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Lactose intolerance

Lactose intolerance is one of the most common types of food intolerance. It is mostly misperceived as allergy to milk by a layman, but milk allergy and lactose intolerance are two different phenomena.

Lactose intolerance is a disorder mostly found in adults. Even if detected in children is usually seen to be outgrown by adulthood. Lactose intolerance is usually not too dangerous but loaded with discomfort and ill effects.

What is lactose intolerance?

Lactose intolerance is inability to digest lactose, a form of sugar found in milk and other dairy products. People with lactose intolerance lack the enzyme lactase that helps in the digestion of lactose; therefore, their lactose digestion process is impaired. In other words, lactose intolerance is a metabolic disorder.


Lactose intolerance occurs mainly due to insufficient production of lactase enzyme and mal-absorption of lactose. Lactase helps in breaking down lactose into simpler particles. When milk or any other dairy product is consumed, the small intestine cannot digest lactose completely due to the absence of enough lactase and the lactose moves directly to the large intestine, ultimately reaching colon without being digested properly. The colon absorbs water from stool to convert it into solid form. The bacteria present in colon act on the undigested lactose to break it down into fluid and gas. This causes uncomfortable symptoms in the body.

Lactase production is also disrupted either on a temporary or permanent basis after any short-term or life-long illness or surgery related to small intestine.

Some premature babies also suffer from lactose intolerance, very rare though. Their intolerance to lactose occurs as their bodies are not capable to produce lactase as yet. This is a temporary phenomenon if at all occurs and is gradually got rid of as their bodies start making lactase.


The common symptoms of lactose intolerance include the following:

  1. Abdominal bloating
  2. Gas
  3. A feeling of fullness or heaviness
  4. Swelling in the abdomen
  5. Nausea
  6. Diarrhea

The onset of these symptoms occurs within 30 minutes to 2 hours after consuming milk or milk based products. Some people do not show any significant symptom of lactose intolerance. The symptoms range from mild to severe on the basis of the amount of lactose ingested and the amount of lactose one can tolerate. So, the severity of symptoms is variable and vastly differs from person to person.

Risk factors

Lactose intolerance might be a problem with many yet some factors put you on the verge of risk as compared to others. Let us have a glance at them:


Unlike milk allergy, lactose intolerance attains its prevalence with increasing age. It is very rarely found in infants and young children.

Premature birth

Premature babies are prone to lactose intolerance because lactase production in fetus usually begins late in third trimester. Therefore, they either lack lactase or have reduced lactase level in their body.

Diseases associated with small intestine

People with some short-term intestinal disorders such as celiac disease, bacterial overgrowth, Crohn’s disease and stomach flu have increased susceptibility to develop intolerance to lactose as lactase production is largely disrupted in them.

People who have undergone certain cancer treatment

Those who have complications in the intestine due to chemotherapy are at increased risk of lactose intolerance. Radiation therapy in the abdomen for cancer also leads to greater risk of lactose intolerance.

People who have had surgery related to small intestine

Any sort of surgery related to small intestine can put an abrupt end to the production of lactase enzyme thus leading to lactose intolerance.


Black, Hispanic, Asian and American Indian people are more prone to lactose intolerance.

Products/food containing lactose

Lactose is inevitably present in milk and milk products. Some other products have the possibility of containing small amount of lactose. Therefore, people with lactose intolerance should be aware of the wide spectrum of products that contain lactose.

  1. Baked stuffs including bread
  2. Processed breakfast cereals
  3. Pancakes, cookies, biscuits, waffles, doughnuts, sweet rolls, pastries
  4. Processed snacks such as potato chips, corn chips
  5. Soups, instant potatoes, breakfast drinks
  6. Salad dressings
  7. Candies
  8. Processed meats such as sausage, lunch meats, bacon, hot dog
  9. Protein powders
  10. Protein bars
  11. Margarine
  12. Non-dairy coffee creamers (both liquid and powdered)
  13. Non-dairy whipped toppings

Besides the above mentioned list, some medicines also have lactose content such as medications for stomach acid and gas and contraceptive pills.

Diagnosis of Lactose intolerance

Lactose intolerance is diagnosed in the following ways:

Reviewing diet, medical and family history along with symptoms:

Although some healthcare providers opt for this category of diagnosis but detecting lactose intolerance solely on the basis of histories is quite misleading. Other examinations should also be conducted besides reviewing of all the histories.

Physical examination

In this category of diagnosis, abdominal bloating is checked for. A stethoscope is employed to listen to any kind of sound within the abdomen. The abdomen is also checked for tenderness or pain by tapping.

Medical tests

Two tests are primarily carried out for detecting if a person can digest lactose well. They are hydrogen breath test and stool acidity test.

Treatment of lactose intolerance

Lactose intolerance cannot be treated as such; it can only be managed by making a few changes to your diet. Reducing lactose intake or avoiding lactose is the best way to control the adverse effects of lactose intolerance. Instead, you can look for lactose-free alternatives.

Diet, nutrition and caution

If you suffer from lactose intolerant, the exact changes in your diet would largely depend on how sensitive you are to lactose. There are people who have no issues digesting small amount of lactose whereas some people are highly sensitive to lactose and cannot tolerate even the slightest amount of it. Accordingly, the amount of lactose intake can be determined. Reduced intake of lactose containing products might make you deficient of other vitamins and minerals; therefore, you should seek help of a dietician so that you get enough nutrition from your dietary supplements.

While you purchase any food product, you should be extremely cautious about the labels. If the label contains any of these, the product has lactose content:

  1. Milk
  2. Whey
  3. Milk by-products
  4. Curds
  5. Dry milk solids
  6. Non-fat dry milk powder