Lactose intolerance is the inability to completely digest lactose, the sugar found in milk leading to symptoms such as bloating, cramps, gas, flatulence and possibly diarrhoea.
It is caused by the lack of an enzyme called lactase that is responsible for breaking down lactose found in milk and dairy products in the digestive system. Lactase intolerance affects more than half of the world population and it may also be the cause of baby colic in many babies. Moreover, according to various studies, lactose intolerance accounts to more than half of wrongly diagnosed patients with irritable bowel syndrome (IBS). Lactose intolerance is the most common form of food intolerance; others include carbohydrate, fructose, and gluten. Lactose Intolerance can also be a side effect of gluten Intolerance. Lactose intolerance can be treated by avoiding dairy products or by lactase supplements. Lactose intolerance must not be confused with milk allergy, of which comparison details are listed below.
Milk
contains lactose which is a disaccharide (two sugars joined together).
Our body is not able to absorb lactose due to its size, hence requires
to be broken down into two monosaccharides (two single sugars). To get
around this a protein enzyme called lactase that is produced in
the lining of the small intestine has the ability to split lactose
so it could be absorbed. This figure shows lactose sugar,
a disaccharide (top) broken down into two monosaccharides by means
of the lactase enzyme (centre) into glucose and galactose, (bottom)
which are then small enough to get through the lining of the small
intestine.
Our body utilises glucose as a fuel, so any sugar that is not glucose that enters our system is then changed and reconfigured by separate proteins as glucose. But that is another story which we will not dive into here.
If there is insufficient lactase, or nothing at all (in extreme rare cases), lactose remains in the digestive system which is then fermented by the healthy bacteria living further down in our digestive tract in the large intestine. This results in excess gas, stomach rumbling and bloating. Severe intolerance may lead to cramps, diarrhoea and perhaps other uncomfortable symptoms.
Lactase activity is normally high in babies, although baby colic may be caused by temporarily lactase deficiency (see baby colic). After the ages of 5-6 lactase production starts decreasing in many individuals but the rate varies from one person to another and also between races. From the table below one can conclude that the majority of people in the world are lactose intolerant.
| Human Group | % Lactose Intolerance |
|---|---|
| Caucasians | 10-20% |
| Mediterranean | 40-50% |
| Oriental | 90% |
| American Blacks | 75% |
| African | 50% |
| Aborigines | 85% |
However there are other people irrelevant of what race or age they are that may develop lactose intolerance:
Lactose left in our digestive system causes extraction of fluids (water) from the body into the guts by a process called osmosis. Examples of osmosis in daily life is when for example we put salt on onions, the juice is extracted out. The combination of these fluids and lactose in the digestive system is an attractive combination for the bacteria living in the large intestine that will digest lactose producing gases associated with flatulence and leading to other symptoms.
The symptoms are:
The most common tests used to measure the absorption of lactose in the digestive system are the lactose tolerance blood test, the hydrogen breath test, and the stool acidity test performed on babies. These tests are performed on an outpatient basis at a hospital, clinic, or doctor's office. However, one can do a Homepage self-test in which after fasting for 12 hours a person drinks a large glass of milk taking nothing else for the next 3-5 hours. If symptoms develop one can be certain he/she has lactose intolerance.
The most common tests used to measure the absorption of lactose in the digestive system are the lactose tolerance blood test, the hydrogen breath test, and the stool acidity test performed on babies. These tests are performed on an outpatient basis at a hospital, clinic, or doctor's office. However, one can do a Homepage self-test in which after fasting for 12 hours a person drinks a large glass of milk taking nothing else for the next 3-5 hours. If symptoms develop one can be certain he/she has lactose intolerance.
Lactose intolerance must not be confused with milk allergy. Milk allergy is caused when our immune system thinks proteins found in milk are harmful, hence an immune response is triggered causing symptoms related to food allergy, such as rash, hives, swelling etc. However, some symptoms such as vomiting and diarrhoea can be common for both so it is important to read and understand the difference for better diagnosis.
| Lactose Intolerance | Milk Allergy | |
|---|---|---|
| Cause | not enough enzymes to breakdown the sugars, such as lactose consumed in foods. | immune system thinks that some proteins in foods (such as milk) are of those of harmful bacteria, hence, an immune response is triggered. |
| Age | starts later in childhood but most common in adults, may be temporarily present in the form of colic in babies. | starts usually from early infancy and more common in children who overgrow it, triggered in later adult life in some who never had it in childhood. |
| Symptoms |
affect the digestive system only: Some may experience vomiting. The magnitude of the above symptoms are inversely related to the amount of enzyme produced. Some people can produce less than others. |
usually immediate and affecting more that one part
of the body- |
Food allergy is caused when the immune system mistakenly responds to food proteins thinking they are harmful substances. Symptoms include vomiting, itching, rash, and hives. Allergies in children are very common, but treatment with digestive enzymes may prove very helpful.
In Coeliac Disease, gluten causes damage to the small intestines, however, more people are wheat sensitive. This shows negative in blood tests. Read how to diagnose and avoid false negative screening results.
Baby colic is very distressing to both the baby and the parents. However, studies conclude that half the babies suffer due to lactase deficiency. This is easily treated by neutralising milk with lactase enzyme.
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