationship between sodium and autoimmune diseases are cited in the review, too. Nevertheless, further clinical trials are needed to clarify their interplay. In conclusion, for salt-sensitive risk groups in the population, even stricter limits of sodium consumption should be set than for young, healthy individuals. Therefore, the question raised in the title should be rephrased as follows: “how much salt is harmful” and “for whom is elevated salt intake harmful?”

高钠摄入对高血压和免疫介导疾病严重程度的影响仍在医学文献和普通媒体中激烈争论。这篇评论旨在论证有关该主题的两种相互矛盾的观点，第一部分引用了过量食盐的有害影响。钠在容量和血压稳态中起着核心作用，钠摄入量与血压之间的正相关性已被广泛研究。尽管全球日平均食盐摄入量超过了国际协会的建议，但过量食盐摄入对健康的损害仍然存在争议。盐敏感性的个体差异在很大程度上归因于这一矛盾。患有某些疾病的患者以及其他弱势群体（无论是未成年人还是成年个体）在食用低钠饮食时表现出更明显的血压降低。此外，过去二十年的研究结果使人们深入了解了肾外钠储存的概念。然而，这种现象的长期后果却鲜为人知。评论中还引用了钠与自身免疫性疾病之间关系的证据。然而，需要进一步的临床试验来阐明它们的相互作用。总之，对于人群中对盐敏感的危险人群，应设定比年轻健康人群更严格的钠摄入量限制。因此，标题中提出的问题应该改写为：“多少盐有害”和“盐摄入量过高对谁有害？”