Common Medical Conditions

Lactose Intolerance - Causes, Symptoms and Treatments

Written by
Dr. Divya Banu M
and medically reviewed by Dr. Anshul Varshney

03 Oct 2019  -  3 min read



Do you feel bloated and have abdominal cramps after consuming milk products? This can be due to your inability to digest lactose (sugar) in milk. Learn more about lactose intolerance.

Lactose Intolerance - Causes, Symptoms and Treatments

Lactose is a carbohydrate compound having two sugar molecules, hence, it is a disaccharide. The two sugars are glucose and galactose. It is used as a source of energy after its breakdown in the body by an enzyme called lactase and ultimately being absorbed in the bloodstream and providing energy.

The deficiency of lactase leads to transport of undigested lactose through the gut and can present with digestive symptoms like bloating, abdominal cramps and/or diarrhea.

Hence, lactose intolerance can be explained as a disorder of the digestive system in people having less lactase enzyme and thus, possess decreased ability to digest lactose.

This condition is very rare to be seen in children less than 5 years of age and statistics show that almost 75 % of the population in the world is lactose intolerant.


The causes can be broadly classified into two types:

1. Primary.

2. Secondary.

Primary lactose intolerance:

It is the most common among both and is caused by the reduction in the production of lactase and thus, lactose absorption becomes poor. Since it is seen more commonly in some populations than others, genetics is believed to be one of the major causes. Studies have shown that Asians and Africans are the most affected.

Secondary lactose intolerance:

This form is rare and is secondary to some disease or illness like stomach issues or sometimes, serious issues like celiac disease. The mechanism is that the gut wall inflammation can lead to a decrease in the production of lactase temporarily.


It can present with simple to major gastric symptoms. The most commonly seen symptoms include:

· Bloating.

· Abdominal cramps.

· Gas in stomach.

· Loose motions/ Diarrhea.

Some others experience the following symptoms also:

· Urgency to pass stool.

· Nausea and vomiting.

· Lower abdominal pain.

· Rarely, constipation.

The reason behind the loose motion is the lactose in the small intestine that is undigested which leads to the movement of water into the digestive tract.

After reaching the colon, fermentation of lactose happens by the bacterias present in the gut, leading to the formation of short-chain fatty acids and gas. All this leads to bloating, flatulence, and pain.

The severity of symptoms varies from person to person depending on the lactose tolerance level of the individual and how much consumption has been done.

Disadvantages of Avoiding Dairy Products

These patients avoid dairy products so that they can avoid the symptoms and thus, they are lacking the nutrients available through dairy products.

Foods containing lactose:

Lactose is commonly found in dairy products. The dairy food s that contain lactose are cow’s or goat’s milk, butter, yogurt, cheese, ice cream. Some foods can be expected to contain lactose in some amounts like cakes, biscuits, bread, instant soups, processed meats, sauces, etc.

Studies have shown that though it is advisable to avoid milk products some people show no effect to very minimal lactose content or on the consumption of minimal lactose-containing foods like certain variants of cheese, curd, butter, etc.

Alternative sources of Calcium:

Since such people can lack calcium due to the limited or less intake of dairy products, they need to add other foods that are rich in calcium. Some of the good food sources for calcium are as follows:

1. Calcium-fortified food like juices, almond milk, soy milk, bread, etc.

2. Boned fishes like sardines, whitebait.

3. Plant sources like broccoli, soybeans, etc.


Giving up dairy products can be very difficult. So, you can try the following remedies but with your physician’s consent.

1. Enzyme containing supplements.

There are commercially available enzyme supplements that help in digesting lactose. They are available as either tablet that can be swallowed or as drops that can be added to the food or drinks before consumption. But the effectiveness can vary from person to person.

2. Exposure to lactose.

This is based on the fact that continuous exposure to lactose can make the body adapt t it. But, there are not enough studies to prove this fact and thus, seek medical consultation before trying this.

3. Probiotics and prebiotics.

Probiotics are those microorganisms that deliver health benefits after consumption, whereas, prebiotics are the fibers that act as the food source for these micro-organisms. One of the most beneficial ones that have been documented is the Bifidobacteria that is found in probiotic curds and supplements.

Lactose intolerance can affect the day-to-day life in terms of not being able to consume dairy products and thus can make the person deprived of some essential nutrients like calcium. Hene, it is important to take such nutrients through other food sources.

With the help of online medical platform, it has become easy to consult an expert to know the details regarding any health issues. So, before trying anything for lactose intolerance ask an expert to clear your doubts.

Last reviewed at:
03 Oct 2019  -  3 min read




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