Scientists have linked nitrates found in tap water and processed meats with an increased risk of dementia.
Nitrates, which are essential for a string of bodily functions, are found naturally in plants and vegetables, and are also used in the production and preservation of some foods, namely bacon and ham.
Some of the most nitrate-rich vegetables include spinach, broccoli, cabbage, kale, lettuce and beetroot.
The minerals are also present in tap water because nitrate-rich chemicals – which are used as fertiliser in the farming industry – seep into the soil and affect groundwater, eventually making their way into reservoirs.
A diet high in nitrate-treated, processed meats has long been associated with cancer, but now a new study by a team based at Australia’s Edith Cowan University (ECU) and the Danish Cancer Research Institute (DCRI) has linked them with an increased risk of developing dementia, too.
Researchers used data from nearly 55,000 adults in Denmark, none of whom had dementia at the start of the study, and followed them for a period of nearly 27 years.
They investigated the link between source-specific nitrate, nitrite intake and early-onset dementia, and found that people who obtained most of their nitrates from plants (like vegetables) had a lower risk of developing dementia.
In fact, the people with the highest plant nitrate intake – the equivalent of a cup a day of baby spinach – had about a 10 per cent lower risk of developing the degenerative brain disease than the people who scored lowest for consuming plant nitrates.
Nitrates from vegetables can protect against dementia, claim researchers
Everyone experiences dementia differently. Use this checklist to help you make a note of your symptoms before you talk to your GP.
Opposingly, people who consumed most of their nitrates from processed foods and tap water were at a higher risk of dementia.
ECU Associate Professor Catherine Bondonno said that nitrate intake from vegetables has been linked with a lower risk of dementia because they are naturally rich in antioxidants – unlike processed foods and tap water.
She said:’ ‘When we eat nitrate-rich vegetables, we are also eating vitamins and antioxidants which are thought to help nitrate form the beneficial compound, nitric oxide, while blocking it from forming N-nitrosamines which are carcinogenic and potentially damaging to the brain.
‘Unlike vegetables, animal-based foods don’t contain these antioxidants.
‘In addition, meat also contains compounds such as heme iron which may actually increase the formation of N-nitrosamines.
‘We think this is why nitrate from different sources has opposite effects on brain health, but we need laboratory studies to confirm exactly what’s happening.’
This is the first time that nitrate from drinking water has been linked to higher risks of dementia.
In Denmark and the EU – and the UK – the limit for nitrate in groundwater and drinking water is set at 50 mg/L.
Beetroots are naturally rich in nitrates
However, the researchers observed a higher risk for drinking water containing as low as 5 mg of nitrate per litre.
The study found that participants exposed to drinking-water nitrate at levels below the current regulatory limits, had a higher rate of dementia, however, Dr Bondonno stressed that this was only one study, and more research was required.
She said: ‘Water doesn’t contain antioxidants that can block formation of N-nitrosamines. Without these protective compounds, nitrate in drinking water may form N-nitrosamines in the body.’
She also stated that the study doesn’t mean people should stop drinking water, and that a lot more research is warranted.
This is also because it is an observational study, which cannot establish that nitrate directly causes dementia and it cannot be ruled out that other factors in participants’ diets or lifestyles contributed to them developing dementia.
‘Importantly, our results do not mean that people should stop drinking water,’ she said.
‘The increase in risk at an individual level is very small, and drinking water is much better for your health than sugary drinks like juices and soft drinks.
‘However, our findings do suggest that regulatory agencies should re-examine current limits and better understand how long-term, low-level exposure affects brain health.
‘Eating more vegetables and less red meat and processed meat is a sensible approach.’
Nitrate minerals are essential for a swathe of bodily functions, including blood pressure control, the movement of oxygen through the body, cellular health and a healthy immune system and gut microbiome.
Oxygen molecules are constantly splitting in the body, releasing chemicals called free radicals which are unstable and can roam around wreaking havoc on other cells.
In peak condition, the body is able to keep the number and activity of free radicals in check, but when if the body is under too much ‘oxidative stress,’ these transient chemical waste products can damage cells, DNA and proteins.
High oxidative stress is involved in aging and has been linked to increased risks of several diseases and chronic conditions, including cancer.
Antioxidants, however, act as neutralising agents.
Once ingested, antioxidants bind to free radicals and keep them from needling other cells or DNA and encouraging mutations – including mutations that fuel cancer development.
Currently, around 900,000 people in the UK are living with dementia. That number is expected to rise to 1.4 million by 2040, driven largely by Alzheimer’s disease.
According to the Alzheimer’s Society, more than a third of people with the condition do not yet have a diagnosis.
