Salt has long been vilified for its role in raising blood pressure and increasing the risk of heart disease and stroke. However, a growing counter-argument suggests that a low-salt diet may be just as dangerous as consuming too much, casting doubt on decades of research.
Sodium, a key component of salt, is essential for maintaining fluid balance, transporting oxygen and nutrients, and enabling nerve function. Yet most populations consume far more than recommended. The World Health Organization (WHO) advises limiting sodium to less than 2g per day (about 5g of salt), while the UK's NHS recommends no more than 6g of salt daily. In the UK, average intake is 8.4g per day; in the US, it is 8.5g; globally, it has risen to nearly 10.8g per day.
Only about a quarter of our salt intake comes from salt added during cooking or at the table; the rest is hidden in processed foods such as bread, sauces, soups, and cereals. Nutritionist May Simpkin notes that confusion arises because food labels often list sodium rather than salt content, with 2.5g of salt containing about 1g of sodium. The US Centers for Disease Control and Prevention (CDC) reports that 40% of sodium consumed in the US comes from foods like pizza, deli meats, and savoury snacks.
Excess salt causes the body to retain water, raising blood pressure. Over time, this can lead to hypertension, which the WHO says causes 62% of strokes and 49% of coronary heart disease events, and is linked to 1.89 million deaths annually. A meta-analysis of 13 studies found that an extra 5g of salt per day increased the risk of cardiovascular disease by 17% and stroke by 23%.
Conversely, reducing salt intake can lower blood pressure. An analysis of the Health Survey for England found that a decline of 1.4g per day likely contributed to a 42% drop in fatal strokes and a 40% fall in heart disease deaths. A 2023 clinical trial showed that a low-sodium diet for one week had a blood pressure-lowering effect comparable to a common hypertension drug.
However, some researchers argue that moderate sodium consumption (3-6g per day) may be optimal. Observational studies struggle to separate the effects of salt reduction from other healthy behaviours, as those who watch their salt intake tend to eat better, exercise more, and smoke less. The debate continues, highlighting the need for more research to clarify the ideal salt intake for health.
