This was very much the case with Coeliac disease. It only hit the headlines last month when Dr Chris Steele MBE, from the ITV show This Morning, revealed he had it.

Dr Steele, who for the past three years has been an ambassador for Coeliac UK, the national charity for people with the disease, is now leading the call for more publicity.

Not an allergy, the condition is an auto-immune disease which means sufferers are unable to process the protein gluten, found in wheat, barley and rye, often found as ingredients in everything from cake to gravy.

Every time they eat some form of gluten, the lining of the sufferer's intestine is damaged, which can lead to a range of symptoms including bloating, abdominal pain, constipation, anaemia, headaches, mouth ulcers and weight loss.

You'd think it would be easy to spot, but in fact the opposite is true, because of the plethora of symptoms.

Estimated to affect one per cent of the UK population (600,000 people), only 12.5 per cent are currently diagnosed.

This effectively means there are more than half a million people walking around with a disease which can, if not treated correctly with a strict no-gluten diet, lead to malnutrition, osteoporosis, infertility, multiple miscarriages and bowel cancer.

Dr Steele said: "I think I've been having symptoms of diarrhoea, abdominal pain and fatigue on and off for many years, but it wasn't until they got so bad recently that I did anything about it.

"I will be encouraging everyone with similar symptoms to see their GP and be tested, rather than suffering in silence."

He added: "I strongly support the need to raise awareness among the medical profession for diagnosing coeliac disease. It is often misunderstood and mis-diagnosed."

This is backed by Coeliac UK, on whose behalf he will hand in a petition to 10 Downing Street, highlighting the need for increased diagnosis of the condition.

The petition, signed by 8,783 people, asked the Government to introduce a target for diagnosis of the disease in the latest national GP contract.

Sarah Sleet, chief executive of the charity, said: "The disease was very poorly recognised for a long time. We hope doctors in the future will be in a better position to identify it."

As the condition is hereditary, it's also hoped that those with an affected relation will get mandatory testing.

Sarah added: "If you have been diagnosed with Coeliac disease, others in your family are more likely to have it too."

For further information, log on to the Coeliac UK website using this link.