What Is Lactose Intolerance?
Lactose intolerance is a common digestive issue affecting millions of people worldwide. It occurs when the body cannot produce enough of the enzyme lactase, which is essential for breaking down lactose, the sugar found in milk and dairy products.
Without sufficient lactase, the body struggles to digest lactose, leading to uncomfortable gastrointestinal symptoms like bloating, cramping, diarrhoea, and nausea after consuming dairy.
The severity of lactose intolerance varies from person to person. Some people may experience severe symptoms after consuming just a small amount of lactose, while others can tolerate certain dairy products like yogurt or goat’s milk with minimal discomfort.
The onset of symptoms typically occurs within 30 minutes to 2 hours after dairy consumption. In some cases, individuals may be able to manage their lactose intolerance by using lactase supplements or consuming lactose-free products. Let’s look at the symptoms:
Lactose Intolerance Symptoms
Lactose Intolerance Symptoms: What to Look Out For
Lactose intolerance typically presents itself within 30 minutes to two hours after consuming dairy products. The severity of symptoms varies depending on how much lactose you’ve consumed and how well your body can digest it (Corgneau et al., 2017).
Here are the most common symptoms of lactose intolerance:
These symptoms are caused by undigested lactose making its way into the large intestine, where it ferments, causing discomfort. Depending on the individual, symptoms might even appear up to a day or two after consumption.
Less commonly (Bayless et al., 1975), lactose intolerance may present with additional symptoms such as:
The onset and intensity of these symptoms can vary, but recognizing them early can help manage lactose intolerance effectively.
Up to 65% of People Have Lactose Intolerance
Lactose intolerance is quite a common occurence; however, it is rare in children younger than 5. It is most often seen in adolescents and young adults. On average, 65% of the world’s population is lactose intolerant (Bayless et al., 2017).
Lactose intolerance often develops as children grow older. In infancy, the body produces high levels of lactase to digest breast milk or formula, but this production declines with age. In fact, by the age of 5, lactase activity drops to just 5-10% of its initial levels for many individuals, leading to difficulties in digesting lactose as they get older (Romero-Velarde et al., 2019), (Malik et al., 2023).
Although not a dangerous condition, lactose intolerance can lead to discomfort and an aversion to dairy, a key source of calcium and vitamin D. In some cases, lactose intolerance can also be caused or worsened by other gastrointestinal conditions like coeliac disease, irritable bowel syndrome (IBS), or ulcerative colitis, which damage the lining of the digestive tract.
Understanding lactose intolerance and its causes can help individuals make informed dietary choices and avoid unnecessary discomfort. By identifying the foods that trigger symptoms and exploring alternatives like lactose-free or dairy-free options, those with lactose intolerance can maintain a balanced and enjoyable diet.
Key Points to Remember:
Lactose Intolerance Testing
Diagnosing lactose intolerance typically involves various tests to confirm how well the body digests lactose. Each of these tests plays a role in diagnosing lactose intolerance and determining the best way to manage the condition. Here are the the most common methods used:
Dietary Elimination: By eliminating lactose-containing foods and observing symptom resolution, then reintroducing them to see if symptoms return, lactose intolerance can be identified (Carroccio et al., 1998).
Hydrogen Breath Test: This is the most common diagnostic test. After ingesting lactose, the test measures the hydrogen in the breath. If the hydrogen level rises by more than 20 ppm compared to baseline, it indicates lactose malabsorption (Beyerlein et al., 2008).
Milk Tolerance Test: After drinking 500 mL of milk, blood glucose levels are checked. If blood sugar rises less than 9 mg/dL, it suggests lactose malabsorption (Arola 1994).
Lactose Tolerance Test: Blood glucose is measured after ingesting a lactose-containing liquid. A failure to increase glucose levels by at least 20 mg/dL after 120 minutes indicates lactose intolerance. This test has a specificity of 96% and a sensitivity of 75%. (Hermans et al., 1997).
Genotyping: A newer and more precise test, genotyping identifies genetic predispositions for lactose intolerance. It is commonly used in countries like Germany and Nordic states but is not yet widely available elsewhere (Waud et al., 2008).
Stool Acidity Test: Used mainly for infants and young children, this test measures the acidity of the stool. When lactose isn’t absorbed, it ferments in the colon, producing lactic acid, which lowers stool pH.
Small Bowel Biopsy: Rarely performed due to its invasive nature, this test is mainly used to diagnose celiac disease (Freeman 2018).
What is “Lactose-Free”?
Since lactose can only be found in milk, only milk-containing items can be lactose-free. As a result, the only dairy products that can be lactose-free are those that contain milk.
Therefore, people who are lactose intolerant are advised not to consume cream, buttermilk, some cheeses, ice cream, sour cream, or even hot chocolate mixtures that are not “lactose free”. Fortunately, many of these foods are available on supermarket shelves in lactose-free varieties. The “lactose-free” designation can be found on the label.
Just because a dairy product is labelled as “lactose free”, doesn’t make it allergy free, because it will still contain casein, the protein many people are allergic to.
Greek Yogurt Is Tolerated By Many
If you are lactose intolerant however, you should still be able to tolerate yogurt. The lactose content for natural Greek yogurt containing live cultures is negligible. The enzyme called bacterial lactase found in yogurt facilitates lactose metabolism more efficiently than in any other dairy product. (Savaiano 2014)
Lactose the Prebiotic for Healthy People
A recent study published reveals that lactose may positively affect the gut microbiota in healthy people, offering insights into how dairy products can enhance human health by influencing the gut ecosystem.
Cow’s, sheep’s, and goat’s milk are all rich in various nutrients—proteins, fats, carbohydrates, vitamins, minerals, and bioactive compounds. While much research focuses on milk proteins, there has been less attention to the specific benefits of lactose.
This study examined the impact of lactose on the gut microbiome in 18 healthy adults to understand its role in gut health. (Firrman 2023)
The study results showed:
Lactose, by promoting bacteria like Bifidobacterium and increasing good metabolites, acts as a beneficial moderator of the gut microbiota, suggesting its role in maintaining a healthy gut.
Quit ALL Dairy for 12 Weeks With Any Gut Problem
If you’re dealing with persistent gut issues like cramps, bloating, gas, constipation, or diarrhoea, eliminating dairy for 12 weeks may be the solution you need. If you are suffering with chronic Candida overgrowth, SIBO, IBS, or IBD, my clinical recommendations are to preferably avoid all dairy foods (cow) for several months to allow your gut to heal.
In my natural medicine practice, I’ve seen countless clients resolve long-standing digestive problems after going completely dairy-free for three to six months.
Why Try Dairy-Free Diet?
For many, the body’s inability to properly digest milk proteins or lactose can lead to bloating, cramping, diarrhoea, or constipation. Removing dairy for a period of time allows your digestive system to reset, and gives you a clear indication of whether dairy is contributing to your symptoms.
Whether you consume a little or a lot of cow’s milk—sometimes even just half a cup a day—it can be enough to trigger issues if your body is sensitive to dairy proteins.The only way you’ll know is to stop for a long period of time to establish cause and effect. If you’re after more information, the following pages will give you a lot more detailed information.
Case Studies:
Our clinic has seen numerous patients who chose not to re-introduce dairy into their diets after seeing significant improvements in their health. For example, after:
This 12-week break from dairy, combined with avoiding processed foods and alcohol, has helped many people resolve issues they’ve struggled with for years. If you’re experiencing chronic bowel or sinus problems, giving up dairy for a few months could be the key to restoring your health.
Is It Lactose Intolerance Or A Milk Allergy?
When digestive issues arise after consuming dairy, many people assume they are lactose intolerant. However, it’s important to distinguish between lactose intolerance and a milk allergy—two very different conditions that are often confused.
While lactose intolerance involves the body’s inability to digest lactose, a sugar found in milk, a milk allergy triggers an immune response to milk proteins, such as casein or whey.
In the past, our clinic has seen several patients who thought they were lactose intolerant but later discovered they had an allergy to casein, the protein found in milk.
Symptoms of lactose intolerance are more likely to involve stomach cramps and diarrhea, often triggered by cold dairy products like ice cream.
On the other hand, a milk allergy can manifest in broader ways, affecting not only the digestive system but also the skin (eczema) and respiratory tract (mucus, sinusitis, cough).
Key Differences Between Lactose Intolerance and Milk Allergy:
Commonly Misdiagnosed
Some individuals diagnosed with lactose intolerance may actually have a milk protein allergy, as verified by food allergy blood testing. It’s easy to confuse the two conditions because both can cause similar digestive symptoms.
In fact, health care professionals sometimes misdiagnose irritable bowel syndrome (IBS) when lactose intolerance or a food allergy is the true underlying issue (Cancarevic et al., 2020).
Overlooked Dairy Products:
Many people who eliminate dairy from their diet still unknowingly consume hidden sources of milk, such as chocolate, which often contains milk solids. It’s crucial to check labels carefully, as even small amounts of dairy can trigger symptoms in those with a milk allergy.
Lactose Intolerance in Children:
True lactose intolerance is rare in children. Most cases of digestive discomfort in children due to milk are more likely related to a milk protein allergy. In fact, cow’s milk contains over 60 different proteins, many of which can irritate the immune system.
If your child experiences digestive issues like constipation or diarrhea, it may be wise to evaluate not only milk but also other sources of cow-related proteins like beef and lamb.
Diet Recommendations for Children:
In my clinical practice, I’ve seen children with milk allergies or sensitivities make dramatic improvements in concentration and hyperactivity when dairy is eliminated. Supplementing with Omega-3 fish oil, high in DHA, for at least three months has led to significant behavioural improvements. A good multivitamin and mineral complex also supports their overall health, especially when combined with a well-balanced diet.
Lactose Intolerant Recommendations
Cheese and Lactose Intolerance
While cheese is a dairy product, not all types contain enough lactose to cause digestive issues for those with lactose intolerance. The lactose content in cheese varies significantly depending on how it’s made and aged. In fact, there are over 1,000 different types of cheese, and many of them are tolerable for people who struggle with lactose.
Studies suggest that fermented dairy products, including most cheeses, are often easier to digest for individuals with lactose intolerance. This is because the fermentation process breaks down much of the lactose. Aged cheeses like Parmesan, pecorino, Swiss, and manchego have little to no lactose, making them a safe choice for many.
On the other hand, fresher cheeses such as ricotta, paneer, or boursin contain higher amounts of lactose and are more likely to cause symptoms. If you have lactose intolerance or other gut concerns, opting for aged, hard cheeses is a smart choice. These cheeses not only have minimal lactose but also deliver more robust flavors.
Cheese Recommended:
By selecting the right types of cheese, even those with lactose intolerance or gut issues can still savor the pleasures of cheese without discomfort.
Eric Bakker N.D.
Greetings! I am a naturopathic physician from New Zealand. Although I’ve retired from clinical practice since 2019, I remain passionate about helping people improve their lives. You’ll find I’m active online with a focus on natural health and wellbeing education through my Facebook page and YouTube channel, including this website.
