Seawater seeping into drinking water may be raising people's blood pressure and increasing their risk of heart disease and stroke, according to a global health expert. The risk from consuming salty water is comparable to that of a sedentary lifestyle, scientists claim.
Researchers at Florida International University, led by Professor Rajiv Chowdhury, analysed studies involving over 74,000 people worldwide. They found that individuals exposed to saltier drinking water tended to have significantly higher blood pressure, with the strongest link observed in coastal areas where seawater increasingly contaminates freshwater supplies.
More than a billion people globally have hypertension, a leading cause of heart disease and stroke. While prevention efforts typically focus on dietary salt and lifestyle, the researchers note that when water is saltier than usual, drinking sources can add to a person's total sodium intake. In many coastal regions, rising sea levels are pushing seawater into freshwater aquifers, making groundwater saltier.
Dr Chowdhury stated that exposure to high-salinity water was linked to a 26 per cent higher risk of developing hypertension, especially among coastal populations. He emphasised that even small shifts in blood pressure at the population level can have significant public health effects. The risk posed by water salinity is similar to that of low physical activity, which increases hypertension risk by approximately 15 to 25 per cent.
The study pooled data from 27 studies in Europe, the US, Australia, Israel, Bangladesh, Vietnam, and Kenya. People drinking saltier water had systolic blood pressure about 3.22 mmHg higher and diastolic blood pressure about 2.82 mmHg higher on average. Dr Chowdhury warned that this environmental factor could become a greater problem as climate change accelerates, affecting over 3 billion people living in coastal regions, many in low- and middle-income countries where groundwater is the main drinking source.
