Lactose intolerance is a common condition where the body has reduced ability to digest lactose, the sugar in milk and many dairy products. It often causes digestive symptoms after consuming dairy, such as bloating, gas, abdominal pain, and diarrhea. Here’s how to tell if you might have it and what to do next. What symptoms to look for
- Bloating, gas, and abdominal discomfort after dairy products
- Diarrhea or loose stools following dairy intake
- Nausea or stomach cramps within a couple of hours after consuming lactose-containing foods
- Symptoms that improve when dairy is avoided and recur when dairy is reintroduced
Ways to determine if you’re lactose intolerant
- Dairy elimination trial: Remove most or all dairy from your diet for 1–2 weeks and monitor whether symptoms improve. If symptoms improve, reintroduce dairy to see if symptoms return.
- Lactose-containing challenge: After an elimination period, reintroduce dairy and observe whether symptoms reappear.
- Medical testing: If symptoms persist or you want confirmation, a clinician can order tests such as a hydrogen breath test or a lactose tolerance test. These are standard, non-invasive tests used to diagnose lactose intolerance.
Important distinctions
- Lactose intolerance is not the same as a milk allergy. A milk allergy involves the immune system and can cause reactions beyond digestive symptoms, such as hives or swelling, and is more common in children. Lactose intolerance is due to the digestive system’s ability to break down lactose and does not involve an immune reaction.
- Lactose intolerance can vary by degree. Some people tolerate small amounts of dairy, while others may need to avoid most dairy to prevent symptoms.
What you can do now
- Try a dairy-elimination approach for a short period and monitor symptoms.
- If you suspect dairy is the culprit, look for lactose-free or reduced-lactose dairy products, or try alternative calcium sources (fortified plant milks, leafy greens, almonds, tofu with calcium, and fortified cereals).
- Consider talking to a healthcare provider or a registered dietitian, especially if you have other dietary restrictions (vegetarian, vegan) or need guidance on meeting calcium and vitamin D needs without lactose.
When to seek medical advice
- If you have persistent or severe symptoms, or if you experience unintended weight loss, persistent vomiting, or severe dehydration.
- If you have a family history of other digestive conditions and are unsure about the cause of your symptoms.
- If you’re unsure how to manage your diet to maintain nutrition while avoiding dairy.
Notes on diagnostic tests
- Hydrogen breath test and lactose tolerance blood tests are common diagnostic options used by clinicians to confirm lactose intolerance. Your doctor can discuss which test is appropriate for you based on your symptoms and medical history.
If you’d like, share a brief description of your typical dairy intake and symptoms (timing, severity, and any other foods that trigger symptoms). I can help you interpret what that pattern might suggest and outline a practical plan to try at home or discuss with a healthcare professional.
