Abdominal pain after a glass of milk, bloating after yoghurt, or diarrhoea after cheese — for people with lactose intolerance, these are all too familiar. But what exactly is lactose intolerance, how do you recognise it, and what can you eat without symptoms? This article offers a complete overview based on current nutritional insights.
Key takeaways
- Lactose intolerance means the body produces insufficient lactase to fully break down lactose (milk sugar)
- Symptoms include abdominal pain, bloating, flatulence, and diarrhoea — appearing 30 minutes to 2 hours after consuming dairy
- Most people with lactose intolerance can tolerate up to 10–15 grams of lactose per meal without significant symptoms
- Hard cheeses and fermented dairy contain very little lactose and are generally well tolerated
- Plant-based alternatives (soy, oat, almond) and lactase supplements are effective solutions
What is lactose intolerance?
Lactose is the sugar that occurs naturally in milk and dairy products. To digest lactose, your body needs the enzyme lactase, produced in the small intestine. In lactose intolerance, the production of this enzyme is reduced or absent. Undigested lactose reaches the large intestine, where gut bacteria ferment it — producing the familiar symptoms.
Lactose intolerance is not an allergy. A cow's milk allergy is an immune reaction to milk proteins (such as casein or whey), whereas lactose intolerance is a digestive issue. The distinction matters, because the management approaches differ.
Globally, a large proportion of the adult population produces less lactase than in childhood. In the Netherlands, approximately 5% of the population experiences lactose intolerance, but this figure is considerably higher in people of non-European origin — in Asian and African populations it can reach 70–90%.
Recognising the symptoms
The most common symptoms of lactose intolerance are:
- Abdominal pain or cramps — caused by gas and fluid accumulating in the large intestine
- Bloating — fermentation of lactose by gut bacteria produces gas
- Flatulence — a direct consequence of that gas production
- Diarrhoea or loose stools — undigested lactose draws water into the intestines
- Nausea — less common, but possible with larger amounts of lactose
Symptoms typically appear 30 minutes to 2 hours after eating lactose-containing products and resolve within 3 to 6 hours. Their severity depends on the amount of lactose consumed and the individual's remaining lactase activity.
How much lactose can you tolerate?
There is no sharp threshold. Research suggests that most people with lactose intolerance can consume up to 10–15 grams of lactose per meal without serious symptoms — roughly the amount in a glass of milk (240 ml). Spread throughout the day, and combined with other food, tolerance is often even higher.
Factors that influence tolerance include:
- The amount of lactose per serving
- Whether dairy is consumed with or without other food
- Individual residual lactase activity
- The composition of your gut microbiome
Which dairy can you still eat?
Not all dairy is equally problematic. Hard cheeses such as Gouda, Edam, and Parmesan contain almost no lactose — most of it breaks down during the ripening process. The same applies to fermented products such as yoghurt and quark, which contain less lactose than fresh milk and are partly broken down further by gut bacteria.
Lactose content by product:
- Whole milk: ~4.7 g per 100 ml
- Buttermilk: ~3.5 g per 100 ml
- Yoghurt: ~3–4 g per 100 g
- Hard cheese (Gouda, Parmesan): <0.1 g per 100 g
- Butter: ~0.1 g per 100 g
- Lactose-free milk: <0.1 g per 100 ml
Plant-based alternatives
If you want to avoid dairy entirely, or find you tolerate it only in small amounts, there are good plant-based alternatives:
- Soy milk — closest to cow's milk in protein content; choose a fortified variety for calcium and vitamin D
- Oat milk — creamy in flavour, works well in coffee and porridge; note that it contains carbohydrates
- Almond milk — low in calories, mild flavour; low in protein
- Rice milk — mild and slightly sweet, but relatively low in nutrients
- Coconut milk (canned) — higher in fat; not suitable as a daily milk replacement in large amounts
Always choose fortified varieties — without added calcium, vitamin B12, and vitamin D, cutting out dairy entirely can quickly lead to shortfalls.
Lactase supplements
Another option is taking lactase supplements — tablets or drops taken together with lactose-containing food. The enzyme breaks down the lactose in the gut before symptoms can develop. This is an effective approach for people who want to eat dairy occasionally without discomfort, though daily use involves ongoing cost and requires discipline.
Preventing nutritional deficiencies
Dairy is an important source of calcium, vitamin B2, and vitamin B12. If you significantly reduce or eliminate dairy, pay extra attention to these nutrients:
- Calcium: legumes, broccoli, kale, almonds, and fortified plant-based drinks
- Vitamin D: oily fish, eggs, fortified products — consider a supplement, especially in winter
- Vitamin B12: meat, fish, eggs, and fortified plant-based products — or a supplement
If in doubt, consult a registered dietitian for personalised advice. Moveno lets you track what you eat and instantly see whether you are getting enough calcium and other essential nutrients. Our article on food tracking explains how to put this into practice.
Getting a diagnosis
If you recognise the symptoms, see your GP rather than experimenting with elimination on your own. Commonly used tests include:
- Hydrogen breath test — you drink a lactose solution and the hydrogen content of your breath is measured; elevated hydrogen production indicates undigested lactose
- Blood glucose test — measures the rise in blood sugar after lactose intake; in lactose intolerance, the rise is minimal
- Intestinal biopsy — less common, but gives direct information about lactase activity in the intestinal wall
Sources
- MDL Fonds — Lactose-intolerantie
- Voedingscentrum — Lactose-intolerantie
- Voedingsgeneeskunde — Lactose-intolerantie (VG 2025)
