Lactose Mary
Frances
intolerance Sowers,2
M.S.,
ABSTRACT and
tested
not
related
based
among and
Thirty-three for
lactose
by birth,
on
a
rise
less
17 nonrelated from
rise
generations lactose
than
Meter Mexican
in blood
four
the
families of three
intolerance
glucose had
and
25
100
mg/
families
symptoms and
a genetic
lactose
in both basis,
ml
of
sexes
blood There
as load. and
adds
17 persons
intolerance by
Forty-seven
an
percent
relationship
was Ames of the between
distention.
Sixteen
children
of intolerance
in two
successive
support
sex predilection.
interviewed
and
measured
a marked
findings
families
60 were
16 children of lactose
was
flatulence, The
of the
of 9 and
glucose
of a lactose
intolerance.
without
ages included
Determination
intolerant.
of diarrhea,
of 50%
the study
children.
consumption
were
an incidence
has
of the
of the
following
Americans
between
participants
parents
Americans1
Ph.D.
Americans
The
including of
Winterfeldz,3
Mexican
intolerance.
Dextrostix/Reflectance low
Esther
Mexican
Am.J.
to the Clin.
contention
Nuir.
that
28:704-705,
1975.
Lactase deficiency resulting in gastrointestinal disturbance and lactose intolerance has been reported among various racial and ethnic populations. These populations include American Indian, Oriental, Negro, Mediterranean groups and Mexican Americans (1-5). This investigation was designed to determine the prevalence of intolerance among Mexican Americans and to observe patterns of intolerance among Mexican American families.
Results
Methods Thirty-three
Mexican
Americans between the ages of 9 selected, interviewed, and tested The participants included 16 children from four families and 17 persons not related by birth, including the parents of the children. The participants were healthy with no known intestinal diseases. Following an overnight fast, each of the subjects consumed a lactose test dose containing I g of lactose/kg of body weight. The lactose was dissolved in 350 ml of water for participants weighing less than 150 pounds and 400 ml of water for those weighing more than 150 pounds. A fingerprick blood sample was taken before administering the lactose to determine fasting blood glucose and to provide a basis of comparison for maximum blood glucose rise following administration of the lactose load. Three fingerprick blood samples were taken at 20-mm intervals following lactose consumption and the results evaluated immediately in a calibrated Ames Dextrostix/Reflectance Meter. Normal lactose absorption was indicated when the maximum rise in blood glucose was greater than 25 mg/ 100 ml.
and 60 were randomly for lactose intolerance.
Subjects
were also observed for onset of flatulence, diarrhea, distention or gastrointestinal disturbance for hours following administration of the lactose solution.
704
The
American
Journal
of Clinical
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/7/704/4716456 by Washington University, Law School Library user on 21 May 2018
6
A limited rise in blood glucose following administration of a lactose test was found in 8 of the 17 nonrelated Mexican American subjects, including parents of the children (47%). There was a limited rise in blood glucose found in 8 of the 16 children in the four families (50%). There was a marked relationship between limited rise in blood glucose and the onset of diarrhea, flatulence, distention, and other gastrointestinal disturbance following administration of the test dose. Members of Family 1 (Fig. I) showed rises in blood glucose above the 25 mg/lOO ml level with no clinical symptoms of lactose intolerance. Parents in Family 2 exhibited low rise in blood glucose and had severe symptoms. Their three older children, ranging in age from 17 to 21, had low rises in blood glucose and marked symptoms; however, two children, ages 9 and 11, had normal rises in blood glucose. One parent in Family 3 was intolerant and three of the five children were also intolerant. In Family 4, only one parent was available for testing. This individual showed no rise in blood glucose and exhibited severe symptoms. Two of four children were intolerant. ‘From Oklahoma lahoma 74074. 2 Food and Nutrition ice.
Nutrition
Professor
28: JULY
State
and
1975,
University,
Specialist, Head
pp.
OSU
Stillwater,
Ok-
Extension
Serv-.
of Department
704-705.
Printed
of F.N.I.A.
in U.S.A.
LACTOSE
INTOLERANCE
Ag
Fas
AMONG
12
F.’1v3
T,1,-si
Q
M.L
(,,,..1
Mal,
gloto.r
(blood
belos
or
FIG. Mexican
nLas,
,...d
a
ml
lotoirosot
.
b1d
Ittol
rraot
Mal,
tot
i.,
and
25
,g/LOO
sye#{231}xon$)
Frnalr aoailabtr
I. Incidence American
lot
trst
of lactose families.
intolerance
among
four
Discussion These results indicate lactose intolerance among almost 50% of Mexican American subjects when tested by the lactose loading procedure. Dill et al. (5) found 54% of eleven Mexican American males had limited lactase activity. Jones and associates (6), in a study of seven Latin Americans, found that 57% were intolerant. With approximately three million Mexican Americans in the United States, there is potential for many to be intolerant of milk and unfermented dairy products. A genetic etiology has been proposed by several researchers to explain the origin of lactose intolerance. For instance, the tribal differences among Africans suggest such a genetic basis. Though two tribes may live side by side, tests from one tribe indicate them to be intolerant while tests from the other tribe show them to be tolerant of lactose. Other studies indicate that incidence among families may be greater than among individuals from the population as a whole (1, 2, 8). Among the families tested in this study, there is indication of a genetic etiology. In Family 1, neither parent was intolerant and
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/7/704/4716456 by Washington University, Law School Library user on 21 May 2018
MEXICAN
AMERICANS
705
none of the children were intolerant, as would be the expected genetic pattern if lactose tolerance was a dominant trait or if lactose intolerance was recessive. In Family 2, both parents were intolerant. Three of the five children were also intolerant. It was of interest that three older children were intolerant while the two younger children were tolerant. It may be expected the two younger children may become intolerant as they become older, if lactose intolerance is a recessive trait. The pattern in Family 3 indicates that when one parent was tolerant and the other parent intolerant, three of the five children were intolerant. Third generation members in Families 2 and 3 were diabetic and consequently not tested. In Family 4, one parent was intolerant and two of the four children were intolerant. If tested, the male parent might have been shown to be tolerant. While this is not a large enough sample of family groups to allow conclusive prediction of tolerance, the genetic pattern found is indicative of the heritable trait. The genetic pattern found is compatible with an. autosomal recessive trait for lactose intolerance and a dominant gene for lactose tolerance. fl References I.
D. P.,
BOSE,
AND
J. D.
tion in Oklahoma 1320, 1973. 2.
REDDY,
V.,
Indians.
Am.
AND
J.
Lactose
Am.
PERSHAD.
malabsorp-
J. Clin. Nutr.
Lactase
26: in
deficiency
J. Clin. Nutr. 25: 114, 1972. D. A., AND B. K. ADADEVOH. Lactase in Nigerians. Am. J. Digest. Diseases 16:
3. OLATUNBOSUN, deficiency 909, 1971. 4. GILAT, T., R. Lactase
Am.
WELSH.
Indians.
deficiency
J.
Digest.
E.
KUHN, in
GELMAN
Jewish
AND
communities
0.
MIZRAHY.
in
Israel.
Diseases 15: 895, 1970. 5. DILL, J., M. LEVY, R. F. WELLS AND E. WESER. Lactase deficiency in Mexican-American males. Am. J. Clin. Nutr., 25: 869, 1972. 6. JONES, D. V., AND M. C. LATHAM. Lactose intolerance in young children and their parents. Am. J. Clin. Nutr. 27: 547, 1974. 7. KRETCHMER, N. Lactose and lactase. Sci. Am. 227: 70, 1972. 8. WELSH, J. D., 0. M. ZSCHIESCHE, V. L. WILLITS AND L. RUSSELL. Studies of lactose intolerance in families. Arch. Intern. Med. 122: 135, 1968.
Frances
intolerance Sowers,2
M.S.,
ABSTRACT and
tested
not
related
based
among and
Thirty-three for
lactose
by birth,
on
a
rise
less
17 nonrelated from
rise
generations lactose
than
Meter Mexican
in blood
four
the
families of three
intolerance
glucose had
and
25
100
mg/
families
symptoms and
a genetic
lactose
in both basis,
ml
of
sexes
blood There
as load. and
adds
17 persons
intolerance by
Forty-seven
an
percent
relationship
was Ames of the between
distention.
Sixteen
children
of intolerance
in two
successive
support
sex predilection.
interviewed
and
measured
a marked
findings
families
60 were
16 children of lactose
was
flatulence, The
of the
of 9 and
glucose
of a lactose
intolerance.
without
ages included
Determination
intolerant.
of diarrhea,
of 50%
the study
children.
consumption
were
an incidence
has
of the
of the
following
Americans
between
participants
parents
Americans1
Ph.D.
Americans
The
including of
Winterfeldz,3
Mexican
intolerance.
Dextrostix/Reflectance low
Esther
Mexican
Am.J.
to the Clin.
contention
Nuir.
that
28:704-705,
1975.
Lactase deficiency resulting in gastrointestinal disturbance and lactose intolerance has been reported among various racial and ethnic populations. These populations include American Indian, Oriental, Negro, Mediterranean groups and Mexican Americans (1-5). This investigation was designed to determine the prevalence of intolerance among Mexican Americans and to observe patterns of intolerance among Mexican American families.
Results
Methods Thirty-three
Mexican
Americans between the ages of 9 selected, interviewed, and tested The participants included 16 children from four families and 17 persons not related by birth, including the parents of the children. The participants were healthy with no known intestinal diseases. Following an overnight fast, each of the subjects consumed a lactose test dose containing I g of lactose/kg of body weight. The lactose was dissolved in 350 ml of water for participants weighing less than 150 pounds and 400 ml of water for those weighing more than 150 pounds. A fingerprick blood sample was taken before administering the lactose to determine fasting blood glucose and to provide a basis of comparison for maximum blood glucose rise following administration of the lactose load. Three fingerprick blood samples were taken at 20-mm intervals following lactose consumption and the results evaluated immediately in a calibrated Ames Dextrostix/Reflectance Meter. Normal lactose absorption was indicated when the maximum rise in blood glucose was greater than 25 mg/ 100 ml.
and 60 were randomly for lactose intolerance.
Subjects
were also observed for onset of flatulence, diarrhea, distention or gastrointestinal disturbance for hours following administration of the lactose solution.
704
The
American
Journal
of Clinical
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/7/704/4716456 by Washington University, Law School Library user on 21 May 2018
6
A limited rise in blood glucose following administration of a lactose test was found in 8 of the 17 nonrelated Mexican American subjects, including parents of the children (47%). There was a limited rise in blood glucose found in 8 of the 16 children in the four families (50%). There was a marked relationship between limited rise in blood glucose and the onset of diarrhea, flatulence, distention, and other gastrointestinal disturbance following administration of the test dose. Members of Family 1 (Fig. I) showed rises in blood glucose above the 25 mg/lOO ml level with no clinical symptoms of lactose intolerance. Parents in Family 2 exhibited low rise in blood glucose and had severe symptoms. Their three older children, ranging in age from 17 to 21, had low rises in blood glucose and marked symptoms; however, two children, ages 9 and 11, had normal rises in blood glucose. One parent in Family 3 was intolerant and three of the five children were also intolerant. In Family 4, only one parent was available for testing. This individual showed no rise in blood glucose and exhibited severe symptoms. Two of four children were intolerant. ‘From Oklahoma lahoma 74074. 2 Food and Nutrition ice.
Nutrition
Professor
28: JULY
State
and
1975,
University,
Specialist, Head
pp.
OSU
Stillwater,
Ok-
Extension
Serv-.
of Department
704-705.
Printed
of F.N.I.A.
in U.S.A.
LACTOSE
INTOLERANCE
Ag
Fas
AMONG
12
F.’1v3
T,1,-si
Q
M.L
(,,,..1
Mal,
gloto.r
(blood
belos
or
FIG. Mexican
nLas,
,...d
a
ml
lotoirosot
.
b1d
Ittol
rraot
Mal,
tot
i.,
and
25
,g/LOO
sye#{231}xon$)
Frnalr aoailabtr
I. Incidence American
lot
trst
of lactose families.
intolerance
among
four
Discussion These results indicate lactose intolerance among almost 50% of Mexican American subjects when tested by the lactose loading procedure. Dill et al. (5) found 54% of eleven Mexican American males had limited lactase activity. Jones and associates (6), in a study of seven Latin Americans, found that 57% were intolerant. With approximately three million Mexican Americans in the United States, there is potential for many to be intolerant of milk and unfermented dairy products. A genetic etiology has been proposed by several researchers to explain the origin of lactose intolerance. For instance, the tribal differences among Africans suggest such a genetic basis. Though two tribes may live side by side, tests from one tribe indicate them to be intolerant while tests from the other tribe show them to be tolerant of lactose. Other studies indicate that incidence among families may be greater than among individuals from the population as a whole (1, 2, 8). Among the families tested in this study, there is indication of a genetic etiology. In Family 1, neither parent was intolerant and
Downloaded from https://academic.oup.com/ajcn/article-abstract/28/7/704/4716456 by Washington University, Law School Library user on 21 May 2018
MEXICAN
AMERICANS
705
none of the children were intolerant, as would be the expected genetic pattern if lactose tolerance was a dominant trait or if lactose intolerance was recessive. In Family 2, both parents were intolerant. Three of the five children were also intolerant. It was of interest that three older children were intolerant while the two younger children were tolerant. It may be expected the two younger children may become intolerant as they become older, if lactose intolerance is a recessive trait. The pattern in Family 3 indicates that when one parent was tolerant and the other parent intolerant, three of the five children were intolerant. Third generation members in Families 2 and 3 were diabetic and consequently not tested. In Family 4, one parent was intolerant and two of the four children were intolerant. If tested, the male parent might have been shown to be tolerant. While this is not a large enough sample of family groups to allow conclusive prediction of tolerance, the genetic pattern found is indicative of the heritable trait. The genetic pattern found is compatible with an. autosomal recessive trait for lactose intolerance and a dominant gene for lactose tolerance. fl References I.
D. P.,
BOSE,
AND
J. D.
tion in Oklahoma 1320, 1973. 2.
REDDY,
V.,
Indians.
Am.
AND
J.
Lactose
Am.
PERSHAD.
malabsorp-
J. Clin. Nutr.
Lactase
26: in
deficiency
J. Clin. Nutr. 25: 114, 1972. D. A., AND B. K. ADADEVOH. Lactase in Nigerians. Am. J. Digest. Diseases 16:
3. OLATUNBOSUN, deficiency 909, 1971. 4. GILAT, T., R. Lactase
Am.
WELSH.
Indians.
deficiency
J.
Digest.
E.
KUHN, in
GELMAN
Jewish
AND
communities
0.
MIZRAHY.
in
Israel.
Diseases 15: 895, 1970. 5. DILL, J., M. LEVY, R. F. WELLS AND E. WESER. Lactase deficiency in Mexican-American males. Am. J. Clin. Nutr., 25: 869, 1972. 6. JONES, D. V., AND M. C. LATHAM. Lactose intolerance in young children and their parents. Am. J. Clin. Nutr. 27: 547, 1974. 7. KRETCHMER, N. Lactose and lactase. Sci. Am. 227: 70, 1972. 8. WELSH, J. D., 0. M. ZSCHIESCHE, V. L. WILLITS AND L. RUSSELL. Studies of lactose intolerance in families. Arch. Intern. Med. 122: 135, 1968.
