Lactase is a crucial enzyme produced in the small intestine, responsible for breaking down lactose into simpler sugars: glucose and galactose. When lactase levels are insufficient, undigested lactose travels to the large intestine, where bacteria ferment it, creating gases and fluids that cause gastrointestinal distress. This low lactase activity, and the resulting inability to digest lactose, defines the condition known as lactose intolerance.
The Difference Between Lactase Deficiency and Lactose Intolerance
While often used interchangeably, there is a technical difference between lactase deficiency (the physiological cause) and lactose intolerance (the symptomatic result).
- Lactase Deficiency: This refers to the root cause—the lack of the enzyme lactase in the small intestine. It is the most important factor contributing to the condition.
- Lactose Intolerance: This describes the symptoms that occur when an individual with lactase deficiency consumes lactose. Everyone with lactose intolerance has some degree of lactase deficiency, but not everyone with low lactase experiences significant symptoms.
Types of Lactase Deficiency
Low lactase is not a one-size-fits-all condition; it can be categorized into four main types, each with a different underlying cause.
Primary Lactase Deficiency
This is the most common form of the condition and is genetically determined. It is often referred to as lactase non-persistence. In infancy, lactase production is high, as it is necessary for digesting milk. However, as a person ages and milk is replaced by other foods, lactase production naturally decreases. In individuals with primary lactase deficiency, this decline is more pronounced, leading to symptoms in adolescence or adulthood.
Secondary Lactase Deficiency
This type results from damage to the small intestine lining, where lactase is produced. Illnesses, surgery, or injuries can cause this damage.
- Associated diseases: Conditions such as celiac disease, Crohn's disease, and intestinal infections (like rotavirus) can trigger secondary lactase deficiency.
- Reversibility: Often, treating the underlying condition allows the small intestine to heal and lactase levels to be restored over time.
Congenital Lactase Deficiency
This is an extremely rare genetic disorder where an infant is born with little to no lactase production. This can cause severe diarrhea and malnutrition from birth if not diagnosed and managed promptly with a lactose-free diet.
Developmental Lactase Deficiency
This type is seen in premature infants. Lactase production begins late in the third trimester, so premature babies may have insufficient levels. This is usually a temporary problem that resolves as the infant's small intestine matures.
Symptoms and Diagnosis
The symptoms of low lactase are largely dependent on the amount of lactose consumed and the severity of the deficiency. Symptoms typically appear 30 minutes to 2 hours after consuming dairy.
Common symptoms include:
- Bloating
- Abdominal cramps and pain
- Diarrhea
- Gas
- Nausea or gurgling sounds in the abdomen
Diagnosis is typically achieved through one of the following methods:
- Hydrogen Breath Test: A patient drinks a lactose-rich liquid, and the amount of hydrogen in their breath is measured over time. High levels of hydrogen indicate that undigested lactose is being fermented by bacteria in the colon.
- Elimination Diet: For a period of a few weeks, a healthcare provider may recommend removing all dairy products to see if symptoms improve. Symptoms that return upon reintroduction of dairy suggest lactose intolerance.
Managing Lactase Deficiency
There is no cure for genetically determined lactase deficiency, but symptoms are highly manageable. Management strategies focus on dietary adjustments and supplements.
Dietary Adjustments
Most people with low lactase can tolerate a certain amount of lactose. Experimentation is key to determining personal tolerance levels.
- Limit Lactose Intake: Reduce or avoid foods with high lactose content, such as milk and ice cream.
- Choose Low-Lactose Foods: Hard, aged cheeses (like cheddar and parmesan) and yogurt often contain less lactose due to the fermentation process.
- Use Lactose-Free Products: Many grocery stores offer lactose-free milk, yogurt, and other dairy alternatives that have the lactase enzyme added to them.
- Combine with Meals: Consuming dairy with other foods can slow digestion and may reduce symptoms.
Enzyme Supplements
- Lactase Tablets: Over-the-counter lactase enzyme tablets can be taken just before consuming dairy to aid digestion. These supplements break down the lactose in the food, mimicking the function of natural lactase.
- Adding Drops to Milk: Lactase drops can be added directly to milk to break down the lactose before consumption.
Comparison of Dairy Products for Low-Lactase Individuals
| Dairy Product | Lactose Content | Tolerability | Notes |
|---|---|---|---|
| Milk (Cow's) | High | Low | Often a major trigger; lactose-free versions are available. |
| Hard Cheeses (e.g., Cheddar, Parmesan) | Very Low | High | Lactose is broken down during the aging process. |
| Yogurt | Moderate to Low | Moderate to High | The live active cultures help break down lactose. |
| Soft Cheeses (e.g., Cottage, Ricotta) | Moderate | Variable | Contains more lactose than hard cheeses, but often better tolerated than milk. |
| Butter | Trace | High | Mostly fat, with very little lactose. |
| Lactose-Free Milk | Zero | High | Lactase enzyme is added during processing. |
The Importance of Calcium and Vitamin D
For individuals with low lactase, avoiding dairy can sometimes lead to deficiencies in calcium and vitamin D. Both nutrients are essential for bone health. To prevent complications like osteopenia and osteoporosis, it is crucial to find alternative sources or consider supplementation.
- Calcium Sources: Include leafy green vegetables, almonds, fortified cereals, and canned fish with soft bones.
- Vitamin D Sources: In addition to fortified products, sources include eggs, fatty fish like salmon, and safe sun exposure.
Conclusion
When your lactase is low, it indicates a deficiency of the enzyme necessary to digest lactose, resulting in the gastrointestinal symptoms associated with lactose intolerance. This condition is common and, for many, a natural part of aging, though it can also be caused by intestinal damage or be present from birth. By understanding the specific type of deficiency and implementing dietary changes—such as consuming low-lactose products, using lactase supplements, and finding alternative nutrient sources—you can effectively manage the symptoms and maintain a healthy diet. Consulting a healthcare provider or a registered dietitian is the best way to develop an individualized plan for managing lactase deficiency and ensuring nutritional needs are met.
