What is Lactose Intolerance?
Awareness around food and dietary sensitivities has grown significantly in recent years, and one of the most common sensitivities is lactose intolerance. Lactose is a sugar found naturally in milk and dairy products. It is normally broken down in the gut by an enzyme called lactase. However, many people produce too little lactase—or none at all—making it difficult for them to digest lactose properly. When undigested lactose moves to the colon, it draws in water and is fermented by the bacteria, producing gas. This can cause uncomfortable symptoms such as:
- Bloating
- Cramping
- Gas
- Diarrhea
- Nausea
What Causes Lactose Intolerance?
It’s estimated that about 65% of people, worldwide, are lactose intolerant. While most people can digest dairy in infancy, lactase production often decreases after childhood, leading to symptoms of intolerance during adolescence or adulthood. Thousands of years ago, a gene mutation emerged that allowed some populations to maintain lactase production into adulthood – meaning they could continue tolerating lactose. This trait is more common among people with northern European, as well as some Middle Eastern, African, and southern Asian ancestry. Lactose intolerance can also result from:
- Damage to the small intestine from conditions like Celiac disease, infections, or surgery. Because lactase is produced by the cells lining the small intestine, anything that harms this lining can reduce lactase levels and impair lactose digestion.
- Congenital lactase deficiency, a rare genetic condition present from birth.
- Underlying gastrointestinal conditions such as irritable bowel syndrome (IBS), small intestinal bacterial overgrowth (SIBO), or visceral hypersensitivity.
How Does Lactose Intolerance Get Diagnosed?
Many people self-diagnose lactose intolerance based on patterns of symptoms after eating dairy. Symptoms can begin as soon as 30 minutes after consuming lactose and may last up to 48 hours as the lactose passes through the digestive tract. To test yourself, try eliminating lactose-containing foods for at least 3 days or up to 2 weeks, then reintroduce them and observe any changes in your symptoms. For a formal diagnosis, other tests are available as well, including:
Hydrogen breath test.
After consuming a lactose-containing drink, your breath is tested for hydrogen. Higher hydrogen levels indicate poor lactose absorption and fermentation by gut bacteria.
Blood sugar test.
After drinking lactose, your blood sugar response is measured. If lactose is properly digested and absorbed, blood sugar rises. If not, there will be little or no change.
Stool acidity test.
Primarily used for infants, this test detects acidic byproducts like lactic acid in the stool, indicating poor lactose digestion.
What Can I Eat if I am Lactose Intolerant?
Lactose is found only in dairy products, so avoiding or limiting dairy—or choosing lactose-free alternatives—is key to managing symptoms. However, some dairy products have a lower lactose content and may be tolerable, depending on each individual person and their symptoms. Most people can tolerate some level of lactose without causing symptoms, so it may take some experimenting to determine your tolerable threshold. For example, most people can also tolerate dairy cooked or baked into foods, however some people still cannot. In general, Greek yogurt and hard cheeses tend to have lower lactose content than milk, ice cream, or soft cheese. There are also now many lactose-free and plant-based options available. Consider exploring these options:
Milk
- Dairy-based but lactose-free: Lactaid, Fairlife
- Non-dairy: Oat, almond, soy, or coconut milk
Yogurt
- Dairy-based but lactose-free: Chobani Lactose-Free, Fage Lactose-Free
- Non-dairy: Almond or coconut-based (e.g., Silk)
Cheese
- Dairy-based but lactose-free: Good Culture Lactose-Free Cottage Cheese, Lactaid Cottage Cheese, LactoFree cheeses
- Non-dairy: Cashew-based cheese, nutritional yeast
- Low-lactose cheese options: Hard cheeses (parmesan, Swiss), and some soft cheeses (brie, feta, mozzarella)
Ice Cream
- Dairy-based but lactose-free: Breyers Lactose-Free, Lactaid, Fairlife
- Non-dairy: Oatly, So Delicious Dairy Free
Protein Powders & Shakes
- Dairy-based but lactose-free: Fairlife protein shakes
- Non-dairy: OWYN, Vega, Orgain, PB2, PBFit
Butter
- Dairy-based but lactose-free: LactoFree, Green Valley
- Non-dairy: Earth Balance, Smart Balance
Need Help Managing Lactose Intolerance?
Think you might have lactose intolerance? A registered dietitian can help you navigate your tolerance level and find foods and meal options that support your health and reduce symptoms. You can schedule online here or call 919-237-1337 (option 4) to schedule over the phone.
