Lactose: The Quiet Troublemaker for Most People on the Planet – and What You Can Do About It

If a glass of milk or a creamy latte leaves you bloated, gurgling and rushing for the bathroom, you are not the odd one out – you are actually in the majority. A large analysis published in The Lancet Gastroenterology & Hepatology estimated that about 68% of adults worldwide have lactose malabsorption. Using genetic data alone, the figure rose to 74%. In other words, for most of humanity, the ability to fully digest milk sugar fades after childhood. That is a normal human trait, not a rare disorder.

Even world-famous people deal with it. Pop star Miley Cyrus once described her own experience to fans in a short tweet: "Worst tummy ache ever… no more lactose for me!" (ActiveBeat). Kylie Jenner has also said she changed her diet after discovering she was lactose intolerant. Many of our readers tell a similar story. One of them, a teacher in her thirties, put it like this: "For years I blamed stress for my afternoon bloating. When I swapped my milky morning coffee for a plant-based version and kept my yogurt, the difference surprised me within a couple of weeks."

Why lactose becomes a problem over time

Lactose is the natural sugar in milk. To absorb it, the small intestine needs an enzyme called lactase. According to the U.S. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), many people make less lactase as they grow older. Sensitivity to lactose can therefore change over the years, and many people first notice symptoms in their teens or early adulthood. Lactose that isn't digested travels on to the colon, where gut bacteria ferment it. That can lead to bloating, gas, stomach cramps and diarrhea, usually somewhere between 30 minutes and two hours after eating dairy.

Research suggests that a large share of the world's population has some degree of difficulty with milk and dairy products. For most people the reaction is unpleasant but not dangerous: bloating, a feeling of excess stomach acid and other digestive discomfort. It is worth knowing the difference from a milk allergy. That is a reaction of the immune system to milk proteins, it is far less common, and it can be serious. Anyone who suspects a milk allergy should talk to a doctor.

Scientists are also studying how dairy relates to long-term health, including cancer risk. So far the findings are mixed and depend on the type of dairy and the population studied. Organizations such as the World Cancer Research Fund regularly review this evidence. That is one more reason to listen to your own body rather than follow extreme claims in either direction.

The real question, then, is a practical one: how can you stay comfortable and still enjoy the nutrients dairy provides? If bloating is a frequent companion, you may also find our article Get Rid of Bloating and Excess Water helpful.

1. Choose fermented dairy products first

Even mild lactose sensitivity can mean that undigested lactose builds up in the large intestine. There it draws in water, speeds up the gut and can cause diarrhea, along with bloating and wind. Fermented dairy products such as yogurt, kefir and quark (fresh curd cheese) usually cause fewer problems, because fermentation has already used up part of the lactose. The active bacteria in yogurt and kefir also help break down lactose, and these foods remain an excellent source of calcium, potassium and protein.

The European Food Safety Authority has looked at this closely. In its 2010 scientific opinion, the EFSA panel reported that 13 of 14 human studies showed better lactose digestion when people with lactose maldigestion ate yogurt containing live cultures. It is one of the very few officially recognized benefits of live bacteria in food. Kefir has been studied too: a well-known trial by Hertzler and Clancy in the Journal of the American Dietetic Association found that kefir was linked to better lactose digestion and tolerance in adults who digest lactose poorly.

Look for "live and active cultures" on the label. It's also worth knowing that aged hard cheeses such as Parmesan or mature cheddar contain only traces of lactose, so many people tolerate them well.

2. Consider alternatives to milk

If you want to cut down on milk in coffee, puddings or baking, try coconut, almond, oat or rice milk. You can also replace butter with coconut oil in some recipes. Keep in mind, though, that coconut oil is high in saturated fat, which the American Heart Association advises limiting, so olive oil or rapeseed oil are often a better everyday choice.

From a nutritionist's point of view, one detail matters: plant drinks are not the same as milk. Consumer organization Which? found that almond drink can contain less than 0.5 g of protein per 100 ml, compared with about 3.6 g in dairy milk and 3.3 g in soya drink. Choose versions fortified with calcium and vitamin B12 where possible. Another simple option is lactose-free milk: it is real cow's milk with the lactase enzyme already added, so it tastes almost the same.

3. Probiotic foods may support lactose digestion

Probiotics are live beneficial bacteria. According to the International Scientific Association for Probiotics and Prebiotics (ISAPP), they can offer a health benefit when consumed in adequate amounts, and they are linked to digestion, the immune system and a range of metabolic processes. Probiotics are often described as a supportive way to help rebuild a disrupted gut flora.

Interesting evidence comes from Stanford School of Medicine. In a 10-week trial, people who ate more fermented foods, such as yogurt, kefir and fermented vegetables, showed greater gut microbial diversity and lower levels of several inflammatory markers. A varied, fiber-rich diet feeds those good bacteria too; read more in our articles The Secret Weapon Against Stubborn Weight: Is Fiber the One Thing Missing From Your Diet? and Easily digestible grain that protects your digestion.

A practical tip: if you're new to kefir or probiotic yogurt, start with small portions. Some people notice a little extra gas for the first few days while the gut adjusts.

4. Apple cider vinegar – an old home remedy

Apple cider vinegar is a traditional home remedy that many people use to feel more comfortable after meals. Some believe it supports digestion and helps balance stomach acid, easing the digestive discomfort that dairy can cause. A popular approach is to drink a glass of water mixed with one tablespoon of apple cider vinegar before a meal.

Be realistic about it, though. The Canadian Digestive Health Foundation notes that there isn't yet solid research showing it relieves bloating, although some people say it eases the heavy feeling after meals. Medical News Today likewise points out that its benefits are often overstated. Always dilute it, drink it through a straw to protect tooth enamel, and skip it if you have acid reflux or a sensitive stomach. If you prefer a gentler morning ritual, try our The Two-Minute Fix That Might Just Be the Simplest Wellness Ritual You've Never Tried, or a vegetable smoothie from Recipe that will improve your digestion.

A few more everyday tricks

• Smaller portions, spread out: According to Examine.com, many people with lactose intolerance can handle moderate amounts of lactose, up to roughly one cup of milk, without symptoms.


• Dairy with a meal: milk taken together with other foods is often easier to tolerate than on an empty stomach.


• Lactase tablets: these enzyme supplements, taken with dairy-containing meals, are an option many people find useful. Ask your pharmacist.


• Read labels: lactose hides in bread, processed meats, sauces, milk chocolate and ready meals.