This article was originally written on October 22, 2018 and fully updated on December 24, 2022.
Most people who have lactose intolerance can tolerate a small amount of lactose per day. The lactose content can vary greatly from one yogurt to another, so how to know which yogurt to choose? Here are some explanations to shed light on this question!
Lactose is a sugar naturally found in milk and dairy products. It is a disaccharide, or in other words, a carbohydrate molecule that is composed of two simple sugars. In order for lactose to be used by our body, an enzyme called lactase must break it down to release the simple sugars that it’s made of, namely glucose and galactose, and allow their absorption. In some people, the amount of lactase enzymes is decreased in their intestines, which decreases their ability to digest lactose. Lactase deficiency may be due to genetic factors. However, it may also be a temporary disorder caused by certain factors that damage the lining of the small intestine, for example acute gastroenteritis, inflammatory diseases such as Crohn’s disease and celiac disease, as well as some medications. In the latter case, lactose intolerance can occur at any age and can be reversible, provided the causing factor is eliminated. The amount of lactose that can be digested depends on the amount of lactase enzymes available in the gut, which varies from person to person. Studies show that the majority of people who have lactose intolerance can tolerate about 4 to 7 grams of lactose per meal and up to 12 grams of lactose per day, distributed throughout the day.
In plain yogurt, the only sugar present is naturally occurring lactose, since no other sugar has been added. Thus, the amount of sugar indicated on the Nutrition Facts label corresponds directly to the amount of lactose. With regard to flavored yogurt, it is not possible to determine the amount of lactose by looking at the nutritional label since the indicated amount of sugar includes both the amount of lactose and the amount of added sugar. Finally, in the case of lactose-free yogurt, the lactose has already been broken down into simple sugars, so the amount of sugar on the label reflects the amount of glucose and galactose instead.
Yogurt is created by the fermentation of milk. To do this, bacteria are added to the milk who then in turn convert some of the lactose into lactic acid. Thus, regular yogurt contains about 20 to 30% less lactose than milk for an equivalent portion. As for the process of manufacturing Greek yogurt, it requires one more step. The yogurt is drained to remove the liquid portion, and in doing so a large part of the lactose is also removed. Thus, Greek yogurt contains less lactose than regular yogurt
The amounts of lactose vary between brands of yogurt, but plain Greek yogurt contains about 5g of lactose per serving, while regular plain yogurt contains about twice as much. Monash University uses a 1g lactose threshold to determine portions of dairy products that are low FODMAP. Thus, a portion that contains less than 1g of lactose is considered low FODMAP. According to Monash, plain regular yogurt is low FODMAP for 20g, while plain Greek yogurt is low FODMAP for 23g. This is not a big difference for people who are very sensitive to lactose, but some people who are lactose intolerant can tolerate more than 1g of lactose per serving, and therefore might be able to consume larger servings of Greek yogurt. This is why it is recommended to do a lactose reintroduction trial to determine your own threshold of tolerance.