Lactose intolerance – symptoms, causes & other complications

lactose intolerance

Lactose intolerance is a very common digestive problem where your body is unable to digest lactose, which is a type of sugar that is found in dairy products and milk. There are some studies which are done in UK and it is said that in this country lactose intolerance is more common in people of African – Caribbean or Asian descent [1]. This type of digestive problem can develop at any age. In the most cases people who are aged 20 to 40 have increased chances of getting this condition but also there are some cases in which babies and young children can be also affected with it. Lactose intolerance is not the same condition as dairy allergy or milk allergy. Food allergies are caused by our immune system reacting to some types of food. This is causing symptoms such as itching, wheezing and rash. If you are allergic to something, even a tiny particle can be enough to trigger the allergic reaction. The most people, who have lactose intolerance, can still consume small amounts of lactose and they will not experience any problems. But this can vary from person to person.

Symptoms of lactose intolerance

Symptoms of this condition usually develop within a few hours consuming drink or food which has lactose. They may include:

  • Feeling sick
  • Stomach rumbling
  • Stomach cramps and pains
  • Bloated stomach
  • Diarrhea
  • Flatulence (wind)

The severity of the symptoms and when they are appearing is depending on the amount of lactose that we have consumed. There are some people who will be able to drink a small glass of milk without triggering their symptoms while other people will not be able to add milk in their coffee or tea because it will trigger their symptoms.

Causes for lactose intolerance: Our bodies are digesting lactose using a substance which is called lactase. This is breaking down the lactose into 2 sugars which are called galactose and glucose and they can be easily absorbed into our bloodstream. People who suffer from lactose intolerance do not produce enough lactase so the lactose is staying in the digestive system where it is fermented by bacteria. This is leading to production of many gases which is causing the symptoms that are associated with lactose intolerance. Lactose intolerance may be temporary or permanent and this is depending on the underlying reason why our bodies are not producing enough lactase. Most cases of lactose intolerance which are developing in adults are inherited and they tend to be life – long. [2] But cases when young children are having lactose intolerance, then this is often caused by an infection in the digestive system and it can last for a few weeks. Talk with your doctor as soon as possible because if you let this condition untreated, then it can lead to complications.

Lactose Intolerance

Complications of lactose intolerance

Milk and other dairy products contain vitamins such as Vitamin A, Vitamin B12, Vitamin D, protein and calcium. Lactose can also help your body to absorb many minerals such as zinc and magnesium. These minerals and vitamins are very important for the development of healthy and strong bones. If you are lactose intolerant, then getting the right amount of important minerals and vitamins can be difficult for you. This can lead to unhealthy weight loss and also it can lead to increased risk of developing these conditions:

  • Malnutrition: This is a condition when the food you eat does not give you the nutrients which are important for the healthy functioning of your body. If you suffer from this condition, then wounds can take longer to heal and you may start to feel depressed or tired. [3]
  • Osteoporosis: This is a condition where your bones are weak and thin. If you suffer from this condition, then you have increased risk of getting broken bones and fractures. [4,5,6]
  • Osteopenia: This is a condition where you have a very low bone – mineral density. If you do not treat this condition, then it can develop into osteoporosis. [5,6]

If you are concerned that your dietary restrictions are putting you at a risk of complications, then you need to talk with a dietitian.  They can tell you what you should include in your diet and what kind of food supplements do you need.


[1] NHS. Lactose intolerance. Retrieved from

[2] Mattar R, de Campos Mazo DF, Carrilho FJ. Lactose intolerance: diagnosis, genetic, and clinical factors. Clinical and Experimental Gastroenterology. 2012;5:113–21.

[3] Nyeko R, Kalyesubula I, Mworozi E, Bachou H. Lactose intolerance among severely malnourished children with diarrhoea admitted to the nutrition unit, Mulago hospital, Uganda. BMC Pediatrics. 2010;10:31.

[4] iPhysio. Scientists link drinking milk with Osteoporosis. 2018. Retrieved from

[5] Hodges JK, Cao S, Cladis DP, Weaver CM. Lactose intolerance and bone health: The challenge of ensuring adequate calcium intake. Nutrients. 2019;11(4):718.

[6] Facioni MS, Raspini B, Pivari F, et al. Nutritional management of lactose intolerance: the importance of diet and food labelling. Journal of Translational Medicine. 2020;18.


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