The bracelet that tailors patients’ diets to their DNA by scanning food barcodes

Don’t bother with a shopping list – an app could soon tell you what foods to buy based on your DNA.

It works by scanning the barcodes of supermarket products and indicating which may be unsuitable for those genetically susceptible to conditions such as heart disease and diabetes.

The app is installed on either a smartphone or a bracelet-like device similar to a Fitbit. Before using it, patients undergo a DNA test of their saliva to see whether they are very sensitive to sugar, salt, fat, carbohydrates or caffeine.

The results are put on the app. Patients then use their phone or bracelet to scan products before putting them into their trolley. If the device flashes red, the item should be avoided. A green light suggests the product is fine for their diet.

The app is being tested in London by patients with type 2 diabetes and certain mental health conditions.

It has been designed by scientists at Imperial College London and backed by Claire Murdoch, national director for mental health at NHS England and chief executive of the Central and North West London NHS Foundation Trust, who wants it routinely prescribed by GPs.

Patients who have the app can use it to scan barcodes of different foods. If the device flashes red, the item should be avoided. A green light suggests the product is fine for their diet

The DnaNudge app has also been put through its paces by a family in Essex for BBC1’s Inside Out London. Andrew Crowne-Spencer, 48, his wife Samantha, 44, and their daughter Charlotte, 19, have been using it for nearly two weeks.

Mr Crowne-Spencer and Charlotte have heart conditions and DNA tests indicated they should avoid salt. Mrs Crowne-Spencer has a family history of type 2 diabetes and was told she was particularly sensitive to salt, sugar, fat and carbohydrates. She said the app had given her a ‘new lease of life’ by helping her change her diet.

‘My energy levels are through the roof,’ she said. ‘I suffer from serious insomnia but I’m sleeping before 11, which is rare.

‘I assumed my mood changes were hormonal but I’m not as grumpy and angry. I’m singing all the time, which I haven’t done for years. I’m happier, well-rested and my body feels cleaner. I feel like I’m in my twenties again.’

Professor Chris Toumazou, an electronic engineer from Imperial College London who designed the app, said: ‘It’s just well-known clinical evidence that if you’ve got the gene for cardiovascular disease or high blood pressure, you have to avoid salt.

‘If you’ve got the gene for obesity then saturated fat is very important. If you’ve got the gene for type 2 diabetes then saturated fat and salt are culprits.’

But Dr Frances Elmslie of the Clinical Genetics Society said it should be used ‘with a degree of scepticism’, adding: ‘These apps at this stage are, I would say, too early to predict risk for a particular individual. The science behind it has been based on populations.’

Inside Out is on BBC1 London at 8.30pm tonight and available on BBC iPlayer from tomorrow.