How much lactose can lactose-intolerant people have?

People who are lactose-intolerant can usually tolerate the following amounts:

• Up to 12 grams of lactose at once (i.e. 250 milliliters of milk. or about one glass)
• Up to 24 grams of lactose over the course of the day (i.e. 500 ml milliliters of milk, or about two glasses)

It can be a good idea to combine the lactose-containing foods with other types of food. This is because solid foods and fatty foods slow down the digestion process in the stomach. As a result, less lactose enters the bowel (intestine) in one go, and the bowel reacts less sensitively.

Some research suggests that people can get used to lactose in their diet if they carefully and gradually increase their intake. Experts think that the flora (bacteria) in their large intestine can adapt if they eat and drink dairy products on a regular basis. It hasn't been proven that this actually works, though.

How can you adapt your diet?

The symptoms can usually be relieved by eating fewer high-lactose products. This isn't a problem for people who don't like things like dairy milk, yogurt or buttermilk very much anyway. But others will find it difficult at first to eat less dairy, or none at all – even if tastes can sometimes change over time. It can be particularly hard to adjust to a special diet if the rest of your family and your friends continue to eat as normal. Dealing with lactose intolerance eventually becomes a normal part of daily life for most people who have it.

Replacing high-lactose dairy products with some that contain less lactose is usually enough to make a difference. As a general rule, the more fermented milk-based products are, the less lactose they contain. So foods like sour cream or mature cheeses contain less lactose than fresh dairy products do, for example. Many hard cheeses contain no lactose or almost no lactose. Some people tolerate certain kinds of yogurt better than others.

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It can be helpful to learn how to understand ingredient lists on food labels so that you can find information on how much lactose a particular food has quickly. Many processed foods, such as baked goods, sausage products or sweets, may contain lactose. (more...)

There is an expanding selection of purely vegetable-based (vegan) foods, which are also lactose-free. Dairy-free alternatives like soy milk, oat milk, almond milk, or rice milk are good examples. Some of these products also contain added calcium. The number of dairy-free recipes is increasing too.

Worrying about your diet or whether particular meals will cause problems can be stressful. It may even cause more anxiety than the actual lactose intolerance symptoms do. But over time most people work out what they can eat.

Are special products like lactose-free milk a good option?

Nowadays, most supermarkets stock dairy milk that is low in lactose or lactose-free. This milk is made by filtering out the lactose or breaking it down by adding lactase. They are more expensive than normal cow's milk.

One systematic review found that people who drank lactose-reduced milk (0 to 2 g of lactose per glass) did not have fewer symptoms than people who drank regular milk (up to 12 g of lactose per glass). This is probably because most lactose-intolerant people can tolerate up to 12 g of lactose anyway, or only have mild symptoms after consuming this amount. So the research hasn't shown whether lactose-reduced milk is actually tolerated better by people who have lactose intolerance.

Can lactase products or prebiotic/probiotic dietary supplements help?

Dietary supplements containing lactase are available as tablets and capsules. They are meant to break down the lactose and make it easier to digest. It is unclear whether they have a benefit, though: Some studies suggest that lactase tablets might be able to relieve the typical symptoms. But there were very few of these studies, and they were small and not very reliable. Overall, more research is needed in order to assess the effects better.

Individual studies looked into whether prebiotic and probiotic dietary supplements can relieve the symptoms. Prebiotics and probiotics are bacteria in the bowel that help in the digestion of food. They are in some foods and can also be taken in dietary supplements. It is not yet clear whether they help in lactose intolerance.

Can cutting out dairy lead to a calcium deficiency?

Dairy products aren't an essential part of a balanced diet. But they do contain a lot of calcium. This mineral is an important nutrient that is needed for things like strong bones, teeth, and nails. Young people, pregnant women and older people need higher amounts of calcium. People who eat and drink less dairy, or none at all, may find it more difficult to get enough calcium in their diet. But calcium isn't only found in dairy products. Other foods and drinks are also rich in calcium, such as spinach or calcium-enriched plant-based milks.

Sources

• Marklund B, Ahlstedt S, Nordstrom G. Food hypersensitivity and quality of life. Curr Opin Allergy Clin Immunol 2007; 7(3): 279-287. [PubMed: 17489049]
• Marklund B, Wilde-Larsson B, Ahlstedt S, Nordstrom G. Adolescents' experiences of being food-hypersensitive: a qualitative study. BMC Nurs 2007; 6: 8. [PMC free article: PMC2104527] [PubMed: 17922926]
• Shaukat A, Levitt MD, Taylor BC et al. Systematic review: effective management strategies for lactose intolerance. Ann Intern Med 2010; 152(12): 797-803. [PubMed: 20404262]
• Wilt TJ, Shaukat A, Shamliyan T et al. Lactose intolerance and health. Evid Rep Technol Assess (Full Rep) 2010; (192): 1-410. [PMC free article: PMC4781456] [PubMed: 20629478]

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  Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

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