Lactose Intolerance: Symptoms and Management

Lactose Intolerance is a medical condition in which the person is not able to digest the milk sugar i.e. lactose completely and complains of digestive symptoms such as flatulence(gas), diarrhea and bloating. The problem also occurs with the consumption of other dairy and food products which contains lactose such as ice-cream, cheese, buttercream etc.

Lactose malabsorption is the just the condition in which the small intestine is not able to digest the lactose and if it is associated with the symptoms mentioned above then it is known as lactose intolerance. This means that not all people having lactose malabsorption have lactose intolerance.

According to experts about 68% of the world population suffers from lactose malabsorption and in United States it is 36%.

Symptoms of Lactose Intolerance

These signs and symptoms usually appear within a few hours after you have taken milk or other products containing lactose as follows

• Flatulence or gas
• Diarrhea
• Bloating
• Pain in abdomen due to abdominal cramps
• Nausea
• Vomiting

The symptoms may be mild or severe which generally depends upon the amount of lactose-containing products you have taken

Causes of Lactose Intolerance

Lactose intolerance is always due to lactose malabsorption where the small intestine produces low levels of an enzyme called as lactase which digest the lactose (milk sugar). This undigested lactose passes into your colon where it is broken and metabolised by the bacteria which releases acid and gas as the by-products. In some people these by-products cause the symptoms of lactose intolerance.

On the basis of cause of lactose malabsorption there are different types of lactose intolerance as

• Primary lactose intolerance: It is the most common type and depends upon your genes. The levels of lactase enzyme are normal at birth and the infant is able to digest the milk normally but the levels start declining after infancy and go on decreasing with the increasing age. The age when person presents with the typical complaints is highly variable ranging from early childhood to late adulthood. The symptoms also depend upon the amount of consumption of lactose containing products
• Congenital or developmental lactose intolerance: It is a rare genetic condition and starting from birth the small intestine produces very small or no lactase.
• Secondary lactose intolerance: This is not due to genetic defect in enzyme but conditions such as premature babies, infections, diseases, drugs, or any other injuries to small intestine can cause less production of enzyme. If the underlying cause is removed then the person becomes tolerant to lactose.

Risk factors for Lactose Intolerance

Some people are at high risk of developing lactose malabsorption due to the following risk factors

• Racial or ethnic groups: Africans, Asian or Hispanic people are more prone of having lactose malabsorption
• Age: The lactose intolerance is mainly the disease of old people or adults. Young people have low chances.
• Drugs or radiation therapy: Medicines or radiation therapy for the treatment of cancer can also cause injury to the small intestine

Diagnosis of Lactose Intolerance

To make the diagnosis your doctor will ask you questions about your medical history, family history and can perform certain tests to confirm it.

History: Your doctor will ask you about your symptoms, eating habits and relation of symptoms with the intake of dairy products. Your doctor may advise you to stop the consumption of dairy products to look for any improvements

Physical exam: Your doctor can perform a complete physical examination but he or she will try to look for the signs that are specific for the digestive symptoms such as

• Rumbling sounds of the abdomen listening through the help of a stethoscope
• Pain or tenderness in the abdomen by tapping over the abdomen

Laboratory tests: if the history is not helpful to determine the cause alone, laboratory tests should be performed because these symptoms are also present in other diseases of digestive system such as Crohn’s, ulcerative colitis, irritable bowel syndrome, celiac disease.

• Hydrogen breath test – The patient is given a high lactose containing liquid to drink, after that amount of hydrogen present in the breath is tested at regular intervals. In a normal person there is very little amount of hydrogen detectable but in a person suffering from lactose intolerance the lactose is fermented in the colon releasing hydrogen with other gases which passed to the blood and finally exhaled. So, increased quantity of exhaled hydrogen signifies that the lactose is not completely digested by your body.
• Stool acidity test – Young children or infants cannot undergo above tests so, stools are tested for the presence of lactic and other acids.

Management of Lactose Intolerance

If there is an underlying cause that is reducing the amount of lactase produced by the intestine then treating it can treat the intolerance other wise no treatment can increase the amount of produced enzyme. Sometimes, you have to see an allergist for management of this condition.

Changing diet: Your doctor will advise you some modification in your daily diet as follows

Limiting the amount of lactose intake by reducing the consumption of dairy products. Some people have to avoid lactose completely.

Increasing the amount of other non-dairy products containing calcium so that you don’t become calcium deficient.

Lactase products: these are available as lactase enzyme-containing tablets or liquid drops. It can be taken before you drink milk or eat dairy products. This enzyme will digest the lactose present in the food and helps in reducing the symptoms.

You might want to read our article, about Non dairy alternatives available for people with milk allergy.

References

• Storhaug CL, Fosse SK, Fadnes LT. Country, regional, and global estimates for lactose malabsorption in adults: a systematic review and meta-analysis. The Lancet. Gastroenterology & Hepatology.
• Misselwitz B, Fox M. What is normal and abnormal in lactose digestion? The Lancet. Gastroenterology & Hepatology.
• Luyt D, Ball H, Makwana N, et al; Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI). BSACI guideline for the diagnosis and management of cow’s milk allergy. Clinical and Experimental Allergy.
• Bayless TM, Brown E, Paige DM. Lactase non-persistence and lactose intolerance. Current Gastroenterology Reports