Figures show a dramatic rise in the number of people across the UK being diagnosed with coeliac disease, caused by an intolerance to gluten.
The charity, Coeliac UK, has attributed the rise to better screening tools and increased awareness of the condition.
However, it estimates three quarters of people with the condition - around 500,000 - remain undiagnosed.
The auto-immune disease is caused by an intolerance to gluten, a protein found in wheat, barley and rye.
Left untreated, the condition can lead to infertility, osteoporosis and small bowel cancer.
The only treatment for the condition is a strict, lifelong gluten-free diet.
Symptoms range from mild to severe, including gut problems, extreme tiredness, anaemia, headaches, skin problems, depression, and joint or bone pain.
Jennifer Fox's daughter Kathryn, 9, was diagnosed with the condition, aged six.
Jennifer, 37, from Bearsden, who also has a second daughter Helen, 6, said: "We were on holiday and prior to that Kathryn had been complaining about a sore tummy.
"We weren't sure if she was just playing up but it went on for about six months.
"It was diagnosed fairly quickly. They took blood
and did an endoscopy under
a general anaesthetic.
"All the typical fast foods that are quick and easy to prepare, such as pizza and fish fingers, are out.
"I make all her birthday cakes because I've never been able to get a gluten free
one. She never complains though.
"There are a lot more products on the market than there were when she was first diagnosed."
This week the charity is asking people across the UK
to support the Gluten-free Guarantee, which asks supermarkets to commit to stock eight core items of gluten-free food.
Sarah Sleet, chief executive of Coeliac UK, said: "This latest research shows that nearly a quarter of people with coeliac disease have now been diagnosed and gives an up-to-date picture of the diagnosis levels across the UK.
"Of course, increasing numbers with a diagnosis is good news and will inevitably mean that there will be an increased demand for gluten-free products in supermarkets.
"But the three quarters undiagnosed is about 500,000 people - a shocking statistic that needs urgent action."
The average time from onset of symptoms to diagnosis of coeliac disease is 13 years.
One in four people diagnosed with the condition had previously been diagnosed with irritable bowel syndrome.
One crumb of gluten can be enough to make some people ill, so it is essential there is no cross contamination while preparing and serving food.
There is no register by the NHS to state how many people in the UK have been diagnosed with coeliac disease.
For more information see the website: www.coeliac.org.uk