Children are suffering damage to their hearts as early as 12 due to poor diets, a study has warned. 

Researchers found most people start life with robust heart health, but can lose it quickly through unhealthy eating habits.

The American study showed few children under the age of 12 had an ideal diet and almost a third (30 per cent) were overweight or even obese.

The researchers said the better equipped children are to make healthy choices, the healthier their hearts will be in adulthood.

Study senior author Doctor Donald Lloyd-Jones, professor and chair of preventive medicine at the Northwestern University Feinberg School of Medicine in Chicago, said: ‘Our findings indicate that, in general, children start with pretty good blood pressure.

‘But if they have a horrible diet, it will drive a worsening body mass index (BMI) and cholesterol levels.

‘The better we can equip our children to make healthy choices, the more cardiovascular health will be preserved into adulthood.

‘And those who preserve their heart health into middle age live much longer and are much healthier while they live.’

Researchers examined BMI, healthy diet, total cholesterol and blood pressure – four of the seven components of heart health – in children aged two to 11.

In the sample of 8,961 children, the researchers found that all children had at least one ideal measure, but none had all four.

An ideal diet score was the least prevalent health indicator, with less than one per cent of children having four or five of the five components of a healthy diet. 

The five indicators of a healthy diet include low intake of sugar-sweetened drinks and salt, and high intake of wholegrains, fish, plus fruit and vegetables.

Fewer than 10 per cent ate the recommended amounts of fruit and veg of more than 4.5 cups or more per day or fish, and wholegrains were the least frequently achieved component with just three per cent of boys and 2.4 per cent of girls hitting the target.

Ninety per cent ate more salt than recommended, and more than half consumed more than the recommended number of calories from sugar-sweetened drinks.

Around four out of ten of the children had ‘poor’ or ‘intermediate’ cholesterol levels, according to the findings published in the journal Circulation: Cardiovascular Quality and Outcomes.