- #1
bobf
Hello,
I was reading a thread that was locked, so I wasn't able to respond, but I wanted to present some information on racial differences. I do not wish to debate the issue since I do not have the time, but I wanted to put this information out there for everyone who may wish to have it.
1. Fiber-type Differences:
---------------------------------------------
J Appl Physiol 1986 Nov;61(5):1758-61
Skeletal muscle characteristics in sedentary black and Caucasian
males.
Ama PF, Simoneau JA, Boulay MR, Serresse O, Theriault G, Bouchard C.
Twenty-three male Black African and 23 male Caucasian subjects,
ascertained as sedentary, participated in this study designed to
determine whether there were differences in skeletal muscle
histochemical and biochemical characteristics between racial groups.
Muscle fiber type proportions (I, IIa, and IIb), fiber areas and
activities of several enzyme markers of different energy metabolic
pathways were determined from a biopsy of the vastus lateralis.
Results indicated that Caucasians had a higher percent type I (8%, P
less than 0.01) and a lower percent type IIa (6.7%, P less than 0.05)
fiber proportions than Africans. No significant differences were
observed between the two racial groups in the type IIb fiber
proportion or in the three fiber type areas. Enzymes catalyzing
reactions in phosphagenic [creatine kinase (CK)] and glycolytic
[hexokinase (HK), phosphofructokinase (PFK), and lactate
dehydrogenase (LDH)] metabolic pathways had significantly higher
activities (about 30-40%) in the Black African group than in the
Caucasian group (P less than 0.01). No significant difference was
noted in the activities of oxidative enzymes [malate dehydrogenase
(MDH), oxoglutarate dehydrogenase (OGDH), and 3-hydroxyacyl-CoA
dehydrogenase (HADH)]. Consequently, the PFK/OGDH ratio was
significantly elevated in Africans (P less than 0.05). The racial
differences observed between Africans and Caucasians in fiber type
proportion and enzyme activities of the phosphagenic and glycolytic
metabolic pathways may well result from inherited variation. These
data suggest that sedentary male Black individuals are, in terms of
skeletal muscle characteristics, well endowed for sport events of
short duration.
-----------------------------------------------
2. ACE differences:
-----------------------------------------------
Am J Med Sci 2000 Jul;320(1):18-23
Elevated mortality rates from circulatory disease in African American
men and women of Los Angeles County, California--a possible genetic
susceptibility?
Henderson SO, Coetzee GA, Ross RK, Yu MC, Henderson BE.
OBJECTIVE: Reports of higher mortality in African Americans have
often focused on socioeconomic differences. Such differences do not
explain the excess mortality in African Americans compared with
Hispanics in Los Angeles County. We suggest the existence of genetic
factors to explain at least some of the differences in mortality
risk. METHODS: We compared the mortality rates from circulatory
diseases in African American and Hispanic adults of Los Angeles
County for 1988 to 1992 with the frequency of the angiotensin-
converting enzyme (ACE) genotype. RESULTS: African American adults 45
to 74 years old had a 2-fold higher overall mortality rate than
Hispanics. The largest differences were seen for hypertensive disease
and cardiomyopathy in men; the most striking differences were seen in
the youngest age group. Rates were lower in women than in men, but
African American women also showed substantial excess compared with
Hispanics. ACE genotype also showed a significant difference between
the Hispanic and African American population; the latter had a
significantly higher prevalence of the DD genotype, which is
associated with a higher level of circulating enzyme, and lower
prevalence of the II genotype, which is associated with a lower
enzyme level.
CONCLUSION: African American adults aged 45 to 74 years
in Los Angeles County have a substantial excess mortality from
hypertensive diseases compared with a similar Hispanic population.
The frequency of the ACE DD genotype was higher in African Americans
than in Hispanics. These studies may indirectly support the
possibility of a genetic contribution to the excess hypertensive
disease mortality in African Americans.
-----------------------------------------------
3. Body and Bone Mass Differences:
-----------------------------------------------
Ethn Health 1996 Dec;1(4):337-47
Ethnic differences in body composition and their relation to health
and disease in women.
Gasperino J.
Differences in body composition between black and white women have
been well established. Black women have more bone and muscle mass,
but less fat, as a percentage of body weight, than white women, after
controlling for ethnic differences in age, body weight, and height.
In addition, black women have more upper-body fat than white women.
These ethnic differences in body composition appear to be associated
with disease risk in women. The greater skeletal and muscle mass in
black compared to white women appears to protect them from
osteoporosis. The relationship between fat distribution and
cardiovascular disease also appears to be influenced by ethnicity.
This review has two purposes: (1) To examine previous research
investigating ethnic differences in body composition between black
and white women; and (2) To demonstrate the relationship between body
composition and disease in women as a function of ethnicity.
-----------------------------------------------
Am J Clin Nutr 2000 Jun;71(6):1392-402
Measures of body composition in blacks and whites: a comparative
review.
Wagner DR, Heyward VH.
Biological differences exist in the body composition of blacks and
whites. We reviewed literature on the differences and similarities
between the 2 races relative to fat-free body mass (water, mineral,
and protein), fat patterning, and body dimensions and proportions. In
general, blacks have a greater bone mineral density and body protein
content than do whites, resulting in a greater fat-free body density.
Additionally, there are racial differences in the distribution of
subcutaneous fat and the length of the limbs relative to the trunk.
The possibility that these differences are a result of ethnicity
rather than of race is also examined. Because most equations that
predict relative body fat were derived from predominantly white
samples, biological variation between the races in these body-
composition indexes has practical significance. Systematic error can
result in the inaccurate estimation of the relative body fat of
blacks, and therefore of definitions of obesity, if these inherent
differences are ignored.
--------------------------------------------
I was reading a thread that was locked, so I wasn't able to respond, but I wanted to present some information on racial differences. I do not wish to debate the issue since I do not have the time, but I wanted to put this information out there for everyone who may wish to have it.
1. Fiber-type Differences:
---------------------------------------------
J Appl Physiol 1986 Nov;61(5):1758-61
Skeletal muscle characteristics in sedentary black and Caucasian
males.
Ama PF, Simoneau JA, Boulay MR, Serresse O, Theriault G, Bouchard C.
Twenty-three male Black African and 23 male Caucasian subjects,
ascertained as sedentary, participated in this study designed to
determine whether there were differences in skeletal muscle
histochemical and biochemical characteristics between racial groups.
Muscle fiber type proportions (I, IIa, and IIb), fiber areas and
activities of several enzyme markers of different energy metabolic
pathways were determined from a biopsy of the vastus lateralis.
Results indicated that Caucasians had a higher percent type I (8%, P
less than 0.01) and a lower percent type IIa (6.7%, P less than 0.05)
fiber proportions than Africans. No significant differences were
observed between the two racial groups in the type IIb fiber
proportion or in the three fiber type areas. Enzymes catalyzing
reactions in phosphagenic [creatine kinase (CK)] and glycolytic
[hexokinase (HK), phosphofructokinase (PFK), and lactate
dehydrogenase (LDH)] metabolic pathways had significantly higher
activities (about 30-40%) in the Black African group than in the
Caucasian group (P less than 0.01). No significant difference was
noted in the activities of oxidative enzymes [malate dehydrogenase
(MDH), oxoglutarate dehydrogenase (OGDH), and 3-hydroxyacyl-CoA
dehydrogenase (HADH)]. Consequently, the PFK/OGDH ratio was
significantly elevated in Africans (P less than 0.05). The racial
differences observed between Africans and Caucasians in fiber type
proportion and enzyme activities of the phosphagenic and glycolytic
metabolic pathways may well result from inherited variation. These
data suggest that sedentary male Black individuals are, in terms of
skeletal muscle characteristics, well endowed for sport events of
short duration.
-----------------------------------------------
2. ACE differences:
-----------------------------------------------
Am J Med Sci 2000 Jul;320(1):18-23
Elevated mortality rates from circulatory disease in African American
men and women of Los Angeles County, California--a possible genetic
susceptibility?
Henderson SO, Coetzee GA, Ross RK, Yu MC, Henderson BE.
OBJECTIVE: Reports of higher mortality in African Americans have
often focused on socioeconomic differences. Such differences do not
explain the excess mortality in African Americans compared with
Hispanics in Los Angeles County. We suggest the existence of genetic
factors to explain at least some of the differences in mortality
risk. METHODS: We compared the mortality rates from circulatory
diseases in African American and Hispanic adults of Los Angeles
County for 1988 to 1992 with the frequency of the angiotensin-
converting enzyme (ACE) genotype. RESULTS: African American adults 45
to 74 years old had a 2-fold higher overall mortality rate than
Hispanics. The largest differences were seen for hypertensive disease
and cardiomyopathy in men; the most striking differences were seen in
the youngest age group. Rates were lower in women than in men, but
African American women also showed substantial excess compared with
Hispanics. ACE genotype also showed a significant difference between
the Hispanic and African American population; the latter had a
significantly higher prevalence of the DD genotype, which is
associated with a higher level of circulating enzyme, and lower
prevalence of the II genotype, which is associated with a lower
enzyme level.
CONCLUSION: African American adults aged 45 to 74 years
in Los Angeles County have a substantial excess mortality from
hypertensive diseases compared with a similar Hispanic population.
The frequency of the ACE DD genotype was higher in African Americans
than in Hispanics. These studies may indirectly support the
possibility of a genetic contribution to the excess hypertensive
disease mortality in African Americans.
-----------------------------------------------
3. Body and Bone Mass Differences:
-----------------------------------------------
Ethn Health 1996 Dec;1(4):337-47
Ethnic differences in body composition and their relation to health
and disease in women.
Gasperino J.
Differences in body composition between black and white women have
been well established. Black women have more bone and muscle mass,
but less fat, as a percentage of body weight, than white women, after
controlling for ethnic differences in age, body weight, and height.
In addition, black women have more upper-body fat than white women.
These ethnic differences in body composition appear to be associated
with disease risk in women. The greater skeletal and muscle mass in
black compared to white women appears to protect them from
osteoporosis. The relationship between fat distribution and
cardiovascular disease also appears to be influenced by ethnicity.
This review has two purposes: (1) To examine previous research
investigating ethnic differences in body composition between black
and white women; and (2) To demonstrate the relationship between body
composition and disease in women as a function of ethnicity.
-----------------------------------------------
Am J Clin Nutr 2000 Jun;71(6):1392-402
Measures of body composition in blacks and whites: a comparative
review.
Wagner DR, Heyward VH.
Biological differences exist in the body composition of blacks and
whites. We reviewed literature on the differences and similarities
between the 2 races relative to fat-free body mass (water, mineral,
and protein), fat patterning, and body dimensions and proportions. In
general, blacks have a greater bone mineral density and body protein
content than do whites, resulting in a greater fat-free body density.
Additionally, there are racial differences in the distribution of
subcutaneous fat and the length of the limbs relative to the trunk.
The possibility that these differences are a result of ethnicity
rather than of race is also examined. Because most equations that
predict relative body fat were derived from predominantly white
samples, biological variation between the races in these body-
composition indexes has practical significance. Systematic error can
result in the inaccurate estimation of the relative body fat of
blacks, and therefore of definitions of obesity, if these inherent
differences are ignored.
--------------------------------------------