It’s estimated that between 30 and 50 million Americans experience lactose intolerance and that 75 percent of the world’s population suffers from the condition to some degree. There are varying ranges of the condition. It may affect some people mildly and cause others to have a severe allergic reaction. Lactose intolerance is different than a milk allergy, which can cause a life-threatening reaction, but it can still hamper the quality of life in patients. Read on to learn more about lactose intolerance, what its causes are, and how to effectively avoid foods that cause a reaction. 

What Is Lactose Intolerance?

Lactose intolerance is a reaction to milk and milk products, which causes digestive disturbances in a patient who has the condition. It is different than a milk allergy, which is a reaction to the proteins found in milk. Lactose refers to the sugars found in milk, not the proteins, and lactose intolerance is a reaction to the sugar. More specifically, those with lactose intolerance do not produce enough of the lactase enzyme. To process any type of sugar efficiently, we require enzymes. Lactase helps us process and digest lactose.

Lactose is comprised of two sugars, meaning it is a disaccharide and made up of glucose and galactose. When we digest sugars, they are converted into energy. Lactase is needed to break down the molecules of glucose and galactose. Without enough lactase, lactose is not digested properly, which can cause a whirlwind of digestive problems. Lactose intolerance also develops over time. Lactose is also prominent in breast milk, but it is rare to see an infant or toddler with lactose intolerance, as many digest lactose just fine. The intolerance is rarely diagnosed under the age of five. 

Causes of Lactose Intolerance

There are two separate types of lactose intolerance, and both have different causes. The first type is known as primary lactose intolerance, which is the most common type that affects the world’s population. In primary lactose intolerance, our bodies produce less lactase over time, which leads to digestive problems. Researchers and scientists believe that this type of lactose intolerance may be genetic, as it profoundly affects the Asian population. It’s estimated that up to 80 to 90 percent of Asians have primary lactose intolerance, while it affects 44 percent of Americans. Only 5 to 17 percent of Europeans are affected, leading to a genetic correlation. 

Secondary lactose intolerance is a rare condition that is caused by illness. It is usually temporary and is caused by inflammation in the gut due to illness. The gut inflammation causes a temporary pause in lactase production. This type of lactose intolerance may also be caused by celiac disease. 

What Are the Symptoms of Lactose Intolerance?

There are several marked symptoms of lactose intolerance. When lactose reaches the small intestine and colon undigested, it has had a reaction with gut bacteria, which in turn causes gas and short-chain fatty acids. The most common symptom of lactose intolerance is bloating and gas, but it can also cause pain and abdominal cramps. Those who are severely lactose intolerant may experience diarrhea and urgency to go to the bathroom. Others may experience constipation. Severe lactose intolerance can also cause vomiting and sharp pain in the lower abdomen. Those who have diarrhea and/or vomiting could also experience dehydration. The severity of symptoms can vary widely in each patient. This depends on the severity of the patient’s lactose intolerance itself, along with how many milk products were consumed. 

Which Foods Contain Lactose?

Many foods contain lactose. Anything that has a dairy ingredient in it or dairy products will contain lactose. This can include some favorite staple foods that patients may have a tough time avoiding. Lactose is contained in:

  • All types of cow’s milk
  • All types of cheese
  • Butter
  • Ice cream
  • Yogurt
  • Goat’s milk

It’s important to read the ingredient list when you shop or ask questions when dining out, as lactose can “hideout” in many other foods. You want to check for lactose in the following types of foods:

  • Desserts
  • Ready-made meals 
  • Sauces and gravies
  • Cookies and crackers
  • Potato chips
  • Nuts
  • Breakfast cereals
  • Quiche
  • Cookies
  • Biscuits
  • Bread
  • Chocolate (many types are milk chocolate)

However, it can be hard to understand food labels sometimes. Many labels in modern times carry a warning that says “may contain milk products.” To be sure, you can look for the following ingredients while shopping: milk solids, milk powder, buttermilk, whey protein or whey protein concentrate, sour cream, milk casein, curds, malted milk, and milk byproducts. Of course, ingredient lists that list cheese or milk/milk products are dead giveaways. 

Some things on ingredient lists are not lactose, and this can be confusing for some. It’s important to remember that casein, lactate, lactic acid, or lactalbumin are not related to lactose. Casein only is if it specifically says milk casein.

Those who are severely intolerant may want to avoid all types of lactose, but many patients can eat small amounts of lactose - and dairy contains many nutrients that the body needs. Therefore, it’s good to know which foods contain small amounts. Those with mild lactose intolerance may be able to tolerate up to 18 grams of lactose in a 24-hour period. Butter and many kinds of cheese contain small amounts of lactose, such as Swiss, mozzarella, Colby, cheddar, and Monterey Jack. Yogurt also does not exacerbate symptoms in many patients. 

Those who are severely intolerant should still seek out the nutrients that dairy provides. Dairy contains calcium, protein, and vitamins A, B12, and D. However, it’s perfectly okay to eat a diet without dairy products, as many vegans do. You can take vitamin supplements to enhance your diet and look for calcium-fortified foods. Other good sources of calcium include boned fish, spinach, kale, tahini, almond butter, and tempeh. Patients can also look for lactose-free foods, such as lactose-free milk, which contains the same vitamins. 

Lactose Intolerance Diagnosis and Treatment

If you’re experiencing digestive issues, your healthcare provider will want to pinpoint the cause. A simple way to tell is to try a lactose-free diet for two weeks. If symptoms improve, the cause is likely lactose intolerance. However, your physician may want to run tests, such as a hydrogen breath test, stool sample, or a biopsy to look for underlying conditions. 

There is no medical treatment for lactose intolerance other than to avoid the foods that cause the condition. After a person goes lactose-free for two weeks, they can then try to introduce foods that contain lactose at a small rate to see how much they can tolerate. A bit of guesswork is involved, but many patients find they can tolerate small amounts of lactose, sometimes upward of 12 grams a day. 

If you are experiencing digestive problems or believe you may have lactose intolerance, book an appointment at Needham Gastroenterology Associates today. Our office and endoscopy unit is open Monday through Friday to provide a wide scope of gastrointestinal needs.