Lactose Intolerance in infants and children

What is Lactose?

Lactose is a disaccharide (carbohydrate) made of glucose and galactose, which can be found in many foods that children love, especially milk and other dairy products. That is why it is also known as Milk Sugar.
The list of other foods containing Lactose is long and includes breads, cereals, and frozen or canned foods, among others.

What is lactose Intolerance?

Lactose is normally broken down by an enzyme called Lactase found in the small intestine, where most of food digestion and absorption of nutritional components takes place.
The Lactase breaks down the Lactose into two sugars, glucose and galactose, which are absorbed to the body.
Now imagine that there is a decrease or complete deficiency in the amount of the Lactase enzyme, where Lactose cannot be broken down properly. From the small intestine, it continues down the digestive tract to the large intestine, where intestinal bacteria will eventually do the job in a process called fermentation.
This fermentation may cause unpleasant symptoms in the GI track such as bloating, gas, discomfort… Therefore, it is more accurate to call the phenomenon Lactose Intolerance.
It is important to mention that Lactose Intolerance is not a food allergy. There is no involvement of antigens that cause an allergic reaction, as can appear as a reaction to cow’s milk protein or many other proteins.
Lactose is a carbohydrate (sugar) and the symptoms are related to a sensitivity or rather to an intolerance.

What is the difference between Lactose Intolerance and Cow Milk Allergy?

It is easy and common to confuse these two terms: Lactose Intolerance and Cow Milk Allergy. Although they may share similar symptoms, they are completely different conditions. Lactose Intolerance is a gastrointestinal problem in which the body has a partial or complete deficiency of the enzyme that breaks down a carbohydrate called Lactose.
A Milk Allergy involves the immune system, which identifies the milk protein as an enemy and attacks it. There are cases of sensitivity to cow’s milk protein, usually manifests as mucous diarrhea in infants (read more here) but milk allergy can range between light symptoms on skin, GI track and up until severe and life-threatening symptoms involving breathing and airways.
So, while Lactose Intolerance can cause great discomfort, it cannot generate a significant or sometimes life-threatening reaction like an allergy can.
Another difference is age related. Of course – milk sensitivity or allergy tends to appear during the first year of life, when an infant’s digestive system is not yet mature whereas Lactose Intolerance can appear in infancy, childhood, adolescence and may be more pronounced in adulthood.

What types of Lactose Intolerance are known?

Congenital Lactase deficiency

An extremely rare genetic condition in which an infant is born with a complete deficiency of Lactase enzymes. An infant with this type of intolerance will present with severe diarrhea from the first day of life along with failure to thrive. They demand a special nutrition regimen from birth which supports normal growth and development.
This group is the exception. The vast majority of babies are lactose tolerant.

Primary Lactose Intolerance (genetic)

This is also a genetic condition that occurs in up to 70% of the population. This is actually a gradual decrease in the amount of Lactase enzymes in the small intestine, usually presented in childhood. The typical symptoms may appear after the age of 5 years, but they are usually more pronounced in adolescence and young adults.

Secondary lactose intolerance

A very common situation that every parent should be familiar with.
When does this condition appear and in which children? Usually after GI infections such as gastroenteritis (indigestion), which can temporarily damage the intestinal mucosa. That is, due to severe diarrhea/vomiting, where a temporary decrease in lactase will lead to intolerance. This type of Lactose Intolerance is short-term and usually resolves within a few weeks.
The typical story is that of a child has severe diarrhea due to some type of virus. The symptoms improve for a day or two and then reoccur. The recurrent diarrhea that is usually very watery is the secondary lactose intolerance caused by the same damage to the intestinal lining and Lactase, in the first diarrheal disease.
Read more about Diarrhea in children at the following link.
Conditions such as Celiac disease (which can also cause diarrhea among other symptoms) can also lead to secondary Lactose Intolerance. Once these conditions are properly treated, Lactose Intolerance should be resolved. Read more about Celiac disease and who should be screened for Celiac at the following link.

What are the symptoms of Lactose Intolerance?

Common symptoms of lactose intolerance are:
• Gas.
• Nausea.
• Abdominal pain and bloating.
• Diarrhea.
• Borborygmi (rumbling sounds).
• Recurrent diaper rash (due to diarrhea).
• Irritability
• Difficulty in gaining weight – in cases of congenital complete lactase deficiency.
Notice that these symptoms are common in healthy babies. It does not mean they necessarily have lactose intolerance. Proper diagnosis is needed.

How is Lactose Intolerance diagnosed?

The first question is whether a diagnosis is always necessary.
What does that mean? If your child has diarrhea for a few days, then improved for a day or two but worsens again, you might consider them suffering from Secondary Lactase Deficiency, as we explained above.
Of course, you may consult your pediatrician to help assess, but assuming that the pediatrician also suspects this common condition, there is no need for any diagnostic tests (especially since it will take quite some time to reach a diagnosis), but it is simply recommended to start treatment as you will see below.
In older children or adults there are 2 main tests that can be done:
Hydrogen breath test – the subject will drink a standard amount of Lactose. The amount of hydrogen gas emitted is measured. Children with lactose Intolerance have higher levels of hydrogen on exhalation. Of course, this test is not suitable for small babies because of the difficulty in performing the test.
Elimination diet – involves transitioning to lactose-free formula or removing lactose-containing foods from your diet to see if symptoms improve. If symptoms return as soon as lactose foods are re-introduced, lactose intolerance is most likely the cause of the problem.

What is the treatment for Lactose Intolerance?

Treatment in infants and children directly depends on the cause. If it is a congenital lactase deficiency (very rare as mentioned), it is important to contact both a pediatrician and pediatric nutritionist as soon as possible.
Treatment for Secondary Lactose Intolerance, mainly caused by indigestion (gastroenteritis), depends on what the baby/child is fed with.
• Breastfed infant – the recommendation is to continue breastfeeding normally. This is because breast milk has so many nutritional benefits to it and Lactose (also found of course in breast milk) is important for the baby’s growth.
• Formula-fed infants or infants you are considering offering formula to – transitioning to a low-lactose or lactose-free formula should be considered after a consultation with your family doctor or nutritionist. .
Remember, according to guidelines and position papers of various professional associations, it is recommended to transition to low- or lactose-free formula only after at least five days (some even say two weeks) of diarrhea. However, in reality, transitioning sometimes occurs earlier and often benefits the child with diarrhea. But, I have seen quite a few infants transition to low-lactose formula too early which is not always necessary and may lead to a decrease in the amount of milk intake, due to difference in taste.
In these cases, I recommend weighing the advantages versus disadvantages of transitioning to lactose-free formula with your pediatric physician/nutritionist.
• Older children – reducing the amount of lactose in their diet should be considered. There is usually no need to completely eliminate lactose-containing products, especially if your child only eats small amounts of them along with other foods throughout the day.

What is the recommended formula for transient secondary lactose intolerance?

Concentrate.
In the past, we had to transition infants to plant-based formula. Why? Because only there had no lactose. But I hope you’re all moving uncomfortably in your seat now because in a plant-based formula the protein also changes, from cow’s milk protein to soy-based protein. And this is really not necessary.
Fortunately, there are other options today that do not require protein replacement at the same time as lactose.
The other possible options are formulas that exist in various companies and is actually Lactose reduced. Note that the Lactose content differs between brands. Formula producers designate Comfort formulas for use in colic infants (gassy).
This is a great time to mention that the main carbohydrate in breast milk is Lactose. Therefore, normally, there is no problem with an infant receiving Lactose and it makes no sense to lower or eliminate it (lowering also does not help with gas/infantile colic, as you will see here). But in situations where lactose reduction is needed, this is a good option.
The second option is a Lactose free formula and it will of course be required in the more severe cases, and here too the use is usually temporary.

Is there a drug treatment to treat Lactose Intolerance?

In addition to alternations in diet, there are drops, tablets or capsules containing Lactase substitutes. Lactase replacement replace Lactase that the small intestine is lacking, which can relieve symptoms by helping the body break down the Lactose.
These meds are available on the market but are usually not given to infants and small children. In any case, consult a physician before administration.
Routinely, this is really not part of the treatment in infants and small children with secondary intolerance. In these cases as I mentioned, one only needs to wait for the intestinal lining to be restored and there is no need for long-term treatment.

How can a child with Lactose Intolerance be provided with enough calcium?

In those infrequent cases of congenital or primary intolerance, it is of great importance to address and supply a sufficient amount of calcium for infants and children.
Even if the child is Lactose Intolerance, he can still eat Lactose-free dairy products (as detailed below). In addition, your child can get calcium from leafy green vegetables such as spinach, broccoli and kale, tofu, nuts and almonds (as spreads/butters of course at young ages), white beans, fish (sardines, salmon).
If you are concerned for calcium intake, you can consult your pediatrician to consider supplementing calcium or contact a nutritionist to help increase calcium sources in diet.

What dairy products can we continue offering to Lactose Intolerant children?

• Cheeses with very low lactose content, such as hard cheeses (brie, camembert, cheddar, feta, gouda, mozzarella, parmesan, halloumi…)
• Yogurt – the bacteria in yogurt break down lactose so that it can usually be tolerated.
• Low/lactose-free Cow’s milk.
• Butter and cream – contain small amounts of lactose.

Is Lactose Intolerance a lifelong condition?

The answer, of course, depends on the type of intolerance.
In most cases as mentioned in the secondary cases, Lactose Intolerance is temporary and will pass after a few days/weeks.
On the other hand, if intolerance has another cause, as well as in primary cases’ sometimes it is a long-term condition that requires many children and adults to change their diet in order to avoid symptoms.

So, what did we learn?

About the milk sugar called Lactose.
About an enzyme that breaks it down called Lactase.
About primary states that are less common and on a secondary state that is common and transient.
About how to think and how to diagnose.
Most importantly, seek the help of an experienced pediatrician or professional pediatric nutritionist, for proper diagnosis and treatment.