What Is Lactose, Anyway?

Many dairy foods like milk, cheese and yogurt contain some lactose. We'll answer what is lactose, and if it's in all dairy products.

What Is Lactose?

Lactose is the natural sugar in cow’s milk, and milk products like yogurt, some cheeses and ice cream. If you cannot properly absorb lactose, it’s due to a lack of the enzyme, lactase. Lactase is necessary to break lactose down in the small intestine.

People without enough lactase have a condition known as lactose intolerance. If not properly absorbed, lactose passes into the large intestine where it’s fermented by intestinal bacteria. This fermentation process can cause uncomfortable symptoms, such as gas, bloating, abdominal pain and diarrhea.

Exactly what lactose is and what foods it’s found in, are common questions.

Does Lactose-Free Mean Dairy-Free?

If you discover you’re lactose intolerant, you’re probably wondering if you have to avoid dairy foods altogether. Contrary to popular belief, not all dairy products contain lactose. The good news is, if you are avoiding lactose you do not have to go completely dairy-free. (Though, these dairy-free dinners make it incredibly easy to do so.) There are dairy products that are lactose-free and can be safely consumed, if you or a family member is lactose intolerant.

Which Foods Contain Lactose?

Lactose is in most dairy products—the levels will vary depending upon fat content, and if they are filtered or strained. Generally, most buttermilk and fresh, soft cheeses contain lactose. Examples of this include:

  • Mozzarella
  • Ricotta
  • Feta
  • Cottage cheese
  • Brie
  • Camembert
  • American cheese

Most yogurt and kefir also contain lactose. Because Greek-style yogurt is strained though, this removes some of the whey protein and lactose. Also, full-fat yogurt contains less lactose, as its high fat content displaces some of the whey in the final product. The live, active cultures (probiotics) in yogurt and kefir have been reported to make it easier to tolerate.

What Dairy Products Are Lactose Free?

Naturally aged, hard cheeses are drained off of whey protein, which is where most of the lactose comes from. Examples include

  • Cheddar
  • Swiss
  • Parmesan

Technically, butter and clarified butter (ghee) are lactose-free as they contain very minute, trace amounts of lactose. Heavy cream with its high fat content, contains just a small amount of lactose. Happily, small additions to your morning coffee would be a safe choice, if you have to watch your lactose intake.

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Vicki Shanta Retelny, RDN
A registered dietitian nutritionist, book author and speaker, Vicki has a passion for helping others embrace simple lifestyle habits that lead to health and happiness. When she is not in the kitchen whipping up tasty, nourishing meals for her family: two children, a husband and pet pug named Stella. Vicki enjoys a soothing face mask, Pilates and the occasional trip to their local sushi hotspot.