Health and Fitness

Fact Sheet Series: Lactose Intolerance

Lactose intolerance is a general description used to refer to people who have varying degrees of difficulty digesting lactose. Lactose is a sugar that is found in different types of milks in varying amounts. Once consumed, lactose is broken down by an enzyme called lactase into two simpler forms of sugar called glucose and galactose. These are then absorbed into the bloodstream and used by the body for energy. People who have lactose intolerance have a reduction in the amount of lactase enzyme they produce (although not necessarily a complete absence). This in turn contributes to the symptoms of lactose intolerance.



Lactose intolerance affects many people and it can be a permanent condition or it can be temporary, for example, occurring after an infection in the gut. Lactose intolerance must not be confused with a cow’s milk allergy. Milk allergy is a reaction by the body’s immune system to one or more milk proteins and can be life threatening when just a small amount of milk or milk product is consumed. Milk allergy most commonly appears in the first year of life while lactose intolerance occurs more often in adulthood.

People with lactose intolerance do not need to eliminate milk and products made from milk completely. They can often tolerate small to moderate amounts in the diet without experiencing symptoms.

Lactose intolerance can be diagnosed by several methods, 1) Elimination Diet, 2) Hydrogen Breath Test and 3) Stool Acidity Test. If you suspect you have lactose intolerance, speak to your doctor in order to confirm which testing method may be best for you.


Signs and Symptoms indicating Lactose Intolerance

Symptoms of lactose intolerance may appear 30 minutes to 2 hours after consuming milk and milk products. Some of the common symptoms are:

  • abdominal pain
  • abdominal bloating
  • gas
  • diarrhoea
  • nausea

The severity of symptoms may vary based on the amount of lactose consumed and the amount a person can tolerate. For some people, the symptoms can be quite mild and therefore difficult to link to any particular component of the diet. If you suspect lactose intolerance is the cause of your symptoms, it is important to obtain a definite diagnosis prior to reducing your intake of milk and to consult your health-care professional to ensure that you are mindful of your current health and any restrictions that are appropriate for you. You should immediately seek medical attention if there are any unanticipated changes to your physical condition at any time.

It is also important to eliminate the possibility of other gastro-intestinal diseases that share similar symptoms. Before changing your diet, seek advice from your doctor or an Accredited Practising Dietician.

Sources of Lactose

The table below lists the lactose content of some commonly consumed dairy products. Yoghurt may be tolerated by some individuals because some of the lactose is pre-digested by the bacteria in the yoghurt.

Please note the lactose content varies between brands, and as such may vary from the amounts listed below.


Managing Lactose Intolerance

Symptoms of lactose intolerance can be managed with dietary changes or simple exclusion. Some people with lactose intolerance may be able to tolerate a certain amount of lactose in their diet but it isn’t necessary to try to keep it in the diet as there are so many alternatives to cow’s milk products on the market.

Here are a few tips which will help you when making changes to your diet:

  • Try excluding milk first to see if this has a positive effect, if symptoms persist then move to eliminate more or all cow’s milk based products from the diet.
  • Lactose free and lactose reduced milk and milk products are available at most supermarkets.
  • They are identical to regular milk except that the lactase enzyme has been added to it.
  • Soy milk and soy products are great alternatives which are lactose free and most are fortified with calcium (check the label).
  • Try rice, almond or oat milk as these are great alternatives. With these products and soy milk, experiment with different brands to find the one you like the best as many taste quite different.
  • Try milk based products from other animals such as a sheep or a goat yoghurt and cheese. It may sound a bit strange to start with but they often taste better and this is why many gourmet restaurants use these products in their cooking.
  • Don’t worry about your calcium intake as there are plenty of calcium in things like baby spinach and other green leafy vegetables.


Other important points to remember when managing lactose intolerance

Calcium is absorbed and used in the body only when enough Vitamin D is present so it’s important to also be aware of how much Vitamin D you are getting. Vitamin D comes from food sources such as eggs, liver and more. Regular exposure to sunlight also helps the body naturally absorb Vitamin D. To get enough sunlight to produce Vitamin D, expose your hands, face and arms (around 15% of your body surface) to sunlight for about 6-8 minutes, 4-6 times per week (before 10am or after 2pm Standard Time in summer, for moderately fair people).

Milk and milk products are present in many processed foods, hence when following a low lactose or lactose free diet it’s important to read the ingredients on the food labels. Items to look out for on the ingredient list are: – milk, lactose, whey, curds, milk by-products, dry milk solids and non-fat dry milk powder.

Lactose is also commonly used in some prescription medicines, including birth control pills, and over-the-counter medicines including products to treat stomach acid and gas. These medicines can cause symptoms in people with severe lactose intolerance.

The following food products contain small amounts of lactose. If you have severe lactose intolerance, they may cause symptoms.

  • Bread and baked goods
  • Pastries
  • Breakfast drinks varying amounts
  • Instant soup
  • Processed meats such as sausages, margarine
  • Salad dressings
  • Protein powder and bars
  • Chocolates and some confectionary
  • Liquid and powdered milk based meal replacements
  • Powdered coffee creamers