Lactose Intolerance Symptoms

Lactose intolerance symptoms are caused by the inability to digest lactose (the sugar in milk and milk products). They affect the gastrointestinal tract and include:

Lactose intolerance symptoms include bloating, abdominal pain, nausea and gas.

  • Abdominal pain

  • Bloating

  • Diarrhea

  • Gas or flatulence

  • Nausea

The severity of these symptoms varies from person to person depending both on the level of lactase1 your body produces as well as the amount of lactose you have eaten.

Some people experience mild lactose intolerance symptoms, whilst for others the effects are severe. Likewise, some can manage small amounts of lactose without provoking symptoms, whilst others cannot. Generally speaking though, if you are lactose intolerant, the more lactose you include in your the diet the greater the likelihood that you will experience symptoms.

Be aware though that a wide range of digestive conditions can cause the symptoms listed above. If you have these symptoms don’t automatically assume that you are lactose intolerant. Be sure to visit you physician to discuss the problem.

Foods Containing Lactose

The following foods are likely to cause symptoms of lactose intolerance in susceptible people:


All animal milk contains lactose. Different animal milks contain different levels. Have a look at our table below to see the exact lactose content of the most common animal milks:

Animal MilkLactose (g/100ml)

All Milk-Based Foods

All milk-based foods contain lactose. These include:

  • Yogurt: Store-bought yogurt contains a good deal of lactose. However if you make your own yogurt, you can virtually eliminate the lactose by fermenting it for between 24 and 30 hours. See our page on probiotic yogurt for more details.

  • Cheese: Hard cheeses contain less lactose than soft or cream cheeses.

  • Cream

  • Butter

  • Buttermilk

  • Ice cream

Many Processed Foods

Be aware too of hidden lactose in processed foods. Foods that may contain lactose include:

  • Bread and other baked goods

  • Cookies or biscuits

  • Chocolate

  • Breakfast cereals

  • Soup mixes

  • Salad dressings

  • Instant potato mix

  • Margarine

  • Candies or sweets

Pharmaceutical Medicines

Many pharmaceutical medicines also contain small amounts of lactose.

Making Dietary Choices

It therefore make sense to check the packet of any manufactured foods or medicines before you ingest them!

Finally some people with lactose intolerance find that they can enjoy foods containing lactose if they take lactase enzymes with these foods. These enzymes are available in capsule or liquid form. For some taking these enzymes totally eliminates their lactose intolerance symptoms, whilst for others they merely reduce them.

Types of Lactose Intolerance

There are three types of lactose intolerance:

  • Congenital lactose intolerance is inherited and manifests from birth in an inadequate, defective or total lack of lactase production. This type of lactose intolerance is rare.

  • Primary lactose intolerance is the term given to lactose deficiency that either develops in individuals who could previously tolerate lactose (Late Onset Lactose Deficiency) or in premature babies, who are often lactose deficient due to their immaturity (Development Lactase Deficiency). Late onset lactose deficiency is by far the most common type of lactose intolerance.

  • Secondary lactose intolerance occurs as the result of gastrointestinal disease such as Crohn’s disease, colitis, celiac disease, food intolerance and severe gastroenteritis.

Individuals from these three groups differ in their degree of intolerance and thus in the level lactose intolerance symptoms.

Treatment for Lactose Intolerance

Milk contains lactose

Treatment for all three types of lactose intolerance involves a lactose-free diet and/or lactase enzymes.

In recent years the discovery that certain strains of probiotic bacteria help digest lactose by converting it into lactic acid2, has led to consideration of the role of beneficial bacteria in treating lactose intolerance.

Studies to date suggest that certain probiotic bacteria, specifically Streptococcus thermophilus (S.thermophilus) and Lactobacillus bulgaricus (L. bulgaricus) 3 and to a lesser extent Lactobacillus acidophilus4 (L. acidophilus), may indeed be useful in treating lactose intolerance. However more research is needed in this area. Both S. thermophilus and L. bulgaricus are used to culture yogurt and thus the results of this research may go some way to explaining why many people who are lactose intolerant can manage yogurt.

If you are interested in trying probiotics for lactose intolerance symptoms be sure to choose either probiotic yogurt or one of the probiotic supplements containing S. thermophilus and L. bulgaricus. Both these strains of probiotic bacteria are available as single strain high potency probiotic supplements from Custom Probiotics. By far the most cost effective way of trying these specific probiotic strains, however, is simply to eat probiotic yogurt. This will not supply you with as many probiotic organisms as the Custom Probiotics supplements.

The choice is yours!


1. Lactase is the enzyme produced in the small intestine that digests the milk sugar, lactose

2. Sanders ME; "Considerations for use of probiotic bacteria to modulate human health; The Journal of Nutrition; (February 2000); 130 (2S Suppl): 384S–390S

3. De Vrese M et al; Probiotics: Compensation for Lactase Insufficiency?; Am J Clin Nutr; Feb 2001;73:421-429

4.Lin MY et al, Management of Lactose Maldigestion by Consuming Milk Containing Lactobacilli; Dig Dis Sci Jan 1998;43(1):133-7

Return from Lactose Intolerance Symptoms to Human System Digestive Diseases

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