Friday, October 31, 2014

Is an Unacknowledged Eurocentric Paradigm Widening Ethnic Disparities in U.S. Health Care?


            African-Americans consume substantially less than the recommended daily intake of calcium and yet have the densest bone mass of any American ethnic group, and are at the lowest risk of osteoporosis, fragile bone disease and other calcium deficiency disorders. Studies have shown that this occurs because blacks have higher rates of calcium retention and greater calcium utilization efficiency than other ethnicities. So what public health message is given to black parents?  It is that their children suffer from calcium deficiency and should therefore be fed more dairy products in order to prevent osteoporosis. But what might the implications be of pushing high sodium, high fat dairy products on a population that is not in need of supplemental calcium but that is suffering from skyrocketing rates of juvenile obesity and salt-sensitive hypertension?  The medical response is that those ailments are probably caused by a calcium-deficiency as well. 

           
            The greatest danger in perceiving all ethnicities to be biological carbon copies of Northern Europeans is that such an unacknowledged paradigm blocks group testing of its underlying assumptions.  For instance, the public health model employed by researchers in the   United States is one based on the concept of  "Northern European universality.”  It operates from the unexamined premise that whatever nutritional guidelines and health messages are most beneficial for mainstream Americans, who are predominantly of Northern European ancestry, are ipso facto deemed best for all ethnicities and population groups. Thus the Food and Drug Administration offers a one-size-fits all set of  nutritional guidelines for food labeling. 

The Eurocentric Paradigm
            But how do we tell when a paradigm does not conform to a universal biological standard?  It will only be when too many paradoxes in the research findings pile atop one another.  In fact, African-Americans are suffering from growing health disparities at a time when the larger society is making its greatest health strides.  In 2010, The American Public Health Association issued an ongoing progress analysis entitled “Black-White Health Disparities in the United States and Chicago.”  It noted: “With more than 15 years of time and effort spent at the national and local level to reduce disparities the impact remains negligible.”([1]) Blacks are not getting poorer. But they are getting sicker and the anomalies are stacking up in a wobbling heap of file folders stamped with a “?”
            However, a clarification is in order.  Even though the subject of this article is “ethnicity,” it repudiates 19th century pseudo-scientific racial classifications as bogus.  Because over the past fifty thousand years, the human species has migrated and adapted to new climactic, nutritional and epidemiological environments, biogeneticists have shown that there are an infinite number of ways to parse micro-populations.  For example, convergent evolution has allowed African-Americans to share dark pigmentation with East Indians of Dravidian ancestry, the sickle-cell gene with southern Mediterranean populations, Saudi Arabians and East Indians because of the presence of malaria.([2])  East and Southern Africans share lactase persistence with Northern Europeans because of their dairy-farming food culture.([3]) African-Americans share salt-sensitivity with Yamamoto Indians of the Brazilian rain forest because both groups originated in sodium-deficient tropical regions far from the coast.[4])  In spite of these adaptations, the human species has in common  99.9 percent of all its biological traits.([5]
            However, in a multi-ethnic society like the United States, the small margin of genetic variants that are  environmentally influenced must be identified and addressed in their own right.   It becomes the responsibility of the dominant ethnicity to ensure that it does not universalize its own medical standards and pathologize any differing biological norms observed in minority ethnicities.  If the medical and public health system does not rise to the challenge of establishing different sets of standards for diverse populations when needed, it is inevitable that the majority demographic will see health improvements over time.  However, those minority ethnicities whose nutritional or other medical norms are at greatest deviance from those of the majority will see a deterioration in health no matter how well intentioned government efforts might be at rectifying disparities. 
            One illustration of this potential problem has already arisen in regards to ethnic differentials in nutritional standards for daily sodium intake. Growing medical evidence points to African-Americans being at greater risk of salt-sensitive hypertension and also of dying from end stage renal failure at 3.5 times the rate of whites.([6])   Studies have consistently shown that an exceptional sodium retention capacity in the kidneys of many black Americans compared to whites is caused by the longer length of time it takes to excrete a sodium load and higher red blood cell sodium levels.([7]) The reasons may relate to the biological adaptations of their ancestors, who were forced to survive sweltering tropical climates, which were geologically deficient in sodium (being far inland from the salt-rich coastal areas).([8]) The Institute of Medicine has therefore come to recommend that healthy African-Americans reduce their daily sodium intake to 1500 mg./daily, which is a full 800 mg. less than the federally-recommended intake for the American public.([9])  However recent studies by Scandinavian researchers have called into question the 2300 mg. federal standard, even claiming that it is too low.([10])  The popular media has widely reported this medical report under such headlines as “Sodium Intake Guidelines are Too Low.” ([11])   While this debate may indeed hold validity for people of Northern European ancestry, not a single medical journal disputes the dangers of a high-sodium diet for African-Americans.([12])  And yet, blacks have no way of knowing that they are placing themselves at higher risk of end-stage-renal-failure unless they ignore  FDA nutritional labels as well as the popular media and start poring through medical journals.
   
Whose Calcium Deficiency?
            However, the clearest evidence of the Eurocentric paradigm’s blindspot regarding biological differences in nutritional values has been the medical community’s preoccupation with correcting calcium deficiency in blacks. ([13]) The focus on this issue began with an article that appeared in a 2005 issue of The Journal of the American College of Nutrition entitled: “The Myth of Increased Lactose Intolerance in African-Americans. Its authors asserted:
The 'African-American diet' is more likely to be low in a variety of vitamins and minerals, including calcium. African-Americans consume low amounts of dairy foods and do not meet recommended intakes of a variety of vitamins and minerals, including calcium. Low intake of calcium and other nutrients put African-Americans at an increased risk for chronic diseases.  .  .  Research has shown that lactose maldigesters, including African-American maldigesters, can consume at least one cup (8 oz) of milk without experiencing symptoms, and that tolerance can be improved by consuming the milk with a meal, choosing yogurt or hard cheeses, or using products that aid in the digestion of lactose such as lactase supplements or lactose-reduced milks. ([14])
However lactase non-persistence, commonly referred to in the United States as lactose intolerance is not a disorder.  It is an ethnic trait, like skin color.  It is most commonly seen in populations of non-dairy farming ancestry.  In fact, seventy-percent of the human species ceases after weaning,  to produce lactase, the enzyme required to metabolize the dominant milk sugar, lactose.  While less than five percent of Americans being of Northern European ancestry carry this trait, eighty to one hundred percent of American Indians do, seventy- five percent of African-Americans, ninety-five percent of Asians, fifty to eighty percent of Hispanics, as well as sixty to eighty percent of Ashkenazic Jews.([15])
            In the U.S., because the mainstream population has inherited the gene mutation that allows them to digest lactose, the  medical community is generally unfamiliar with lactase non-persistence.  It is clinically defined as a disorder, for which a range of medications, treatments, and dietary supplements are offered to ameliorate the symptoms.([16])  However, a closer examination of the matter shows that lactose intolerance is only a disorder (and one that can indeed prove fatal) for those members of lactose tolerant ethnic populations, who are born with a congenital defect in which the gene is missing or whose digestive organs have been damaged and thus the enzyme cannot be produced.  As for the lactose non-tolerant,  the same principles of genetic adaptation that protects Congolese people from skin cancer, protects blacks and others of non-dairy farming ancestry from needing the supplemental calcium that the bodies of lactose tolerant adults have come to require for bone health. 
           
Calcium Efficiency
            More than two decades of research studies have confirmed that African-Americans are not calcium deficient. The Third National Health and Nutrition Examination Survey (NHANES) 1988-1991 documented the fact that blacks have lower calcium intakes than whites but higher bone mass. ([17])     This finding was initially labeled a “paradox.”  However, since then, medical researchers have continued to study the phenomenon in order to piece together the mechanism by which a non-dairy consuming ethnicity would have a stronger skeletal mass and exhibit genetic protections against osteoporosis and other fragile bone disorders.  These subsequent studies have revealed a highly efficient utilization mechanism for lower level intakes of dietary calcium.  Black adolescents were shown to have higher rates of calcium absorption, increased net skeletal retention and lower urine calcium than their white counterparts.([18]) Such processes occurring in childhood in addition to relative resistance to the bone resorption of parathyroid hormone also offer bone protections, which persist into old age.([19]-[20])

            Nevertheless, in  2006, an article appeared in the Journal of Nutrition asserting that healthy blacks were Vitamin D deficient and that this condition, created by their dark skin complexions, put them at risk of osteoporosis, cardiovascular disease, cancer, diabetes, and other serious chronic conditions.([21])   A popular website cautioned African-Americans that they needed ten times more sun exposure to produce the same amount of Vitamin D as a person with pale skin.([22])  Fortunately, by 2013 a new study had appeared in the New England Journal of Medicine correcting the earlier report and asserting that blacks had been misdiagnosed as Vitamin D deficient.([23])
                                                           
Inversion Theories
            These kinds of mistakes should be easily spotted.  But the “Eurocentric Paradigm” hides them behind  easily-generated “inversion theories.”  They borrow the same data sets and research findings but switch symptoms.    An example of an inversion theory would be acknowledging that blacks do not suffer from osteoporosis, fragile bones or other calcium deficiency disorders common to whites.  But the theory asserts that their calcium deficiency symptoms merely manifest themselves in a different set of disorders, which just so happen to be whatever disorders African-Americans are at greatest risk of suffering.  In this case the diseases are obesity, high blood pressure, diabetes II and prostate cancer.([24])   No actual research is needed to tie these disorders to calcium, since the data already exists both that blacks suffer a calcium deficiency and that they suffer from this other range of disorders as well.  This is a classic case of falsely inferring causation from correlated but mismatched data.


Worsening of Health Disparities

            A flawed Eurocentric Paradigm and the inversion theories it spawns cannot help but worsen health disparities.  This is because they carry consequences.  Vital clues are lost. Time and funding are frittered away on quixotic journeys to cure phantom diseases.  In the meantime, the real disorders take lives that might have been saved had public health knowledge identified a particular ethnicity’s biological signatures rather than founder in undifferentiated data.    
            For example, African-American men have the highest rate of prostate cancer in the world.([25])  A growing body of research has also pointed to the fact that overconsumption of calcium increases the risk of prostate cancer, including in black males.  This rate of prostate cancer does not however extend to West African males, who share the same genetic ancestry.  But neither do the latter consume dairy products.  On the other hand, this has become a steadily increasing part of the black American diet because of the public health focus on calcium deficiency among blacks.

            Over the past two decades, the prevalence of obesity among African-American adolescents has nearly doubled, rising from 13.4 percent to 24.4 percent.([26])  Earlier studies appeared to show that dairy products might have a weight-loss effect, but on whom?   The primary dietary shift for black juveniles has been the addition of high fat-dairy to their diets during this same period and at the instigation of health experts concerned at possible calcium deficiencies.
Also, if  lactose intolerant African-Americans are born with genetic advantages, which protect them from osteoporosis and bone disease, through a mechanism of calcium homeostasis, and which also reduces the amount of calcium intake required, is it necessary or even safe for them to over-consume calcium?  What might happen if this homeostatic process is unbalanced?

            There is an urgent need to establish micro-population/ethnic databases, so that the most critical findings and medical advances that could be of special relevance to target ethnic population do not vanish into the mainstream data ocean.  Such an undertaking would also require some effort at substituting population genetics for antequated racial classifications.  While ethnic terminology can be a convenient shorthand, we must be careful.  Most American ethnicities, including black Americans are admixed populations, meaning that genetic biomarkers, rather than self-identification will be required to distinguish populations in research purporting to establish causes and correlations.  For example, the range of African-American ancestry goes all the way from individuals with 100% West African ancestry to those who might, for example, have 1% West African Ancestry, 97% European Ancestry, and 2% Native American ancestry.  Thus studies looking for correlations between disorders or traits common to West Africans but not to Europeans would spoil their data findings without first having clarified the genetic admixture of the test pool.  If for instance a study showed that  African-Americans who drank milk also had lighter complexions, did the milk lighten their complexions, or did darker blacks refrain from drinking milk because of lactose intolerance, a trait that those having more European ancestry had not inherited?


Conclusion
            The Eurocentric Paradigm does not need to be jettisoned.  It needs to be seen for what it really is – a model and standard of excellence for what general human biology and all ethnic medicine must become in the U.S.  The care and sophistication with which populations of Northern European ancestry are being examined becomes a methodology for  approaching genetic variants identified in African-Americans, Latinos, Asian-Americans, Ashkenazic Jews, Native-Americans and other ethnicities. This is an enormous challenge but it is one worth embracing.  For, it recognizes the unique position America may hold for the biological future of the human species, as the wanderings of 50,000 years of global migrations find their way home.   








([1])Orsi JM, Margellos-anast H, Whitman S. Black-White health disparities in the United States and Chicago: a 15-year progress analysis. Am J Public Health. 2010;100(2):349-56.

([2] ) El-Hazmi MA, Al-Hazmi AM, Warsy AS. Sickle cell disease in Middle East Arab countries. Indian J Med Res. 2011;134(5):597-610.

([3])Catherine J. E. Ingram, C.J.E.,  Elamin, M.F., Mulcare, C.A.,  Weale, M.E., Tarekegn, A.,Raga, T.O., Bekele, B. Elamin, F.M., Thomas, M.G., Bradman, N. A novel polymorphism associated with lactose tolerance in Africa: multiple causes for lactase persistence? Human Genetics. February 2007, Volume 120, Issue 6, pp 779-788

([4]) Gleiberman,L. Sodium, Blood Pressure, and Ethnicity: What Have We Learned? American Journal of Human Biology. 2009;21:679-686
                                                                                                 
([5]) Shastry, B.S.  SNP alleles in human disease and evolution. Journal of Human Genetics. November 2002, Volume 47, Issue 11, pp 0561-0566

([6] ) Lipworth, L., Mumma, M.T., Cavanaugh, K.L., Edwards, T.L., Ikizler, T.A., Tarone, R.E., McLaughlin, J.K., Blot, W.J.,  Incidence and Predictors of End Stage Renal Disease among Low-Income Blacks and Whites. PLOS, Published: October 24, 2012.

([7]) Gleiberman,L. Sodium, Blood Pressure, and Ethnicity: What Have We Learned? American Journal of Human Biology. 2009;21:679-686

([8]) Gleiberman,L. Sodium, Blood Pressure, and Ethnicity: What Have We Learned? American Journal of Human Biology. 2009;21:679-686

([9] ) Available at: http://www.iom.edu/Reports/2013/Sodium-Intake-in-Populations-Assessment-of-Evidence/Report-Brief051413.aspx. Accessed June 30, 2014.

([10]) Graudal, N, Alderman, M.H. . Compared With Usual Sodium Intake, Low- and Excessive Sodium Diets are Associated.  American Journal of Hypertension. Mar 20, 2014.

([11])Available at: http://www.thehealthierlife.co.uk/natural-health-articles/nutrition/low-sodium-intake-myth/. Accessed June 30, 2014.        

([12] ) Appel, L.J., Frohlich, E.D., Hall, J.E., Pearson, T.A., Sacco, R.L., Seals, D.R., Sacks, F.M.
The Importance of Population-Wide Sodium Reduction as a Means to Prevent Cardiovascular Disease and Stroke; A Call to Action From the American Heart Association. Circulation.2011 (123) 1138-1143

([13])Heaney, R.P. Low Calcium Intake Among African Americans: Effects on Bones and Body Weight.The Journal of Nutrition 136 (4) 1095-1098

([14]) Byers, K.G., Savaiano, D.A.  The myth of increased lactose intolerance in African-Americans. Journal of the American College of Nutrition. 2005 Dec;24(6 Suppl):569S-73S.

([17]) Alaimo K, McDowell MA, Briefel RR, Bischof AM, Caughman CR, Loria CM, Johnson CL. Dietary intake of vitamins, minerals, and fiber of persons 2 months and over in the United States: Third National Health and Nutrition Examination Survey, Phase 1, 1988–91. Advance data from vital and health statistics; no. 258. Hyattsville, Maryland: National Center for Health Statistics. 1994.
([18]) Bryant RJ, Wastney ME, Martin BR, Wood O, McCabe GP, Morshidi M, Smith DL, Peacock M, Weaver CM: Racial differences in bone turnover and calcium metabolism in adolescent females. J Clin Endocrinol Metab 88: 2003. 1043–1047.

([19])Heaney R P. Ethnicity, bone status, and the calcium requirement. Nutritional Research. 2002;22:153–78.

([20]) Aloia JF, Mikhail M, Pagan CD, Arunachalan A, Yek JK, Flaster E. Biochemical and hormonal variables in black and white women matched for age and weight. J Lab Clin Med. 1998;132:383–9.

([21]) Harris, S.S. Vitamin D and African Americans.  Journal of Nutrition, 2006 Volume 136 (4) 1126-1129.

([23]), Powe, C.E., Evans, M.K., Wenger, J., Zonderman, A.B., Berg, A.H. Nalls, M. Tamex, H. Zhang, D., Bhan, I. Karumanchi, S.A., Vitamin D–Binding Protein and Vitamin D Status of Black Americans and White Americans New England Journal of Medicine  2013; 369:1991-2000

([24]) Heaney, R.P. Low Calcium Intake Among African Americans: Effects on Bones and Body Weight.The Journal of Nutrition 136 (4) 1095-1098         

([25]) McIntosh, H. Why Do African- American Men Suffer More Prostate Cancer? Why Do African- American Men Suffer More Prostate Cancer? Journal of the National Cancer Institute. 89 (3): 1997

([26]) Ogden CL, Carroll MD, Curtin LR, Lamb MM and Flegal KM, Johnson CL.
Prevalence and Trends in Overweight Among US Children and Adolescents, 1999-2000. Journal of the American Medical Association, 288(14): 1728-1732, 2002.
 
Post a Comment