Despite the public outcries to reduce salt the research is not so clear. In fact in support of what I have ben writing for many years now another very large study says that at best salt only leads to a small reduction in blood pressure and reduction in heart disease in hypertensive individuals. However, this lower risk is outweighed by individuals lowering salt below the average which increases the increase the risk of cardiovascular events and death.
While there is controversy in the relationship between consuming less salt and lowering blood pressure levels the message for everyone to lower blood pressure may be doing more harm than good.
The latest study found that a low-salt diet only modestly reduces blood pressure. However, the authors asked asked a more important question “The key question is not whether blood pressure is lower with very low salt intake, instead it is whether it improves health”.
The meta analysis looked at the health of around 133 118 individuals from 49 countries and found benefits for everyone, even those with higher blood pressure. It appears that everyone benefits from eating an average amount of salt, even including people with high blood pressure. This equates to around 3.5 to 4 grams.
Salt protects us from heart attack, stroke and death from heart disease, as previous studies have already found. It’s only an issue for people with high blood pressure who are eating around 6 grams of salt every day, and this represents less than 10 per cent of the population.
The small increases in systolic blood pressure in individuals with hypertension was 2·08 mm Hg change per g sodium increase compared with individuals without hypertension 1·22 mm Hg change per g.
Despite this in those individuals without hypertension, compared with 4–5 g/day higher sodium excretion was not associated with an increased risk of cardiovascular events and death of the population without hypertension. Whereas a low salt consumption (an excretion of less than 3 g/day) was associated with a significantly increased (11%) risk of cardiovascular events and death of the population without hypertension.
While a high sodium intake may be associated with an increased risk of cardiovascular events and death in hypertensive populations (no association in normotensive population), the association of low sodium intake with increased risk of cardiovascular events and death is observed in those with or without hypertension. These data suggest that lowering sodium intake to an average levels of around 4–5 g/day is best targeted at populations with hypertension who consume high sodium diets.
This study turns on it head the common strategy of demonizing something like salt and making it the public enemy number 1. Therefore lowering it is good, without even looking at the health outcomes. The same occurs for cholesterol, another public enemy number 1. The statin drugs are very good at lowering cholesterol but they don’t prevent heart attacks.