What Does Lactate Do for Lactose Intolerance? Clarifying the Confusion

October 19, 2025 •

4 min read

Affecting roughly 70% of the world's population, lactose intolerance is a widespread condition caused by a deficiency of the enzyme lactase. While many people are aware of lactase supplements, there is often confusion about the role of lactate, a different compound entirely. Understanding the specific function of both lactase and lactate is key to effectively managing lactose intolerance symptoms and improving digestive comfort.

Quick Summary

This article clarifies the difference between lactase, the enzyme needed to break down milk sugar (lactose), and lactate (lactic acid), a byproduct of bacterial fermentation. We explore how undigested lactose in the colon leads to the production of gas and lactate, causing uncomfortable symptoms. We then discuss how probiotic lactic acid bacteria can mitigate these symptoms by breaking down lactose or producing lactate more efficiently, which beneficial gut bacteria can then use.

Key Points

Lactase vs. Lactate: Lactase is the enzyme that breaks down lactose, while lactate is a byproduct of its fermentation, a crucial distinction for managing intolerance.
Source of Symptoms: Undigested lactose fermented by bacteria in the colon produces gas and lactate, causing common symptoms like bloating and diarrhea.
Probiotics are Key: Probiotic lactic acid bacteria, found in fermented foods, can help manage symptoms by producing their own lactase or by fermenting lactose into lactate rather than gas.
Fermented Foods Offer Relief: Products like yogurt and aged cheese are often better tolerated because their lactose content is already reduced by bacterial fermentation.
Adaptation is Possible: Regular consumption of small amounts of dairy or probiotic-rich foods can promote colonic adaptation, improving the gut's ability to handle lactose over time.
Tailored Strategy: Effective management often involves a combination of strategies, including lactase supplements for high-lactose meals and incorporating probiotic-rich foods for long-term gut health.

The Crucial Difference: Lactase vs. Lactate

The fundamental cause of lactose intolerance lies in a deficiency of the digestive enzyme lactase. This enzyme is naturally produced in the small intestine and is responsible for breaking down lactose, the sugar found in milk and dairy products, into simpler, more easily absorbable sugars: glucose and galactose.

When there isn't enough lactase, undigested lactose travels to the large intestine. Here, it is fermented by the resident gut bacteria. This fermentation process creates several byproducts, including gases (like hydrogen, methane, and carbon dioxide) and lactate, or lactic acid. It is this bacterial fermentation in the colon—and the byproducts it creates—that causes the unpleasant symptoms of lactose intolerance, such as bloating, abdominal pain, and diarrhea. Lactate itself does not solve lactose intolerance; rather, it is part of the problem, an indicator of improper digestion.

The Function of Lactic Acid Bacteria (LAB) in Managing Intolerance

Paradoxically, while lactate is a byproduct of poor digestion, certain lactic acid bacteria (LAB) can be beneficial for those with lactose intolerance. These are the probiotic bacteria found in fermented foods like yogurt, kefir, and sauerkraut. They can help manage symptoms in two main ways:

Providing the enzyme: Some probiotic strains, particularly certain Lactobacillus and Bifidobacterium species, possess their own beta-galactosidase enzyme, which is a form of lactase. When ingested, these bacteria can help break down lactose in the gut, reducing the amount that reaches the colon undigested.
Modifying the fermentation process: Certain LAB convert lactose into lactic acid rather than gas. While this still results in lactate, it significantly reduces the amount of gas produced, which is a major contributor to bloating and flatulence. Furthermore, the resulting lactate can be utilized by other beneficial gut bacteria, leading to a healthier overall gut microbiome.

Lactase Supplements vs. Lactic Acid Bacteria: A Comparison


Feature	Lactase Supplements (e.g., Lactaid)	Probiotic Lactic Acid Bacteria (in fermented foods)
Primary Mechanism	Directly supplements the missing lactase enzyme in the small intestine.	Introduces beneficial bacteria that can either produce lactase or ferment lactose more favorably.
Timing	Must be taken just before consuming dairy.	Effectiveness may build over time with regular consumption, promoting colonic adaptation.
Dairy Type	Designed to help with fresh dairy products like milk.	Especially effective in fermented products like yogurt and kefir, where much of the lactose is already broken down.
Longevity of Effect	Provides temporary relief; another dose is needed for the next dairy meal.	May provide longer-term improvement through changes to the gut microbiome.
Overall Gut Health	Focuses on lactose digestion only.	Can provide broader benefits to gut health and the immune system.

The Science of Colonic Adaptation and Fermented Dairy

For many lactose-intolerant individuals, consuming fermented dairy products like yogurt and aged cheese is often more manageable than drinking fresh milk. This is because the bacteria used in the fermentation process have already broken down a significant portion of the lactose. Aged cheeses, for instance, have very little lactose remaining.

Beyond just the reduced lactose content, regular consumption of these foods can lead to a phenomenon known as colonic adaptation. This refers to the process where the gut microbiome becomes more efficient at handling lactose, leading to fewer symptoms over time. Some studies suggest that the regular intake of fermented dairy introduces beneficial bacteria that can improve the overall ability to process lactose and reduce discomfort. This creates a more symbiotic relationship within the gut, where microbes help manage what the body cannot properly digest on its own.

Practical Dietary Strategies for Lactose Intolerance

Managing lactose intolerance can involve a combination of approaches. Here are some strategies:

Small, regular doses: Some research indicates that consuming small, regular amounts of dairy can help the gut adapt over time. Start slowly and monitor your body's reaction.
Choose fermented products: Opt for yogurt and kefir, which contain beneficial bacteria that aid in digestion. Studies have shown probiotic yogurt can significantly reduce lactose intolerance symptoms like bloating and flatulence.
Use lactase supplements: For meals or drinks containing high amounts of fresh dairy, an over-the-counter lactase supplement can be very effective when taken just before eating.
Explore prebiotics: Feeding the beneficial lactic acid bacteria with prebiotics (fiber that promotes their growth) can further support a healthier, more adaptable gut microbiome.
Consider low-lactose alternatives: Many lactose-free milk, cheese, and ice cream products are available, providing a convenient alternative for dairy enjoyment.

Conclusion

To manage lactose intolerance effectively, it is essential to distinguish between lactase and lactate. Lactase is the enzyme you need more of, while lactate is a byproduct of the digestive problem. The solution lies not in consuming lactate directly but in introducing beneficial lactic acid bacteria, which can either supply the lactase you lack or create a more favorable environment in your gut. By incorporating probiotics through fermented foods or supplements and understanding the specific roles of these compounds, individuals can significantly alleviate their symptoms and enjoy a wider range of foods.

[Authoritative outbound link: https://www.ncbi.nlm.nih.gov/books/NBK532285/ on Lactose Intolerance from StatPearls - NCBI Bookshelf].

Frequently Asked Questions

No, lactate and lactase are two different things. Lactase is the enzyme that digests lactose (milk sugar). Lactate, or lactic acid, is a byproduct created when gut bacteria ferment undigested lactose in the colon.

Yes, many people with lactose intolerance can tolerate fermented dairy products like yogurt and kefir more easily than fresh milk. This is because the bacteria used in fermentation have already broken down much of the lactose.

Lactase supplements, like Lactaid, provide the enzyme needed to digest lactose and are effective for many people. However, results can vary depending on the severity of the intolerance and the amount of dairy consumed. They work best when taken just before eating dairy.

Probiotics, particularly certain lactic acid bacteria, can help by providing their own lactase enzyme to aid digestion or by fermenting lactose in a way that produces less gas, thereby reducing symptoms like bloating.

Colonic adaptation is the process where the gut microbiome adjusts to handle lactose more effectively over time. By regularly consuming small amounts of lactose or probiotic-rich foods, the gut's bacterial population can adapt, leading to reduced intolerance symptoms.

During the aging process of cheese, the bacteria involved break down the remaining lactose. Hard, aged cheeses contain very little lactose, making them a safe option for many with lactose intolerance.

No, taking a probiotic cannot cure lactose intolerance, as the genetic lactase deficiency remains. However, probiotics can help manage and reduce the severity of symptoms by improving how the gut processes lactose.