When lactose intolerance is due to secondary lactase deficiency, treatment of the underlying disease may allow lactase activity to return to normal levels. In people with celiac disease, lactose intolerance normally reverts or improves several months after starting a
gluten-free diet, but temporary dietary restriction of lactose may be needed. People with primary lactase deficiency cannot modify their body's ability to produce lactase. Lactase deficient individuals vary in the amount of lactose they can tolerate, However, as a rule of thumb, people with primary lactase deficiency and no small intestine injury are usually able to consume at least 12 grams of lactose per sitting without symptoms, or with only mild symptoms, with greater amounts tolerated if consumed with a meal or throughout the day. Lactose is found primarily in
dairy products, which vary in the amount of lactose they contain: •
Milk – unprocessed cow's milk is about 4.7% lactose;
goat's milk 4.7%;
sheep's milk 4.7%;
buffalo milk 4.86%; and
yak milk 4.93%. •
Sour cream and
buttermilk – if made in the traditional way, this may be tolerable, but most modern brands add milk solids. •
Yogurt –
lactobacilli used in the production of
yogurt metabolize lactose to varying degrees, depending on the type of yogurt. Some bacteria found in yogurt also produce their own
lactase, which facilitates digestion in the intestines of lactose intolerant individuals. cheddar contains less than 1.5% of the lactose found in an equivalent mass of milk. There used to be a lack of standardization on how lactose is measured and reported in food. The different molecular weights of anhydrous lactose or lactose monohydrate result in up to 5% difference. One source recommends using the "carbohydrates" or "sugars" part of the nutritional label as surrogate for lactose content, although it may also simply indicate the product was produced on equipment shared with other products containing milk derivatives. Lactose is also a commercial
food additive used for its texture, flavor, and adhesive qualities. It is found in additives labelled as
casein,
caseinate,
whey,
lactoserum,
milk solids,
modified milk ingredients, etc. As such, lactose is found in foods such as processed meats (
sausages/
hot dogs, sliced meats,
pâtés), sliced
breads, breakfast cereals,
potato chips,
processed foods,
medications, prepared meals, meal replacements (powders and bars), protein supplements (powders and bars), and even
beers in the
milk stout style. Some barbecue sauces and liquid cheeses used in fast-food restaurants may also contain lactose. When dining out, carrying lactose intolerance cards that explain dietary restrictions in the local language can help communicate needs to restaurant staff. Lactose is often used as the primary filler (main ingredient) in most prescription and non-prescription solid pill form medications, though product labeling seldom mentions the presence of 'lactose' or 'milk', and neither do product monograms provided to pharmacists, and most pharmacists are unaware of the very wide scale yet common use of lactose in such medications until they contact the supplier or manufacturer for verification.
Milk substitutes Plant-based milks and derivatives such as
soy milk,
rice milk,
almond milk,
coconut milk,
hazelnut milk,
oat milk,
hemp milk, macadamia nut milk, and
peanut milk are inherently lactose-free. Low-lactose and lactose-free versions of foods are often available to replace dairy-based foods for those with lactose intolerance.
Lactase supplements When lactose avoidance is not possible, or on occasions when a person chooses to consume such items, then enzymatic lactase supplements may be used. Lactase enzymes similar to those produced in the small intestines of humans are produced industrially by
fungi of the
genus Aspergillus. The enzyme,
β-galactosidase, is available in tablet form in a variety of doses, in many countries without a prescription. It functions well only in high-acid environments, such as that found in the human gut due to the addition of gastric juices from the stomach. Unfortunately, too much acid can denature it, so it should not be taken on an empty stomach. Also, the enzyme is ineffective if it does not reach the small intestine by the time the problematic food does. Lactose-sensitive individuals can experiment with both timing and dosage to fit their particular needs. While essentially the same process as normal intestinal lactose digestion, direct treatment of milk employs a different variety of industrially produced lactase. This enzyme, produced by
yeast from the genus
Kluyveromyces, takes much longer to act, must be thoroughly mixed throughout the product, and is destroyed by even mildly acidic environments. Its main use is in producing the lactose-free or lactose-reduced dairy products sold in supermarkets.
Rehabituation to dairy products Regular consumption of dairy foods containing lactose can promote a colonic bacteria adaptation, enhancing a favorable microbiome, which allows people with primary lactase deficiency to diminish their intolerance and to consume more dairy foods. The way to induce tolerance is based on progressive exposure, consuming smaller amounts frequently, distributed throughout the day. Lactose intolerance can also be managed by ingesting live yogurt cultures containing
lactobacilli that are able to digest the lactose in other dairy products. == Epidemiology ==