What Foods to Avoid with Lactose Intolerance

If you are one of the 65% of people affected by lactose intolerance, you're familiar with the discomfort dairy products can cause. The lactose-free diet is a strategic approach that excludes lactose-containing foods to help manage these symptoms. While many recognize that milk products contain lactose, hidden sources in other foods can complicate avoidance. This article will explore which foods are safe to enjoy and which should be avoided to help manage lactose intolerance effectively.

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Understanding Lactose Intolerance

Lactose intolerance is a digestive condition resulting from the inability to digest lactose, the sugar found in milk and dairy products. This condition is caused by lactose malabsorption, which occurs due to a lactase deficiency, an enzyme produced in the small intestine that breaks down lactose into its building blocks, glucose and galactose. However, not everyone with lactose malabsorption experiences symptoms; only those who do are considered lactose intolerant. 

Symptoms typically occur within 30 minutes to two hours after consuming lactose-containing products and may include:

• Abdominal pain or cramping
• Bloating
• Gas and flatulence
• Nausea
• Diarrhea
• Stomach rumbling

Lactose Intolerance vs. Milk Allergy

Milk allergy is an immune-mediated response to one or more proteins in cow's milk. Symptoms can range from mild to severe and may include hives, wheezing, itching, swelling, vomiting, and, in severe cases, anaphylaxis, which can be life-threatening.

Unlike milk allergy, lactose intolerance does not involve the immune system.

Types of Lactose Intolerance

Lactase non-persistence, the gradual decline in lactase activity beginning in infancy, is the most common cause of lactose intolerance. It is particularly prevalent in individuals of Asian, African, Hispanic, and American Indian descent, with symptoms typically arising in adolescence or early adulthood. (25) 

Acquired, or secondary, lactose intolerance results from injury to the cells lining the small intestine (25). Causes include:  

• Crohn's disease
• Celiac disease
• Gastroenteritis
• Small intestinal bacterial overgrowth (SIBO)
• Chemotherapy or radiation
• Antibiotics 

In rare cases, lactose intolerance can present from birth, caused by an inherited genetic mutation in the lactase gene, resulting in lactase deficiency (25).  

Premature birth can result in temporary lactose intolerance in infancy due to an underdeveloped digestive tract. This is unrelated to genetics and will resolve as the child and digestive tract mature. (25) 

Diagnosing Lactose Intolerance

Diagnosis of lactose intolerance typically involves a combination of patient history, symptom evaluation with dietary manipulation, and specific tests such as the hydrogen breath test, lactose tolerance test, or stool acidity test (for pediatrics). The hydrogen breath test is most commonly used. It involves the patient collecting a series of breath samples after consuming an oral dose of lactose. The test is positive if hydrogen levels in the breath exceed 20 ppm over baseline within three hours.

Why Avoid Foods With Lactose?

Unlike other gastrointestinal conditions, such as celiac disease or milk allergy, consuming lactose with lactose intolerance is not life-threatening and does not risk permanent damage to the digestive tract. However, recurrent digestive upset and irregular bowel movements can significantly impact an individual's quality of life. Persistent discomfort, the need to frequently visit the bathroom, and the anxiety around consuming dairy products can interfere with daily activities, work productivity, and socializing.

Chronic diarrhea, a common symptom in those who continue to consume lactose despite intolerance, poses a risk for consequences, including nutrient malabsorption, anemia, dehydration, electrolyte imbalances, and even kidney injury.

Additionally, chronic irritation and inflammation of the bowel due to continuous lactose consumption can weaken the integrity of the intestinal lining, potentially leading to a condition known as leaky gut syndrome. This condition may contribute to systemic inflammation and exacerbate other health issues.

Common Foods Containing Lactose

To help manage symptoms of lactose intolerance, doctors may suggest eating a lactose-free or lactose-restricted diet. Lactose is naturally present in milk and dairy products and is often used as an additive in many processed food goods. 

Dairy Products

Lactose is naturally present in all cow's, goat's, and sheep's milk and milk-derived products unless removed. However, the concentration of lactose in dairy products varies. Some dairy products contain low amounts of lactose and can be tolerated by individuals with lactose intolerance. For example, butter contains trace amounts of lactose and is unlikely to cause symptoms if eaten in moderation. The chart below provides examples of dairy products and their respective lactose content. (19)

While yogurt contains lactose, yogurts with live bacterial cultures are often better tolerated than other forms of dairy because they contain bacterial-derived lactases that assist with digestion. 

Processed and Prepared Foods

Lactose is often added to prepared foods as a binder, stabilizer, or to enhance flavor and texture. Examples of processed and prepared foods that may contain lactose include: 

• Bread and baked goods
• Pancake, biscuit, and cookie mixes
• Breakfast cereals
• Instant potatoes and soups
• Flavored potato chips
• Cream-based sauces
• Margarine
• Processed lunch meats
• Salad dressings
• Candy (11, 31) 

Hidden Sources of Lactose

Lactose is used as a filler in over 20% of prescription medications and over 65% of over-the-counter drugs (24).  

Identifying Lactose in Foods

Learning to read food labels and identify lactose-containing ingredients is extremely helpful for navigating a lactose-free diet. 

Ingredients that indicate a product contains lactose include:

• Milk
• Skim milk
• Milk sugar
• Lactose monohydrate
• Whey
• Whey protein concentrate
• Curds
• Milk by-products
• Milk solids
• Milk powder
• Butter
• Cheese (12, 24) 

Alternative Options to Avoid Lactose

Non-dairy, unprocessed foods are naturally free of lactose. The following foods can be safely consumed by people who are lactose intolerant: 

• Meat, poultry, and seafood
• Eggs
• Fruits 
• Vegetables
• Whole grains
• Nuts
• Seeds
• Legumes
• Herbs and spices
• Beverages: water, black coffee, tea, juice

Lactose-free and lactose-reduced milk products are widely available in grocery stores and cater to those with lactose intolerance. They offer the nutritional benefits of regular dairy without digestive discomfort. Popular brands include Lactaid, Fairlife, and Green Valley.

Plant-based dairy alternatives are safe for people with lactose intolerance to consume. Dairy-free milk, cheese, yogurt, and butter products from soy, almond, coconut, rice, and oats don't contain lactose. 

Tips for Managing a Lactose-Free Diet

Many people with lactose intolerance can safely consume up to 12 grams of lactose (equivalent to one cup of milk) without experiencing symptoms, allowing for some dietary flexibility. Here are some tips for effectively managing a lactose-free diet:

Meal Planning and Preparation

Plan meals ahead to ensure they are balanced and meet nutritional requirements without relying on lactose-containing products. Preparing meals at home allows for better control over ingredients. A sample meal plan can be found here.

Consulting with a nutritionist or dietician can help tailor a dietary plan to individual needs and ensure all nutritional needs are met despite eliminating foods from the diet. 

Try incorporating low-lactose foods into your diet. Hard cheeses, cottage cheese, kefir, live culture yogurt, and reduced-lactose milk tend to be well-tolerated, especially in small servings and spaced throughout the day. (5) 

Taking lactase digestive enzymes with meals can also increase tolerance to lactose-containing foods and help reduce lactose-associated gastrointestinal symptoms. 

Eating Out and Social Situations

When dining out, check the restaurant's menu beforehand to ensure it has items conducive to a lactose-free diet. Inform the restaurant staff about your lactose intolerance, and don't hesitate to ask about lactose-free options or substitutions. 

Bringing lactose-free snacks or dishes to share can ease the challenge of managing dietary restrictions in social settings.

Nutritional Considerations

Dairy products contain important nutrients, including calcium, phosphorus, and vitamins A, B2, and D. If precautions are not taken to replace these nutrients in the diet with other foods or supplements, long-term dairy elimination can lead to nutrient deficiencies, especially calcium and vitamin D. (11) 

The following chart outlines recommended daily intakes and lactose-free sources of calcium and vitamin D:

When to Seek Professional Guidance

Patients are encouraged to see their doctor if they suspect they have lactose intolerance. A comprehensive and diagnostic health evaluation can confirm the diagnosis before patients unnecessarily change their diets.

Routine follow-up is encouraged, especially if patients continue to experience digestive symptoms despite eliminating lactose from their diet or if they have concerns about nutritional inadequacies due to a restricted diet. 

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Key Takeaways

• Individuals with lactose intolerance should avoid dairy products. Alternatives, such as lactose-free or plant-based dairy products, can provide suitable replacements.
• Learning to read food labels helps navigate and implement a lactose-free diet. Patients should also be encouraged to maintain a balanced diet, paying extra attention to their dietary calcium and vitamin D intake, which can easily become deficient when following a dairy-free diet.
• Taking a positive approach to dietary changes can greatly improve the quality of life for those with lactose intolerance. By focusing on delicious and satisfying lactose-free alternatives, individuals can enjoy meals without discomfort.