Discussion

While adherence to the DGA 2005 using the HEI-2005 has been estimated within the US population as a whole and among demographic subsets⁽Reference Guenther, Juan and Lino^10–Reference Juan, Guenther and Kott¹²⁾, few studies have applied the HEI-2005 to regional US populations⁽Reference Savoca, Arcury and Leng¹³⁾. When examining total and component HEI-2005 scores by demographic characteristics within the LMD population, younger age was the most important determinant of low diet quality. HEI-2005 total, total fruit, whole fruit, total vegetables, GOV&L, total grains, whole grains and SoFAAS scores declined with decreasing age. Previous studies in the LMD have focused on dietary pattern differences by race, income or food security status, with less attention given to the implications that age has on dietary intake⁽Reference Champagne, Bogle and McGee^4, Reference Champagne, Casey and Connell^14, Reference McCabe-Sellers, Bowman and Stuff¹⁵⁾. The present study's findings suggest that race and income may have smaller effects on diet quality when considered in conjunction with other demographic characteristics, such as age. Tailoring educational messages to age-specific groups may be more critical to the success of a dietary intervention than targeting groups delineated by race or socio-economic status in the LMD region.

Unlike previous applications of HEI-2005 that simply focus on total and component scores⁽Reference Guenther, Juan and Lino^10–Reference Savoca, Arcury and Leng¹³⁾, the current unique investigation of top dietary sources contributing to HEI-2005 components provides insight into strategies and messages that could improve the diet quality and health of a region. Although some messages are appropriate for the entire LMD population, others may be more appropriate for specific demographic groups. All five of the demographic variables considered had an effect on food consumption patterns. For sex and race, ten of thirty and twelve of thirty-one top foods differed between males and females, and between whites and AA, respectively. For age, twenty-one of forty-two top foods differed among the four age groups. For income and education, fourteen of thirty-five and fourteen of thirty-three top foods differed among the three income groups and the three education groups, respectively. Interestingly, one food (biscuits) and one beverage (sweet tea), identified as regional foods for the LMD⁽Reference Tucker, Maras and Champagne³⁾, were top dietary sources for the total grains and SoFAAS components, respectively. This highlights the importance of taking cultural food preferences into account when designing dietary interventions.

Regarding the targeting of dietary modifications, the substitution of more healthful foods or preparations for less healthful ones may work well in this population. Substitutions should account for not only the type of food, but the timing and location of meals as well. For example, the consumption of more whole fruits and less fruit juices and drinks should be encouraged for the entire LMD adult population, with perhaps stronger emphasis for males, AA and those less than 40 years of age. Substituting whole fruits for fruit drinks is an especially important message since fruit drinks contain little fruit juice while contributing a significant amount of added sugar to the diet. Similarly, the consumption of vegetables other than white potatoes, particularly French fries and potato chips, should be encouraged for the entire LMD population, with added focus on those less than 30 years of age and those in the lowest income group. This substitution will not only help to reduce the amount of saturated fat in the diet, a DGA 2010 recommendation⁽¹⁶⁾, but also help to increase the variety of vegetables being consumed, particularly if the consumption of healthy preparations of culturally acceptable vegetables such as sweet potatoes and collard greens are encouraged. However, because foods such as French fries are often consumed outside the home, typically at fast-food restaurants, a more suitable substitution may be a side salad, which is available at most fast-food establishments. In a large, prospective cohort of middle-aged women, the intake of fruit juice was found to be positively associated with the development of diabetes, while the intake of whole fruit and leafy green vegetables had an inverse association⁽Reference Bazzano, Li and Joshipura¹⁷⁾. Further, evidence suggests that eating whole fruit (v. fruit puree or juice) at the start of a meal can be an effective strategy for increasing satiety and decreasing energy intake⁽Reference Flood-Obbagy and Rolls¹⁸⁾.

The presence of salty snacks as a top food source for both total and whole grains deserves particular attention since such foods add to the overabundance of sodium and saturated fat in the American diet. The consumption of lower-sodium, lower-fat, wholegrain snack foods should be encouraged, particularly for those 30–39 years of age and those in the middle income and education groups. Increasing intake of whole grains, a DGA 2010 recommendation⁽¹⁶⁾, has been associated with lower adiposity in adults⁽Reference McKeown, Troy and Jacques¹⁹⁾. However, those investigators caution that emphasis should be placed on the substitution of refined grains with whole grains rather than the addition of whole grains to a diet already high in refined grains⁽Reference McKeown, Troy and Jacques¹⁹⁾.

The SoFAAS category appears to provide the most opportunity for improving the diet of adult LMD residents. Indeed, the DGA 2010 gives special attention to solid fats and added sugars, two components of the SoFAAS category, because they are consumed in excessive amounts by Americans⁽¹⁶⁾. The fact that the top five sources accounted for only 35 % of the SoFAAS component attests to the ubiquitous presence of SoFAAS in the American food supply. In this study, only eleven of the 165 food and beverage groups did not contribute to the SoFAAS category (data not shown). The consumption of soft drinks requires special focus since these drinks are a significant source of added sugars in the diet of LMD adults, particularly younger adults. Consumption of soft drinks and other sugar-sweetened beverages (SSB; e.g. fruit drinks and sweet tea) should be strongly discouraged. Intervention and social marketing strategies should focus on social norms associated with beverage consumption patterns among younger adults. Alternatives such as water and artificially sweetened soft drinks and teas should be encouraged as more healthful substitutes. Results from women participating in a weight-loss intervention suggest that replacing SSB with water may be an effective method to lower total energy intake in free-living individuals⁽Reference Stookey, Constant and Gardner²⁰⁾. In another study conducted in both men and women, investigators found that reduction of SSB intake was significantly associated with weight loss⁽Reference Chen, Appel and Loria²¹⁾. Hence, advocating the replacement of less healthy foods and beverages with more healthful ones is a viable strategy to improve the diet quality and health of individuals.

The present study is not without limitations. The data were collected in 2000 and may not fully represent current dietary intake of LMD adults. For example, anecdotal evidence through discussions with Delta residents suggests that intake of wholegrain breads may have increased since the time the data were collected. Furthermore, because the populations of most LMD counties have been declining in recent decades, the demographic profile of this region may have also changed since 2000. Nevertheless, the FOODS 2000 data set was collected using a highly sophisticated stratified sampling plan and the same multiple-pass dietary recall methodology used by the National Health and Nutrition Examination Survey (NHANES). Finally, the impact of food availability on diet quality or food sources was not assessed because this information was not collected. The low availability of supermarkets and healthy food in the region has been highlighted in previous research as possible determinants of diet quality⁽Reference Blanchard and Lyson^22, Reference Connell, Yadrick and Simpson²³⁾.

In conclusion, the findings of the present study showed that the assessment of diet quality and identification of top dietary sources revealed the presence of demographic differences in selected HEI-2005 components, information that is necessary for tailoring nutrition interventions in the LMD region. Not only do these findings allow for identification of food patterns and culturally appropriate messaging that could reach the entire population through social marketing and media approaches, they also highlight the difficulties of treating this region as a homogeneous population. The assessment of dietary pattern quality and adherence to dietary guidelines, as well as the determination of top food sources, are critical steps in the development of culturally appropriate dietary modifications for a given population. To improve adherence to DGA in the LMD population, intervention studies are needed to promote culturally familiar foods of higher nutritional quality.