Understanding lactose intolerance

There are three main types of lactose intolerance; recognizing the symptoms and causes can help treat and manage the problem.

What is lactose intolerance?

Lactose intolerance is a digestive problem where the body is unable to digest lactose, a sugar mainly found in milk and dairy products^2,5. This is usually a result of an absence or deficiency of lactase, an enzyme that breaks down lactose into glucose and galactose, which are more easily absorbed into the bloodstream^1-3.

There are three main types of lactose intolerance:

➣ Congenital lactose intolerance (extremely rare)

This rare condition is caused by the absence of lactase from birth². Babies born with congenital lactose intolerance cannot tolerate any breastmilk or infant formula³.

➣ Primary lactose intolerance (genetically inherited)

This is associated with a developmental decline of the lactase enzyme, which gradually occurs after weaning^4,8. Primary lactose intolerance is uncommon before two to three years of age and normally becomes apparent after five years of age^2-4.

➣ Secondary lactose intolerance (more common, but temporary)

This occurs after damage to the brush border of the gut where lactase is produced, e.g. during acute gastroenteritis, persistent diarrhea or coeliac disease. This type of lactose intolerance can occur at any age but is more common in infancy. It is usually temporary and once the underlying problem is resolved, lactose can be reintroduced^1-4.

In addition to these three main types of lactose intolerance, there is also ‘developmental lactose intolerance’. This occurs in premature infants, when lactase is deficient in the gut until 34 weeks’ gestation^2-4.

Recognising the symptoms

Lactose intolerance causes gastrointestinal symptoms such as diarrhea, cramping and bloating. These are the result of any undigested lactose passing into the large gut. The undigested lactose has an osmotic effect, drawing in water, leading to diarrhea. It is then fermented by the bacteria in the gut, producing gas, which causes bloating and cramping^2,5-7.

Lactose intolerance has some similar symptoms to delayed cows’ milk allergy (CMA), so the two conditions are often mistaken for each other^1,2,8. Read our article ‘The differences between lactose intolerance and CMA’ to find out more.

Treating lactose intolerance

There are no official guidelines on the treatment of lactose intolerance in infants or adults for the African continent. Depending on the type of lactose intolerance, treatment can either involve the reduction or removal of lactose in the diet, while achieving optimal nutritional intake¹. Even if lactase levels are reduced by 50%, individuals can still digest a significant amount of lactose^3,9.

➣ Treating congenital lactose intolerance

Lactose must be completely removed from the diet and a lactose-free formula must be used for infants^3,5.

➣ Treating primary lactose intolerance

Children may be able to consume small amounts of lactose without experiencing symptoms. In other cases, where lactose may need to be avoided completely, care should be taken to ensure that the diet is still nutritionally balanced. For formula-fed infants under one year, a lactose-free formula may be used¹.

➣ Treating secondary lactose intolerance

Opinion on the treatment of secondary lactose intolerance varies. The American Academy of Pediatrics suggests that it ‘generally does not require elimination of lactose from the diet but, rather, treatment of the underlying condition’². Other healthcare professionals recommend total lactose avoidance until lactase production resumes after the underlying cause has been resolved⁵.

How low dairy intake affects bone health

Avoiding lactose by restricting dairy foods in the diet can lead to an insufficient intake of calcium and other key nutrients, impacting on healthy bone development.

At birth, the skeleton has only 20-30g of calcium; approximately 150mg of calcium is deposited in the bones each day until the age of around 20. If calcium intake is insufficient when bones are growing and developing, they may never reach full strength or peak bone mass. Other nutrients key to bone health are phosphorus, magnesium, vitamin D and protein^10,11. It is therefore important to ensure these nutrients are supplied through other foods or supplements.

Lactose intolerance is a condition that can have a serious effect on an infant’s health and development. However, by understanding its symptoms and the treatment options available, healthcare professionals can help parents effectively manage their child’s condition.

References