FODMAP Explained: “D” Stands for Disaccharides

AdobeStock_Milk has lactose.jpeg

Welcome back to my “FODMAP Explained” Series! This is a set of articles dedicated to explaining the acronym FODMAP and giving practical tips to avoid symptoms while including as wide a variety of foods as possible.


The “D” in FODMAP stands for “Disaccharides”, which means two-sugar molecules. The “disaccharide” of concern here is lactose, made of glucose and galactose. Our body is not able to digest lactose as is and needs to split it into its two components, glucose and galactose, using an enzyme called lactase.

People who don’t produce enough lactase have trouble digesting lactose. As a result, it travels through the digestive tract unabsorbed until it reaches the large intestine where it is fermented by our bacteria. This may cause symptoms such as excess gas, bloating, abdominal pain and/or diarrhea.

Lactose in the low FODMAP Diet

Lactose is found in milk and other dairy products. One common misconception is that the low FODMAP diet is a lactose-free or dairy-free diet. It is a low lactose diet and you can still include a few low-lactose or lactose-free dairy products. Even people who are lactose intolerant can tolerate a few grams of lactose without having symptoms. You will need to find your personal tolerance level.

Including a few dairy products while following a low FODMAP diet gives you more variety and makes it easier to get enough calcium – although as I have written before, it is not necessary, as there are many alternate sources of calcium, such as fortified non-dairy milks, legumes, some vegetables and some nuts and seeds.

Bottom line: what can you eat?

During the strict elimination phase of the low FODMAP diet, you will need to avoid high-lactose products such as milk, regular yogurt, kefir and ice cream. You will be able to enjoy low-lactose or lactose-free dairy products such as:

  • Aged cheeses (cheddar, Swiss, Parmesan)

  • Non-aged cheeses (mozzarella, feta, paneer, queso fresco) – in small portions

  • Half and half, sour cream, whipped cream – in small portions

  • Lactose free milk, yogurt, kefir, cream cheese and sour cream

  • Whey protein isolate (99% lactose free)

  • Butter and ghee (these are virtually lactose-free as they are mostly a source of dairy fat)

After testing their tolerance to lactose during the re-challenge phase, many people find they can tolerate lactose, or tolerate it in small portions, and can re-introduce it into their diet long term. If you cannot, you will need to avoid it and make sure you include other calcium-rich foods. Even so, you are encouraged to re-test your tolerance every 3-6 months, as symptoms wax and wane and are also related to stress levels, which may change overtime.

Antonella Dewell