The FrieslandCampina Institute provides information and advice to
professionals about diet, dairy products and health, based on the latest
scientific information. This information is intended exclusively for
professionals and not for consumers, clients or patients.
Spotlight on
lactose intolerance
A low lactase activity is hardly
seen among the original people
of Nothern and Western European
countries and their decendants and
the most among the populations far
East. In the Netherlands a relatively
low percentage of 6% of the
population is lactase intolerant.
Lactose intolerance
“In lactose intolerance lactose from dairy products is not
broken down into glucose and galactose by the enzyme
lactase.” The speaker is Professor Gertjan Schaafsma, long
active in the field of human nutrition and with a special
interest in dairy products. “This is because there is a shortage
or absence of lactase in the small intestine. This means that
lactose arrives largely undigested in the large intestine, where
the intestinal flora ferments the lactose. This leads to the
development of volatile fatty acids and gases. In severe forms
of lactose intolerance osmotic diarrhoea may develop. With
milder forms patients may complain of stomach cramps and a
bloated feeling.” Lactose intolerance is diagnosed when these
complaints arise from the consumption of a normal quantity of
milk products (1-3 glasses per day).
Different forms
Lactose deficiency causes three different forms of lactose
intolerance. We will begin by discussing primary lactose
intolerance. Every baby at birth has sufficient lactase
available to digest the lactose in the mother’s milk. With the
introduction of different foods, lactase production in people
with this form of lactose intolerance gradually drops off to
such an extent that at a certain point a shortage arises. We
identify this as primary lactose intolerance. The prevalence of
this form of intolerance varies widely between populations,
from less than 5% in Swedish adults to 80-90% in Japan
(Schaafsma 2008). In the case of disease or surgery on the
gastrointestinal tract, secondary lactose intolerance may arise
from damage to the intestinal wall. This shortage of lactase
is generally temporary in nature, as the body can resume
production of adequate amounts of lactase following repair
of the intestinal wall. Thirdly there is a rare hereditary form of
lactose intolerance. In this case lactase is absent or virtually
absent from birth (Villako, 1994). Lactose intolerance can also
arise as a consequence of an excess of bacterial growth in
the intestines, without any lactase deficiency. In this situation
lactose intolerance
the bacteria cause fermentation of the lactose, giving rise to
complaints. This may be as the result of an intestinal resection
or a narrowing (stenosis) of the intestine.
A diagnosis of lactose intolerance is generally based on the
Hydrogen Breath Test, a Lactose Tolerance Test (LTT) or an
elimination-challenge diet. Less commonly used methods
include the stool acidity test and a recently developed genetic
test. The genetic test allows lactase deficiency to be identified
by means of a buccal smear.
Prevalence
The Caucasian race, to which the majority of the Dutch
population belong, have the unique characteristic that lactase
activity continues throughout life. We are exceptions to
the rest of nature in this regard”, says Professor Schaafsma.
“In other population groups, for example from Africa and
the Antilles, lactase activity declines after childhood and
people become lactose intolerant. Lactose intolerance in the
Netherlands is therefore found primarily among immigrant
populations.” There is an increase in lactose intolerance among
those in the indigenous population aged over 40. Schaafsma
explains: “Enzyme activity declines with age, a natural process.
Not everyone becomes intolerant however, as the intestinal
flora often adapts. In that case lactose acts as a sort of
prebiotic in the intestines and the modified intestinal flora can
convert the lactose without producing gas. Lactase activity
remains low, but the person involved can tolerate milk because
of the adaptation of the intestinal flora.”
Diet
A low lactose or lactose-free diet forms the basis for the
treatment of lactose intolerance. The required degree of
restriction is dependent on the amount of lactose the person
can tolerate (Solomons 2002; Montalto 2006; Byers 2005;
In brief
Nearly 1 in 10 Dutch residents have problems with lactose
intolerance, in particular those of foreign origin.
This means that they are not able to tolerate lactose
(milk sugar) because too little lactase is produced in their
intestines. Lactase is an enzyme required for the digestion
of lactose. Lactose intolerance gives rise to complaints like
stomach pain, cramps, nausea, bloating, wind and diarrhoea.
It is important to limit the amount of lactose in the diet, but
that does not mean that dairy products need to be taken
completely off the menu. That is also not advisable, as milk
is a basic foodstuff which makes a substantial contribution
to the intake of vitamin B2, vitamin B12 and calcium: all
important nutrients. Most people can tolerate a little lactose
(around 10-12 grams per day) spread out between their meals.
This would equate to a large cup of milk with every meal.
Acidic milk products like yoghurt and buttermilk are generally
better tolerated. Hard Dutch cheese actually contains no
lactose. Milk is an outstanding basic product and delivers a
substantial quantity of foodstuffs such as vitamin B12, vitamin
B2 and calcium, combined with a usefully low energy quotient.
Drinking milk together with a meal means that the lactose
remains longer in the small intestine, allowing more time
for it to be broken down. Acidic milk products like yoghurt
and buttermilk are also an excellent dietary choice, and are
generally better tolerated. Lactic acid bacteria producing
lactase are required in the preperation of yoghurt, and break
down 25 to 50% of the lactose in milk. According to Professor
Schaafsma they also maintain their lactase activity in the
intestine. Hard Dutch cheese actually contains virtually no
lactose.
and Lomer 2007). It is a question of trying things out.
Schaafsma: “Even if they are lactose intolerant and there is
little lactase activity, most people can still tolerate around
10-12 g of lactose per day, spread between their meals. This
equates to around 300 ml of milk, or a large cup of milk with
each meal. From a nutritional standpoint it is not advisable
to completely remove milk products from the diet. Milk is a
unique food, naturally.
A selection of the literature consulted for this edition of Spotlight *
The FrieslandCampina Institute on lactose intolerance
The information and recommendations provided by the FrieslandCampina
Institute in the field of nutrition, dairy products and health are based
on the latest scientific findings. Even lactose intolerance people can still
tolerate a large cup of milk a day. Fermented milk products like yoghurt
and cheese or buttermilk can be consumed anyways. The complete
elimination of lactose is seldom necessary. A dietician is the appropriate
person to assist people with lactose intolerance in finding a remedy for
their complaints without bringing about dietary deficiencies.
t 0800 2345600, i www.frieslandcampinainstituut.nl, e instituut@
frieslandcampina.com.
Byers, K. et al., JACN, (2005), 24 (6): 569S-573S
Bloom G., Sherman P., Evaluation and Human Behavior, (2005), 26 (4): 301-312
Burger J. et al., PNAS, (2007), 104 (10): 3736-3741
Heyman M., Pediatrics, (2006), 118 (3): 1279-1286
Lomer M. et al., Alimentary Pharmacology and Therapeutics, (2007), 27 (2): 93-103
Montalto, M. et al., World Journal of Gastroenterl, (2006), 12 (2): 187-191
Schaafsma G., International Dairy Journal, (2008), 18: 458-465
Solomons N., EJCN, (2002), 56 (suppl 4): S5-S55
Sahi T., Scand J Gastroenterol (1994) Suppl: 202:7-20
Villako K, Scand J Gastroenterol (1994);29 suppl 202:36-54.
*You can request a full list of literature via [email protected].