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Is Greek Yogurt Lactose-Free? Lactose Content, Intolerance and What the Cultures Do

Writer: Vangelis Pallis
Vangelis Pallis
2 days ago
4 min read

Updated: 1 day ago

Short answer: no, Greek yogurt is not lactose-free, but it is one of the lowest-lactose dairy foods that is not specifically treated to remove lactose, and many people with lactose intolerance tolerate it well. Two things make that possible: straining removes part of the lactose with the whey, and the live bacteria in yogurt digest lactose for you.


Infographic: lactose per 100 g in milk, regular yogurt, Greek yogurt and hard cheese
Lactose per 100 g. Source: USDA FoodData Central; EFSA 2010.

How much lactose is in Greek yogurt

Food (plain, per 100 g)

Lactose

Cow's milk

about 4.7 g

Regular whole-milk yogurt

3.4 g

Greek yogurt, whole milk

2.6 g

Greek yogurt, nonfat

2.6 g

Hard cheese (cheddar, graviera)

under 0.1 g


Figures for yogurt come from USDA FoodData Central's analysed entries (April 2026 release). A 170 g cup of plain Greek yogurt therefore contains about 4.4 g of lactose, roughly what you would get in 90 ml of milk.


Flavoured Greek yogurts can carry more total sugar, but the extra is usually sucrose or fruit sugar, not lactose. "Lactose-free" Greek yogurt, where sold, has had the enzyme lactase added to split the lactose into glucose and galactose; it tastes slightly sweeter for that reason.


Why straining lowers lactose

Lactose is dissolved in the water phase of milk. When yogurt is strained, the whey that drains away takes a proportional share of the lactose with it. Fermentation has already consumed some lactose before straining begins: the starter bacteria convert roughly 20–30% of milk lactose into lactic acid during a normal fermentation. Straining then removes a further share. The result is a product with around half the lactose of the milk it came from.


What the live cultures do

Yogurt's two defining bacteria, Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, carry their own lactase enzyme. When you eat yogurt with live cultures, the bacteria reach the small intestine, and bile salts make their cell walls permeable enough for that enzyme to act on the lactose in the meal. This is one of very few health claims about yogurt that European regulators have formally accepted: in 2010 the European Food Safety Authority concluded that live yogurt cultures improve lactose digestion in people who maldigest lactose, provided the yogurt contains at least 100 million live starter bacteria per gram.


Heat-treated yogurts (pasteurised after fermentation to extend shelf life) lose this effect. Greek law requires at least 10 million live cells per gram to the end of shelf life in anything sold as yogurt; US rules allow heat-treated yogurt if it is labelled as such.


What this means for lactose intolerance

Lactose intolerance is a matter of degree. EFSA's 2010 opinion on lactose thresholds concluded that most people with lactose maldigestion tolerate at least 12 g of lactose in a single dose with few or no symptoms, and more when it is spread across the day or eaten with other food. A cup of Greek yogurt sits well under that, and its live cultures lower the effective dose further. In practice:


  • Mild to moderate intolerance. Plain Greek yogurt is usually fine in normal portions. Start with half a cup and build up.

  • Severe intolerance or galactosaemia. Choose a lactase-treated "lactose-free" product, or avoid dairy. Galactosaemia is a different, inherited condition in which no dairy is safe; yogurt does not help.

  • Cow's milk protein allergy. This is unrelated to lactose. Greek yogurt made from cow's milk is not safe; sheep's or goat's milk yogurt is also often unsafe because the proteins cross-react. Ask an allergist.


Tips that help tolerance: eat yogurt with other food rather than alone on an empty stomach; prefer products that state "live cultures"; and avoid heat-treated or very long-dated ambient yogurts.


Greek yogurt compared with other options

  • Regular yogurt has more lactose (about 3.4 g per 100 g) but the same live-culture benefit.

  • Skyr and labneh are drained further and are usually as low or lower in lactose.

  • Kefir carries more and more varied microbes and is often well tolerated, though its lactose content is similar to milk before fermentation.

  • Aged cheeses are effectively lactose-free but offer no live-culture effect.

  • Plant-based "Greek-style" alternatives contain no lactose and no milk protein; check the protein line, which is often much lower than dairy Greek yogurt.


Summary

Plain Greek yogurt contains about 2.6 g lactose per 100 g, around half that of milk, and its live cultures help digest it. For most lactose-intolerant adults it is a workable dairy food in sensible portions; for people with severe intolerance, galactosaemia or a milk allergy it is not a substitute for medical advice or lactose-free products. For the full nutrition picture see Greek yogurt nutrition facts, and for the culture question in depth see Greek yogurt and probiotics.


Disclaimer. This article is general information, not medical or dietary advice. Nutrition values are typical figures from the cited databases and vary by brand and batch; always read the label. If you suspect lactose intolerance, a milk allergy or another digestive condition, talk to a doctor or registered dietitian before changing your diet; symptoms of several conditions overlap.

Sources

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