What is Lactose Intolerance?

Lactose intolerance is a common digestive problem where the body lacks the ability to break down and absorb lactose. It is a physiological condition normally referred to as malabsorption of lactose.

What is Lactose?

Lactose is a common, natural sugar. It is a disaccharide in nature. It is formed by a condensation reaction between glucose and galactose.

Lactose is commonly found in dairy products, such as milk and yogurt. For its absorption into the body, it is first broken down into its constituent sugars. Only then the linings of the small intestine can absorb lactose.

What causes Lactose Intolerance? 

“Lactase” is the enzyme which is primarily involved in the digestion of lactose. A person becomes lactose intolerant when his/her small intestine lacks the respective enzyme. The condition is also termed as “Lactase deficiency.”

When lactose isn’t broken down, it remains undigested. The undigested lactose moves into the large intestine. The bacteria inhabiting the large intestine interact with the undigested lactose and cause the symptoms of bloating, gas, and diarrhea.

Types of Lactose Intolerance

Lactose intolerance is generally of four kinds. Depending upon their potential causes, kinds of lactose intolerance are as follow,

  • Primary Lactose Intolerance

It is the most common type of lactose intolerance that is normally a result of aging. Most of the people have enough lactase at the time of their birth. Babies need lactase to digest their mother’s milk. However, the amount of lactase a person makes may decrease over time. One of its possible causes may be that people consume a more diverse diet, as they age, and rely less on milk. Thus, corporal lactase decreases gradually. Primary lactose intolerance is more common in people with Asian, African, Native American, or Mediterranean ancestry.

  • Secondary Lactose Intolerance

Secondary lactose intolerance is usually a result of illnesses or injuries. Intestinal diseases such as celiac disease and inflammatory bowel disease or a surgery or injury to your small intestine can add to the situation. We can restore the levels of lactase if the underlying disorder is treated.

  • Congenital Lactose Intolerance

In very rare cases, lactose intolerance may be congenital in nature. It means that people may be born with lactase deficiency. Yes, lactose intolerance is inheritable. A defective form of the gene, encoding lactase enzyme, can be passed from the parents to a child. It can result in the complete absence of lactase in the child. This is what we call congenital lactose intolerance.

In such cases, the newly born babies cannot even digest breast milk. They show symptoms of intractable diarrhea as soon as they come in contact with human milk or any formula containing lactose. The condition can be life-threatening, if not treated in time. Diarrhea can cause dehydration and electrolyte loss among the affected infants. We can control or treat the situation by giving the baby a lactose-free infant formula instead of milk.

  • Developmental Lactose Intolerance

Lactose intolerance can be developmental, occasionally. It usually occurs if the baby is born prematurely. Lactase production in the baby begins after at least 34 weeks of pregnancy and a premature birth leads to the deficiency of the enzyme.

Lactose intolerance is a common adult problem. It is mostly observed among Asian, African, Native American, or Mediterranean population. Mayo Clinic reports nearly 30 million American people, over the age of 20, to be lactose intolerant. The condition isn’t serious but may be unpleasant.

What are the symptoms of Lactose Intolerance?

Lactose intolerant individuals usually exhibit gastrointestinal symptoms. These may include gas, bloating, and diarrhea. The symptoms usually appear about thirty minutes to two hours after ingesting milk or other dairy products employing lactose. Other symptoms also include abdominal cramps and nausea.

The extent of the symptoms ranges from mild to severe. The severity of the symptoms depends upon two factors i.e.

  1. How much lactose is consumed?
  2. How much lactase is produced by the individual?


Confirmatory tests for Lactose Intolerance

Individuals who experience cramps, bloating, or diarrhea after consuming milk or relevant products are advised to see a doctor. They must take tests for lactose intolerance. These tests measure the activity of lactase in our body and are as follow,

  • Lactose Intolerance test

It is a kind of blood test that measures the reaction of our body to the liquids containing lactose in high amount.

  • Hydrogen Breath test

It measures the amount of hydrogen in your breath after consuming a drink, high in lactose. Lactose, if not digested, is broken down by the intestinal bacteria. Bacteria break down sugars by a process named “fermentation”. It releases hydrogen and other gases that are eventually exhaled.
If the test indicates a higher amount of hydrogen in your breath than the normal levels, it means you are lactose intolerant.

  • Stool Acidity test

Stool acidity test measures the amount of lactic acid in a stool sample. This test usually involves infants and children. Lactic acid accumulates when bacteria in the intestine ferment the undigested lactose.

Treatment for Lactose Intolerance

There is currently no definite procedure or treatment for lactose intolerance. However, people can carry out some simple practices to avoid the adverse effects of the condition,

  • Avoid Lactose

The first and foremost instruction for the lactose intolerant people is to avoid eating the products that contain lactose in them.

Lactose intolerant people can have up to 1/2 cup of milk without experiencing any symptoms. Lactose-free milk products are also available at the supermarkets.

Moreover, not all dairy products contain a lot of lactose like some hard cheeses, such as cheddar, Swiss, and Parmesan, or cultured milk products like yogurt. People can also consume the low-fat or nonfat milk products that typically employ less lactose.

  • Lactase supplements

People can also opt for medicines and supplements that contain lactase enzyme. Lactase enzyme, over the counter, is also available in the form of capsule, pills, drops or chewables. The drops, containing lactase enzymes, can also be added to a carton of milk.

  • Use calcium supplements

Milk and dairy products are not only rich in lactose but other nutrients too. Avoiding these products due to lactose intolerance can lead to a deficiency of various other nutrients.

Lactose intolerance brings with it some side situations involving deficiency of calcium, vitamin D, riboflavin, and protein. These conditions pose serious health complications and require treatment in time. For such a purpose, people must take calcium supplements or eats foods that are fortified with calcium.

  • Lactose-free diet and lifestyle

Lactose intolerant people can maximally avoid the symptoms of the condition by adjusting themselves to a lactose-free diet and lifestyle. It has long-term effects on the health of the organism.

People must learn to read the food labels carefully. They should detect the products or ingredients that may contain lactose. Aside from milk and cream, whey or whey protein concentrate, casein or caseinates, curds, cheese, butter, yogurt, margarine, dry milk solids or powder, nougat contain a significant amount of lactose.

Many times, the food that we’re not expecting to contain lactose are an actually rich source of it. Examples include salad dressings, frozen waffles, sauces, dry breakfast cereals, instant soups etc.

Click here for lactose free food list

Processed foods contain milk and its relevant products. Many non-dairy creamers and medications also contain lactose. People should avoid all of these kinds of foods, to keep the symptoms and effects of lactose intolerance at bay.


Lactose intolerance is a common problem in many children and adults across the world. Although it is rarely life-threatening, but it can lead to significant discomfort and a disrupted quality of life. Treatment for lactose intolerance is relatively simple. It aims at reducing or eliminating lactose from the diet. Drinking low-fat or fat-free milk can serve the purpose. Try dairy milk alternatives such as almond, flax, soy, or brown rice milk. Milk products with the lactose removed are also available.




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