Carbohydrate Intakes Below Recommendations With a High Intake of Fat Are Associated With Higher Prevalence of Metabolic Syndrome

Abstract

Background: More than one-third of adults in the United States have metabolic syndrome, and dietary carbohydrate intake may modify the likelihood of developing this condition. Currently, there is a lack of consistent evidence demonstrating the relationship between carbohydrate intake that falls below recommendations and metabolic syndrome. Not accounting for the differences in fatty acid classes of these dietary patterns may be a reason for inconsistent findings.

Objective: This study evaluated the association between a carbohydrate intake below recommendations and metabolic syndrome stratified by fat quantity and fatty acid classes in a nationally representative sample of US adults.

Design: This cross-sectional study acquired data on food and nutrient intake and markers of metabolic syndrome from respondents in the National Health and Nutrition Examination Survey 1999-2018.

Participants/setting: This study included 19,078 respondents who were aged 20 years or older, had reliable and complete data on food and nutrient intake and markers of metabolic syndrome, and were not pregnant or breastfeeding.

Main outcome measures: The main outcome was prevalence of metabolic syndrome.

Statistical analyses performed: Usual dietary intake was estimated using the National Cancer Institute's usual intake methodology. Multivariable logistic regression models assessed the relative odds of prevalent metabolic syndrome between those who had a carbohydrate intake below recommendations and those who met carbohydrate recommendations.

Results: Those who had a carbohydrate intake below recommendations had 1.067 (95% CI 1.063 to 1.071) times greater odds of having metabolic syndrome compared with those who met carbohydrate recommendations (P < 0.001). High intake of fat of any class was associated with higher odds of metabolic syndrome (total fat: 1.271, 95% CI 1.256 to 1.286; saturated fatty acid: 1.072, 95% CI 1.060 to 1.085; monounsaturated fatty acid: 1.317, 95% CI 1.300 to 1.333; polyunsaturated fatty acid: 1.056, 95% CI 1.047 to 1.066; P < 0.001 for all comparisons) in those who had a carbohydrate intake below recommendations.

Conclusions: The odds of prevalent metabolic syndrome were higher among individuals who had a carbohydrate intake below recommendations compared with individuals who met carbohydrate recommendations.

Keywords: High fat; Low carbohydrate; Metabolic syndrome; NHANES; Restricted carbohydrate.