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Nutrition and Chronic Disease Prevention: Priorities for US Minority Groups

Posted on: Saturday, 25 February 2006, 03:01 CST

By Kumanyika, Shiriki

Persistent disparities affecting US racial/ethnic minorities present a continuing challenge within the larger picture of chronic disease prevention, in part because of the socio-political disadvantages that affect minority populations. Many of these disparities are nutrition related. Complementary approaches to identifying priorities for nutrition assessment and intervention in minority populations include: 1) a dietary perspective that considers eating patterns in relation to current dietary guidelines, and 2) a chronic disease perspective that considers dietary implications of population risk profiles. Integrating these perspectives requires additional considerations of feasibility and relative priority for the population in question.

Key words: diet, ethnic groups, health disparities, obesity

2006 International Life Sciences Institute

doi: 10.1301/nr.2006.feb.S9-S14

INTRODUCTION

Priorities for nutrition assessment and intervention may differ for racial/ethnic groups, particularly when race/ethnicity defines "minority group" status. In the United States, many racial/ethnic minority populations are socially and politically disadvantaged1,2 and generally have higher rates of nutrition-related health problems than the majority population.3,4 It is useful to consider nutrition assessment and intervention priorities for minority populations from: 1) a dietary perspective, the extent to which eating patterns differ from current dietary guidelines; and 2) a chronic disease perspective, an analysis of population risk profiles to identify implications for dietary change. Integrating these two perspectives requires additional considerations of feasibility and relative priority for the population in question.

In this article, examples from the United States are used to illustrate and consider the implications of these perspectives. A similar approach could be applied to other countries. The general issues are finding out what factors lead to poorer nutrition- related health status among socially and politically disadvantaged populations, and deciding how approaches implemented for the population at large differ in order to be appropriate and effective for ethnic minority subgroups.

MINORITY POPULATIONS

Racial and ethnic categorizations are now understood to be primarily social-cultural or socio-political designations that do not reflect meaningful biological or genetic differences.1 However, there are genetic differences among populations. The debate relates to whether genetic differences at the group level outweigh the much larger complement of genetic similarities within the human species, and whether genetic differences are responsible for observed differences in health and life chances among different populations. It is argued that environmental factors strongly influence the expression of underlying genetic predispositions to develop diseases; however, social structural factors that place certain ethnic groups at a systematic disadvantage are viewed as the more important causes of health disparities.1,5,6

Also, racial and ethnic classifications are usually self- designated and change in concert with the societal context, underscoring arguments that these classifications are more socially and politically than biologically descriptive.1 For example, the US Census, which used "white,""black, and "mulatto" in 1860, first added and then removed more specific designations for the percentage of African ancestry, and has added progressively more numerous categorizations for certain other non-white or non-European populations.2

In the 2000 US Census, a major paradigm expansion occurred again, when individuals could claim more than one racial/ethnic category.7 Racial and ethnic categories may not have biological meaning, but they do carry social validity. In fact, as socially constructed categories, they are extremely real in that they have a major role in how people view themselves and how they view and interact with others.1 These categories are also very real with respect to their ability to identify population groups with disadvantaged health status, regardless of their numbers.3,4,8 Because of the social position of people of color in the United States, the disadvantaged health status of minority populations will persist even as their share in the population increases.1

Minority populations are diverse. Table 1 lists social- structural variables that contribute to diversity within minority populations and also to differences from the majority (either the numerical majority or the politically dominant group).1,2,4,9 The complex diversity within and between populations is potentially very relevant to setting nutrition priorities and to designing interventions. For example, social-structural variables impact on the diet of origin, degree of acculturation to the mainstream diet, food access and food purchasing power, meal patterns, access to information and the ability to understand it, cultural practices and preferences related to food and eating, overall health status, and health behavior orientation.4,9-11 Age, social class, and gender are other important sources of diversity in the nutrition-related health profiles of populations.4

DIET-RELATED HEALTH DISPARITIES AFFECTING US MINORITY POPULATIONS

The important role of dietary factors for health disparities was recognized in the 1985 US Task Force Report on Black and Minority Health.12 This report pointed out that many of the major causes of high death rates in minority populations are diet or nutrition related, particularly cardiovascular disease (heart disease and stroke) and cancer in African Americans (Table 2) and diabetes in all minority populations.3,4,8,12,13

Table 1. Examples of Sources of Diversity Within and Among Racial/ Ethnic Minority Populations1,2,4,9

More prevalent obesity among minority populations has been consistently observed for several decades (with the exception of Asian Americans).14-17 Diabetes is more prevalent in Native Americans and black-, Hispanic-, and Pacific Islander Americans than in whites, and is associated with a higher prevalence of obesity. Diabetes is also more prevalent in Asian Americans after adjusting for differences in body-mass index (BMI) levels.16 Asian Americans have less generalized obesity than whites, but are relatively more likely to have diabetes. The Diabetes Prevention Program confirmed the potential value of weight loss interventions compared with pharmacological treatment or usual care in a diverse population that included substantial numbers of African Americans, Hispanic Americans, and Native Americans.18

In summary, minority groups tend to be defined by classifications that reflect their social and political status within a given environment and time period. Minority health status is defined by biological, socioeconomic, political, cultural, and behavioral factors. There is also diversity within and among minority populations that is directly relevant to the task of identifying priorities for nutrition assessment and intervention, including the diversity along gender and age lines that affects all populations. Taking US minority populations as an aggregate, some striking similarities can be noted in the higher than average occurrence of obesity and diabetes. Cardiovascular diseases and cancer are major concerns as well, particularly for African Americans.

DIETARY PERSPECTIVE: ETHNIC GROUP DIETS AND DIETARY GUIDELINES

The types of dietary changes that result from acculturation to a Western-type diet are relatively predictable and are in a direction that is considered physiologically maladaptive (at least in an evolutionarily short-term sense) and to predispose to chronic diseases.19 These changes include increased consumption of animal foods and decreased consumption of plant foods or, more specifically, interrelated increases in calories, refined carbohydrates, animal protein, fat (both saturated and unsaturated), sodium, phosphorous, dairy products, processed foods, and the variety of foods eaten, with commensurate decreases in complex carbohydrates, vegetable protein, and potassium.20 An increased occurrence of obesity seems to be an extremely predictable consequence of westernization based on comparisons of people of African descent in Africa, the Caribbean, the United Kingdom, and the United States,21 and also on comparisons of successive generations of Asian American22 and Hispanic23 immigrants.

Table 2. Death Rates (per 100,000 people) by Race and Hispanic Origin in the United States in the Year 20008,13

A focus on dietary patterns is therefore critical. Considering eating habits and their evolution helps to elucidate the implications of guidance toward intakes of specific foods or food components within the context of typical eating patterns, cultural food meanings, and related lifestyle issues for the ethnic group in question. How big a change is required, and in what direction? How threatening or compatible are these changes relative to core dietary principles? What will be the tradeoffs associated with making the dietary changes that are recommended with respect to other aspects of dietary quality or to quality of life?

In many cases, the referent eating pattern of interest is rel\atively less healthful than the mainstream eating pattern when compared with extant dietary guidance. For example, among minorities, African Americans have the widest deviance from guidelines compared with nonHispanic whites4,24 based on indices of consumption of 10 components for which specific minima or maxima are recommended: grains, vegetables, fruits, milk, meat, total fat, saturated fat, cholesterol, sodium, and food variety. Dietary quality scores show a strong positive gradient with education; however, the ethnic differences do not appear to be explained primarily by differences in educational attainment.4,24 Although the diets of non-Hispanic whites and other ethnic groups also fall considerably short of the mark in many respects, these observations imply that retention of typical eating patterns is particularly harmful for African Americans.

This raises the question of why African-American eating patterns have not equilibrated with mainstream eating patterns after so many generations, and emphasizes the importance of examining dietary patterns in a historical, socio-political, and current environmental context. Ancestral eating patterns of African Americans were altered during forced migration, slavery, and post-slavery living conditions and are currently negatively influenced by availability and access.9,10 Similarly, dietary issues for Native Americans/Alaska Natives flow from the ways in which ancestral eating patterns have been disrupted by historical, socio-political, and current ecological factors. Overall, dietary quality scores for Native Americans/Alaska Natives are better than those for African Americans, but are otherwise less favorable than for other ethnic groups.4,24

On the other hand, dietary quality scores reported for Mexican Americans are somewhat better overall and particularly for fruits, total fat, and saturated fat compared with whites.24 The fiber intake of Mexican Americans is higher than for non-Hispanic whites,4 which may reflect a combination of a referent diet that is closer to the recommended balance of plant versus animal foods and is retained (to some extent) even after generations of life in the United States. Dietary quality scores are higher for US residents who are born in Mexico than for those born in the United States.24

Data for Asians/Pacific Islanders, who have the highest dietary quality scores overall,4 also appear to reflect retention of a relatively favorable dietary pattern over generations in the United States and among recent immigrants (with the exception of a high sodium intake, although this is difficult to quantify from dietary intake data).

All of this translates into two general scenarios, where some populations have a relatively healthful diet to retain or fall back on, while others do not. This does not mean that any minority population can or will retain ancestral or even modern ethnic dietary practices in an environment where a different set of dietary patterns dominates. However, it does indicate that the types of changes that are likely to be recommended on the basis of our understanding of the role of dietary constituents in chronic disease development must be framed very differently for specific minority populations. In some cases, the message might be to move more toward the mainstream diets to the extent that these diets incorporate components that are more healthful than current practices. In other cases, the implicit message is not to embrace the mainstream but rather to retain and emphasize typical ethnic eating practices that are protective.

DISEASE PERSPECTIVE: DIETARY IMPLICATIONS OF CHRONIC DISEASE DISPARITIES

In spite of the inherent limitations of taking a disease perspective as the sole basis for dietary guidance, this perspective is important for identifying where, among the many potentially relevant pathological pathways, dietary intake seems to make the most difference to the health of populations and particularly to disparities in the health of populations. Against the backdrop of current knowledge of diet-related risk factors,19 one can ask whether the dietary patterns or obesity prevalence of a particular minority population are consistent with their risk factor or disease profiles. For example, do populations with a high prevalence of hypertension have a higher sodium intake or sodium/potassium intake ratio or more obesity?25 This type of ecological comparison is not definitive, but may provide clues.

Studies within minority populations are even more important than studies comparing aggregate diet and disease associations across populations. For example, does the dietary or nutritional risk factor predict who develops or does not develop disease within the particular population? Sensitivity to a particular risk factor may vary across populations based on interactions between genetic predispositions and generations of adaptations to environmental exposures, including exposure to malnutrition or cycles of feast and famine.19,26 Observations of greater sensitivity of African Americans to develop elevated blood pressure at a given level of sodium intake or sodium to potassium intake ratio are often interpreted in this light,27 and are supported by findings suggestive of a greater potential for reducing blood pressure by dietary means in African Americans than in whites.28

A further question is where the identified dietary or nutrition risks fit into the overall picture of potentially modifiable risk factors for multifactorial chronic diseases. What proportion of the overall disease burden in the population is attributable to a diet or nutritional factor? What other factors have similar or higher attributable risks for the same outcome, such as alcohol intake, physical inactivity, or stressful living conditions? In other words, how beneficial for improving health and reducing disparities will it be to focus on changing diet, both overall and in relation to other risk factors?

From a chronic disease perspective, one finds clear support in the literature for giving priority to obesity prevention and weight reduction as strategies for reducing the excess risks of type 2 diabetes.18,19 This applies to all US minority populations and is especially critical in light of the increasing rates of obesity among children in minority populations.29 A focus on obesity necessarily incorporates attention to overall caloric intake and physical activity or inactivity. There is also substantial basis for giving priority to other aspects of diet as priorities in relation to chronic disease risk reduction in African Americans. Lowering obesity and sodium intake and increasing potassium intake, or having a dietary pattern high in fruits and vegetables, grains, and low- fat dairy products leads to reductions in blood pressure and stroke in African Americans.10,27,28

There is less certainty about specific dietary change priorities for other US minority groups because of inadequate data on the associations of diet with disease in these populations.4 However, some priority areas can be derived indirectly; for example, a focus on weight control should incorporate advice to maintain or increase a high fiber intake and to substitute fruits and vegetables for more calorically dense foods. The lack of evidence about specific minority groups also means that the associations found generally have not been disproven for these groups. Considering that cardiovascular diseases and cancer are leading causes of death for all population groups, and that diabetes is a major risk factor for the development of cardiovascular diseases, all indicated dietary changes that are safe and otherwise compatible with health and quality of life can be strongly recommended for minority populations.

INTEGRATING DIETARY AND DISEASE PERSPECTIVES

Dietary changes should be firmly grounded in feasibility considerations, and, unfortunately, the feasibility of the types of changes currently recommended is lower for ethnic minorities. Constraints include a limited availability of recommended foods,30- 33 exposure to targeted marketing of foods with high energy content and low nutritional value,34 the relatively higher costs of some recommended foods,35 and the complexity of products in the food supply that makes it very difficult to ascertain food content and identify the most nutritionally sound choice per unit cost. In addition, recent or continuing periodic experiences with hunger or food insecurity may be more prevalent in minority populations, and may be associated with a particular vulnerability to overeat whenever food is readily available, and when it is sold or served in large portions.36 Food insecurity has been linked to overweight prevalence in adult women.37

The disease perspective tends to fragment eating patterns by focusing on chemical constituents of food and tends to prioritize dietary guidance along these lines. Consequently, underlying drivers of eating patterns such as flavor, price, tradition, and emotional and social meanings, are ignored or devalued in dietary guidance. Typical motivations for eating are defined as "barriers" and typical ways of eating are denned as "non-adherent." This issue is inherent in dietary guidance generally but is particularly important for minority populations. Certain aspects of eating patterns and the distinctiveness of these patterns are strongly tied to ethnic identity and associated with survival under harsh circumstances.9,38 Suggesting changes may be taken as disrespect or discrimination, and resisting change may be a way to resist unwanted assimilation.

Dietary and nutrition considerations should be grounded in a sense of the overall picture of population health profiles. Some minority populations continue to be affected by hunger, food insecurity, and high rates of low birth weight.8,37,39 Unqualified advice to eat less or to de-emphasize high-calorie foods may be inappropriate in such cases\. Non-disease-related causes of death such as violence and accidents and infectious diseases such as tuberculosis and HIV/AIDS (see Table 2) are also focal points for disparity reduction. At younger ages in particular, these other disparities are much more striking than disparities in diet-related chronic diseases, although chronic diseases may potentially affect a larger proportion of the population overall. A comprehensive perspective is therefore needed to integrate these considerations and also to integrate the dietary perspective with the disease perspective outlined earlier.

REFERENCES

1. Smelser JN, Wilson WJ, Mitchell F (eds). America Becoming: Racial Trends and Their Consequences. Vol 1. Washington, DC: National Academies Press; 2001.

2. Pollard K, O'Hare W. America's racial and ethnie minorities. Pop Bull. 1999;54:1-34.

3. Kumanyika SK. Diet and nutrition as influences on the morbidity/mortality gap. Ann Epidemiol. 1993;3: 154-158.

4. Kumanyika SK, Krebs-Smith SM. Preventive nutrition issues in ethnie and socioeconomic groups in the United States. In: Bendich A, Deckelbaum RJ, eds. Primary and Secondary Preventive Nutrition. Totowa, NJ: Humana Press; 2001; 325-356.

5. Link BG, Phelan JC. Understanding sociodemographic differences in health. The role of fundamental social causes. Am J Public Health. 1996;86:471-473.

6. Jones CP. Levels of racism: a theoretic framework and a gardener's tale. Am J Public Health. 2000; 90:1212-1215.

7. Tafoya SM, Johnson H, Hill LE. Who Chooses to Choose Two? Multiracial Identification and Census 2000. Population Reference Bureau. Available online at: http://www.prb.org/ Template.cfm?Section= PRB&template=/ContentManagement/Content Display.cfm&ContentID=11703. Accessed January 7, 2006.

8. National Center for Health Statistics. Health, United States, 2002 with Chartbook on Trends in the Health of Americans. Hyattsville, MD: NCHS; 2002.

9. Kittler PG, Sucher, KP. Food and culture in America: a nutrition handbook. 2nd ed. Washington DC: West/Wadsworth; 1998.

10. Kumanyika SK, Odoms A. Nutrition issues for African Americans. In: Braithwaite RL, Taylor SE, eds. Health Issues in the Black Community. 2nd ed. San Francisco, CA: Jossey-Bass; 2001; 419- 447.

11. Kumanyika SK. Obesity treatment in minorities. In: Wadden TA, Stunkard AJ, eds. Handbook of Obesity Treatment. 3rd ed. New York: Guilford; 2002; 416-446.

12. U.S. Department of Health and Human Services. Report of the secretary's Task Force on Black and Minority Health. Washington, DC: US Government Printing Office; 1985.

13. Racial and ethnic differences in U.S. mortality. Population Reference Bureau. Available online at: http://www.prb.org/ Template.cfm?Section=PRB& template=/ContentManagement/ ContentDisplay. cfm&ContentID=7908. Accessed January 7, 2006.

14. Kumanyika SK. Obesity in minority populations: An epidemiologic assessment. Obes Res. 1994;2:166-178.

15. National Institutes of Health, National Heart, Lung, and Blood Institute. Clinical guidelines in the identification, evaluation, and treatment of overweight and obesity in adults. The evidence report. Obes Res. 1998; 6(suppl 2):51S-209S.

16. McNeely MJ, Boyko EJ. Type 2 diabetes prevalence in Asian Americans. Results of a national health survey. Diab Care. 2004;27:66-69.

17. Hedley AA, Ogden CL, Johnson CL, Carroll MD, Curtin LR, Flegal KM. Prevalence of overweight and obesity among US children, adolescents, and adults, 1999-2002. JAMA. 2004;291:2847-2850.

18. Knowler WC, Barrett-Connor E, Fowler SE, Hamman RF, Lachin JM, Walker EA, Nathan DM, Diabetes Prevention Program Research Group. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med. 2002;346: 393-403.

19. World Health Organization. Diet, Nutrition, and the Prevention of Chronic Diseases. Technical Report Series No. 916. Geneva: World Health Organization; 2003.

20. McCarron DA, Henry HJ, Morris CD. Human nutrition and blood pressure regulation: an integrated approach. Hypertension. 1982;4(5 part 2):2-13.

21. Luke A, Cooper RS, Prewitt TE, Adeyemo AA, Forrester TE. Nutritional consequences of the African diaspora. Annu Rev Nutr. 2001;21:47-71.

22. Lauderdale DS, Rathouz PJ. Body mass index in a US national sample of Asian Americans: effects of nativity, years since immigration and socioeconomic status, Int J Obes Relat Metab Disord. 2000; 24:1188-1194.

23. Fuligni AJ, Christina C. Preparing Diverse Adolescents for the Transition to Adulthood. Available online at: http:// www.futureofchildren.org/usr_doc/fulignihardway.pdf. Accessed January 7, 2006.

24. US Department of Agriculture. The Healthy Eating Index: 1999- 2000. Available online at: http://www. cnpp.usda.gov/Pubs/HEI/HEI99- 00report.pdf. Accessed January 7, 2006.

25. Elliott P, et al. Intersalt revisited: further analyses of 24- hour sodium excretion and blood pressure within and across populations. Brit Med J. 1996; 312:1249-1253.

26. Neel JV. Diabetes mellitus: a "thrifty" genotype rendered detrimental by "progress"? Bull WHO. 1999; 77:694-703.

27. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Washington, DC: National Academies Press; 2004. Available online at: http://www.nap.edu/books/0309091691/html. Accessed January 23, 2006.

28. Svetkey LP, Simons-Morton D, Vollmer WM, Appel LJ, Conlin PR, Ryan DH, Ard J, Kennedy BM. Effects of dietary patterns on blood pressure: subgroup analysis of the dietary approaches to stop hypertension (DASH) randomized clinical trial. Arch Intern Med. 1999;159:285-293.

29. Institute of Medicine of the National Academies. Committee on Prevention of Obesity in Children and Youth. Preventing Childhood Obesity: Health in the Balance. Available online at: http:// www.iom.edu/?id=5867&redirect=0. Accessed January 7, 2006.

30. Morland K, Wing S, Diez Roux A, Poole C. Neighborhood characteristics associated with the location of food stores and food service places. Am J Prev Med. 2002;22:23-29.

31. Morland K, Wing S, Diez Roux A. The contextual effect of the local food environment on residents' diets: the atherosclerosis risk in communities study. Am J Public Health. 2002;92:1761-1767.

32. Block JP, Scribner RA, DeSalvo KB. Fast food, race/ ethnicity, and income: a geographic analysis. Am J Prev Med. 2004;27:211-217.

33. Horowitz CR, Colson KA, Hebert PL, Lancaster K. Barriers to buying healthy foods for people with diabetes: evidence of environmental disparities. Am J Public Health. 2004;94:1549-1554.

34. Tirodkar MA, Jain A. Food messages on African American television shows. Am J Public Health. 2003;93:439-441.

35. Drewnowski A. Obesity and the food environment: dietary energy density and diet costs. Am J Prev Med. 2004;27(suppl 3):154- 162.

36. Diliberti N, Bordi PL, Conklin MT, Roe LS, Rolls BJ. Increased portion size leads to increased energy intake in a restaurant meal. Obes Res. 2004; 12:562-568.

37. Townsend MS, Peerson J, Love B, Achterberg C, Murphy SP. Food insecurity is positively related to overweight in women. J Nutr. 2001;131:1738-1745.

38. Mintz SW. Tasting Food, Tasting Freedom: Excursions into Eating, Culture and the Past. Boston, MA: Beacon Press; 1996.

39. National Women's Law Center and Oregon Health Sciences University. Making the Grade on Women's Health: A National and State- By-State Report Card 2004. Available online at: http://www.nwlc.org/ details.cfm?id=1861§ion=health. Accessed January 7, 2006.

Shiriki Kumanyika, PhD, MPH

Dr. Kumanyika is with the Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.

Please address all correspondence to Dr. Shiriki Kumanyika, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, CCEB, 8th Floor Blockley Hall, 423 Guardian Drive, Philadelphia, PA 19104; Phone: 215-898-2629; Fax: 215-573-5311; E-mail: skumanyi@cceb.med.upenn.edu.

Copyright International Life Sciences Institute Feb 2006

Source: Nutrition Reviews

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