Dementia warning as 27 million Britons at risk because of ‘soft water’

Millions of Britons living in soft water areas may face a significantly higher risk of developing dementia due to their tap water, according to new research.

A groundbreaking study suggests that 27 million people – representing 40 per cent of the UK population – could be at increased risk of degenerative brain disease because their drinking water contains lower levels of minerals such as calcium and magnesium.

The research, conducted by scientists from Imperial College London and China, found that residents in soft water areas face a 34 per cent higher risk of vascular dementia compared to those with hard water supplies.

The study revealed structural changes in 20 different areas of the brain among people living in soft water regions.

Scientists suggest minerals in drinking water may have a protective effect on the brain.

Low mineral levels could also cause water pipes to corrode faster, potentially allowing toxic elements like lead to leach into drinking water.

The research team analysed brain scans from more than 30,000 people, discovering that those in soft to moderately hard water areas had reduced brain volume in various regions compared to residents in hard water areas.

Soft water areas in the UK include Scotland, most of Yorkshire, Cornwall and the west and south coasts of Wales.

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Water hardness is determined by local geology, with hard water forming in areas with limestone or chalk where rivers help release calcium and magnesium.

The most populated regions of the UK, including the South East, East England, the M4 corridor and most of the South Coast, are served by hard water.

The West Midlands, Liverpool, parts of Devon, Northumberland and East Wales have medium-to-hard water supplies.

Hard water is considered better for drinking due to lower sodium content, though soft water is known to be gentler on skin.

The study analysed data from nearly 400,000 people in the UK Biobank, comparing home addresses and water supply details with diagnoses of neurodegenerative diseases.

Researchers identified 2,389 people diagnosed with Alzheimer’s, 1,278 with vascular dementia and 366 with multiple sclerosis.

Those exposed to soft water – containing between zero and 60mg of calcium carbonate per litre – showed a 63 per cent higher risk of dementia generally and a 53 per cent greater risk of MS.

Low magnesium levels were linked to a 25 per cent higher risk of Alzheimer’s.

The findings were based on comparing soft water exposure to hard water supplies, defined as between 120 and 300mg/L.

Dr Tom Russ, director of the Alzheimer Scotland Dementia Research Centre, urged caution about the findings.

“There is more work to be done on any environmental factor that might be linked to dementia, and this shows that water may potentially be a part of that,” he said.

He stressed that the study doesn’t prove water type causes dementia, noting other risk factors like smoking and high blood pressure pose greater concerns.

Dr Emma Anderson, Associate Professor of Epidemiology at King’s College London, criticised the research methodology.

“Overall I think this is a poorly conducted study and not one we should be using to assess whether water hardness should be taken more seriously,” she said.

Current UK regulations do not specify standards for the level of minerals that should be contained in drinking water.

Around 60 per cent of tap water consumed in the UK comes from areas with hard water.

Scientists from the Shanghai Jiao Tong University School of Medicine wrote: “We provide new evidence about the harmful effect of soft water on neurodegenerative diseases that highlight the importance of optimising water quality standards to ensure long-term health benefits.”

Thousands of homeowners in hard water areas choose to install water softeners, costing around £500, to remove magnesium and calcium and prevent limescale build-up.

These systems use resin to draw out minerals, which are then filtered using a brine solution.