Diet and Nutrition

Lactose Intolerance vs. IBS

Know the differences between these disorders to find relief and effective treatment.

Lactose Intolerance vs. IBS


Irritable bowel syndrome (IBS) is a gastrointestinal (GI) disorder that can be mistaken for lactose intolerance and other digestive issues. Know the differences between these disorders to find relief and effective treatment. 

Irritable bowel syndrome (IBS) has a variety of potential causes. However, in most cases, it is triggered by the consumption of certain types of food. Its reaction tends to be similar to food allergies. This condition also affects people differently. Some people may only have mild IBS, while others have severe symptoms, which significantly disrupt daily life. Stress can also contribute to episodes of IBS. 

Around 1 out of 5 people have IBS, which often develop between the ages 20-30. The symptoms of IBS are often experienced long-term. However, there are also people who get long remission periods with mild to severe symptoms. 

When it comes to lactose intolerance, a sugar found in milk and other dairy products called lactose is not properly digested. Lactose intolerance is due to a deficiency in lactase, which is an enzyme produced in the small intestine that helps digest lactose into glucose and galactose for absorption. However, there are also many people who can still digest milk and dairy products even with low levels of lactase. People who tend to experience symptoms right after eating dairy foods truly have lactose intolerance. 

Lactose Intolerance vs. IBS

Sometimes, milk and other dairy products can trigger the symptoms of IBS. However, according to gastrointestinal (GI) specialists, there is a direct link to lactose intolerance when it comes to milk sensitivity. 

Lactose intolerance is certainly not IBS. However, it can be hard to keep track of everything we eat on a daily basis, especially for those with busy lives. Thus, it can be difficult to determine which type of GI disorder we have. However, IBS should be considered if you have symptoms of lactose intolerance and have cut out all possible dairy products in your diet, but still experience digestive issues. 

IBS is one of the most common disorders diagnosed by gastroenterologists. This GI condition accounts for approximately 12 percent of visits in primary care. However, many people cannot easily recognize IBS symptoms in spite of its prevalence.  

Signs and Symptoms

IBS flare-ups may be experienced from time to time. Relief from its symptoms can be achieved within days, weeks, or months, and then come back again after some time. For some people, their symptoms tend to subside for months at a time.

The following are some of the most common symptoms of IBS:

Other symptoms people may experience in IBS include:

The symptoms of IBS can significantly affect people’s daily lives, making them more prone to developing depression and anxiety

For people with lactose intolerance, symptoms are often experienced immediately after drinking or eating foods that contain lactose. They include:

  • Milk
  • Yogurt
  • Cheese
  • Butter
  • Margarine
  • Whipping cream
  • Ice cream
  • Custards
  • Coffee creamers
  • Puddings
  • Cream soups
  • Baked goods (bread, cakes, cookies, etc.)
  • Pancake mixes
  • Drink mixes
  • Breakfast cereals
  • Salad dressings
  • Deli meats

The following are the common symptoms of lactose intolerance:

  • Nausea
  • Vomiting
  • Gas
  • Bloating
  • Stomach cramps

Although lactose intolerance is not a serious medical condition, people who have it may feel uncomfortable and stressed. 

So, what exactly causes IBS?

The specific cause of IBS is not fully understood. Before, experts believed that the condition was stress-induced. Although stress is one of the contributing factors of IBS, scientists now believe that a disturbance on how the brain and stomach interacts may play a role in IBS.

The complex system of the gastrointestinal (GI) tract includes nerves that communicate with the brain, spinal cord, and other organs in the body. The colon or large intestine interacts by relaxing or contracting muscles.

After nutrients have been absorbed, strong contractions enable the movement of waste through the body. However, people who have IBS unusually have active nerves that control these muscles. Spasms are often triggered by certain stimulators, such as:

  • Stress
  • Hormonal fluctuations
  • Certain medications
  • The consumption of certain types of food

In some cases, these spasms can cause rapid movement of stool and cause diarrhea, while sometimes, the stool stays in the large intestine and cause constipation. 

To detect lactose intolerance, you must keep track of the foods that you consume, particularly those with lactose content. After drinking or eating foods that have lactose, they go into the stomach for digestion. Lactose is then digested by lactase in the small intestine. When there are low levels of lactase, lactose moves into the large intestine, where gas and fatty acids are produced. When lactose is broken down in the large intestine, symptoms of intolerance occur. 

IBS Risk Factors

The symptoms that are similar to IBS can also be experienced by many people who don’t have the condition. People who are younger than 45 years old, especially women, are more prone to having an IBS diagnosis.

Other risk factors may include:

  • A history of depression and/or anxiety
  • A family history of IBS

Lactose Intolerance Risk Factors

  • Small intestine diseases
  • Asian, African, American-Indian, and Hispanic descent
  • Increasing age
  • Certain cancer treatments


To diagnose IBS, your doctor will initially ask you some questions to rule out other medical conditions. There two diagnostic guidelines for IBS based on symptoms.

Rome Criteria

In this guideline, certain symptoms must be present before an IBS diagnosis. These symptoms include:

  • Abdominal pain and discomfort (at least three days a month and within the last three months)
  • Improvement of defecation
  • Change in bowel habits (frequency and consistency of stool)

Manning Criteria

This guideline concentrates on pain relief after passing stools, incomplete bowel movements, changes in the consistency of stools, and mucus in stool. 

For lactose intolerance, doctors usually suggest the elimination of all foods that contain dairy in your diet. Taking notes or keeping a diary of the foods you consume can help monitor your dietary intake and symptoms.

There are also diagnostic tests for lactose intolerance. One of these tests is called the hydrogen breath test, which involves blowing in a balloon-like bag to check the level of hydrogen in the breath. A lactose solution is also consumed for further testing of breath. If the breath has high levels of hydrogen, it means that the patient has lactose intolerance.

Another test is a lactose intolerance test, which involves drinking a lactose solution and checking the level of glucose in the blood. If the blood glucose level does not rise, it means that the patient is lactose intolerant because the body is unable to digest or absorb lactose.  

Treatment Options

Mild symptoms of IBS can be easily treated by making lifestyle changes, dietary changes, and learning how to cope with stress. Other tips that can help you manage IBS symptoms include:

  • Drinking plenty of fluids
  • Getting enough sleep
  • Avoiding the consumption of foods that can trigger your symptoms
  • Regular exercise

The following foods can be problematic to people with IBS:

  • Broccoli
  • Cabbage
  • Cauliflower
  • Raw fruits
  • Fried and fatty foods
  • Chocolate
  • Spicy foods
  • Alcohol
  • Carbonated beverages

Lifestyle modifications may not be enough for some people with IBS. Fiber supplements are often used by people who are constipated, while antidiarrheal medications are used by those with constant bowel movements. There are also other types of medications that can help relieve painful spasms.

Both lactose intolerance and IBS are unpleasant since they can be distressing and painful. It is important to get a proper diagnosis to help manage these conditions. 


Lactose Intolerance.

Lactose Intolerance. (April 2018).

What is IBS? (June 2016).

Definition & Facts for Irritable Bowel Syndrome. (November 2017).

Is It IBS or Lactose Intolerance? (February 2018).