Consumption of high sodium drinking water has been shooting up systolic and diastolic blood pressure in adults and pregnant women in coastal areas, and increasing the risk of hypertensive disorders.
And long-term consumption of salty water is indeed related to higher blood pressure in the population and is feared to increase the risk of cardiovascular diseases, a research on "Drinking Water Salinity and Hypertension in Coastal Bangladesh" in 12 different villages said.
These low-lying areas experience frequent floods caused by storm surges due to tropical cyclones triggered off by climate change effect, which contaminate ponds and small wells in which local people rely on for their drinking water.
As climate change affects weather patterns, these floods are predicted to become more frequent in the future and in coastal areas of Southeast Asia, drinking water sources, rather than food, are responsible for high salt intake by the population, the study revealed.
The Imperial College London in collaboration with the Department of Geology at the University of Dhaka and International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) jointly conducted the study funded by Leverhulme Trust, UK, in which adults were followed up for 18 months, measuring their blood pressure, water salinity levels and several factors that could otherwise influence blood pressure.
On a regional scale, Asian deltas, particularly Red-River and Bengal deltas are most vulnerable to drinking water salinisation.
The research found, by drinking just a few litres of water a day, coastal population in Bangladesh consume a considerable part (up to 200%) of the maximum daily salt intake of 5 grams as defined by the WHO and concentrations of salt on ponds were higher in the dry season due to evaporation of the pond water.
The study also revealed, however, that increases in blood pressure could be promptly reversed if people changed to a low-salt alternative water source, such as rainwater or distilled water, for their daily water intake.
It was found that per 100mg/l lower sodium in drinking water can lower systolic/diastolic BP by 0.95/0.57 mm Hg on average and can lower odds of hypertension by 16%.
Low-salt drinking water alternatives would help the coastal populations to control their salt intake and therefore keep their blood pressure low. Currently the availability of these low-salt alternatives is however very limited in the area, Dr Md Ashiqur Haider Chowdhury, senior research investigator of Non Communicable Disease Initiative, ICDDR,B.
We investigated the factors that control the salt concentration in ponds and tube wells: that knowledge would enable us to predict salt levels in drinking water for different seasons and in case of extreme weather events such as cyclones, he added.