Role
of irritable bowel syndrome in subjective lactose intolerance.
Lactose intolerance and self-reported
milk intolerance: relationship with lactose maldigestion and nutrient
intake.
Lactose
handling by women with lactose malabsorption is improved during
pregnancy.
Colonic
adaptation to daily lactose feeding in lactose maldigesters reduces
lactose intolerance.
A
comparison of symptoms after the consumption of milk or lactose-hydrolyzed
milk by people with self-reported severe lactose intolerance.
Fructooligosaccharides
and lactulose cause more symptoms in lactose maldigesters and subjects
with pseudohypolactasia than in control lactose digesters.
A
randomized trial of Lactobacillus acidophilus BG2FO4 to treat lactose
intolerance.
Prospective
study of lactose absorption during cancer chemotherapy: feasibility
of a yogurt-supplemented diet in lactose malabsorbers.
Improvement
of lactose digestion in humans by ingestion of unfermented milk
containing Bifidobacterium longum.
Allaying
fears and fallacies about lactose intolerance.
Do
patients with short-bowel syndrome need a lactose-free diet?
The
relationship between lactose tolerance test results and symptoms
of lactose intolerance.
Tolerance
to small amounts of lactose in lactose maldigesters.
Lactose
malabsorption and irritable bowel syndrome. Effect of a long-term
lactose-free diet.
Lactose
malabsorption is associated with early signs of mental depression
in females: a preliminary report.
Milk
fat does not affect the symptoms of lactose intolerance.
Role
of irritable bowel syndrome in subjective lactose intolerance.
Vesa
TH, Seppo LM, Marteau PR, Sahi T, Korpela R; Am J Clin Nutr
1998 Apr 67:4 710-5
Abstract
It has been suggested that the symptoms of irritable bowel syndrome
(IBS) may be wrongly attributed to lactose intolerance. We examined
the relations among IBS, demographic factors, living habits, and
lactose intolerance. On the basis of a lactose tolerance test with
ethanol, 101 of the 427 healthy subjects studied were lactose maldigesters
and 326 were lactose digesters. IBS was diagnosed by means of the
Bowel Disease Questionnaire, according to the Rome criteria. The
use of dairy products and symptoms experienced after their consumption
were recorded. IBS was found in 15% of both the lactose maldigesters
and lactose digesters. One-third of the subjects reported intolerance
to dairy products containing < or = 20 g lactose. About half
of this third were lactose maldigesters and about half were lactose
digesters. As explanations for this subjective lactose intolerance,
the logistic regression model estimated lactose maldigestion (odds
ratio: 10.3; 95% CI: 5.2, 20.4), IBS (4.6; 2.1, 10.1), experience
of symptoms other than gastrointestinal ones (2.3; 1.2, 4.5), and
female sex (2.1; 1.1, 4.0). Characteristics common to both subjective
lactose intolerance and IBS were female sex and the experience of
abdominal pain in childhood (P < 0.01). Age, regularity of meals,
and the amount of physical activity were not associated with either
subjective lactose intolerance or IBS. Of the subjects with IBS,
the percentage of lactose maldigesters was the same as in the whole
study group (24%) but the number who reported lactose intolerance
was higher (60% compared with 27%, P < 0.001). We showed a strong
relation among subjective lactose intolerance, IBS, the experience
of abdominal pain in childhood, and female sex.
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Lactose
intolerance and self-reported milk intolerance: relationship with
lactose maldigestion and nutrient intake. Lactase Deficiency Study
Group.
Carroccio A, Montalto
G, Cavera G, Notarbatolo A; J Am Coll Nutr 1998 Dec 17:6
631-6
Abstract
BACKGROUND:
The relationship between lactose-maldigestion, self-reported milk
intolerance and gastrointestinal symptoms has not been clearly defined.
OBJECTIVES: To evaluate: a) the prevalence of lactose maldigestion
and lactose intolerance in a sample of the general population taken
from a rural center; b) the frequency of self-reported milk-intolerance
and its correlation with lactose-maldigestion; c) the influence
of lactose maldigestion, lactose intolerance and self-reported milk
intolerance on dietary habits and consumption of total calories,
protein, and calcium. SUBJECTS: We studied a randomized sample of
the general population in a small center in Sicily. 323 subjects
(150 males, 173 females), age range 5 to 85 years (median 44) were
included and underwent H2-breath test after 25 g lactose load. The
preliminary dietary investigation spanned 7 consecutive days using
a printed dietary form and was under the daily control of a team
of dietitians. METHODS: The dietary investigation was completed
in the first part of the study and the results were analyzed for
nutrient composition by a computerized database. The subjects were
then divided into self-reported milk-intolerants and self-reported
milk-tolerants and they underwent H2 breath testing; subjects with
H2 concentration >20 ppm over the baseline concentration were
considered maldigesters and those with one or more symptoms were
classified as intolerants. RESULTS: 104/323 subjects (32.2%) were
lactose maldigesters but tolerants, while 13/323 (4%) were lactose
maldigesters and intolerants. In each age-class group (pediatric,
adult, and elderly subjects) only the lactose maldigester and intolerant
subjects showed differences in nutrient intake with a significantly
lower daily consumption of milk and a lower calcium intake. 49/323
subjects were self-reported milk-intolerants; of these, 26 (53%)
were lactose maldigesters but tolerants, 18 (37%) were lactose digesters
and tolerants and only 5 (10%) were lactose maldigesters and intolerants.
In the whole group of self-reported milk-intolerants, dietary milk
consumption was significantly reduced and calcium intake was lower
than in all the other subjects studied (320 mg/day vs. 585 mg/day,
p<0.05). CONCLUSIONS: In studies of the general population, the
frequency of lactose intolerance is much lower than that of lactose
maldigestion. Gastrointestinal symptoms after lactose load in self-reported
milk-intolerants are found in only a very low number of these subjects.
Furthermore, in these subjects we observed an unnecessary reduction
in milk consumption and an insufficient dietary calcium intake.
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Lactose
handling by women with lactose malabsorption is improved during
pregnancy.
Szilagyi A, Salomon R,
Martin M, Fokeeff K, Seidman E; Clin Invest Med 1996 Dec
19:6 416-26
Abstract
OBJECTIVE:
To evaluate lactose handling among women in late pregnancy and post
partum to determine whether lactose handling is altered in pregnancy.
DESIGN: Prospective study of lactose intolerance among pregnant
women with and without lactose malabsorption. SETTING: Gastroenterology
service of the Sir Mortimer B. Davis-Jewish General Hospital, Montreal.
PATIENTS: Thirty-three pregnant women, of whom 18 had lactose malabsorption,
12 did not and 3 were excluded. OUTCOME MEASURES: Lactose breath
hydrogen (BH2) concentration after ingestion of lactose or lactulose;
comparison before and after delivery of area under the curve (AUC)
for lactose, oral-cecal transit time (OCTT) for lactulose, lactose-BH2-derived
transit time and estimated dietary lactose consumption. RESULTS:
After weaning (at a median time of 9 months after delivery), 28
of the women returned for follow-up. Of the 12 who could absorb
lactose before delivery, 4 could no longer absorb lactose. Of the
other 16 women, lactose intolerance worsened in 12, remained the
same in 2 and improved in 2. The AUC was greater (p < 0.005),
the maximal BH2 concentration was higher (p = 0.004) and the number
of women whose BH2 concentration peaked was fewer (p < 0.025)
post partum than before delivery. The women's symptoms during and
after lactose BH2 tests were also greater post partum. The OCTT
(based on the lactulose BH2 test) was shorter post partum (p = 0.001).
Transit time derived from lactose BH2 tests was also shorter, but
not significantly so. The OCTT was not inversely correlated with
the change in AUC before and after delivery, but the lactose-BH2-derived
transit time was inversely correlated. Pregnant women consumed more
lactose before delivery than afterward (p < 0.004). CONCLUSIONS:
Women with lactose malabsorption handle lactose better than usual
in late pregnancy. Slow intestinal transit and bacterial adaptation
to increased lactose intake may be primarily responsible.
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Colonic
adaptation to daily lactose feeding in lactose maldigesters reduces
lactose intolerance.
Hertzler SR, Savaiano
DA; Am J Clin Nutr 1996 Aug 64:2 232-6
Abstract
We conducted
blinded, controlled crossover studies to determine the effect of
daily lactose feeding on colonic adaptation and intolerance symptoms.
The initial study with nine lactose maldigesters showed a threefold
increase in fecal beta-galactosidase activity after 16 d of lactose
feeding. To determine the effects of this adaptation on breath hydrogen
and intolerance symptoms, 20 lactose-maldigesting adults were randomly
assigned to lactose or dextrose supplementation for 10 d (days 1-10),
crossing over to the other period for days 12-21. The sugar dosage
was increased from 0.6 to 1.0 g.kg-1.d-1, subdivided into three
equal doses, by adjusting the dose every other day. Symptoms during
lactose supplementation and comparison of symptoms during the lactose
and dextrose feeding periods showed no significant differences.
On days 11 and 22, challenge doses of lactose (0.35 g/kg) were administered
after an overnight fast, and breath hydrogen and intolerance symptoms
(abdominal pain, flatulence, and diarrhea) were carefully monitored
for 8 h. Frequency of flatus passage and flatus severity ratings
after the lactose challenge decreased 50% when studied at the end
of the lactose period compared with the dextrose period. The sum
of hourly breath-hydrogen concentrations (1-8 h) was significantly
reduced after the lactose feeding period (9 38 ppm.h) compared with
after the dextrose period (385 52 ppm.h, P < 0.001). We conclude
that there is colonic adaptation to regular lactose ingestion and
this adaptation reduces lactose intolerance symptoms.
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A
comparison of symptoms after the consumption of milk or lactose-hydrolyzed
milk by people with self-reported severe lactose intolerance.
Suarez FL, Savaiano DA,
Levitt MD; N Engl J Med 1995 Jul 6 333:1 1-4
Abstract
BACKGROUND.
Ingestion of a large dose of the milk sugar lactose--for example,
the 50-g load in 1 liter of milk--causes symptoms such as abdominal
pain, diarrhea, bloating, and flatulence in the majority of people
with lactose malabsorption. It is uncertain whether the ingestion
of more common doses of lactose, such as the amount in 240 ml (8
oz) of milk, causes symptoms. Some people insist that even smaller
quantities of milk, such as the amount used with cereal or coffee,
cause severe gastrointestinal distress. METHODS. In a randomized,
double-blind, crossover trial, we evaluated gastrointestinal symptoms
in 30 people (mean age, 29.4 years; range, 18 to 50) who reported
severe lactose intolerance and said they consistently had symptoms
after ingesting less than 240 ml of milk. The ability to digest
lactose was assessed by measuring the subjects' end-alveolar hydrogen
concentration after they ingested 15 g of lactose in 250 ml of water.
Subjects then received either 240 ml of lactose-hydrolyzed milk
containing 2 percent fat or 240 ml of milk containing 2 percent
fat and sweetened with aspartame to approximate the taste of lactose-hydrolyzed
milk; each type of milk was administered daily with breakfast for
a one-week period. Using a standardized scale, subjects rated the
occurrence and severity of bloating, abdominal pain, diarrhea, and
flatus and recorded each passage of flatus. RESULTS. Twenty-one
participants were classified as having lactose malabsorption and
nine as being able to absorb lactose. During the study periods,
gastrointestinal symptoms were minimal (mean symptom-severity scores
for bloating, abdominal pain, diarrhea, and flatus between 0.1 and
1.2 [1 indicated trivial symptoms; and 2, mild symptoms]). When
the periods were compared, there were no statistically significant
differences in the severity of these four gastrointestinal symptoms.
For the lactose-malabsorption group, the mean ( SEM) difference
in episodes of flatus per day was 2.5 1.1 (95 percent confidence
interval, 0.2 to 4.8). Daily dietary records indicated a high degree
of compliance, with no additional sources of lactose reported. CONCLUSIONS.
People who identify themselves as severely lactose-intolerant may
mistakenly attribute a variety of abdominal symptoms to lactose
intolerance. When lactose intake is limited to the equivalent of
240 ml of milk or less a day, symptoms are likely to be negligible
and the use of lactose-digestive aids unnecessary.
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Fructooligosaccharides
and lactulose cause more symptoms in lactose maldigesters and subjects
with pseudohypolactasia than in control lactose digesters.
Teuri U, Vapaatalo H,
Korpela R; Am J Clin Nutr 1999 May 69:5 973-9
Abstract
BACKGROUND: Many lactose maldigesters tolerate more lactose
in experimental studies than in everyday life, in which their symptoms
may result from other carbohydrates as well. OBJECTIVE: The question
of whether the symptoms caused by large quantities of carbohydrates
are more severe in lactose maldigesters than in control lactose
digesters or in lactose digesters who report milk to be the cause
of their gastrointestinal symptoms (pseudohypolactasic subjects)
was studied in a randomized, double-blind, crossover study. Comparisons
between commonly used diagnostic methods for lactose maldigestion
were also made. DESIGN: The subjects were 40 women aged 20-63 y
from 3 groups: lactose maldigesters (n = 12), pseudohypolactasic
subjects (n = 15), and control lactose digesters (n = 13). The subjects
were given either 50 g lactose, 50 g sucrose, 25 g lactulose, or
25 g fructooligosaccharides. After carbohydrate ingestion, urine
was collected and the breath-hydrogen concentration was measured
every 30 min for 3 h. Blood glucose was measured every 20 min for
1 h and subjective gastrointestinal symptoms were monitored for
8 h with a questionnaire. RESULTS: When lactulose and fructooligosaccharides
were ingested, the lactose maldigesters (P = 0.04 and 0.09, respectively)
and the pseudohypolactasic subjects (P = 0.006 and 0.01, respectively)
reported more symptoms than did the control lactose digesters. Sucrose
caused more symptoms in the lactose maldigesters than in the control
lactose digesters (P = 0.05). CONCLUSIONS: Lactose maldigesters
and lactose digesters with pseudohypolactasia experience more symptoms
than control lactose digesters after a single intake of large amounts
of indigestible carbohydrates. Lactose maldigesters also experience
more symptoms after ingesting sucrose.
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A
randomized trial of Lactobacillus acidophilus BG2FO4 to treat lactose
intolerance.
Saltzman JR, Russell
RM, Golner B, Barakat S, Dallal GE, Goldin BR; Am J Clin Nutr
1999 Jan 69:1 140-6
Abstract
BACKGROUND:
Lactose intolerance is the most common disorder of intestinal carbohydrate
digestion. Lactobacillus acidophilus BG2FO4 is a strain of lactobacilli
with properties of marked intestinal adherence and high beta-galactosidase
activity. OBJECTIVE: This study was designed to determine whether
oral feeding of Lactobacillus acidophilus BG2FO4 leads to a lactose-tolerant
state. DESIGN: We studied 42 subjects with self-reported lactose
intolerance and performed breath-hydrogen tests to determine whether
they were lactose maldigesters. Subjects with established lactose
maldigestion (n = 24) were invited to be randomly assigned to an
omeprazole-treated (hypochlorhydric) group or a non-omeprazole-treated
group, but 6 subjects chose not to participate. All randomly assigned
subjects (n = 18) ingested Lactobacillus acidophilus BG2FO4 twice
per day for 7 d and stool samples were collected. Breath-hydrogen
tests were performed and symptom scores were recorded at baseline
and after lactobacilli ingestion. RESULTS: Lactose maldigestion
was established in 24 of 42 subjects (57%) with self-reported lactose
intolerance. In 18 lactose-maldigesting subjects, overall hydrogen
production and symptom scores after ingestion of Lactobacillus acidophilus
BG2FO4 were not significantly different from baseline values. Live
Lactobacillus acidophilus BG2FO4 was recovered in stool samples
from 7 subjects. CONCLUSIONS: Lactose intolerance is overreported
in subjects with gastrointestinal symptoms after lactose ingestion.
Treatment of lactose-maldigesting subjects with and without hypochlorhydria
with Lactobacillus acidophilus BG2FO4 for 7 d failed to change breath-hydrogen
excretion significantly after lactose ingestion.
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Prospective
study of lactose absorption during cancer chemotherapy: feasibility
of a yogurt-supplemented diet in lactose malabsorbers.
Pettoello-Mantovani M,
Guandalini S, diMartino L, Corvino C, Indolfi P, Casale F, Giuliano
M, Dubrovsky L, Di Tullio MT; J Pediatr Gastroenterol Nutr
1995 Feb 20:2 189-95
Abstract
Chemotherapy
is a recognized cause of morphological alterations to the proximal
intestine. Lactose malabsorption, the functional consequence of
a small intestinal enzymatic derangement, has been shown to play
an important role in causing gastrointestinal symptoms in subjects
receiving chemotherapy. To establish a rational basis for the exclusion
of lactose from the diet and to reduce the risk of developing gastrointestinal
symptoms, we conducted a study of lactose absorption in 20 children
during cancer chemotherapy. Because lactose is an important nutritional
sugar, the tolerance of lactose provided by yogurt was examined.
Lactose absorption was investigated by a hydrogen breath test (BT)
after oral ingestion of milk (250 ml) containing physiological doses
of lactose (12 g). The effect of yogurt supplementation was also
tested by BT after meals of yogurt (450 g) also containing physiological
doses of lactose (12.1 g). In 11 children, lactose malabsorption
was detected by BT during the study before any gastrointestinal
symptom revealed this status. Of these 11 children, no gastrointestinal
discomfort developed in five receiving a lactose-excluded diet.
In contrast, in the six children not restricted in lactose intake,
gastrointestinal symptoms were observed 4 to 13 weeks after lactose
malabsorption was detected by BT. The findings of our study suggested
the usefulness of dietary supplementation with yogurt, a lactose-containing
food, in children who developed lactose malabsorption. In fact,
all lactose-malabsorbent children showed good lactose absorption
and tolerance when tested by yogurt BT.(ABSTRACT TRUNCATED AT 250
WORDS)
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Improvement
of lactose digestion in humans by ingestion of unfermented milk
containing Bifidobacterium longum.
Jiang T, Mustapha A,
Savaiano DA J Dairy Sci 1996 May 79:5 750-7
Abstract
Fifteen lactose
malabsorbers were studied to evaluate the effects of consumption
of milk containing different strains of Bifidobacterium longum on
lactose digestion. Influences of different growth substrates, bile
sensitivity, and lactose transport on lactose digestion by bifidobacteria
were also investigated. Lactose malabsorption was determined by
measuring breath hydrogen excretion of subjects fed four different
test milks (three of which contained 5 x 10(8) cfu/ml of B. longum)
on 4 different d using a randomized, double-blinded trial. Test
milks included 1) 400 ml of lowfat milk (control), 2) 400 ml of
milk containing B. longum B6 that had been grown with lactose, 3)
400 ml of milk containing B. longum B6 grown with lactose plus glucose,
or 4) 400 ml of milk containing B. longum ATCC 15708 grown with
lactose. beta-Galactosidase activity was highest in milk containing
B6 grown with lactose but was extremely low in milk containing B6
grown with lactose and glucose. Consumption of milk containing B6
grown with lactose resulted in significantly less hydrogen production
and flatulence than occurring after consumption of control milk
or the milk containing B6 grown with both lactose and glucose. Hydrogen
production after ingestion of 15708 was also significantly lower
than hydrogen production after ingestion of the control milk. We
concluded that milks containing B. longum might reduce breath hydrogen
response and symptoms from lactose malabsorption when the culture
is grown in a medium containing only lactose to induce a higher
beta-galactosidase level and increase rate of lactose uptake.
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Allaying
fears and fallacies about lactose intolerance.
McBean LD, Miller GD
J Am Diet Assoc 1998 Jun 98:6 671-6
Abstract
Public awareness and misunderstandings of lactose intolerance
are at an all-time high. Many people erroneously believe they are
lactose intolerant or develop gastrointestinal symptoms after intake
of lactose. Consequently, lactose-containing foods such as milk
and other dairy foods may be eliminated unnecessarily from the diet.
Because these foods are a major source of calcium, low intake of
them can compromise calcium nutriture. This, in turn, can increase
the risk of major chronic diseases such as osteoporosis (porous
bones) and hypertension. This review is intended to help dietetics
professionals alleviate clients' fears about lactose intolerance
and recommend dietary strategies to improve tolerance to lactose.
Scientific findings indicate that the prevalence of lactose intolerance
is grossly overestimated. Other physiologic and psychologic factors
can contribute to gastrointestinal symptoms that mimic lactose intolerance.
Scientific findings also indicate that people with laboratory-confirmed
low levels of the enzyme lactase can consume 1 serving of milk with
a meal or 2 servings of milk per day in divided doses at breakfast
and dinner without experiencing symptoms. Several dietary strategies
are available to help lactose maldigesters include milk and other
dairy foods in their diet without experiencing symptoms.
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Do
patients with short-bowel syndrome need a lactose-free diet?
Marteau P, Messing B,
Arrigoni E, Briet F, Flourié B, Morin MC, Rambaud JC; Nutrition
1997 Jan 13:1 13-6
Abstract
We compared
the tolerance of a diet providing 20 g/d lactose and a lactose-free
diet in 14 patients with short-bowel syndrome with either the colon
in continuity (group A, n = 8) or a terminal jejunostomy (group
B, n = 6). Lactose tolerance was studied after a single 20-g lactose
load in the fasting state, and during two 3-d periods during which
the subjects consumed their usual diet plus either 20 g/d lactose,
with no more than 4 g/d as milk, or no lactose. Records and measurements
included symptoms, fecal weight, and during the 8 h after the lactose
load, breath-hydrogen excretion (group A) or lactose and hexoses
flow rates in stomal effluents (group B). Results are expressed
as medians with ranges in parentheses. Lactose absorption was 61%
(0-90) in group A and 53% (18-84) in group B, and no symptoms of
intolerance were noticed. During the lactose-rich diet as compared
to the lactose-free diet, no symptoms were noticed nor was there
any worsening of diarrhea: 1534 g/d (240-4760) versus 1466 (1590-7030)
in group A, and 4122 g/d (1730-6830) versus 3496 (1590-7030) in
group B. We conclude that a diet providing 20 g/d lactose with no
more than 4 g/d as milk is well tolerated in the majority of patients
with short-bowel syndrome, and that a lactose-free diet has usually
no benefit in these subjects.
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The
relationship between lactose tolerance test results and symptoms
of lactose intolerance.
Hermans MM, Brummer RJ,
Ruijgers AM, Stockbrügger RW; Am J Gastroenterol 1997 Jun
92:6 981-4
Abstract
OBJECTIVE:
A standard for the assessment of lactose malabsorption does not
exist. As measured by lactose tolerance tests, insufficient increase
in blood glucose or increased breath hydrogen (H2) excretion after
lactose ingestion is regarded as pathological. In this study, we
have tried to elucidate the relationship between lactose tolerance
test results and symptoms after a lactose challenge. This relationship
might be an indicator for the validity of the test. METHODS: In
a prospective study, 309 consecutive patients with suspected lactose
malabsorption underwent a lactose tolerance test. After consumption
of 50 g of lactose, blood glucose and breath H2 concentrations were
measured. During the test (240 min), the severity of bloating, flatulence,
abdominal distention, and diarrhea were semiquantitatively scored
as 0, 1, or 2. The individual sum of these four scores was calculated
and denoted as the total symptom score (TSS). All subjects were
classified according to their TSS to compare symptoms with peak
breath-H2 concentration and change in blood glucose concentration,
respectively. RESULTS: The glucose and breath H2 response were pathological
in 51.1 and 39.5% of cases, respectively. A stepwise increase in
TSS of 1 point was associated with a significant increase (p <
0.05) in mean peak H2 concentration. However, a significantly lower
glucose increment compared with patients with a TSS of 0 was found
only in patients with a TSS of 2 or 4. The mean symptom score differed
significantly between the positive and negative breath tests (p
< 0.001), but did not differ between the positive and negative
glucose response results. CONCLUSIONS: This study shows that GI
symptoms after a lactose challenge are strongly associated with
the amount of H2 excretion. The relationship between the increase
in glucose concentration and symptoms after a lactose load is less
evident. Thus, the H2 breath test seems to be superior to the measurement
of blood glucose increment as a diagnostic tool in lactose malabsorption,
although the true predictive value of this test only can be determined
after a period of dietary treatment.
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Tolerance
to small amounts of lactose in lactose maldigesters
Vesa TH, Korpela RA,
Sahi T; Am J Clin Nutr 1996 Aug 64:2 197-201
Abstract
In this study
we examined whether small doses of lactose induced symptoms in 39
lactose maldigesters and 15 lactose digesters in a randomized, crossover,
double-blind design. The test doses were 200 mL fat-free, lactose-free
milk to which 0, 0.5, 1.5, and 7 g lactose was added. Every third
day of a lactose-free diet, after an overnight fast, the subjects
drank one of the test milks in random order and registered the occurrence
and severity of gastrointestinal symptoms in the next 12 h. During
the study, the maldigesters reported significantly more abdominal
bloating (P = 0.0003) and abdominal pain (P = 0.006) than the digesters.
There was no difference in the mean severity of the reported symptoms
between the test milks and the lactose-free milk in the group of
lactose maldigesters, of whom one-third did not experience any symptoms
from any of the test doses. The same proportion (64%) of the maldigesters
experienced symptoms after both the lactose-free milk and the milk
with 7 g lactose. However, the symptoms occurred inconsistently
with the different test doses in 59% of the maldigesters. Thus,
it can be concluded that the gastrointestinal symptoms in most lactose
maldigesters are not induced by lactose when small amounts (0.5-7.0
g) of lactose are included in the diet.
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Lactose
malabsorption and irritable bowel syndrome. Effect of a long-term
lactose-free diet.
Vernia P, Ricciardi MR,
Frandina C, Bilotta T, Frieri G; Ital J Gastroenterol 1995
Apr 27:3 117-21
Abstract
Lactose malabsorption
may induce abdominal symptoms indistinguishable from those of the
irritable bowel syndrome (IBS), however the exact relationship between
the two conditions and the optimal differential diagnostic workup
are still to be defined. We prospectively studied the prevalence
of lactose malabsorption (by means of a hydrogen breath test) and
the clinical effect of a long-term lactose-free diet in 230 consecutive
patients with a suggested diagnosis of irritable bowel syndrome,
no organic disease of the GI tract, and no history of milk intolerance.
Lactose malabsorption was diagnosed in 157 patients (68.2%). In
48 (43.6%) of the 110 patients who complied with the diet symptoms
subsided, in 43 they were somewhat reduced and in 17 they remained
unchanged. Symptoms never fully subsided in lactose malabsorbers
non-compliant with the diet or in normal lactose absorbers who adhered
to a lactose-free regimen. Partial improvement was observed in 20%
of these subjects. No relation was demonstrated between pre-trial
symptoms and the outcome of the diet. The occurrence of symptoms
during the lactose breath test strongly suggested a favorable response
to diet, but did not help in predicting whether symptoms would subside
or be reduced. Conversely, their absence during the test was not
associated with an acceptable negative predictive value. The high
prevalence of lactose malabsorption in the patients under study
suggests that in Italy IBS and lactose malabsorption are frequently
associated. A test for diagnosing lactose malabsorption should always
be included in the diagnostic workup for IBS and a long-term lactose-free
regimen recommended if the test is positive.
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Lactose
malabsorption is associated with early signs of mental depression
in females: a preliminary report.
Ledochowski M, Sperner-Unterweger
B, Fuchs D; Dig Dis Sci 1998 Nov 43:11 2513-7
Abstract
Lactose malabsorption
is characterized by a deficiency of mucosal lactase. As a consequence,
lactose reaches the colon where it is broken down by bacteria to
short-chain fatty acids, CO2, and H2. Bloating, cramps, osmotic
diarrhea, and other symptoms of irritable bowel syndrome are the
consequence and can be seen in about 50% of lactose malabsorbers.
Having made the observation that females with lactose malabsorption
not only showed signs of irritable bowel syndrome but also signs
of premenstrual syndrome and mental depression, it was of interest
to establish whether a statistical correlation existed between lactose
malabsorption and mental depression. Thirty female volunteers were
analyzed by measuring breath H2 concentrations after an oral dose
of 50 g lactose and were classified as normals or lactose malabsorbers
according to their breath H2 concentrations. All patients filled
out a Beck's depression inventory questionnaire. Of the 30 female
volunteers, six were lactose intolerant (20%) and 24 were normal
lactose absorbers (80%). Subjects with lactose malabsorption showed
a significantly higher score in the Beck's depression inventory
than normal lactose absorbers did. The data thus suggest that lactose
malabsorption may play a role in the development of mental depression.
In lactose malabsorption high intestinal lactose concentrations
may interfere with L-tryptophan metabolism and 5-hydroxytryptamine
(serotonin) availability. Lactose malabsorption should be considered
in patients with signs of mental depression.
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