Some people who have recently been diagnosed with coeliac disease can also have secondary lactose malabsorption.
Lactose is the carbohydrate (or sugar) found naturally in milk. Lactose is made up of two smaller sugars called glucose and galactose and needs to be broken down into these simple sugars to be absorbed and used by the body. The enzyme responsible for breaking lactose down is lactase.
Those with lactose intolerance don’t produce enough lactase, resulting in lactose maldigestion. Undigested lactose passes through the small intestine to the colon, drawing in water. In the colon, natural bacteria cause the lactose to ferment producing acids and gas. This all results in the symptoms of lactose intolerance which may include abdominal pain, bloating, wind and/or diarrhoea.
What causes lactose intolerance?
It is estimated that up to 70% of the world’s population may have lactose intolerance.
It is known that a temporary lactose intolerance may occur due to untreated coeliac disease. The lactase enzyme responsible for breaking down lactose is produced at the tips of the villi that line the surface of the small intestine. In those with untreated coeliac disease, the damage to the villi may affect their ability to produce lactase. The good news is that once a gluten free diet is established and the villi recover, lactase production returns to normal in most people with coeliac disease. Once this occurs, the lactose intolerance will usually resolve.
The occurrence of lactose intolerance is also influenced by a number of other factors and commonly occurs independently of coeliac disease. As age increases the production of lactase can decline, leading to lactose intolerance. The incidence of lactose intolerance also varies with ethnicity.
What is the treatment for lactose intolerance?
Lactose intolerance can vary in severity and the amount of lactose tolerated will vary widely depending on the level of lactase deficiency, the amount of lactose consumed and whether other foods are eaten at the same time.
If you have lactose intolerance, you DO NOT need to avoid all dairy foods. Dairy foods play an important role in a balanced diet and provide over 10 essential nutrients. Calcium is best absorbed by the body from dairy foods. Removing all dairy foods from the diet to treat lactose intolerance will increase the risk of developing osteoporosis. Three serves of dairy or suitable alternatives are recommended each day. One serve is: 1 cup (250mL) of milk, a 200g tub of yoghurt or 2 slices (40g) of cheese. Eat a variety of foods to ensure your diet is well balanced and nutritionally adequate.
The majority of people with low lactase levels can tolerate up to 2 cups of milk a day if consumption is spread throughout the day and is combined with food. Many other dairy foods do not contain large amounts of lactose e.g. cheese contains almost no lactose and yoghurt is generally well tolerated due to the natural bacteria it contains that break down the lactose present over time.
The lactose content of some dairy foods:
|Dairy food||Lactose content (g)|
|Regular milk, 250mL||11.8|
|Skim milk, 250mL||12.5|
|Cheddar cheese, 40g||0.0|
|Parmesan cheese, 40g||0.1|
|Cream cheese, 22g||0.6|
|Yoghurt (natural), 200g||9.4|
|Ice cream, 50g||2.8|
|Butter, 18g (1 Tbs)||0.1|
|Cream, 20g (1 Tbs)||0.6|
|Evaporated milk, ½ cup||13.4|
|Sweetened condensed milk, ½ cup||15.6|
Tips to help those with lactose intolerance include their three serves of dairy each day:
- Drink milk with foods and not on an empty stomach
- Start with small amounts and gradually increase your milk consumption to build up your tolerance levels
- Regular milk contains less lactose than low fat or skim milk
- Yoghurt may be better tolerated
- Cheese is very low in lactose and is well tolerated
There are also gluten free lactose free or calcium fortified soy milks available, as well as lactose digesting products e.g. Lacteez that may be used.
Diagnosing lactose intolerance
If you suspect you may have lactose intolerance, ask your GP to test you for it. Remember that if your lactose intolerance is caused by coeliac disease you should be able to reintroduce lactose-containing foods once the bowel has repaired. An Accredited Practising Dietitian can assist you to manage your lactose intolerance.