Lactose Intolerance

Do you get bloating, nausea and abdominal cramps when you eat dairy products? If so, it may be due to lactose intolerance. In this read, we’ll dive into what that means, its various symptoms, and how you can manage it (spoiler alert: it doesn’t mean avoiding dairy!). 

What is lactose intolerance?

To digest lactose (the sugar found in dairy products) the body releases an enzyme called lactase. In some individuals, not enough lactase is produced when dairy products are consumed and this can lead to uncomfortable gastrointestinal symptoms. For most individuals, lactose intolerance doesn’t mean you have to avoid all dairy foods, it’s more about which foods and quantities you can tolerate. 

Lactase explained

Milk and other dairy products contain a sugar called lactose. When lactose enters the small intestine, an enzyme called lactase needs to be released to help break down lactose into two simple sugars: glucose and galactose. These simple sugars are then absorbed into the bloodstream via the intestinal lining.

Undigested milk sugars

If you are lactose intolerant, this means there’s a deficiency in the enzyme lactase. When lactose travels through the gut, instead of being broken down in the small intestine, it instead reaches the large intestine. Undigested lactose interacts with gut bacteria where it is partially broken down into acids and gases. This fermentation may lead to uncomfortable digestive symptoms such as gas, bloating and abdominal pain. In the intestinal tract, lactose attracts water molecules which may result in watery stools and diarrhoea. 

Potential symptoms of lactose intolerance

Symptoms of lactose intolerance usually appear within a short period of time after eating or drinking dairy products that contain lactose.

Common signs and symptoms include:

• Nausea
• Vomiting
• Bloating
• Abdominal cramps
• Diarrhoea
• Flatulence or gas

Causes of lactose intolerance

There are a number of factors that may affect lactase production and increase the risk of lactose intolerance as a result. These include: 

1. Increasing age: lactose intolerance is rare in babies and young children, as they are designed to digest lactose which is naturally found in breastmilk. However, as we age, lactase production may decline. If lactose intolerance in an infant is suspected, it’s important to discuss this with a healthcare professional.
2. Ethnicity, genetics and traditional food patterns may play a role. For example, lactose intolerance is more common in individuals with Asian, African, Middle Eastern and Aboriginal and Torres Strait Islander backgrounds.
3. Other gastrointestinal symptoms such as medically diagnosed irritable bowel syndrome (IBS) or small intestinal bacterial overgrowth (SIBO). In cases of IBS, it may be due to a wider intolerance to FODMAPs. This is why a temporary low FODMAP diet requires a short period of lactose free dairy products.

Are there different types of lactose intolerance?

There are four classifications of lactose intolerance:

1. Primary lactose intolerance is the most common and occurs in about 70% of the global population. Lactase production may naturally decline in the teenage or young adult years. For many individuals, small amounts of lactose throughout the day may be tolerated.
2. Secondary lactose intolerance may occur if there is damage to the small intestine which impairs lactase production. Damage to the small intestine may result from inflammation present in Crohn’s disease, as a side-effect from surgery, bacterial overgrowth or celiac disease. Treating the underlying disorder may help restore lactase levels.
3. In rare instances, babies can be born with a complete absence of lactase activity which is referred to as congenital lactose intolerance. The disorder is passed on through genetics, where both the mother and father contribute a gene variant for the child to be affected.
4. Developmental lactase deficiency may occur in some infants that are born prematurely. This is because their bodies have insufficient lactase levels which can lead to lactose intolerance.

Management of lactose intolerance

If you have lactose intolerance this doesn’t necessarily mean that you must avoid dairy products altogether. Here are some dietary suggestions so that you can still enjoy dairy without any unpleasant side-effects.

Choose lactose free dairy

There are dairy products available in the supermarket which are lactose free, meaning  that you can still enjoy dairy products such as yoghurt, milk and cheese. These products are usually produced by adding the enzyme lactase to break down the lactose so they don’t cause stomach upset. Look out for lactose-free on the label.

Expert tip: Sometimes it’s about the quantity over time. Spread lactose containing foods out during the day or eat them with other foods to slow down digestion.

Try dairy that is naturally low in lactose

Dairy products each contain varying amounts of lactose. Dairy products that contain higher amounts of lactose should be avoided or consumed in smaller quantities. 

• Yoghurt and kefir are usually lower in lactose as the bacteria (good gut bugs) help to break it down.
• Hard cheeses (such as cheddar) are very low in lactose,  so may be better tolerated.

Supporting the gut

The ability to digest lactose may also be affected by the general health of the gut such as gut lining and balance of gut bugs. Getting the gut basics right may help to improve gut health. This includes eating a balanced diet with enough fibre, drinking around ten cups of water per day, getting enough good quality sleep and exercising regularly. 

Research has also shown that prebiotics such as galacto-oligosaccharide and certain probiotic strains may help to restore levels of friendly bacteria in the colon to support gut health and therefore the ability to metabolise lactose.

If you’re concerned about lactose intolerance or problems with digesting dairy, it’s important to speak with a healthcare professional for individualised advice.

Lactase supplements

If you eat dairy products and suspect that you will experience symptoms you could try supplementing with a product containing lactase. These products are readily available in pharmacy and health food stores as tablets or drops. The drops are ideal for young children and can be added to foods that contain lactose to avoid symptoms.