Lactose intolerance

"Lactose intolerance - Illnesses & conditions | NHS inform Home Illnesses and conditions Symptoms and self-help Tests and treatments Healthy living Care, support and rights Scotlands Service Directory 0 Home Illnesses and conditions Nutritional Lactose intolerance Lactose intolerance About lactose intolerance Causes of lactose intolerance Diagnosing lactose intolerance Treating lactose intolerance Complications of lactose intolerance About lactose intolerance Lactose intolerance is a common digestive problem where the body is unable to digest lactose, a type of sugar mainly found in milk and dairy products. Symptoms of lactose intoleranceusually develop within a few hours of consuming foodor drink that contains lactose. They may include: flatulence (wind) diarrhoea bloated stomach stomach cramps and pains stomach rumbling feeling sick The severity of your symptoms and when they appear depends on the amount of lactose youve consumed. Some people may still be able to drink a small glass of milk without triggering any symptoms, while others may not even be able to have milk in their tea or coffee. When to seek medical advice The symptoms of lactose intolerance can be similar to several other conditions, so its important to see your GP for a diagnosis before removing milk and dairy products from your diet. For example, the symptoms above can also be caused by: irritable bowel syndrome (IBS)  a long-term disorder that affects the digestive system milk protein intolerance  an adverse reaction to the protein in milk from cows (not the same as a milk allergy ) If your GP thinksyouhave lactose intolerance,they may suggest avoiding foods and drinks containing lactose for two weeks to see if your symptoms improve. Read more about diagnosing lactose intolerance What causes lactose intolerance? The body digests lactose using a substance called lactase. This breaks down lactose into two sugars called glucose and galactose, which can be easily absorbed into the bloodstream. People withlactose intolerancedont produce enough lactase, so lactose stays in the digestive system where its fermented by bacteria. This leads to the production of various gases, which cause the symptoms associated with lactose intolerance. Depending on the underlying reason why the body isnt producing enough lactase, lactose intolerance may be temporary or permanent. Most cases that develop in adults are inherited and tend to be lifelong, but cases in young children are often caused by an infection in the digestive system and may only last for a few weeks. Read more about the causes of lactose intolerance Whos affected? In the UK, lactose intolerance is more common in people of Asian or African-Caribbean descent. Lactose intolerance can develop at any age. Many cases first develop in people aged 20 to 40, although babies and young children can also be affected. Is it an allergy? Lactoseintolerance isnt the same as a milk or dairy allergy. Food allergies are caused by your immune system reacting to a certain type of food. Thiscauses symptoms such asa rash, wheezing and itching. If youre allergic to something, even a tiny particle can be enough to trigger a reaction, while most people with lactose intolerance can still consume small amounts of lactose without experiencing any problems (although this varies from person to person). Treating lactose intolerance Theres no cure for lactose intolerance, but limiting your intake of food and drink containing lactose usually helps tocontrol the symptoms. Depending on what dairy products youre able to eat, you may also require additionalcalciumandvitamin Dsupplements to keepyour bones strong and healthy. In some cases, your GP may refer you to a dietitian for further advice. In addition to dietary changes, lactase substitutesmayalso be helpful. These aredrops or tablets you can take with your meals or drinks to improve your digestionof lactose. Read more about treating lactose intolerance Complications of lactose intolerance Milk and other dairy products contain calcium, protein andvitamins such as A, B12 and D. Lactose also helps your body absorb a number of other minerals, such as magnesium and zinc. These vitamins and minerals are important for the development of strong, healthy bones. If youre lactose intolerant, getting the right amount of important vitamins and minerals can prove difficult. This may lead to unhealthy weight loss andput you at increased risk of developing the following conditions: Osteopenia where you have a very low bone-mineral density. If osteopenia is not treated, it can develop into osteoporosis. Osteoporosis  where your bones become thin and weak. If you have osteoporosis, your risk of getting fractures and broken bones is increased. Malnutrition  when the food you eat doesnt give you the nutrients essential for a healthy functioning body. If youre malnourished, wounds can take longer to heal and you may start to feel tired or depressed. If youre concerned that dietary restrictions are putting you at risk of complications, you may find it helpful to consult a dietitian. They can advise you on your diet and whether you require food supplements. Your GP should be able to refer you to an NHS dietitian free of charge. Alternatively, you can contact a private dietician. The British Dietetic Association has information on how to find a private dietitian. Causes of lactose intolerance Lactose intolerance is usually the result of your body not producing enough lactase. Lactase is an enzyme (a protein that causes a chemical reaction to occur) normally produced in your small intestine thats used to digest lactose. If you have a lactase deficiency, it means your body doesnt produce enough lactase. Digesting lactose After eating or drinking something containing lactose, it passes down your oesophagus (gullet) into your stomach, where its digested. The digested food then passes into your small intestine. The lactase in your small intestine should break lactose down into glucose and galactose (other types of sugar), which are then absorbed into your bloodstream. If there isnt enough lactase, the unabsorbed lactose moves through your digestive system to your colon (large intestine). Bacteria in the colon ferment (break down) the lactose, producing fatty acids and gases such as carbon dioxide, hydrogen and methane. The breakdown of the lactose in the colon, and the resulting acids and gases that are produced, cause the symptoms of lactose intolerance such as flatulence and bloating. Types of lactase deficiency The main types of lactase deficiency are outlined below. Primary lactase deficiency Primary lactase deficiency is the most common cause of lactose intolerance worldwide. This type of lactase deficiency is caused by an inherited genetic fault that runs in families. Primary lactase deficiency develops when your lactase production decreases as your diet becomes less reliant on milk and dairy products. This is usually after the age of two, when breastfeeding or bottle-feeding has stopped, although the symptoms may not be noticeable until adulthood. Secondary lactase deficiency Secondary lactase deficiency is a shortage of lactase caused by a problem in your small intestine. It can occur at any age, and may be the result of another condition, surgery to your small intestine, or taking certain medication. Secondary lactase deficiency is the most common cause of lactose intolerance in the UK, particularly in babies and young children. Possible causes of secondary lactase deficiency include: gastroenteritis  an infection of the stomach and intestines coeliac disease  a bowel condition caused by an adverse reaction to a protein called gluten Crohns disease  a long-term condition that causes inflammation of the lining of the digestive system ulcerative colitis  a long-term condition that affects the large intestine chemotherapy  a cancer treatment long courses of antibiotics The decrease in the production of lactase in secondary lactase deficiency is sometimes only temporary, but it may be permanent if its caused by a long-term condition. Its also possible to develop secondary lactase deficiency later in life, even without another condition to trigger it. This is because your bodys production of lactase naturally reduces as you get older. Congenital lactase deficiency Congenital lactase deficiency is a rare condition that runs in families and is found in newborn babies. Its caused by an inheritedgenetic fault that means affected babies produce very little or no lactase. The genetic mutation responsible forcongenital lactase deficiency is passed on in an autosomal recessive inheritance pattern. This meansboth parents must have a copy of the faulty gene to pass onthe condition. Developmentallactase deficiency Some babies born prematurely (before the 37th week of pregnancy) have a temporary lactose intolerance because their small intestine wasnt fully developedby the time they were born. This is known as developmental lactase deficiency and it usually improves asaffected babies get older. Diagnosing lactose intolerance Its important to visit your GP if you think you or your child may have lactose intolerance, as the symptoms can be similar to other conditions. Before seeing your GP, keep a diary of what you eat and drink, and what symptoms you experience. Tell your GP if you notice any patterns, or if there are any foods you seem particularly sensitive to. Your GP may suggest trying toremove lactose from your diet for two weeks to see if it helps to relieve your symptoms. This will provide further evidenceof whetheryoure lactose intolerant. Further testing Other tests arent usually needed, but your GP may sometimes suggest further tests to: help confirm the diagnosis find out how much lactase (the enzyme used to digest lactose) your body is producing try to determine what might be causing your lactose intolerance Some of the main tests that may beusedare described below. Hydrogen breath test A hydrogen breath test is a simple way of determining if you may be lactose intolerant. Youll be asked to avoid eating or drinking during the night before the test. When you arrive for the test, youll be asked to blow up a balloon-like bag.This sample of your breath will be tested to find out how much hydrogen is present, measured in parts per million (ppm). Youll then be given a drink of lactose solutionand your breath will be tested every 15 minutes over the next few hours to see if the level of hydrogen changes. If your breath contains a large amount of hydrogen (more than 20ppm above your baseline) after consuming the lactose solution, its likely that youre lactose intolerant. This isbecauselactose intolerance can cause the bacteria in the colon (large intestine) to produce more hydrogen than normal. Lactose tolerance test In a lactose tolerance test, youll be given a drink of lactose solution and a blood sample will be taken from your arm using a needle. The blood will be tested to see how much glucose (blood sugar) it contains. If youre lactose intolerant, your blood sugar levels will either rise slowly, or not at all. This is because your body is unable to break down the lactose into glucose. Milk tolerance test In a milk tolerance test, youll be given a glass of milk (about 500ml) and your blood sugar levels will be tested. If your blood sugar levels dont rise after drinking the milk, you may be lactose intolerant. Small bowel biopsy Asmall bowel biopsy is rarely used to diagnose lactose intolerance. However, it may be carried out to see if your symptoms are being caused by another condition, such as coeliac disease . In a small bowel biopsy, a sample of your small intestinal lining is taken using anendoscope (a thin, flexible tube with a light and a tiny cutting tool at the end) thats passed down your throat. This will be carried out under local anaesthetic , so it wont hurt. The sample of intestinal lining will be tested to see how much lactase it contains. If it only contains a small amount of lactase,its likely youre lactose intolerant. The sample can also be examined to look for signs of possible underlying conditions such as coeliac disease. Treating lactose intolerance Theres no cure for lactose intolerance, but most people are able to control their symptoms by making changes to their diet. Some cases of lactose intolerance, such as those caused by gastroenteritis , are only temporary and will improve within a few days or weeks. Other cases, such asthose caused by an inherited genetic fault or a long-term underlying condition, are likely to be lifelong. Changing your diet In most cases, cutting down on or avoiding sources of lactose and replacing them with lactose-free alternatives is enough to control the symptoms of lactose intolerance. The exact changes you need to make to your diet depend on how sensitive you are to lactose. Some people are able to tolerate some lactose in their diet without any problems, whereas others experience symptoms after consuming food containing only a tiny amount of lactose. If you decide to experiment with what you can and cant eat, make sureto introduce new foods gradually, rather than all at once. This will help you to get used to any foods you might be sensitive to and identify any that cause problems. Eating fewer products containing lactose, or avoiding them completely, can mean you miss out on certain vitamins and minerals in your diet and increase your risk of complications. Youll also need to make sure youre getting enoughnutrition from either lacto-free foods or dietary supplements. If you or your child are extremely sensitive to lactose, talk to your GP about your diet. Milk products are rich in calcium needed for healthy bones so you may need to have regular bone density checks. You may be referred to a dietitian (an expert in diet and nutrition) whocan advise about what foods should be included in your, or your childs, diet. Sources of lactose Some of the main sources of lactose you may need to cut down on or avoid if youre lactose intolerant are described below. Milk A major source of lactose is milk, including cows milk, goats milk and sheeps milk. Depending on how mild or severe your lactose intolerance is, you may need to change the amount of milk in your diet. For example: you may be able to have milk in your tea or coffee, but not on your cereal some products containing milk, such as milk chocolate, may still be acceptable in small quantities you may find that drinking milk as part of a meal, rather than on its own, improves how the lactose is absorbed If even a small amount of milk triggers your symptoms, there are some alternatives you can try, such as soya or rice milk (see below). Dairy products Other dairy products made from milk, such as butter, ice cream and cheese, can also contain high levels of lactose and may need to be avoided if youre lactose intolerant. Some dairy products however, such as hard cheese and yoghurt, contain lower levels of lactose than milk and other products, so you may still be able to have them. Its worth experimenting with different foods to find out if there are any dairy products you can eat because theyre a good source ofessential nutrients such ascalcium. Other foods and drinks As well as milk and dairy products, there are other foods and drinks that can sometimes contain lactose. These include: salad cream, salad dressing and mayonnaise biscuits chocolate boiled sweets cakes some types of bread and other baked goods some breakfast cereals packets of mixes to make pancakes and biscuits packets of instant potatoes and instant soup some processed meats, such as sliced ham Check the ingredients of all food and drink products carefully, because milk or lactose are often hidden ingredients. The lactose found in some foodswont necessarily be listed separately on the food label, so you need to check the ingredients list for milk, whey, curds and milkproducts such as cheese, butter and cream. Some ingredients may sound like they contain lactose when they dont, such aslactic acid, sodium lactate and cocoa butter. These ingredients dont need to be avoided if youre lactose intolerant. Medication Some prescription medicines, over-the-counter medicines and complementary medicines may contain a small amount of lactose. While this isnt usually enough to trigger the symptoms of lactose intolerance in most people, it may cause problems if your intolerance is severe or youre taking several different medicines. If you need to start taking a new medication, check with your GP or pharmacist in case it contains lactose. Lactose-free foods and drinks There are a number of alternative foods and drinks available in supermarkets to replace the milk and dairy products you need to avoid. Food and drinks that dont usually contain lactose include: soya milks, yoghurts and some cheeses milks made from rice, oats, almonds, hazelnuts, coconut, quinoa, and potato foods which carry the dairy-free or suitable for vegans signs carob bars You can also buy cows milk containing additional lactase (the enzyme used to digest lactose). This means you still get the nutritional benefits of the milk, but youre less likely to experience any symptoms after consuming it. Getting enough calcium If youre unable to eat most dairy products, you may not be getting enough calcium in your daily diet.Calcium has several important functions, including: helping build strong bones and teeth regulating muscle contractions (including heartbeat) ensuring blood clots normally Therefore, its a good ideato choose lactose-free products with added calcium and ensure your diet contains alternative sources of calcium, such as: green leafy vegetables, such as spinach, kale, broccoli, cabbage and okra soya beans tofu nuts bread and anything made with fortified flour fish containing edible bones (for example, sardines, salmon, and pilchards) You can also buy combined calcium and vitamin D supplements from most pharmacists to help maintain good bone health. Its important to check with your GP or dietitian whether you should be taking supplements, however, as taking excessively high levels of calcium can cause side effects. Lactase substitutes In addition to dietary changes, you may also find it useful to takeliquid drops, tablets or capsules that containlactase substitutes. These are available from most health foods shops. Lactase substitutes replace the lactase your small intestine isnt producing, whichcan reduce your symptoms by helping your body break down any lactose in your diet more easily. Lactase substitutescan either be added to milkor taken justbefore eating a meal containing lactose. Lactose intolerance in children If your child is lactose intolerant, they may be able to consume small amounts of lactose without experiencing symptoms. This is quite safe, but you may need to experiment to find out how much they can comfortably eat or drink. If your child is unable to tolerate any lactose, your doctormay refer you to a dietitian for nutritional advice because its importantfor young children to have certain nutrients in their diet to ensure healthy growth and development. In general, the same rules about foods to try or to avoid are similar for children and adults (see above). For babies with lactose intolerance, lactose-free formula milk is available to buy from pharmacies and supermarkets. However, soya formula isnt recommended for children under six months because it contains hormones that may interfere with your babys future physical and sexual development. Breastfed babies may benefit from lactase substitute drops to help their bodies digest the lactose in breast milk. For many children, lactose intolerance is only temporary and will improve after a few weeks. After this point its safe to gradually reintroduce milk and dairy products into their diet. Complications of lactose intolerance Milk and other dairy products are an important part of a healthy diet. They contain calcium, protein and vitamins such as vitamins A, B12 and D. Lactose is also important because it helps your body absorb a number of other minerals, including magnesium and zinc. These vitamins and minerals are important for the development of strong, healthy bones. If you are lactose intolerant, getting the right amount of important vitamins and minerals can prove difficult. This may lead to unhealthy weight loss andput you at increased risk of developing the following conditions. Osteopenia  where you have a very low bone-mineral density. If osteopenia is not treated, it can develop into osteoporosis. Osteoporosis  where your bones become thin and weak. If you have osteoporosis, your risk of getting fractures and broken bones is increased. Malnutrition  when the food you eat does not give you the nutrients essential for a healthy functioning body. If you are malnourished, wounds can take longer to heal and you may start to feel tired or depressed. If you are concerned that dietary restrictions are putting you at risk of complications, you may find it helpful to consult a dietitian. They can advise you on your diet and whether you require food supplements. Your GP should be able to refer you to an NHS dietitian free of charge. Alternatively, you can contact a private dietician. The British Dietetic Association has information on how to find a private dietitian. Source: NHS 24 - Opens in new browser window Last updated: 21 November 2023 How can we improve this page? Help us improve NHS inform Thank You Your feedback has been received Dont include personal information e.g. name, location or any personal health conditions. Email Address e.g. you@example.com Message Maximum of 500 characters Send feedback Add this page to\n            Info For Me Other health sites Allergy UK: Cow's milk allergy Allergy UK: Cow's milk allergy in adults British Dietetic Association NHS inform About NHS inform Editorial policy Contact us Webchat Give feedback about NHS inform Info for Me tool Terms and conditions Privacy and cookies policy Freedom of information (FOI) Accessibility Other languages and formats  2023 NHS 24  v1.1.1.17852"