Overview

Lactose intolerance is a common digestive condition in which the body has difficulty breaking down lactose, the natural sugar found in dairy products, due to low levels of the enzyme lactase. As a result, consuming dairy may lead to symptoms such as bloating, gas, abdominal discomfort, or diarrhea. While symptoms can be bothersome, lactose intolerance is not dangerous and can usually be managed effectively with dietary adjustments and, when needed, enzyme supplements.

What is Lactose Intolerance?

Lactose intolerance is the most common food intolerance worldwide and a frequent cause of digestive symptoms. It occurs when the body does not produce enough lactase, the enzyme required to digest lactose, the natural sugar found in dairy products such as milk, cheese, yogurt, and ice cream.

When lactose is not properly digested, it passes into the colon and can cause symptoms including bloating, gas, abdominal pain, and diarrhea. Lactose intolerance affects people of all ages and backgrounds, and symptoms can range from mild to severe depending on individual tolerance and the amount of lactose consumed.

What Are The Causes of Lactose Intolerance?

There are several reasons why lactase levels may be low:

• Primary lactase deficiency (most common): For most people, lactase production naturally decreases after early childhood. This is a normal, genetically programmed change that affects most of the world’s population. Symptoms may not appear until the teenage years or adulthood.
• Secondary lactase deficiency: Certain conditions that affect the small intestine, such as infections, celiac disease, Crohn’s disease, or intestinal surgery can temporarily reduce lactase production. Once the underlying condition is treated, lactose tolerance often improves.
• Congenital lactase deficiency (rare): In very rare cases, babies are born without the ability to produce lactase.

What Are The Signs And Symptoms of Lactose Intolerance?

Symptoms typically begin 30 minutes to 2 hours after eating or drinking foods containing lactose and may include:

• Bloating
• Gas
• Abdominal cramps or pain
• Nausea
• Diarrhea

The severity of symptoms varies from person to person and depends on how much lactose you consume and how much lactase your body produces. Many people can tolerate small amounts of lactose without any problems.

What Are The Risk Factors of Lactose Intolerance?

Lactose intolerance is highly prevalent worldwide, affecting approximately 65-75% of the global adult population, though prevalence varies substantially by ethnicity and geographic ancestry. In the United States, an estimated 30-50 million adults have lactose intolerance. Certain ethnic and racial populations are more widely affected than others.

Other risk factors include:

• Age: Lactase production naturally declines after childhood
• Conditions affecting the small intestine: Such as celiac disease, Crohn’s disease, or intestinal infections

How is Lactose Intolerance Diagnosed?

If lactose intolerance is suspected, one of the following tests may be recommended:

• Hydrogen breath test: This is the most commonly used test. Elevated levels of hydrogen in the breath after ingestion of lactose can represent insufficient digestion of lactose.
• Small bowel biopsy: Lactase deficiency can also be measured directly during an upper endoscopy with a small biopsy of the small intestine that can be analyzed to measure level of this enzyme.

What Are Possible Treatments For Lactose Intolerance?

Lactose intolerance is common and highly manageable. While there is no way to increase the body’s production of lactase, the enzyme needed to digest lactose, most people can control symptoms through simple dietary changes and, when needed, enzyme supplements.

Many older children and adults do not need to completely avoid dairy. Lactose tolerance varies from person to person, and many individuals can enjoy small amounts of dairy without symptoms.

Managing lactose intolerance often involves trial and error to identify which foods and portion sizes are best tolerated. Some people find they do well by choosing lower-lactose foods, eating dairy in smaller amounts, or spreading intake throughout the day.

For those who are sensitive to even small amounts of lactose or prefer more flexibility, lactase enzyme supplements are available without a prescription. These supplements help digest lactose and are typically taken just before eating dairy-containing foods.

Lactose-free and lactose-reduced dairy products, such as lactose-free milk and cottage cheese, are also widely available. These products provide the same nutrients as regular dairy and have a similar shelf life.

With the right approach, most people with lactose intolerance can manage symptoms effectively and maintain a balanced, enjoyable diet.

Balancing Nutritional Needs with Lactose Intolerance

Dairy products are a major source of important nutrients in the typical American diet, most notably calcium, which is essential for building and maintaining strong bones throughout life. Inadequate calcium intake can increase the risk of osteoporosis, a condition in which bones become thin and fragile.

For individuals with lactose intolerance, the goal is not simply to avoid dairy, but to ensure adequate calcium and vitamin D intake while minimizing symptoms.

Getting Enough Calcium Without Dairy

Many people with lactose intolerance worry about meeting their calcium needs. Fortunately, there are many low-lactose or lactose-free sources of calcium, including:

• Leafy green vegetables (such as kale, collard greens, and broccoli)
• Fish with soft, edible bones (such as canned salmon or sardines)
• Calcium-fortified foods and beverages
• Certain nuts, seeds, and legumes

With thoughtful meal planning, it is entirely possible to meet daily calcium requirements without consuming traditional dairy products.

Yogurt and Lactose Intolerance

Yogurt can be well tolerated by many people with lactose intolerance, despite containing lactose. The live bacterial cultures used in yogurt production help break down lactose, making it easier to digest. Individual tolerance varies, so small amounts are often a good place to start.

The Role of Vitamin D

Calcium is best absorbed when the body has adequate vitamin D. A balanced diet, safe sun exposure and, when appropriate, supplementation can help maintain healthy vitamin D levels.

Supplements and Professional Guidance

If there is concern about meeting calcium or vitamin D needs, your healthcare provider can determine whether supplementation is appropriate. Taking vitamins or minerals in incorrect amounts can be harmful, so guidance from a physician or registered dietitian is recommended. A dietitian can also help create a nutrition plan that maximizes nutrients while minimizing digestive discomfort.

With proper planning and guidance, most people with lactose intolerance can maintain excellent nutrition without unnecessary dietary restriction or discomfort.