If milk, ice cream, or cheese leave you bloated and running to the bathroom, lactose intolerance may be the reason. It is one of the most common food sensitivities, and it happens when your body does not make enough of the enzyme that breaks down the sugar in dairy. The good news is that it is easy to identify and very manageable once you know what is going on. Here is how it works and what you can do about it.
What Lactose Intolerance Is
Lactose is the natural sugar in milk and dairy products. To digest it, your small intestine makes an enzyme called lactase. When you do not make enough lactase, undigested lactose moves into the colon, where bacteria ferment it and produce gas and fluid. That is what leads to the symptoms.
Symptoms
Symptoms usually start 30 minutes to a couple of hours after eating or drinking dairy, and they often include:
- Bloating and gas
- Stomach cramps
- Diarrhea
- Nausea
- A rumbling or gurgling stomach
How strong the symptoms are depends on how much lactase you make and how much dairy you eat. Many people can handle small amounts without trouble.
Lactose Intolerance Is Not a Milk Allergy
These two are often mixed up, but they are different. Lactose intolerance is a digestive problem caused by a missing enzyme. A milk allergy is an immune reaction to the protein in milk, and it can cause hives, swelling, or trouble breathing. A milk allergy can be dangerous, while lactose intolerance is uncomfortable but not harmful in that way.
What Causes It
The most common form develops naturally with age, as the body makes less lactase over time. It runs in families and is more common in some ethnic groups. Lactose intolerance can also appear after an illness or condition that affects the small intestine, such as a stomach bug, celiac disease, or Crohn's disease. When it follows another condition, treating that condition can sometimes bring the tolerance back.
How It Is Diagnosed
Often the pattern is clear from your symptoms, but testing can confirm it. The most common test is a hydrogen breath test, where you drink a lactose solution and we measure the gas in your breath over a couple of hours. A simple step is to remove dairy for a couple of weeks and see if symptoms settle, then add it back. If your symptoms are not clearly from dairy, I may also check for celiac disease or IBS, which can feel similar.
Managing Your Diet
- Choose lactose-free products, which taste like regular dairy but have the lactose already broken down.
- Try lactase supplements taken right before a meal with dairy.
- Start with smaller portions, since many people tolerate a little dairy, especially with other foods.
- Pick lower-lactose options like hard cheeses and yogurt, which are often easier to digest.
- Watch for hidden lactose in baked goods, sauces, processed foods, and some medications.
- Get enough calcium and vitamin D from non-dairy sources or supplements so cutting back on dairy does not affect your bones.
When to See a Doctor
See a gastroenterologist if your symptoms are severe, if avoiding dairy does not help, or if you also have weight loss, blood in your stool, or symptoms that wake you at night. Those point to something other than lactose intolerance and are worth a closer look.
Talk to a Gastroenterologist in Mountainside, NJ
If your symptoms keep coming back or you are not sure what is causing them, Dr. Amber Khan can help. We see patients from across Union County and New Jersey.