Low-Salt Diets May Increase Risk of Cardiovascular Disease (CVD) and Death
A large worldwide study has found that, contrary to popular thought, low-salt diets may not be beneficial and may actually increase the risk of cardiovascular disease (CVD) and death compared to average salt consumption. In fact, the study suggests that the only people who need to worry about reducing sodium in their diet are those with hypertension (high blood pressure) and have high salt consumption.
In the study, involving more than 130,000 people from 49 countries, investigators from the Population Health Research Institute (PHRI) of McMaster University looked specifically at whether the relationship between sodium (salt) intake and death, heart disease and stroke differs in people with high blood pressure compared to those with normal blood pressure.
“These are extremely important findings for those who are suffering from high blood pressure,” said Andrew Mente, lead author of the study. “While our data highlights the importance of reducing high salt intake in people with hypertension, it does not support reducing salt intake to low levels.
“Our findings are important because they show that lowering sodium is best targeted at those with hypertension who also consume high sodium diets.”
Previous studies have shown that low-sodium, compared to average sodium intake, is related to increased cardiovascular risk and mortality, even though low sodium intake is associated with lower blood pressure.
Further, the findings show that while there is a limit below which sodium intake may be unsafe, the harm associated with high sodium consumption appears to be confined to only those with hypertension.
Only about 10 per cent of the population in the global study had both hypertension and high sodium consumption (greater than 6 grams per day).
Mente said that this suggests that the majority of individuals are consuming the right amount of salt.
He added that targeted salt reduction in those who are most susceptible because of hypertension and high salt consumption may be preferable to a population-wide approach to reducing sodium intake in most countries except those where the average sodium intake is very high, such as parts of central Asia or China.
“Low sodium intake reduces blood pressure modestly, compared to average intake, but low sodium intake also has other effects, including adverse elevations of certain hormones which may outweigh any benefits. The key question is not whether blood pressure is lower with very low salt intake, instead it is whether it improves health,” Mente said.
Source: Andrew Mente et al. Associations of urinary sodium excretion with cardiovascular events in individuals with and without hypertension: a pooled analysis of data from four studies. The Lancet, 2016 DOI: 10.1016/S0140-6736(16)30467-6