Program Name:
Educating Patients on Nutritional Options for Lactose Intolerance
Planning Committee:
Andrew Szilagyi, MD
Susan I. Barr, PhD, RD, FDC
Phyllis Bedder, MD
Lydia Hatcher, MD, CCFP, FCFP
Alan Bell, MD, CCFP
Accreditation Information:
This version of the program is unaccredited and intended for
informational purposes only. An accredited version is available online at
www.mdBriefCase.com / www.AdvancingIn.com until May 9, 2017.
Sponsor:
This case study is supported by an educational grant from Dairy Farmers
of Canada
Contents
Contents ........................................................................................................................................................ 2
Planning Committee ..................................................................................................................................... 4
Learning Objectives....................................................................................................................................... 4
Pre-Course Survey ......................................................................................................................................... 5
Pre-Test ......................................................................................................................................................... 6
Introduction .................................................................................................................................................. 7
Symptoms of Lactose Intolerance................................................................................................................. 7
Lactose Maldigestion vs. Lactose Intolerance .............................................................................................. 8
Key Concepts Associated with Lactose Maldigestion/Intolerance: .......................................................... 8
Prevalence of Lactose Intolerance in Canada ............................................................................................... 9
Causes of Lactose Maldigestion .................................................................................................................. 10
Test your Knowledge .............................................................................................................................. 10
Risk Factors ................................................................................................................................................. 10
Diagnosis ..................................................................................................................................................... 11
Poll Question: .......................................................................................................................................... 12
The Benefits of Milk Products ..................................................................................................................... 12
Additional Benefits of Milk Products ...................................................................................................... 13
Management of Lactose Intolerance .......................................................................................................... 14
Health Authorities Recommendations.................................................................................................... 14
Ingest limited amounts of lactose at a time ........................................................................................... 14
Consume milk and milk products with other foods ................................................................................ 14
Yogurt, cheese and chocolate milk ......................................................................................................... 14
Lactose-free and lactose-reduced milk and milk products ..................................................................... 15
Test your Knowledge .............................................................................................................................. 15
Lactase enzyme pills................................................................................................................................ 15
Colonic Adaptation.................................................................................................................................. 15
Probiotics18 .............................................................................................................................................. 15
Poll Question: .......................................................................................................................................... 16
Case #1 ........................................................................................................................................................ 16
Medical History ....................................................................................................................................... 16
Diagnosis ................................................................................................................................................. 16
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2
Strategies for Management .................................................................................................................... 17
Follow-up – 3 months later ..................................................................................................................... 17
Case #2 ........................................................................................................................................................ 17
Medical History ....................................................................................................................................... 17
Difference Between Milk Allergy and Lactose Intolerance ..................................................................... 17
Symptoms ............................................................................................................................................... 18
Follow-Up – 2 Weeks Later ..................................................................................................................... 19
Key Learning Points ..................................................................................................................................... 20
Discussion Forum Questions ....................................................................................................................... 21
References .................................................................................................................................................. 22
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3
Planning Committee





Andrew Szilagyi, MD
Susan I. Barr, PhD, RD, FDC
Phyllis Bedder, MD
Lydia Hatcher, MD, CCFP, FCFP
Alan Bell, MD, CCFP
Learning Objectives
By the end of this course, the course participant will be able to:





Describe the pathophysiology of lactose maldigestion and the signs and symptoms of lactose
intolerance
Describe the diagnostic process for lactose maldigestion
Define the differences among lactose intolerance, lactose maldigestion, and milk allergy
Identify health authorities’ recommendations for the consumption of milk products for patients
with lactose maldigestion and intolerance
Identify practical and educational patient tips for dietary modifications
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4
Pre-Course Survey
Please answer the following question on a scale of 1 to 5 (1 = not likely, 5 = very likely)
1. How likely are you to advise eliminating milk products from the diets of your patients with lactose
intolerance?
Please answer the following question on a scale of 1 to 5 (1 = not complicated, 5 = very complicated)
2. Do you find it complicated to recommend that your patients with lactose intolerance consume milk
products?
Please answer the following question on a scale of 1 to 5 (1 = not comfortable, 5 = very comfortable)
3. What is your comfort level discussing recent health authorities’ recommendations concerning milk
products and lactose intolerance?
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5
Pre-Test
1. What is required for proper lactose digestion?
a. Galactose
b. Glucose
c. Lactase
d. Prebiotics
e. Hydrogen
2. Which of the following is true?
a. All lactose maldigesters are lactose intolerant
b. All patients who believe they are lactose intolerant are lactose maldigesters
c. Lactose maldigestion is the same as self-reported lactose intolerance
d. All of the above
e. None of the above
3. Which is the most common and objective test for lactose maldigestion?
a. Hydrogen breath test
b. Lactose tolerance test
c. Stool acidity test
d. Intestinal biopsy
e. Genetic testing
4. Which of the following is a good management strategy for incorporating milk products into the diet
of an individual with lactose intolerance?
a. Start with small amounts of lactose
b. Consume milk products with other foods
c. Consider hard cheeses and/or yogurt
d. Try lactose-reduced products
e. All of the above
5. Which of the following is a true statement regarding lactose intolerance or milk allergy?
a. Children can outgrow milk allergies
b. Milk allergies are digestive disorders
c. Individuals with lactose intolerance patients must always eliminate all milk products from
their diets
d. Milk allergies are more common in adults than children
e. Lactose intolerance is characterized by respiratory symptoms
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Introduction
Lactose is a disaccharide found in milk and milk products, but it is also added in small amounts to some
processed and prepared foods (e.g., salad dressings).1
The enzyme lactase, produced in the lining of the small intestine, is needed for the body to digest
lactose. During normal digestion, lactase helps to break lactose down into glucose and galactose in the
small intestine.2
In the absence of lactase, or without high enough levels of this enzyme, the body does not break down
all the lactose into component monosaccharides for digestion and absorption. The undigested lactose
goes into the colon, where it is fermented by bacteria. If there are large amounts of undigested lactose,
this causes the symptoms of lactose intolerance.3
Symptoms of Lactose Intolerance
Lactose intolerance is an issue of tolerability, not safety.
The signs and symptoms of lactose intolerance usually begin 30 minutes to two hours after eating or
drinking foods that contain lactose. Common signs and symptoms include:4





Flatus and belching
Bloating
Abdominal cramps
Nausea, and sometimes, vomiting
Diarrhea
Symptoms are usually mild, but may sometimes be severe.
Tool Tip:
Diarrhea is a tricky symptom in patients who can digest lactose. If the person has
irritable bowel syndrome (IBS) it could be a feature of IBS. However, if the person has
new onset diarrhea specifically related to lactose, the person may have a secondary
cause of lactose maldigestion (e.g., Celiac disease) and this should be investigated to
rule out such possibilities. Another and perhaps more common cause of secondary
lactose maldigestion may be diarrhea as a result of use of antibiotics.
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Lactose Maldigestion vs. Lactose Intolerance
Lactose maldigestion is the physiologic condition that occurs due to a decreased ability to digest lactose
caused by an insufficient amount of lactase in the small intestine.3,5 People with maldigestion may or
may not actually have the symptoms of lactose intolerance.
Lactose intolerance refers to the gastrointestinal symptoms associated with lactose maldigestion.
However, individuals may experience symptoms but may not actually have lactose maldigestion.
Conversely, the majority of individuals who have lactose maldigestion do not have clinical lactose
intolerance (i.e., they do not experience the associated gastrointestinal symptoms).3
Many patients think that a variety of intestinal disorders are due to lactose intolerance without
undergoing testing.6 If they have self-reported lactose intolerance but do not actually have lactose
maldigestion, their symptoms could be caused by other food intolerances or other (as yet not
understood) mechanisms.
Symptoms of lactose intolerance are highly subjective and may or may not accompany lactose
maldigestion. Many factors determine whether a person who maldigests lactose develops
gastrointestinal symptoms associated with lactose intolerance. Examples of such factors include:




Dose of lactose ingested
Residual intestinal lactase activity
Ingestion of other foods or nutrients together with lactose
Individual sensitivity
Perception also plays a large role – a previous experience with the symptoms of lactose intolerance
could be associated with consuming lactose whereas the causal link is not necessarily true, creating a
negative association but no true maldigestion. Or alternately, someone with true maldigestion who
experienced disturbing symptoms after a large lactose load may associate this with smaller amounts of
lactose (even when no symptoms would be experienced if the smaller amounts were consumed in a
blinded manner).
Key Concepts Associated with Lactose Maldigestion/Intolerance:
Lactose maldigestion: inability to digest lactose due to low levels of the enzyme lactase. May or may not
be symptomatic. Synonymous with lactose malabsorption and lactase nonpersistence. For the sake of
consistency, the term maldigestion will be used throughout.
Lactose intolerance: Gastrointestinal symptoms that may occur after lactose ingestion in an individual
who is a lactose maldigester. Whether or not symptoms are experienced in a given individual will
depend, at least in part, on the amount of undigested lactose that is present.
Perceived or self-reported lactose intolerance: Gastrointestinal symptoms that an individual attributes
to lactose, but which may or may not be associated with lactose maldigestion, and which do not occur
when lactose is consumed under blinded conditions. As self-reported lactose intolerance is not
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medically or objectively based, it is hard to know if it is accurate. A diagnostic test is required to confirm
a medical diagnosis.
The answer here would include the presence of GI symptoms (re Lactose Intolerance).
Prevalence of Lactose Intolerance in Canada
The true prevalence of lactose intolerance is unknown. According to a national Canadian survey, the
prevalence of self-reported lactose intolerance is 16%.7 However, many patients who self-report lactose
intolerance show no evidence of lactose maldigestion as determined by objective diagnostic tests. Thus,
the cause of their gastrointestinal symptoms is unlikely to be related to lactose.3
In a study of 2,251 Canadians age 19 years and over, results indicated the following:7





16% (or about 1 in 6) reported that they were lactose intolerant with a higher prevalence among
o women
o younger adults
o non-whites
o English respondents (vs. those who completed the survey in French)
Prevalence did not differ by level of education
Individuals with lactose intolerance had less favourable beliefs about the healthiness of milk
products, and substantially lower intakes
Individuals with intolerance consumed less cheese, even though most hard cheeses contain low
amounts of lactose.
Individuals with lactose intolerance had significantly lower mean calcium intakes from the
combination of milk products, alternatives, and supplements compared to individuals who did
not report lactose intolerance (739 mg/d vs. 893 mg/d respectively, p<0.001).7
Make the Connection:
It is known that non-whites are more likely to have reduced lactase levels with
increased age (e.g., child to teen to adult), but there is no physiological basis for higher
reported levels of lactose intolerance in women versus men or in younger versus older
adults.
Health professionals should advise individuals with lactose intolerance—whether physician-diagnosed or
self-reported—about how to avoid associated nutrient shortfalls preferably by consuming milk products
in a way that does not provoke symptoms.7,8 Consuming alternatives that provide similar “nutrient
packages” to milk products should also be considered if milk products cannot be incorporated (at
present, this would include fortified soy beverages but not rice, almond or cashew beverages).
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Causes of Lactose Maldigestion
There are three types of lactose maldigestion:2
 Primary lactose maldigestion
The body typically produces large amounts of lactase at birth and during early childhood, when milk is
the primary source of nutrition. This lactase production usually decreases as the diet becomes more
varied and less reliant on milk. This gradual decline may lead to symptoms of lactose intolerance.
 Secondary lactose maldigestion
This occurs when the small intestine decreases lactase production after an illness, surgery or injury to
the area. It can occur as a result of intestinal diseases, such as celiac disease, gastroenteritis and an
inflammatory bowel disease like Crohn's disease. Treatment of the underlying disorder may restore
lactase levels and improve signs and symptoms, though it can take time.
 Congenital lactase deficiency
Although rare, babies can be born with lactose maldigestion caused by a complete absence of lactase
activity. This is an autosomal recessive disorder. Infants with congenital lactase deficiency are intolerant
of the lactose in their mothers' breast milk and have diarrhea from birth. These babies require lactosefree infant formulas. Premature infants may also have lactose maldigestion because of an insufficient
lactase level.
Test your Knowledge
Which of the following is true of lactase production?
a.
b.
c.
d.
It generally decreases with age
It is highest in most Caucasians
It is lower in premature infants than in term infants
All of the above
Risk Factors
Risk factors for lactose intolerance include:9
1. Increasing age. Lactose maldigestion becomes more common with age and is uncommon in
babies and young children.
2. Ethnicity. Lactose maldigestion is most common in Black, Asian, Hispanic and American Indian
people.
3. Premature birth. Lactase increases in the fetus late in the third trimester; as such, infants born
prematurely may have reduced levels of the enzyme.
4. Diseases affecting the small intestine. Bacterial overgrowth, celiac disease and Crohn's disease
are examples of conditions or disorders that affect the small intestine and could cause lactose
intolerance.
5. Certain cancer treatments. Radiation therapy in the abdomen or intestinal complications from
chemotherapy can result in increased risk of lactose intolerance.
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Diagnosis
In order to determine if an individual is, in fact, a lactose maldigester, a diagnostic test must be
performed. Standardized and objective testing should be done to confirm the diagnosis, as it is
important to distinguish lactose intolerance from other causes of gastrointestinal symptoms. Selfdiagnosis of lactose intolerance is often incorrect and can lead to unnecessary dietary restrictions.5
Hydrogen breath test.
The hydrogen breath test is the most objective test to diagnose lactose maldigestion.3,5 The hydrogen
breath test requires that patients consume a standard dose of lactose (usually 50 g of lactose, which is
equivalent to the amount in 1 L of milk) after fasting. Hydrogen levels in the breath are then measured
over a 3-hour period.5,10 Note that the current trend in testing is to be more reflective of actual
physiological values by using a 25 g or 12.5 g lactose load.
Normally, very little hydrogen is detectable. However, the fermentation of undigested lactose by
intestinal flora produces hydrogen, carbon dioxide and methane, which are eliminated by the lungs
through the breath.
These gases are also responsible for the bloating, flatulence, abdominal pain and diarrhea associated
with lactose intolerance. Lactose maldigestion is diagnosed if hydrogen levels are elevated. In the case
of lactose intolerance, gastrointestinal symptoms will also occur.
This test is widely used, but its reliability depends on the activity of bacterial flora.10 False-negative tests
can occur due to several conditions that may affect the intestinal flora, e.g., recent use of
antibiotics/antimicrobial agents.
Lactose tolerance test5,10
The lactose tolerance test assesses the body's reaction to a liquid that contains high levels of lactose. It
involves a series of blood glucose measurements over 3 hours following the ingestion of a lactose load.
A diagnosis of lactose maldigestion is consistent with a failure to raise blood glucose above 1.11 mmol/L.
False-positive results can occur because of a lack of increase in blood glucose, which is attributable to
normal insulin response.
Tool Tip:
The lactose tolerance test is an older test and has mostly been replaced by the
hydrogen breath test due to the former’s high rate of false-negative and false-positive
results
Stool acidity test11
For infants and children who can't undergo other tests, a stool acidity test may be used. The fermenting
of undigested lactose creates lactic acid and other acids that can be detected in a stool sample.
Intestinal biopsy5,10
Lactase activity from a duodenal biopsy is measured through direct biochemical assay. However,
because of the invasiveness of intestinal biopsies, lactose tolerance tests have been developed.
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Genetic testing5,10
Genetic testing can be conducted for the common polymorphisms that are linked to lactase
maldigestion, but other polymorphic variants can affect diagnostic accuracy. Such tests are generally not
useful for the clinical evaluation of lactose intolerance, but are used in epidemiological studies.
Tool Tip:
Lactose maldigestion is most objectively diagnosed by the hydrogen breath test.
However, the majority of people with lactose maldigestion do not have clinical lactose
intolerance as they do not experience gastrointestinal symptoms following lactose
ingestion in amounts lower than the 50 g used in the test, especially when the doses
used are more reflective of physiological quantities.
Poll Question:
Which test for lactose intolerance have you used?
a.
b.
c.
d.
e.
Hydrogen breath
Lactose tolerance
Stool acidity
Intestinal biopsy
Genetic testing
The Benefits of Milk Products
One of the concerns about self-reported lactose intolerance is the health implication of restricting the
consumption of milk products.
Although restricting lactose intake may improve gastrointestinal symptoms, as noted in open but not
controlled and blinded trials, the long-term effects of a diet low in or free of milk products are of
nutritional concern.12 Restricting milk product intake deprives individuals of readily accessible sources of
calcium, vitamin D and other key nutrients.3
Milk is fortified with vitamin D, which enhances calcium and phosphorus absorption to enable the
formation of strong bone growth and maintenance. Milk is also a natural source of 15 other essential
nutrients, as outlined in Table 1.13
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12
Table 1: Nutrients occurring naturally in milk and their functions13
Nutrient
Protein
Function/Benefit
Helps build and repair muscles, bones and other tissues, and helps
create antibodies, which fight infection
Vitamin A
Aids in the development of bones and teeth. Aids the maintenance of
night vision and healthy skin
Vitamin B12
Folate
Supports formation of red blood cells
Vitamin B6
Riboflavin
Niacin
Thiamine
Pantothenic acid
Zinc
Magnesium
Releases energy from carbohydrate and aids normal growth.
Calcium
Magnesium
Phosphorus
Aids in the formation and maintenance of strong bones and healthy
teeth
Potassium
Aids in the correct functioning of nerves and muscles
Selenium
Factor in the correct functioning of the immune system, due to its
antioxidant effect
Additional Benefits of Milk Products
Bone Health
Furthermore, the most recent Canadian health survey indicates that children and adolescents who do
not consume the recommended amounts of milk and milk products do not reach their calcium and other
bone-building requirements, which may prevent them from reaching peak bone mass. Two-thirds of
Canadian adults also don’t consume enough milk products, which may increase the risk for osteoporosis
among older adults and has been linked to a higher risk of fractures.3, 12
Hypertension, colorectal cancer, diabetes
Milk and milk products may have beneficial effects on different health outcomes, including a reduction
of the risk of hypertension, colorectal cancer and diabetes. In a national multi-ethnic U.S. survey, higher
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rates of hypertension and diabetes were observed among individuals with self-perceived lactose
intolerance.14
Management of Lactose Intolerance
Given the many benefits of milk products, health authorities now advise health professionals to discuss
with individuals with lactose intolerance—whether physician-diagnosed or self-reported—how to
continue to incorporate milk products in a way that does not provoke symptoms.7, 8
Health Authorities Recommendations
The National Institutes of Health (NIH), the American Academy of Pediatrics Committee on Nutrition,
and the National Medical Association (which represents African American physicians) all recommend
that milk and milk products should still be incorporated into the diets of individuals with lactose
intolerance.3, 5, 15 This is because a diet low in or free of milk products is of nutritional concern.
Restricting milk product intake deprives individuals of readily accessible sources of calcium, vitamin D
and other key nutrients.
To that end, various management approaches have been shown to effectively alleviate the symptoms of
lactose intolerance.
Ingest limited amounts of lactose at a time
•
•
•
Incorporate small amounts of milk or milk products or other lactose-containing foods. Most
studies show that individuals with lactose intolerance do not experience symptoms after
consuming small amounts of lactose-containing foods.
Space out intake throughout the day. Most people with lactose intolerance, including children,
can tolerate up to 2 cups of milk a day, divided into smaller quantities.5, 6
In general, up to 12 grams of lactose (1 cup of milk) in a single dose can be tolerated without
significant symptoms, especially if taken with other foods.3
Consume milk and milk products with other foods
•
•
•
Milk and milk products seem to result in fewer symptoms if consumed with other foods or
incorporated in a dish.
The digestion of milk is slowed down when the beverage is paired with a meal. This equals a
slower release of lactose in the small intestine, thereby reducing the lactose load to be digested
at any one time.16
Consuming milk with other solid foods, especially those high in soluble fibre, also delays gastric
emptying, which provides additional time for intestinal lactase to digest the lactose.5, 17
Yogurt, cheese and chocolate milk




Both yogurt and cheese are produced by the fermentation of milk by lactic acid bacteria
During this process, a certain quantity of lactose is converted to lactic acid
Therefore, yogurt is generally well tolerated, particularly those with active bacterial cultures,
which help digest lactose.6, 17
In addition, the semisolid state of yogurt slows gastric emptying and gastrointestinal transit,
providing more time for lactose digestion.5, 15
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

Most hard and aged cheeses contain little lactose. Some examples of cheeses that contain very
little lactose are Mozzarella, Cheddar, Swiss, Brie and Blue.3, 15
Chocolate milk also tends to be better tolerated than plain milk, although the reason for this is
still unknown.16
Lactose-free and lactose-reduced milk and milk products
•
Lactose-free milk products are an ideal substitute for regular milk products among individuals
with lactose intolerance.15 Evidence also indicates that most children prefer lactose-free cow’s
milk over soy beverages.15
•
Fortified beverages (excluding fortified soy beverage) and other calcium-containing foods are
not nutritionally equivalent replacements for cow’s milk. Incorporating such foods may alter a
patient’s overall dietary pattern, which could mean a suboptimal intake of other key nutrients
such as protein, magnesium, potassium, riboflavin and vitamin B12.17 However, among
individuals who are not willing to incorporate milk products in their diets, fortified soy
beverages contain protein in amounts similar to cow’s milk and are enriched with nutrients at
levels generally equivalent to those found in cow’s milk. This is not the case for most other
plant-based beverages (e.g., rice, almond, or cashew beverages), which contain very little
protein.
Test your Knowledge
True or False: Hard cheeses have some of the highest lactose content of all milk products.


True
False
Lactase enzyme pills
•
Oral lactase enzyme pills may also improve lactose digestion for patients with lactose
intolerance. The pills should be taken with the first sip or bite of the milk product.3, 15
Colonic Adaptation
•
•
•
In this strategy, lactose intake is gradually increased over time.3
This routine exposure to lactose can improve the efficiency of colonic bacteria to metabolize
lactose in some people, improving tolerance.6
For example: Take half a glass of milk with 1 meal on the first day, then with 2 meals, gradually
increasing the frequency and quantity every day.16
Probiotics18
•
•
•
•
Probiotics are beneficial bacteria present in the intestines that help maintain a healthy digestive
system
Are available as active or "live" cultures in some yogurts and as supplements in capsule form
Sometimes used for gastrointestinal conditions, such as diarrhea and irritable bowel syndrome
and may also help with lactose digestion.
Probiotics are generally considered safe and may be worth a try if other methods don't help.
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Poll Question:
Do these strategies seem like techniques that your patients could adhere to?


Yes
No
Given these strategies and the importance of milk products, it may be helpful to direct patients to
resources that outline the lactose content of some common milk products.
Tool Tip:
Lactose intolerance, whether real or perceived, should not be a barrier to achieving a
healthy diet.
Case #1
Meet Krista, 30. She is at Dr. Brown’s for her regular check-up.
Medical History
Krista, a Caucasian female, is at Dr. Brown’s office for her regular check-up. When Dr. Brown asks Krista
about her overall health, Krista replies that she has had some stomach trouble for the last few months.
She thinks it is linked to milk products and describes cramps, bloating and diarrhea after she drinks milk
or has a lot of ice cream. Krista says that she has done some research on the web and has concluded
that she is lactose intolerant. She asks Dr. Brown if she should eliminate milk products from her diet.
Dr. Brown knows that many of her colleagues would agree right away that Krista should eliminate milk
products from her diet. However, Dr. Brown is aware of some of the NIH’s recommendations about
incorporating milk products into the diet of patients with lactose intolerance. She tells Krista that she
wants to explore the issue a bit more.
Dr. Brown reviews with Krista the benefits of milk products. Krista reacts favourably, mentioning that
she had heard a lot of negative things about milk products and didn’t think it would harm her to
eliminate them. She didn’t realize how many nutrients milk products offered, or the protein content of
milk. She also wasn’t aware of the possible beneficial association between milk products and significant
diseases like cancer, diabetes or cardiovascular disease..
Diagnosis
Together, Krista and Dr. Brown decide that Krista will have a hydrogen breath test to determine if she is
a lactose maldigester. When the results are available, they review them and confirm that Krista does
have low levels of lactase, making her a lactose maldigester. The presence of her gastrointestinal
symptoms confirms that she indeed has lactose intolerance. However, now that Krista has learned about
the full extent of the benefits of milk products, she is keen to be able to incorporate them into her diet.
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Tool Tip:
Consider the following analogy for use with patients with lactose intolerance: We are
all “maldigesters” of some of the carbohydrates in beans and legumes – humans don’t
possess the enzymes to digest raffinose or stachyose. However, provided modest
quantities of these beans are consumed, most of us “tolerate” these foods well (and we
are advised to consume more of them). Having said that, however, if we consumed a
very large amount in one sitting we could experience unpleasant symptoms. Similarly,
people who maldigest lactose can almost always “tolerate” modest intakes without
distressing symptoms, but would be symptomatic with large amounts.
Strategies for Management
Dr. Brown reviews with Krista the recommendations for incorporating milk products into her diet. She
reminds Krista about the benefits of milk products. Finally, she directs Krista to some recipes for cooking
with milk products and menus for different ways to consume milk products. They decide that Krista will
be referred to a registered dietitian who will work with Krista on meal planning and help to monitor her
progress.
Follow-up – 3 months later
Back in Dr. Brown’s office, Krista is discussing her diet. She tells Dr. Brown that she finds that she is able
to have a glass of milk with a meal, or in her cereal in the morning. She often adds milk to her main
course meals, such as in a rosé sauce for pasta or in a homemade pudding dessert for her and the kids.
She sticks to yogurt and hard cheese and had found that her symptoms have decreased – plus, she feels
that she is eating more healthfully and feels good about getting nutrients in food form rather than
supplements. They agree that they will continue to monitor Krista’s progress.
Case #2
Meet Liam, age 6. He is with his mother at Dr. Brown’s office because Liam has stomach trouble.
Medical History
Liam and his mother May are at Dr. Brown’s office because Liam has been having some stomach trouble
of late. May tells Dr. Brown that Liam has been experiencing gas, bloating and diarrhea, although his diet
has not changed. He also seems to have a runny nose and some rashes. May is worried that it might be a
milk allergy as Liam consumes a lot of milk products and the symptoms seem to fit. On the advice of her
friends, May has switched to almond beverage.
Difference Between Milk Allergy and Lactose Intolerance
Dr. Brown first discusses with May the differences between milk allergy and lactose intolerance:19, 20
About Milk Allergies
•
Rare in adults - fewer than 1% of adults and 3% of children have a clinically proven milk allergy,
and children tend to outgrow a milk allergy by the age of 3. As milk products are a major source
of up to 16 essential nutrients, it is best to reintroduce milk products into children's diets as
early as possible.
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•
Involve immunological reactions, while lactose intolerance involves digestive factors – as such,
they are distinct conditions that should be treated differently.
•
A milk allergy is the body’s immune system’s response to the protein in milk. The severity of milk
allergies varies and symptoms can range from hives to anaphylactic shock. This is different from
the lack of lactase that causes lactose maldigestion.
•
Patients with milk allergies must completely eliminate milk products from their diets while
making sure they get all of the nutrients found in milk products through other foods and/or
supplements.
Symptoms
There is a wide range of milk allergy symptoms:19, 20

Gastrointestinal tract symptoms: may present as abdominal pain, vomiting or diarrhea.
Constipation is sometimes present as well. They make up about 50% of milk allergy symptoms

Respiratory tract symptoms: Include nasal congestion, coughing and sneezing - account for
about 20% to 30% of symptoms

Skin symptoms: These include rash, eczema and hives. They represent about 30% of milk allergy
symptoms

Other symptoms such as colic, ear infections, migraines and behavioural problems are
sometimes associated with milk allergies, but this relationship is not yet clear
Tool Tip:
Infantile colic, involving prolonged episodes of irritability, fussiness and crying, is often
attributed to an allergy to cow's milk protein. However, evidence fails to support that
an allergy to cow's milk is the cause of colic. The exact cause of colic remains
unknown.19,20
Given the possibility of a milk allergy, they agree that Dr. Brown will refer Liam to an allergist for testing.
Liam’s symptoms are just too inconclusive for Dr. Brown to make the call, and given the numerous
benefits of milk products, Dr. Brown is wary of May eliminating the whole class from Liam’s diet. Dr.
Brown is also aware that almond beverage does not supply the proper amount of protein and reminds
May of the protein content of cow’s milk, a real benefit especially for a growing boy like Liam.
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Follow-Up – 2 Weeks Later
Following the appointment with the allergist, Dr. Brown is able to share with May that Liam does not
have a milk allergy. Liam’s runny nose has cleared up on its own so it could have been a result of it being
winter and plenty of viruses being shared at school and daycare. Likewise, his skin conditions have
cleared up with the passing of the cold front, so they could have been caused by dry air.
Dr. Brown believes that Liam is likely a lactose maldigester - Liam’s ethnicity is Asian and this means that
it is more likely that his lactase levels have dropped as compared to a Caucasian child of his age.
However, given his age, he doesn’t have any negative perception towards milk products – in fact, he
loves them! Therefore, there are no mental/ perception barriers to overcome with recommending to
slowly re-introduce milk products in a step-wise fashion. Sometimes the diagnostic test is most helpful
in revealing to patients that there is no physiological condition that would cause them to be lactose
intolerant. Given this, she realizes that a diagnostic test is not really necessary as the recommendations
are the same if Liam was a lactose maldigester or not. Instead, she and May review the
recommendations of the NIH for incorporating milk products.
Summary of Recommendations for Incorporating Milk Products:








Up to 12 g lactose (e.g., 1 cup of milk) is generally well tolerated.
Chronic/repeated intake of lactose-containing foods promotes colonic adaptation.
Consuming lactose-containing foods with meals is a recommended strategy.
Hard cheeses contain very little lactose and are generally well tolerated
Yogurt is usually well tolerated due to bacterial digestion of lactose.
Commercially available lactase drops or tablets (that can be added to milk products or
consumed prior to milk products intake, respectively) can be used.
Lactose-free milk is a widely available option.
Fortified beverages (excluding fortified soy beverage) and other calcium-containing foods are
not nutritionally equivalent replacements for cow’s milk. Incorporating such foods may alter a
patient’s overall dietary pattern, which could mean a suboptimal intake of other key nutrients
such as protein, magnesium, potassium, riboflavin and vitamin B12.
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Key Learning Points

Lactose maldigestion is a condition that can affect some individuals who have a deficiency in the
enzyme lactase, resulting in an inability to digest lactose properly. To diagnose lactose
maldigestion, an objective test such as the hydrogen breath test is needed.

Lactose intolerance is a group of symptoms including diarrhea, flatus, belching and bloating that
patients experience after consuming lactose, whether they are lactose maldigesters or not.

If lactose intolerance is suspected, standardized and objective testing should be done to confirm
diagnosis, as it is important to distinguish lactose intolerance from other causes of
gastrointestinal symptoms. Self-diagnosis of lactose intolerance is often incorrect and can lead
to unnecessary dietary restrictions.

Milk products contain up to 16 nutrients that are essential for health. Calcium, vitamin D and
protein are some of the nutrients in milk products that keep the body functioning properly and
could help reduce the risk of certain diseases.
•
Up to 12 g lactose (e.g., 1 cup of milk) is generally well tolerated.
•
Chronic/repeated intake of lactose-containing foods promotes colonic adaptation.
•
Consuming lactose-containing foods with meals is a recommended strategy.
•
Hard cheeses contain very little lactose and are generally well tolerated.
•
Yogurt is usually well tolerated due to bacterial digestion of lactose.
•
Commercially available lactase drops or tablets (that can be added to milk products or
consumed prior to milk product intake, respectively) can be used.
•
Lactose-free milk is a widely available option.
•
Fortified beverages (excluding fortified soy beverage) and other calcium-containing foods are
not nutritionally equivalent replacements for cow’s milk. Incorporating such foods may alter a
patient’s overall dietary pattern, which could mean a suboptimal intake of other key nutrients
such as protein, magnesium, potassium, riboflavin and vitamin B12
•
Milk products generally should not be avoided (even by individuals with lactose intolerance) as
they have important health benefits.
•
A milk allergy is the body’s immune system’s response to the protein in milk. The severity of milk
allergies varies and symptoms can range from hives to anaphylactic shock. This is different from
the lack of lactase that causes lactose maldigestion.
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Discussion Forum Questions
1) Would you recommend that a patient with lactose intolerance consume milk products? Why or
why not?
2) Do you routinely send patients with lactose intolerance for diagnostic testing? Why or why not?
3) What trends are you seeing in self-reported lactose intolerance? On the rise? In any particular
patient groups?
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References
1) http://www.dietitians.ca/Your-Health/Nutrition-A-Z/Lactose/Managing-LactoseIntolerance.aspx.
2) http://www.mayoclinic.org/diseases-conditions/lactose-intolerance/basics/definition/con20027906
3) Suchy FJ et al. NIH Consensus Development Conference Statement: lactose intolerance and
health. NIH Consens State Sci Statements 2010;27:1-27.
4) http://www.mayoclinic.org/diseases-conditions/lactose-intolerance/basics/symptoms/con20027906
5) Heyman MB. Lactose intolerance in infants, children, and adolescents. Pediatrics
2006;118:1279-1286.
6) Zaitlin P et al. Mistaken beliefs and the facts about milk and dairy foods. Nutr Today
2013;48:135-143
7) Barr SI. Perceived lactose intolerance in adult Canadians: a national survey. Appl Physiol Nutr
Metab 2013;38:830-835.
8) National Institutes of Health. NIH Consensus Development Conference Statement: Lactose
Intolerance and Health. NIH Consens State Sci Statements 2010; Feb 24;27(2).
9) http://www.mayoclinic.org/diseases-conditions/lactose-intolerance/basics/risk-factors/con20027906
10) Mattar R et al. Lactose intolerance: diagnosis, genetic, and clinical factors. Clin Exp Gastroenterol
2012;5:113-121.
11) http://www.mayoclinic.org/diseases-conditions/lactose-intolerance/basics/tests-diagnosis/con20027906
12) Misselwitz B et al. Lactose malabsorption and intolerance: pathogenesis, diagnosis and
treatment. United European Gastroenterol J 2013;1:151-159.
13) http://www.dairygoodness.ca/getenough/benefits-of-milk-products/health-benefits
14) Nicklas TA et al. Self-perceived lactose intolerance results in lower intakes of calcium and dairy
foods and is associated with hypertension and diabetes in adults. Am J Clin Nutr 2011;94:191198.
15) Bailey RK et al. Lactose intolerance and health disparities among African Americans and Hispanic
Americans: an updated consensus statement. J Natl Med Assoc 2013;105:112-127.
16) Heaney RP. Dairy intake, dietary adequacy, and lactose intolerance. Adv Nutr 2013;4:151-156.
17) Rabot S et al. Guidance for substantiating the evidence for beneficial effects of probiotics:
impact of probiotics on digestive system metabolism. J Nutr 2010;140:677S-689S.
18) http://www.mayoclinic.org/diseases-conditions/lactose-intolerance/basics/alternativemedicine/con-20027906
19) Brigino E and Bahna SL. 1995. Clinical Features of Food Allergy in Infants. Clin Rev in Allergy and
Immunology 13:329-345
20) Schrander JJP et al. 1993. Cow's milk protein intolerance in infants under 1 year of age: A
prospective study. Eur J Pediatr 152: 640-64
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An accredited version is available online at www.mdBriefCase.com / www.AdvancingIn.com until May 9, 2016
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