Can Lactose Intolerance Cause Constipation?

 by Dr. Steve Hruby, D.C.
Reviewed by Dr. Steve Hruby, D.C.

SuperHumans are the toughest, fittest, healthiest and happiest human beings on this planet. My mission is to help you realize your superhuman potential and learn how to live a long, happy and healthy life.

  Fact Checked
 by Rhealyn Tropia, RMT
Reviewed by Rhealyn Tropia, RMT

I’m a content organizer, fact-checker and super mom who ensures content is medically-reviewed, highly accurate, and engaging. My passion is organizing information and ensuring the facts are presented in a manner that is interesting and easy to understand.

can lactose intolerance cause constipation

Can you imagine that 36% of Americans suffer from lactose intolerance? How about 68% for worldwide statistics? Primary lactose deficiency, an inherited genetic problem, is a leading cause of this condition.

While intolerance is harmless, there’s no telling the amount of discomfort binging on your favorite yogurt or milk can cause. This problem leads to many gastrointestinal woes, including bloating, gas, and diarrhea.

But can lactose intolerance cause constipation?

While not common, constipation may arise from lactose intake when intolerant. However, you are more likely to get diarrhea than have “durians” shooting from your guts.

Does that mean you should quit taking your dearest lactose-infused foods? Dive in to discover that, plus how lactose intolerance results in constipation and how to handle constipation. 

Constipation and Lactose Intolerance

With lactose intolerance, the body lacks the enzyme lactase, which is crucial in lactose breakdown.

The unabsorbed lactose travels to the colon and undergoes fermentation by gut bacteria. This fermentation process results in increased methane production.

According to a study, methane gas tends to slow food movements in the gut for some. A slackened digestion process may cause constipation.

Another study, highlighted that about one in three people with lactose intolerance might experience constipation. However, it noted that lactose intolerance poop is more likely to be watery (70%), than hard.

That said, studies on methane-induced constipation are mostly on those with gastrointestinal conditions like bacterial overgrowth and spastic bowel (IBS). Hence, many don’t associate constipation and lactose intolerance, though it could be a symptom.

Other Common Lactose Intolerance Symptoms

Besides constipation, those with trouble absorbing lactose can experience the following effects after intake.

woman with headache

1. Abdominal pain: The intensity varies from minor to severe. It can occur anywhere in the abdomen, including the upper, lower, left, right, or even at the center. It may also include bloating, gas, and cramping.

2. Diarrhea: Lactose intolerance may cause loose, watery stools as it may increase the liquid in your gut. Diarrhea may appear anywhere from 0.5 to two hours after consuming dairy.

For one to develop diarrhea from only-lactose intolerance, they’ll need to take at least three or more cups of dairy. And none of that lactose should get digested by the time it reaches your colon.

However, healthy people get up to 20% of undigested carbohydrates in their colons. So, the more carbohydrates you take, the less lactose you need to increase diarrhea chances.

3. Nausea: The feeling of an incoming vomit can present in those with lactose intolerance, along with a sense of fullness and bloating. The severity varies, with nausea lasting from a few minutes to several hours. Some may also vomit.

4. Gas and bloating: Due to fermented lactose, there may be increased methane production causing flatulence and bloating. The condition may also lead to increased water, further distending one’s stomach.

5. Pains: Some lactose-intolerant people experience headaches after consuming dairy products. Others may even have migraines. The condition may also cause joint stiffness and muscle pains.

6. Fatigue: Fatigue is a common symptom of allergies and intolerances, including lactose. Individuals may feel a drain on their energy and more tiredness than usual.

7. Borborygmus: The fermentation of undigested lactose might result in this rumbling or gurgling sensation in the abdomen. Abdominal pain, bloating, and distention are frequently present with borborygmus.

8. Reduced concentration: The body has to work harder to digest the lactose. The strain and reactions leave you feeling more tired, uncomfortable, and less able to concentrate.

Here’s a table summary of how likely one may experience symptoms from lactose intake when they’re intolerant.

SymptomLikelihood (%)
Abdominal pain100
Gas and bloating100
Reduced concentration82
Nausea and vomiting78
Stiff joints71
Muscle pain71
Long-term fatigue63
Allergic reactions40
Mouth ulcers30

Factors Attributed to Constipation

Amongst the lactose-rich foods are dairy, which when taken by lactose intolerance individuals may present issues like constipation. But, if you don’t have this condition, can dairy make you constipated?

people holding ice cream cone

Dairy is high in fat and tough proteins like casein, which can slacken digestion. These elements, in combination with other factors like a lack of fiber, can contribute to constipation.

Also, too much dairy can cause bloating and gas, affecting bowel movements.

That said, lactose, if at all, is a minor contributor to constipation. So, what is likely to give you constipation?

Constipation can arise from illnesses, medications, and personal lifestyles, among other risk factors.

1. Issues With Excrement Muscles

Damaged bowel movement muscles may cause longer stool retention that increases constipation likelihood. This damage may result from

  • Anismus
  • Dyssynergia
  • Pelvic muscle weakness

2. Gut Blockages

A blocked gut leads to reduced food movement speed. That may cause stool drying and constipation. Gut blockages may arise from

  • Rectocele
  • Anal fissures
  • Colon narrowing
  • Bowel obstruction
  • Rectal and colon cancers

3. Nerves System Issues Around the Gut

Issues with nerves around one’s rectum or colon may affect their functioning. Improper functioning may interfere with bowel movements, which may result in constipation. Nervous damage may arise from

  • Stroke
  • Lupus
  • Spinal injury
  • Multiple sclerosis
  • Parkinson’s disease,
  • Autonomic neuropathy

4. Hormone Disruptive Conditions

Some illnesses may disrupt hormones leading to imbalances. Hormonal disruptions impair body functions resulting in several effects like constipation. Some conditions that may cause hormonal imbalance are

  • Diabetes
  • Pregnancy
  • Hypothyroidism
  • Pituitary tumors
  • Hyperparathyroidism
  • Prader-Willi syndrome
  • Hereditary pancreatitis,
  • Endocrine gland injury

5. Certain Medications

Some medications increase your likelihood of getting constipated, including

man holding pill container and white pills
  • Anti-seizure medicines
  • Anti-nausea medicines
  • Allergy drugs like antihistamines
  • Psychiatric drugs like clozapine and olanzapine
  • Tricyclic antidepressants and reuptake inhibitors
  • Some blood pressure drugs like beta and channel blockers
  • Nonsteroidal anti-inflammatory medications like naproxen and ibuprofen
  • Strong painkillers like those containing oxycodone, hydromorphone, and codeine.

6. Other Predisposing Factors

Other factors that raise your chances of getting constipation include:

  • Travelling
  • Being older
  • Being a lady
  • Dehydration
  • Low-fiber diet
  • Inadequate exercise
  • Ignoring defecation urges
  • Mental health concerns like eating disorders and depression

How To Treat and Prevent Constipation

While you may have low control of some predisposing factors like illnesses, there are many constipation risk factors you can address. The right diet in proper amounts and adequate exercise, among other lifestyle factors, help reduce your chances of constipation.

Here are some ways you can treat constipation and avoid it.

Adjust your diet: You may experience less constipation if you increase your fiber intake. Consuming more fiber-rich foods including beans, whole grains, fruits, and veg might aid in maintaining a normal gastrointestinal system.

Additionally, remember to stay sufficiently hydrated throughout the day as dehydration might exacerbate the issue.

Get active: Regular exercise can help you have more regular bowel movements by stimulating your digestion. Do moderate exercises for at least 30 minutes daily.

Take probiotics: Probiotics are living bacteria that are good for the gut. By taking them, you can maintain your digestive system working efficiently and avoid constipation.

Try laxatives: These over-the-counter medications can help you ease constipation. It’s crucial to use them only as instructed and when necessary.

Try bowel training: A regular toilet regimen may help reduce constipation.   Try pooping at the same time daily, and don’t rush through it.

FAQS: What’s Everyone Asking About Lactose Intolerance Constipation?

a glass of milk

How Long Does Lactose Intolerance Constipation Last?

Lactose intolerance constipation lasts for up to two days. And what about other lactose-induced problems? How long do the symptoms of lactose intolerance last? They also last about the same time, though durations vary slightly between symptoms. 

What about other conditions like gluten intolerance? Check out our guide on celiac disease vs lactose intolerance to see similarities and differences.

What Foods Are Most Likely To Cause Constipation?

The least productive and more problematic foods are most likely to cause constipation. Avoid alcohol, fried junk, and fast foods.

Moreover, processed products, persimmons, red meats, gluten-rich foods, and dairy products may lead to constipation.

Is Yogurt Good for Constipation?

Yogurt is good for constipation, but not all kinds are ideal for everyone. Those with lactose intolerance should get lactose-free yogurt. This food abounds in probiotics that nourish guts and support their functions.

Can Lactose Free Milk Cause Gas?

Moderate consumption of lactose-free milk cannot cause gas unless it features additives like guar gum. While often in plant-based dairy alternatives like soya, some brands add guar gum to milkshakes and other milk products like yogurt and ice cream.

Can Lactaid Milk Cause Constipation

Lactaid milk cannot cause constipation. It also is excellent for those with lactose intolerance as it lacks lactose.


When the digestive tract moves food slower than usual, it can become dry and challenging to pass, resulting in constipation. Lactose intolerance may come with constipation because of an accumulation of undigested lactose in the intestines, which causes fermentation.

Lactose fermentation raises methane production, which may cause bloating and abdominal pain. Some studies also link this gas to constipation.

People with lactose intolerance should avoid lactose-rich products to reduce the risk of constipation.

More importantly, ensure your lifestyle supports proper gut functioning. Have ample exercise and take medications if necessary. Avoiding alcohol, processed foods, and fried meals helps.

Finally, boost your nutrition with superb supplements and friendly fiber-rich foods and beverages that support gut health.

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