A plate of pasta or a few rotis at dinner should not leave someone doubled over with cramps two hours later, yet for many people this becomes such a familiar pattern that they simply stop expecting to feel normal after a meal. The bloating gets blamed on eating too fast, the tiredness on a busy week, the loose motions on something that did not agree with them. Home remedies help for a while, blood tests come back normal, and the advice is often to manage stress or cut back on oily food.
For some people, this pattern keeps repeating because the real cause has not been found yet: celiac disease, a condition where the body's own defence system reacts to gluten and slowly damages the small intestine. Understanding what actually happens inside the gut when gluten is eaten helps make sense of symptoms that otherwise seem scattered and unrelated. This blog explains the autoimmune response to gluten, how it affects the small intestine and digestion more broadly, and what can be done to manage the condition and prevent long term problems.
Celiac disease occurs because of a mix up in the body's defence system, not because of a food allergy or a simple upset stomach. Think of the immune system as an army inside the body whose job is to fight off germs and keep everything safe. In people who are born with a certain tendency towards celiac disease, this army gets confused when gluten, a protein found in wheat, barley, and rye, enters the gut. Instead of breaking gluten down like any other food, the immune system mistakes the lining of the small intestine for something dangerous and attacks it. This mistaken attack is what doctors call the autoimmune response to gluten.
This is why celiac disease is different from a wheat allergy, which causes a fast reaction such as a rash or swelling, and different from gluten sensitivity, where the tummy reacts but the intestine itself does not get damaged. In celiac disease, even a small amount of gluten can call the body's defence army into action, whether or not the person feels it happening.
Picture the inside of the small intestine covered in thousands of tiny, soft bumps called villi, a little like the fine bristles on a hairbrush. These bumps help the body soak up nutrients from food. When the immune system attacks gluten, it releases chemical alarm signals, much like an alarm bell ringing to call more defence cells to the scene. Those cells cause swelling, and over time this wears the villi down until they are flattened, almost like the bristles of a hairbrush pressed smooth. This flattening is called villous atrophy, and it is the main way gluten damages the small intestine.
With the villi flattened, the intestine cannot soak up nutrients as well, even if a person eats a normal, healthy diet. This is why some people develop nutrient deficiencies before they notice any tummy trouble at all. The amount of damage is different for everyone. It can be mild, or it can be more serious, depending on how long the condition has gone unnoticed and how much gluten a person keeps eating.
Because the small intestine plays such a big part in digestion, this damage does not stay in one place. Bloating, stomach pain, and changes in bathroom habits, such as diarrhoea or constipation, are some of the most common signs that celiac disease is affecting digestion. Some people also feel sick or too full soon after eating.
Beyond the tummy, poor absorption of nutrients can lead to low iron, tiredness, unexpected weight loss, and low vitamin D or calcium. In children, this can show up as slower growth. Because these signs are not always obviously linked to food, celiac disease is sometimes mistaken for irritable bowel syndrome, everyday tiredness, or simple low iron, which is one reason it can take a while to reach the right diagnosis.
Diagnosis usually starts with a blood test that checks for specific markers made when the immune system reacts to gluten. If these markers are high, the next step is usually an upper gastrointestinal endoscopy, where a doctor takes a tiny piece of tissue from the small intestine to check for the flattened villi described earlier. This small sample, called a biopsy, remains the most reliable way to confirm celiac disease, since a blood test alone cannot always tell it apart from other digestive conditions.
It helps to keep eating gluten before testing, since stopping too early can let the intestine heal a little and lead to a result that looks falsely normal. A gastroenterologist can guide the right order of tests based on each person's symptoms and history.
If celiac disease is not treated, it can affect much more than digestion. Ongoing damage to the intestine can lead to weak bones and a higher risk of fractures, mostly because of poor calcium and vitamin D absorption over time.
A 2025 review of celiac disease epidemiology places the true number of people affected closer to 1% to 2% of the population in places where wheat is a daily food, much higher than earlier estimates, mostly because many cases are missed unless doctors specifically look for them. None of this is guaranteed to happen. It reflects what can happen when the condition goes unnoticed, not what happens once it is properly managed.
The only proven treatment for celiac disease is to stop eating gluten completely, for life. Even a small amount of gluten, including tiny traces left behind on a shared cutting board or in a toaster, can set the immune system off again and slow down healing in the small intestine. For most people, symptoms start to improve within a few weeks of cutting out gluten, though full healing of the intestine can take much longer, especially in adults.
Managing celiac disease well also means regular check ups to test nutrient levels, since deficiencies built up over years are not always fixed by diet alone. Some people need extra iron, calcium, or vitamin D in the early stages of treatment. Working with a gastroenterologist and a dietitian who understands celiac disease helps make sure the diet is safe and gives the body everything it needs, not just gluten free in name.
Many people think celiac disease only shows up in childhood, but it can start at any age, even in people who have eaten wheat and gluten happily for decades. The genetic tendency is present from birth, but the condition itself can be switched on later by things such as a viral infection, surgery, pregnancy, or a period of major physical or emotional stress.
This is why someone can develop gluten intolerance later in life even with no family history of digestive problems, and why new, ongoing digestive symptoms in adulthood are worth mentioning to a doctor rather than brushing off as a new food sensitivity.
Celiac disease is more than just a sensitivity to wheat. It is the immune system quietly damaging the small intestine, upsetting digestion, and affecting nutrient absorption for years before a person gets a clear answer. Noticing the pattern between tummy trouble, tiredness, and nutrient deficiencies is often the first step towards getting help.
If ongoing digestive discomfort, unexplained tiredness, or nutrient deficiencies have been hard to explain, it may be worth asking a gastroenterologist about celiac disease testing. At Ashraya Hospital, Dr. Manoj Kolhe and the gastroenterology team use blood tests and endoscopy to reach a clear diagnosis and guide a treatment plan suited to each patient's needs.
Book your appointment today to get clear answers about your gastrointestinal issues.
