Difference Between Irritable Bowel Syndrome and Lactose Intolerance

When there is an issue with the normal functioning of the intestines, it is called irritable bowel syndrome. It's called lactose intolerance when lactose isn't absorbed correctly and causes stomach aches.

What is Irritable Bowel Syndrome?

Irritable bowel syndrome (IBS) is a disorder of the intestines and the muscles that control them.

Causes − The causes of IBS remain mysterious to researchers. Several elements appear to be at play, including the psychological ones like sadness and stress. The contraction of the intestinal muscles is a physiological aspect.

Diagnosis − Tests like an X-ray endoscopy or a colonoscopy may be used to make the diagnosis after other possible digestive problems have been ruled out.

Symptoms and complications − Symptoms include of bloating, discomfort, and abdominal spasms caused by gas buildup in the digestive tract. The individual may experience both constipation and diarrhoea, or only one of them. There is some evidence that certain meals, stressful situations, and mental health issues can all exacerbate symptoms. Quality of life might suffer for those with IBS.

Treatment − Altering one's diet to include items that are less irritating to the digestive tract may help alleviate symptoms of irritable bowel syndrome (IBS). Possible medications include antispasmodics and SSRIs (selective serotonin reuptake inhibitors).

What is Lactose Intolerance

Lactose intolerance is a condition in which a person is unable to digest the carbohydrate lactose.

Causes − People with lactose intolerance may not produce enough of the enzyme lactase, which is essential for digesting lactose. The inability to digest lactose is a genetic trait that can be passed down through generations. Thus, it is possible that the parents are carriers who unwittingly pass on the genes that reduce lactose synthesis. Infections can also cause intestinal damage.

Diagnosis − Clinical examination, symptom recording, and family history along with a hydrogen breath test can arrive at a diagnosis.

Symptoms and complications − Some symptoms of lactose intolerance, such as bloating, stomach cramps, diarrhoea, and nausea, are shared with other illnesses. Unlike other ailments, however, the symptoms manifest exclusively after consuming lactose-containing dairy products. Osteopenia and osteoporosis can develop when the body does not get enough calcium from the diet.

Treatment − Patients should be educated on what foods to avoid to alleviate their conditions. While avoiding dairy products is simple, lactose may be found in unexpected places. If you want to avoid foods that contain lactose, read the labels. Sometimes it helps to take lactase enzyme supplements before meals.

Differences between Irritable Bowel Syndrome and Lactose Intolerance

The following table highlights the major differences between Irritable Bowel Syndrome and Lactose Intolerance −


Irritable Bowel Syndrome

Lactose Intolerance


Irritable bowel syndrome (IBS) is a medical condition associated with the function of the intestinal muscles.

Lack of the enzyme lactase causes lactose intolerance, which prevents its digestion.


Genes, stress, and depression have all been implicated as potential causes of irritable bowel syndrome.

Insufficient levels of the enzyme lactase are responsible for lactose intolerance.

Risk factors

If you are depressed or anxious, have a family history of IBS and are younger than 49, you may be more susceptible to developing irritable bowel syndrome.

Premature birth, celiac disease, Crohn's disease, and other inflammatory bowel disorders increase the likelihood of lactose intolerance.

Chief digestive symptoms

The motility symptoms of IBS can be either diarrhea or constipation, or sometimes both.

Diarrhea, but never constipation, is the hallmark of lactose intolerance.

Functional disorder or not

IBS is a functional disorder with the intestine's muscles.

Lactose intolerance is caused by the indigestion of the carbohydrate lactose, rather than the muscles.


Irritable bowel syndrome (IBS) treatment involves antispasmodic and SSRI medication, as well as a change in lifestyle that reduces stress.

The symptoms of lactose intolerance can be alleviated by avoiding lactose-containing meals and replacing lactase enzyme with a supplement, or by eliminating the cause of the intolerance.


In this article, we discussed the causes, the risk factors, the symptoms, and the treatments of Irritable Bowel Syndrome and Lactose Intolerance.

Updated on: 23-Jan-2023


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