Greater healthful food variety as measured by the US Healthy Food Diversity index is associated with lower odds of metabolic syndrome and its components in US adults

BACKGROUND

Consuming a wider variety of nutrient-dense foods may promote adherence to healthful dietary patterns, leading to improved dietary quality and enhanced metabolic health.

OBJECTIVE

We used the US Healthy Food Diversity (HFD) index to simultaneously measure dietary variety, quality, and proportionality, hypothesizing a priori that race/ethnicity may moderate associations between diet and health.

METHODS

A representative sample of adults (n = 7470) aged 20+ y with two 24-h recalls and complete outcome data from the cross-sectional NHANES 2003-2006 were selected. US HFD values were generated using a previously validated equation with a theoretical range from 0 to nearly 1, with higher scores indicative of more varied diets with a higher proportion of healthful food groups. Metabolic syndrome (MetS) was defined using the most recent harmonized definition. Survey-weighted multivariable linear and logistic regression, adjusted for demographic factors, smoking, energy, screen time, and leisure activity, were used to compute means and ORs (95% CIs).

RESULTS

Adults in the third vs. first US HFD tertile had 21% lower odds of MetS [OR (95% CI): 0.79 (0.64, 0.98)] as well as lower odds of hypertension [0.83 (0.70, 0.995] and elevated waist circumference [0.75 (0.66, 0.86] after multivariable adjustment (P-trend < 0.05). The age- and sex-adjusted odds of low serum HDL cholesterol and impaired fasting plasma glucose (P-trend < 0.05) were lower in the highest vs. lowest US HFD tertile but attenuated with multivariable adjustment (P = 0.06 and 0.22, respectively). Notably, the US HFD index was only protective against adiposity among non-Hispanic white (NHW) and non-Hispanic black (NHB) adults, and MetS associations were driven by NHW adults. No associations were observed among Hispanic adults for any MetS components.

CONCLUSIONS

Greater healthful food variety was associated with lower odds of MetS and some MetS components in the total population, NHW adults, and NHB adults. This study provides preliminary evidence that healthful food diversity may protect against MetS and highlights the need for longitudinal and experimental research.

Dietary variety is inversely associated with body adiposity among US adults using a novel food diversity index

BACKGROUND

Consuming a variety (vs. monotony) of energy-poor, nutrient-dense foods may help individuals adhere to dietary patterns favorably associated with weight control.

OBJECTIVE

The objective of this study was to examine whether greater healthful food variety quantified using the US Healthy Food Diversity (HFD) index favorably influenced body adiposity.

METHODS

Men and nonpregnant, nonlactating women aged ≥20 y with two 24-h recalls from the cross-sectional NHANES 2003-2006 (n = 7470) were included in this study. Dietary recalls were merged with the MyPyramid Equivalent database to generate the US HFD index, which ranges from 0 to ∼1, with higher scores indicative of diets with a higher number and proportion of healthful foods. Multiple indicators of adiposity including BMI, waist-to-height ratio, android-to-gynoid fat ratio, fat mass index (FMI), and percentage body fat were assessed across US HFD index quintiles. ORs and 95% CIs were computed with use of multivariable logistic regression (SAS v. 9.3).

RESULTS

The US HFD index was inversely associated with most adiposity indicators in both sexes. After multivariable adjustment, the odds of obesity, android-to-gynoid ratio >1, and high FMI were 31-55% lower (P-trend < 0.01) among women in quintile 5 vs. quintile 1 of the US HFD index. Among men, the odds of obesity, waist-to-height ratio ≥0.5, and android-to-gynoid ratio >1 were 40-48% lower (P-trend ≤ 0.01) in quintile 5 vs. quintile 1 of the US HFD index.

CONCLUSIONS

Higher US HFD index values were inversely associated with indicators of body adiposity in both sexes, indicating that greater healthful food variety may protect against excess adiposity. This study explicitly recognizes the potential benefits of dietary variety in obesity management and provides the foundation to support its ongoing evaluation.