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Lactose Intolerance or Milk Allergy? Tests and Diet

Many people believe that they are allergic to milk because whenever they ingest milk or any dairy product, such as yoghurt, cheese or even an ice cream, they experience bloating, gassy stomach pain and diarrhea. Some really are allergic to milk and should better avoid it. But most of them have a common digestive disorder called lactose intolerance. Lactose intolerance is actually not an allergy but one of the most common forms of enzyme deficiency. This condition is due to the missing or insufficient intestinal enzyme called lactase, which role is to break down and digest lactose, the natural milk sugar. In contrast, a milk allergy is a true food allergy when the body’s immune system misinterprets the milk protein as a dangerous foreign substance and tries to attack it.

When people with lactose intolerance consume milk or a dairy product, the unprocessed lactose becomes fodder for natural bacteria in the intestines. The resulting fermentation process causes gas and diarrhea, normally starting from fifteen minutes to several hours after ingestion. However, patients suffering from a true milk allergy might, besides these symptoms, also experience nasal congestion, frequent urination, hives and headache. In addition, milk allergy can be potentially life-threatening as its most severe symptom – anaphylactic shock – involves breathing problems and lowered blood pressure. Although none of these two conditions can be cured, they can be controlled with avoidance of milk and dairy products. Some people with lactose intolerance can, though, tolerate some forms of dairy, whereas those with a milk allergy must avoid dairy completely.

Unlike a milk allergy, lactose intolerance is far more common among Asians and blacks than among white Caucasians. It is estimated that this condition is present in about 80% of Asians, 75% of blacks but only about 20% of whites (only 5% among people of northern European descent). In general, lactose intolerance is a far more prevalent condition than milk allergy.

Diagnosing Lactose Intolerance

Considering the nature of symptoms of lactose intolerance, it is easy to understand why this disorder is sometimes misdiagnosed as an irritable bowel syndrome, ulcer or some other gastrointestinal condition.

Lactose Intolerance Test

Taking a lactose intolerance test, also called lactose tolerance test, can determine whether lactase deficiency really is behind your digestive problems. You will be given a liquid containing lactose to drink. Lactose intolerance is diagnosed if diarrhea, abdominal discomfort and bloating appear within twenty to thirty minutes of ingestion and if blood tests confirm that your blood sugar levels have not increased despite ingesting the milk sugar.

Hydrogen Breath Test

Hydrogen breath test is a safe, inexpensive and the most accurate way of diagnosing lactose intolerance. Here you will also be given a certain amount of liquid that contains lactose to drink on an empty stomach. You will then, over a period of few hours, breathe several times into a device that measures hydrogen in your exhalations. If your small intestine fails to break down the lactose you ingested, excess carbohydrates will reach your colon and undergo fermentation there. This will raise the level of hydrogen in your breath.

Stool Acidity Test

Stool acidity test is used to determine lactose intolerance in infants and little kids who cannot take the aforementioned tests. The fermentation of unprocessed lactose in the small intestine produces lactic acid as well as other acids that can be then detected in a stool sample.


You can also test yourself at home. Avoid all dairy products for at least two weeks to see if formerly frequent problems fade away. Then drink a glass of milk. If bloating, abdominal pain and diarrhea return, lactose intolerance may be the culprit. If you experience no such reactions for a few days, drink a little more milk and eat some dairy products all at one time. If former symptoms do not occur, the problem probably lies somewhere else. Do this test only under your doctor’s guidance in order to make sure you are not triggering a serious allergic reaction.

Living with Lactose Intolerance

Lactose intolerance cannot be cured. However, being lactose intolerant does not necessarily mean you have to avoid milk and all dairy products. In addition to buying lactose-free milk and dairy products such as Lactaid, you can chew or swallow lactase tablets before eating dairy products or add lactase drops to milk 24 hours before drinking it. Depending on the extent of your reaction, you may be able to consume dairy products that are low in lactose, such as hard cheeses or plain yogurt containing active cultures.

Milk happens to be one of the major dietary sources of calcium. If your intolerance is too severe and you need to avoid all products that contain lactose, you may be advised to take calcium supplements. Also, make sure you get enough calcium from your diet by regularly consuming calcium-rich foods including dark green, leafy vegetables, such as broccoli, kale, collard greens and spinach, legumes, such as beans, soybeans and peanuts, sesame seeds and oily fish, such as sardines and salmon, especially the canned fish containing edible bones.

When shopping, read the food labels to identify ingredients that may contain lactose, or if your condition is too serious, buy only lactose-free foods. For a meal out, try an Asian restaurant such as Japanese, Chinese, Korean or Thai. Not surprisingly, milk is not an essential ingredient of these cuisines, since Asians have a very high rate of lactose intolerance.

Where to Get More Information and Advice:
Eat Confidently with Lactose Intolerance