High blood pressure may be linked to an overlooked source of salt - and it’s not what you’d expect.
Drinking water linked to higher blood pressure and increased hypertension risk
While common causes include diet, lack of exercise, smoking and excessive weight, experts say an environmental factor in drinking water may also be a contributing factor.
As sea levels rise, seawater is increasingly seeping into freshwater supplies in some coastal regions, raising sodium levels in drinking water and potentially affecting millions of people without them realising.
A major analysis of existing studies found people exposed to saltier drinking water were more likely to have higher blood pressure and an increased risk of hypertension.
The review pooled data from 27 population-based studies involving more than 74,000 people across the United States, Australia, Israel, Bangladesh, Vietnam, Kenya and several European countries.
Across the data, those drinking higher-salinity water showed average increases of 3.22 mmHg in systolic blood pressure and 2.82 mmHg in diastolic blood pressure. Overall, exposure was linked to a 26 per cent higher risk of developing hypertension, with the strongest effects seen in coastal communities.
More than three billion people are estimated to live in coastal or near-coastal areas worldwide, many relying on groundwater sources that are increasingly vulnerable to saltwater intrusion.
Experts warn this means some households may be consuming extra sodium through drinking and cooking water without being able to taste any difference.
Hypertension affects more than one billion people globally and is a leading cause of heart disease and stroke. Prevention efforts typically focus on lifestyle factors such as diet, exercise, smoking and weight, while environmental contributors receive less attention.
The findings suggest drinking water salinity may pose a blood pressure risk comparable to other recognised factors such as low physical activity. Even small increases across large populations could have significant public health impacts.
Further research is needed to understand whether long-term exposure to saline drinking water also increases the risk of heart attacks, strokes and other cardiovascular disease.