Lactose Intolerance: Symptoms, Causes & Smart Solutions for Better Digestion!

By Ellie Hadjilucas Public Health & Sports Nutritionist

What is Lactose?

Lactose is a natural sugar found in milk and dairy products, as well as in breast milk. It is a primary nutrient for infants and young children, although it is also commonly consumed in adulthood. In the small intestine, an enzyme called lactase breaks down lactose into two simpler sugars: glucose and galactose. These sugars are then absorbed into the bloodstream, providing energy to the body.

What Causes Lactose Intolerance?

Lactose is essential for infants and young children, but its role diminishes with age. As a result, lactase activity often decreases after childhood. When lactase activity is too low, some lactose remains undigested in the small intestine, leading to a condition called lactose malabsorption. In this case, the undigested lactose reaches the colon, where it is fermented by gut microbiota.

Most people with lactose malabsorption do not experience symptoms or health issues. However, when lactose malabsorption causes digestive discomfort, it is known as lactose intolerance.

What is Lactose Intolerance?

Lactose intolerance occurs when lactose malabsorption leads to digestive symptoms. The most common symptoms include:

• Bloating
• Cramps
• Diarrhoea
• Gas

These symptoms arise from the gases and acids produced when undigested lactose is fermented in the colon.

How is Lactose Intolerance Diagnosed?

Diagnosing lactose intolerance can be challenging, as self-diagnosis is often inaccurate. Studies show that only one in two self-diagnoses is confirmed through medical testing. The most reliable diagnostic method is the breath test. During this test, the patient consumes a standard dose of lactose (between 20 and 50g), and their exhaled air is analyzed to measure hydrogen levels. Elevated hydrogen levels, combined with the presence of digestive symptoms, confirm a diagnosis of lactose intolerance.

Is Lactose Intolerance an Allergy?

Despite common misconceptions, lactose intolerance is not a food allergy. Cow’s milk protein allergy, although much rarer, presents different symptoms, such as:

• Hives
• Nausea
• Swelling
• Wheezing

Allergic reactions occur because the immune system overreacts to milk proteins, such as casein and whey proteins. Symptoms may appear within an hour of consuming dairy or even up to three days later.

Should People with Lactose Intolerance Avoid Dairy Products?

Complete avoidance of dairy is not necessary for most people with lactose intolerance. Research suggests that many individuals can tolerate up to 12 grams of lactose per day with minimal or no symptoms, especially when consumed in small amounts throughout the day and with meals.

Lactose Content in Dairy Products

Different dairy products contain varying amounts of lactose:

• Low or lactose-free cheeses: Cheddar, Provolone, Mozzarella, Grana Padano, Camembert, Halloumi, Kefalotyri.
• Yoghurt with live bacterial cultures: Most yoghurts contain active bacterial cultures that help break down lactose, making them easier to digest. The semi-solid texture of yogurt also slows its passage through the intestines, improving lactose digestion.

What Are the Health Risks of Lactose Intolerance?

Lactose intolerance can cause daily discomfort but does not have direct health consequences. However, completely eliminating dairy from the diet without proper nutritional planning can lead to nutrient deficiencies, particularly calcium. Worlwide and European organizations such as the NIH (US-National Institutes of Health ,the NMA (US – National Medical Association), EFSA (European Food Safety Authority) and the FAO (Food and Agriculture Organization of the United Nations) recommend that individuals with lactose intolerance should not entirely avoid dairy products.

Managing Lactose Intolerance

If you experience symptoms of lactose intolerance, consider the following strategies:

• Choose dairy products with low or no lactose.
• Consume dairy in small amounts and with meals.
• Try probiotics or lactase enzyme supplements to improve lactose digestion.
• Explore dairy alternatives, such as almond milk, soy milk, oat milk, or lactose-free milk.

Conclusion

Lactose intolerance does not mean you must completely eliminate dairy from your diet. By understanding your tolerance levels and making informed choices, you can enjoy dairy products while keeping symptoms under control.

References

• Bailey et al. J Natl Med Assoc 2013;105:112-27.
• Black et al. Am J Clin Nutr 2002;76:675-80.
• Commission CA. Codex standard for fermented milks. Food and Agriculture Organization United Nation Roma 2003:1-5.
• Efsa Panel on Dietetic Products N, Allergies. Scientific Opinion on the substantiation of health claims related to calcium and maintenance of normal bone and teeth (ID 2731, 3155, 4311, 4312, 4703), maintenance of normal hair and nails (ID 399, 3155), maintenance of normal blood LDL-cholesterol concentrations (ID 349, 1893), maintenance of normal blood HDL-cholesterol concentrations (ID 349, 1893), reduction in the severity of symptoms related to the premenstrual syndrome (ID 348, 1892), “cell membrane permeability” (ID 363), reduction of tiredness and fatigue (ID 232), contribution to normal psychological functions (ID 233), contribution to the maintenance or achievement of a normal body weight (ID 228, 229) and regulation of normal cell division and differentiation (ID 237) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA Journal 2010;8:n/a-n/a.
• Efsa Panel on Dietetic Products N, Allergies. Scientific Opinion on the substantiation of health claims related to live yoghurt cultures and improved lactose digestion (ID 1143, 2976) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA Journal 2010;8:n/a-n/a.
• Heaney et al. J Am Coll Nutr 2000;19:83S-99S.
• Heaney et al. J Am Coll Nutr 2009;28 Suppl 1:82S-90S.
• Nicklas et al. Am J Clin Nutr 2011;94:191-8.
• Suchy et al. NIH Consens State Sci Statements 2010;27:1-27.