How do I know if I’m lactose intolerant?

Lactose intolerance is a condition in which you’re unable to digest lactose, a sugar found in milk and dairy products. The intolerance is due to an insufficient amount of lactase, an enzyme in the small intestine that breaks down lactose into simple sugars, glucose and galactose. Only simple sugars are able to be absorbed by our digestive system; therefore, when lactose isn’t split into simple sugars, it can’t be absorbed. It stays in the intestine and, as a result, gas is produced, which leads to the development of symptoms.

Symptoms may include abdominal pain and cramps, nausea, bloating, gas and diarrhoea. These typically start between half an hour and two hours after drinking milk or eating dairy products, and the severity of symptoms depends on the amount of lactose ingested. However, it doesn’t cause damage to the lining of digestive system.

There are four types of lactose intolerance: primary lactose intolerance is when the amount of lactase in the small intestine reduces as one ages; secondary lactose intolerance is due to different conditions affecting the small intestine – for example, infection, celiac disease or inflammatory bowel disease; developmental lactose intolerance may occur in premature babies but can improve over time; and congenital lactose intolerance is a condition in which little or no lactase is made from birth.

Diagnosis may be confirmed if symptoms resolve after eliminating lactose from the diet or replacing milk with lactose-free milk. Other tests are sometimes necessary if the relationship between lactose elimination and symptoms is inconclusive; lactose intolerance is tested by a hydrogen breath test.

It’s important to note that lactose intolerance is different from a milk allergy, which is a more serious condition. Milk allergy is an adverse immune reaction to a mild protein called casein. It’s tested by a skin prick or blood test testing for antibodies.

Lactose intolerance is typically managed by decreasing the amount of lactose in one’s diet or taking lactase supplements available over the counter. People with lactose intolerance are usually able to drink small amounts of milk or eat small portions of yoghurt or hard, matured cheese without developing significant symptoms.


It is not necessary to remove completely milk and dairy from the diet (unless specifically recommended), for two main reasons. First, because this grup of foods contain essential nutrients like calcium, zinc, phosphorus, selenium, vitamin A, vitamin B12 and high quality proteins, which are necessary in each period of our life. Secondly, if our body is able to digest very small amount of lactose, it will be easy eating out without triggering any symptoms and this results in a better management of the new condition and causing less stress.

When diagnosis is made, it is sufficient to reduce the daily intake of lactose following few easy tips:

  • spread out during the day the amount of lactose that can be tolerated, instead of consuming different foods with lactose in the same meal;
  • replace normal milk with lactose free milk which is available in cold storage or NTUC or use plant-based milk alternatives added with calcium which are naturally lactose free;
  • use fresh products which contain lactose in small quantity or trace like yogurt, kefir, butter and hard cheese;
  • avoid hidden sources of lactose like processed meat or fish, gravy stock powder, pasta or vegetables with cream/sauces, ice cream, and fast food foods (meat, ham, bread and fries);
  • lactose can come under different names, so learn how to read the labels and look for the following ingredients: milk, milk powder, evaporated milk, condensed milk, non-fat dry milk powder, dry milk solids, milk cream, cream, curd, whey, lactose;
  • when you are eating out, ask to put sauces aside and choose less elaborated preparations without cream or gravy.