Coeliac disease and type 1 diabetes
Coeliac disease is an autoimmune disease, where the body’s immune system attacks its own tissues. In people with coeliac disease, this immune reaction is triggered by gluten. Gluten is a type of protein found in wheat, rye, barley, oats and ingredients derived from these cereals. People with coeliac disease need to avoid these foods.
In coeliac disease, eating gluten causes the lining of the gut to become damaged and may affect other parts of the body. Tiny, finger-like projections called ‘villi’ become inflamed and then flattened, leaving less surface area to absorb nutrients from food and drink.
People with undiagnosed coeliac disease can, as a result, have a wide range of symptoms, such as stomach pain, bloating, diarrhoea and in children an unexplained failure to thrive. If you think you may have coeliac disease it is essential to continue to eat gluten until investigations are done to make a definite diagnosis. This is because taking gluten out of the diet, or reducing the amount of gluten before being tested, is likely to cause false negative results.
What is the link with diabetes?
Coeliac disease and diabetes have similar genetic backgrounds as both are autoimmune conditions. Some people with type 1 diabetes have a ‘silent’ form of coeliac disease which means no symptoms are apparent and it is only diagnosed by screening. Some estimate the proportion of people with type 1 diabetes who may also have Coeliac disease may be as high as 1-16%.
There is no link between coeliac disease and type 2 diabetes.
How is coeliac disease treated?
Once diagnosed with coeliac disease you should immediately start a glutenfree diet and this needs to be maintained for life. Even very small amounts of gluten can be harmful to people with coeliac disease, so sticking to a gluten-free diet is vital. Your doctor should refer you to a dietitian who will help guide you through the initial steps of changing your diet. The amount of time the gut takes to heal varies between people, and commonly takes between six months and two years, however, you should start to feel better in the first few weeks.
What foods contain gluten?
Gluten containing foods include:
• Cereals
• Breads
• Flours
• Pasta
• Pizza bases
• Crackers
• Pastry
• Biscuits.
Gluten-containing cereals are often added to foods which you may not expect such as:
• Sausages
Sauces
• Soups
Burgers
• Ready meals.
Under new EU legislation manufactures must declare if there is even the smallest amount of gluten present.
What are suitable ‘substitutes’
If you have a medical card or use the Drug Payment Scheme, once you are diagnosed with coeliac disease, ask your doctor to prescribe suitable ‘substitute’ foods. These include gluten free:
• Bread
• Pasta
• Flour
• Fibre/bread mixes
• Pizza bases
• Plain biscuits.
A list of these gluten-free dietary foods is available on a food list available from the Coeliac Society.
What about pure oats?
Pure, uncontaminated oats and pure oat products can be tolerated by most people with coeliac disease, although some people will still be sensitive to them. However, most conventional oat products available on the market are contaminated by wheat, rye or barley during production – making them unsuitable.
If you wish to include pure, uncontaminated oats in your diet, consult your healthcare team as you will need to be monitored on an individual basis.
How will this affect diabetes control?
Once gluten has been removed from your diet, the process of gut healing will begin immediately. As your gut heals, your absorption of nutrients from your food and drink will improve, which is likely to affect your diabetes control. It is important you talk to your diabetes healthcare team about this as you may need to start, alter or change your insulin and/or other diabetes medication. If you already have coeliac disease and have just been diagnosed with diabetes, making food choices to improve your diabetes control will benefit your long-term health and how you feel generally.
Eat regularly
Avoid skipping meals and spread your breakfast, lunch and evening meal over the day. Include carbohydrates at each meal.
These include foods such as:
• Gluten-free breads and pasta
• Naturally gluten-free cereal products such as rice – all types including basmati, wild, jasmine, brown, white, long grain and Arborio
• Starchy vegetables such as potatoes and sweet potatoes
• Gluten-free breakfast cereals such asrice and corn varieties.
Check the Coeliac Society food list for a comprehensive range of suitable glutenfree cereals and similar products. Try to include those that are more slowly absorbed (have a lower glycaemic index), as these won’t affect your blood glucose levels as much.
Better choices include:
• Gluten-free pasta
• Basmati or easy cook rice
• Gluten-free multigrain or granary bread
• New potatoes
• Sweet potatoes
• Yam
• Pure, uncontaminated porridge oats (if you can tolerate pure oats) alternatively there is also gluten-free porridge. The amount of carbohydrate you eat is important because it affects how you control your blood glucose levels. The amount of carbohydrate that your body needs varies depending on your age, weight and activity levels. You should discuss this with your dietitian.
Include five-a-day
All fresh, frozen, canned and dried pure fruits and vegetables are naturally glutenfree. Aim for at least five servings in total a day to provide you with vitamins, minerals and fibre to help you balance your overall diet.
One portion equals:
• A banana or apple
• A slice of melon
• Two plums
• A handful of grapes
• A tablespoon of dried fruit
• A small glass of fruit juice or fruit smoothie (about 150mls)
• Three heaped tablespoons of vegetables
• A cereal bowl of salad.
Cut down on fat
Cut down on the fat you eat, particularly saturated fats, as a low-fat diet benefits your health. While butter, margarine, lard, cooking oils, and most reduced and low fat spreads are all gluten-free, they are high in calories. Choose unsaturated fats or oils instead, especially monounsaturated fat (for example, olive oil and rapeseed oil) as these types of fat are better for your heart. Check the Coeliac Society Food List for suitable yoghurts. Fat is the greatest source of calories, so eating less fat and fatty foods will help you to lose weight if you need to.
Eat oily fish at least twice a week
Oily fish contains a type of polyunsaturated fat called omega-3 which helps protect against heart disease. Eat oily fish such as mackerel, sardines, salmon and trout and herring, which are all glutenfree.
Include more plant proteins
Naturally gluten-free examples include:
• Kidney beans
• Butter beans
• Chickpeas
• Red or green lentils.
These foods have less of an effect on your blood glucose levels as they have a lower glycaemic index and may help to control your blood fats. Try adding them to stews, casseroles and soups, or to a salad.
Watch sugar and sugary foods
This does not mean you need to eat a sugar-free diet. Sugar can be used in foods and in baking as part of a healthy diet. Fruit juice, squash (but not barley water or barley squash) and most fizzy drinks are gluten-free. Check the Coeliac Society food list for details.
Using sugar-free, no added sugar or diet squashes and fizzy drinks instead of sugary drinks can be an easy way to reduce the sugar in your diet. Sugary drinks are best used only as a treatment for hypos.
Reduce salt in your diet
More than 6g of salt a day can raise your blood pressure, which can lead to stroke and heart disease. Limit the amount of processed foods you eat (as these are usually high in salt) and try flavouring foods with herbs and spices instead of salt.
Check the food list for suitable ingredients to add flavour like:
• Tomato and garlic puree
• Individual herbs and spices
• Mixed herbs and spices
• Vinegars
• Ground pepper.
Drink alcohol in moderation
Women should drink a maximum of two units of alcohol per day and men should drink not more than three units per day. Wine, spirits, cider, sherry, port, liqueurs and gluten-free beers (made from glutenfree cereals) are suitable.
Avoid drinks that contain gluten like:
• Beer
• Flavoured beer
• Lager
• Ales
• Stouts.
Remember, alcohol can add extra calories, so think about cutting back further if you are trying to lose weight. Never drink on an empty stomach, as alcohol can make hypoglycaemia (low blood glucose levels) more likely to occur when taking certain diabetes medication and/or insulin.
Avoid ‘diabetic’ food and drinks
‘Diabetic’ food and drinks offer no benefit to people with diabetes. They are expensive, contain just as much fat and calories as the ordinary versions, can have a laxative effect and will still affect your blood glucose levels.
What are the long-term effects?
Coeliac disease requires ongoing review and management. People with undiagnosed coeliac disease, or those with coeliac disease who are not following a strict gluten-free diet, are at higher risk of certain complications including: osteoporosis; cancer; and infertility.
Bone problems
If coeliac disease is undiagnosed or not treated by following a strict gluten-free diet, decreased absorption of calcium may result. This puts a person at greater risk of osteoporosis, a condition where bones become thin and more likely to break. The strength of bones is measured by measuring bone mineral density (BMD). Osteopoenia is a condition where BMD is lower than normal, but not as severe as in osteoporosis.
There have been a number of reports showing evidence of reduced BMD, osteopoenia or osteoporosis in 20-50% of people newly diagnosed with coeliac disease. This is largely thought to be related to long-term malabsorption of calcium as a result of delayed diagnosis of coeliac disease.
If you are diagnosed in childhood or during your teenage years with coeliac disease and you follow a gluten-free diet, your long-term bone health is unlikely to be affected. Following a healthy lifestyle and a healthy balanced gluten-free diet containing rich sources of calcium is vital for bone health.
Your dietitian and healthcare team will be able to discuss in greater detail what steps you need to take for optimal bone health. You will not be able to feel your bones thinning, so if you think that you are at risk of osteoporosis, it is advisable to discuss this with your GP
Cancer, infertility, pregnancy
Certain kinds of gut cancer, infertility and poorer outcomes in pregnancy are associated with coeliac disease. Again, following a lifelong gluten-free diet reduces your risk. Once a gluten-free diet has been followed for three to five years, the risk of developing cancer is no greater in comparison to the general population. The risks of infertility and poorer outcomes in pregnancy are also reduced following diagnosis and keeping to a gluten- free diet.
Three steps to diagnosis
There are three steps in the diagnosis of coeliac disease:
1. Discuss your symptoms with your GP or diabetes team
2. Your GP can then take a simple blood test to look for an antibody made by the body in response to eating gluten. A few people with coeliac disease do not make these coeliac disease antibodies, so if you have strongly suggestive symptoms of coeliac disease, you should discuss with your GP about going onto the next step, despite having a negative blood test
3 Your GP will refer you to a gut specialist (gastroenterologist) for a simple test called a ‘gut biopsy’. Small samples of gut lining are collected and later examined under a microscope to check for abnormalities that are typical in celiac disease. Current clinical guidelines recommend that all people with type 1 diabetes are assessed for coeliac disease.
Further information
Contact the Coeliac Society of Ireland for further information. See website www.coeliac.ie or contact their office on 01 8721471. Membership costs €25 annually and this includes a membership pack with regular newsletters and the food list, which is updated throughout the year.
Sinead Hanley is a Diabetes Federation of Ireland Dietitian and Regional Development Officer
APP/KOL/AC 15/07/2010
Sheila O'Kelly, Diabetes Ireland Magazine
Volume 8, Issue 2, Summer 2010
Last updated: July 2010