Lactose Intolerance

After childhood, less than 40% of people retain the ability to digest lactose. The incidence of intolerance is highest among Asians and Native Americans and lowest in Europeans.

Lactose intolerance is very different from lactose-related allergies. For instance, those who have milk allergies experience an immune system reaction to milk, however, the immune system is not what’s reacting for those who are intolerant of milk.

What is Lactose Intolerance?


Lactose intolerance happens when the body fails to produce the enzyme lactase that is used to break down lactose. Lactose is found in milk and other milk-derived products. When lactase works, lactose is broken down into galactose and glucose.

The activity of lactase though is somewhat reduced after breastfeeding wherein the body no longer needs lactase. It is said to come as an adaptation of human beings in their consumption of non-human milk after being weaned off of breast milk. While many people may have adapted to these changes of diet, others struggle with milk products. In a way, lactose intolerance is the natural state of human digestion.

The process in the stomach when intolerance occurs is as follow:

  1. You take in milk or milk derived dairy products.
  2. The stomach receives it but is unable to digest it.
  3. The lactose in the small intestine begins to act as an osmotic agent.
  4. Water and electrolytes will be pulled into the intestine which can result in diarrhoea, bloating and gassiness.

So, milk intolerance is the body’s natural reaction to milk and lactose. That is why lactose intolerance isn’t considered to be a disease.

Around the world, according to Better Health, about two thirds of babies will experience lactase deficiency in their early years. This does not cause them any harm whether they are breast or bottle fed.

This problem among babies may be caused by conditions like gastroenteritis which strips the intestines of lactase. Doctors often prescribe infants with a lactose-free formula until their enzyme levels are stabilised. Although some babies will take some time to stabilise their lactase levels, the lactose-free formula is the best solution for the problem.

Some babies may be born without these enzymes all together. Mothers often remedy this through the use of lactose-free products.

Theories About Lactose Intolerance

In a theory published in Plos Computational Biology, researchers from the College of London traced down the possible mutation that gives some the ability to drink milk while the rest of the world experiences intolerance. According to the study, the mutation appeared more than 7,500 years ago in dairy farmers from a region somewhere in the central Balkans and Europe. They used computer models and other methods to determine the spread of lactase persistence.

Common Lactose Intolerance Symptoms


Common symptoms include:

  • diarrhoea
  • flatulence
  • bloating
  • abdominal pain
  • feeling sick
  • stomach rumbling
  • nausea

The symptoms of the condition may also depend on many other factors including levels of intolerance, amount of lactose, ethnicity and age. Some lactose intolerant people may have the ability to tolerate only a small amount of lactose while others may be able to handle a huge consumption of lactose before they show signs and symptoms.

These symptoms usually develop a few hours after the consumption or can be delayed up to 48 hours before showing up. Usually, lactose levels will build up slowly before showing any full symptoms. Some people who are in the delayed symptoms bracket may attribute the symptoms to some other conditions, but the right thing to do is to check with your doctor to know the best way to deal with the symptoms.

Sources of Lactose

Lactose can be found in milk and milk-derived products. It’s easy to spot for those who are already aware of the condition. Sometimes there may be foods that contain lactose ingredients in parts. These may include food products including:

  1. milk and cheese
  2. bread
  3. baked goods
  4. processed meats
  5. instant coffees
  6. artificial sweeteners
  7. salad dressings
  8. margarine
  9. baked good mixes
  10. processed grains
  11. alcohol

For those who are looking for ways to avoid lactose, reading the ingredients will help. It can also be avoided by sticking to foods or products one is familiar with and requesting restaurants you frequent to do away with any lactose related ingredients.

Causes of Lactose Intolerance

According to types

The causes of lactose intolerance can be categorised based on their types. These include the following:

  1. Primary lactose intolerance
  2. Secondary lactose intolerance
  3. Congenital lactose intolerance

Primary lactose intolerance is a normal result of aging for some people. It’s one of the most common causes for intolerance, wherein the lactase enzymes wane out after weaning from breast milk. When the body becomes less reliant on milk, lactase levels decrease. When one gets older, this may develop into full lactose intolerance.

Secondary lactose intolerance can be a result of illness or injury. Some people may have decreased lactase enzymes when they experience illness or accidents that may affect and injure the intestines. Celiac disease, gastroenteritis and Crohn’s disease are a few well-known diseases that cause decreased lactase. Treating these conditions may help restore lactase levels in the body.

Congenital lactose intolerance is a condition that one is born with. Although it is rare, it can happen as the condition is passed from one generation to the next if both parents have the genes.

Another cause of lactase deficiency is premature deliveries. When babies are born too early, there is a tendency that their small intestines are not yet fully developed.

How is Lactose Intolerance Diagnosed

Lactose intolerance can be diagnosed in several ways, most often through its common symptoms. However hydrogen breath testing and elimination dieting are also popular methods of detection.

Hydrogen breath testing is one effective way to diagnose lactose intolerance. This test measures your breath’s release of hydrogen. Those who have lactose intolerance may produce more hydrogen since the lactose in the stomach isn’t converted but rather fermented.

Eliminating certain foods at a time may also help you determine if you are intolerant. This is done by removing foods that contain lactose one at a time and seeing if it improves the symptoms. Foods are then reintroduced. If the symptoms come back after reintroduction, then it is most likely to be lactose intolerance. This method can take a while, but it’s a good trial and error solution.

How is Lactose Intolerance Managed


Here are some tips to help you manage lactose intolerance:

  1. Avoid baked goods. Baked goods are commonly filled with dairy products that have lactose. If you get the urge to eat baked goods, alternative ingredients can be used to provide lactose-free treats.
  2. Eat aged cheese. Aged cheese that is hard and matured like swiss, edam, brie, fetta, and mozarella contains no lactose. These cheeses can be tolerated by most intolerants. Fresh ones like cottage and ricotta may have low levels of lactose and can be eaten in small amounts.
  3. When eating food with lactose, eat minimal amounts per serving. This will help give you the nutrients you need from the diary but the symptoms will be minimised.
  4. Check medications for any lactose fillers. Some antihistamines contain lactose. If your medication is prescribed, you may remind your doctor about it in case he forgets to check for lactose.
  5. Take calcium supplements instead. So if there is no chance of you getting dairy into your diet, consider taking calcium supplements to provide the nutrients that your bones need.
  6. Drink full fat milk. Full fat milk is slow to digest in the stomach, giving lactase a chance to break down sugars. So avoid low or non-fat milks.
  7. Substitute milk needs with soy products such as soy milk and yogurt. They are lactose-free but can provide a good amount of calcium.


If you are still in the dark about lactose intolerance, see your general practitioner for advice about diet and possible remedies. Or, consult a dietician for your dietary needs. These professionals can help answer all of your questions.

Lactose intolerance shouldn’t be viewed as something that can hinder your life or even food choices since it’s actually a very common and naturally occuring bodily function. With the right management, you can avoid the debilitating symptoms.


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