Lactose intolerance living in adults

Overview

Lactose intolerance means your body has trouble digesting lactose, a sugar found in milk and other dairy products. This can cause uncomfortable digestive symptoms after eating dairy.

Yes, lactose intolerance is very common. In some populations, most adults have it to some degree.

It can affect anyone, but it is more common in people of East Asian, West African, Arab, Jewish, Greek, Italian, and Hispanic ancestry. It often starts after age 2 but can develop at any age.

Symptoms

Common symptoms

• Bloating and gas
• Stomach cramps or pain
• Diarrhea or loose stools
• Nausea, sometimes vomiting
• Rumbling sounds in your stomach

Symptoms in children

• Bloating and gas
• Diarrhea
• Fussiness or crying after eating dairy
• Poor weight gain or growth

Symptoms in older adults

• Same as common symptoms, but may be more severe
• Loss of appetite
• Unintended weight loss
• Dehydration from diarrhea

Causes

Main causes

• Your body does not produce enough lactase, the enzyme that breaks down lactose in your small intestine.
• Genetics — some people inherit a condition where lactase production decreases naturally after childhood.
• A temporary drop in lactase after a stomach infection, surgery, or damage to the small intestine.

Risk factors

• Family history of lactose intolerance
• Being of East Asian, West African, Arab, Jewish, Greek, Italian, or Hispanic ancestry
• Having a digestive disease like Crohn's or celiac disease
• Aging (lactase levels often drop over time)

When to see a doctor

See a doctor urgently if:

• Severe pain or bleeding (call your local emergency number)
• Signs of dehydration from vomiting or diarrhea

Book a routine appointment if:

• Persistent digestive symptoms after eating dairy
• You are losing weight without trying
• You want to confirm the cause of your symptoms

Diagnosis

Your doctor will ask about your symptoms, diet, and medical history. They may recommend avoiding dairy for a while to see if symptoms go away.

Tests that may be done

• Hydrogen breath test — measures the amount of hydrogen in your breath after drinking a lactose solution.
• Lactose tolerance test — checks your blood sugar levels after drinking lactose.
• Stool acidity test — used mainly for babies and children.

What to expect at your appointment

If tests are needed, they are usually done in a clinic or hospital. You may be asked to stop eating and drinking for a few hours before. The results help your doctor confirm the diagnosis.

Treatment

Treatment focuses on managing symptoms by limiting or avoiding lactose in your diet. Most people find relief with simple diet changes.

Self-care at home

• Avoid large servings of milk, ice cream, or soft cheeses.
• Try lactose-free or low-lactose dairy products (such as lactose-free milk).
• Eat smaller amounts of dairy spread throughout the day.
• Take over-the-counter lactase enzyme supplements (follow the package instructions).
• Keep a food diary to find out how much lactose you can handle.

Medical treatments

If diet changes are not enough, a doctor may recommend a strict lactose-free diet for a short time or prescribe medications that help with symptoms. Always talk to your doctor before starting any new treatment.

Living with this condition

Living with lactose intolerance means being mindful of what you eat and drink. Read food labels carefully — lactose is in many processed foods, like bread, cereal, salad dressing, and even some medications.

Lifestyle tips

• Plan your meals and snacks to include dairy alternatives.
• Communicate your needs when eating out or at social events.
• Carry lactase supplements if you think you might eat dairy.
• Build a support network of family or friends who understand.

Diet and exercise

You can still get enough calcium and vitamin D from lactose-free milk, fortified plant milks (like soy or almond milk), leafy greens, canned fish with bones, and supplements. Staying active with walking, swimming, or strength training helps keep your bones strong.

Mental health and emotional wellbeing

It can be frustrating to adjust your diet or worry about symptoms in social settings. It is normal to feel anxious or embarrassed sometimes. Talk to a friend, family member, or a health professional if it bothers you.

Prevention

Lactose intolerance cannot be prevented, but you can keep symptoms under control by managing your diet and knowing your limits.

Complications

If left untreated

• Ongoing diarrhea can lead to dehydration and loss of important minerals.
• Not getting enough calcium over time may increase your risk of weak bones (osteoporosis).
• Poor weight gain or growth in children.

Long-term outlook

With simple diet changes, most people with lactose intolerance lead a normal, healthy life. Your body can still get all the nutrients it needs. The outlook is very good.

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