Lactose

What is it?

Lactose is the sugar of milk. Most adults gradually lose the lactase enzyme that splits it, and what is not split ferments in the colon — bloating, gas, loose stools. The condition is an enzyme shortfall rather than an immune reaction, which is why the amount matters more here than on any other axis.

How much is tolerated, and why no single number fits

EFSA's panel on dietetic products (2010) concluded that the vast majority of people with lactose maldigestion tolerate up to 12 g of lactose as a single dose — roughly a glass of milk — that no single threshold can be set for everyone, and that some react below 6 g. That is an opinion on tolerance and not on composition: it carries no lactose value for any food, and its own finding is that a serving cannot be declared safe for everyone.

Two things decide the lactose of any dairy product

How much water is left, and what ate the sugar dissolved in it. Fat displaces the water — cream, butter, hard cheese. Draining takes it away with the whey — Greek yoghurt, curd cheese. Fermentation eats the sugar that stays — kefir, long-aged cheese. Those three mechanisms, not the animal and not the name, are why two dairy products of similar appearance can sit at opposite ends of this axis.

Hard aged cheese, measured rather than assumed

Portnoi and MacDonald (2009) determined lactose and galactose across 109 samples of 12 cheese types, and in gruyère, emmental, jarlsberg, parmigiano, grana padano and mature cheddar neither sugar was detectable. "Almost lactose-free" is weaker than what they found and also wider: gouda and edam are absent from that list, so their levels here cannot lean on it.

The one health claim the law allows, and what it does not cover

Commission Regulation (EU) No 432/2012 carries a single permitted claim about lactose digestion, and it is about live yoghurt cultures. EFSA substantiated it on the ground that the cultures bring their own lactase into the gut. It is a legal status rather than a measurement: it is not evidence that the claim holds for a particular product, and it says nothing about a yoghurt whose cultures have been killed by pasteurisation after fermentation — which is the difference between two tubs on the same shelf.

Where the figures on this axis come from

Lactose values here are read from three composition tables rather than one: USDA FoodData Central, Ciqual from ANSES in France, and the Swiss Nährwertdatenbank. Each gives values per variety and for its own country's food supply, never per brand, and reading them together is what makes a disagreement visible. None of the three publishes anything beyond composition — no tolerance threshold, and no figure for any other axis here.

Source: EFSA Panel on Dietetic Products, Nutrition and Allergies, EFSA Journal 8(9):1777 (2010), for the 12 g single dose, for there being no single threshold, and for some people reacting below 6 g — an opinion on tolerance that carries no lactose value for any food; Portnoi P.A. & MacDonald A. (2009), for lactose and galactose across 109 samples of 12 cheese types, with six showing neither detectable; Commission Regulation (EU) No 432/2012 and EFSA Journal 8(10):1763 (2010), for the one permitted health claim on live yoghurt cultures and lactose digestion — a legal status, not a measurement, and silent on cultures killed after fermentation; USDA FoodData Central, Ciqual (ANSES) and the Schweizer Nährwertdatenbank, read together for lactose, each per variety and per country's food supply and never per brand

Frequently asked questions