LCT Gene: How Your Body Breaks Down Lactose
- GenesUnveiled Editorial Team
- Dec 12
- 1 min read
The LCT gene provides instructions for producing lactase, the enzyme responsible for digesting lactose—the sugar found in milk and dairy products. Differences in how the LCT gene is regulated largely determine whether someone maintains lactase activity into adulthood or develops lactose intolerance [R].
You can analyze how your LCT gene behaves by checking your DNA at GenesUnveiled.
How the LCT Gene Influences Digestion
The LCT gene controls the production of lactase in the small intestine. Its activity determines [R, R]:
How efficiently you break down lactose
Whether undigested lactose reaches the colon
Your likelihood of experiencing bloating, gas, or discomfort after dairy
How your gut microbiome responds to dairy sugars
In most humans, lactase activity naturally decreases after childhood. In others, the LCT gene remains active throughout adulthood, allowing continued lactose digestion.
Several well-studied genetic variants—such as rs4988235 and rs182549—affect LCT gene expression, but the biology itself is consistent: stable lactase production supports easier dairy digestion.
What This Means for Your Gut Health
Dairy tolerance
Digestive comfort
Microbial fermentation patterns
The amount of lactose reaching the colon
Your nutritional response to dairy foods
Lactase persistence is not inherently “good” or “bad”—it simply reflects how your digestive system handles lactose.
Explore Your Full Gut-Health Genetics
The LCT gene is one part of a larger digestive network involving FUT2, MUC2, IL10, DAO, and other pathways related to gut function and inflammation.
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