Racial Differences in the Relationships Between Gastroesophageal Reflux Disease (GERD), Dietary Macronutrients, and Insulin Resistance in Obese Women

Abstract

Introduction: GERD, which occurs in 20-30% of U.S. adults, has a strong relationship with obesity. Insulin resistance, a consequence of adiposity induced loss of tissue sensitivity to the action of insulin, has also been associated with GERD. Excess dietary fat intake is thought to promote adiposity and insulin resistance. Recent evidence suggests a role for dietary carbohydrates. We examined relationships between GERD symptoms, medication use, dietary macronutrients, and insulin resistance in obese women. We hypothesized that: a) GERD would be associated with dietary carbohydrate more than dietary fat intake; and b) there would be differences in the relationships between GERD, dietary carbohydrate load, and insulin resistance between European American (EA) and African American (AA) obese women. Methods: 100 EA and 43 AA obese (BMI 30-39.9) women were enrolled in a high fat diet intervention and evaluated at baseline and at weeks 9 and 16 by 24-hour diet recalls, body composition, and fasting glucose and insulin. They were matched for ht, wt, BMI, %body fat, dietary energy and macronutrient intake. GERD was determined by weekly report of symptoms and medication use. Results: At baseline, 30% of EA women and 14% of AA women had GERD (P = 0.04). Thus, EA race was a strong predictor for having GERD (P = 0.03). In EA women, dietary total carbohydrate intake (r = 0.34, P < 0.001), added sugars (r = 0.30, P = 0.005) and glycemic load (r = 0.34, P = 0.001) were associated with GERD. Of the sugars, sucrose intake was most strongly associated with GERD (r = 0.33, P = 0.001). Dietary total fat was not significantly associated with GERD. In AA women, GERD was not significantly associated with dietary carbohydrate or fat intake. GERD (r = 0.30, P = 0.004) and dietary carbohydrates (r = 0.40, P < 0.001) were associated with insulin resistance (HOMA-IR score) in EA women, but not AA women. Conclusion: We found a difference by race in obese women in the prevalence of GERD symptoms and medication use. We found racial differences in the relationships between GERD and dietary carbohydrate intake. We detected a racial difference in the relationship between GERD, dietary carbohydrates and insulin resistance. These data suggest that dietary interventions targeting GERD need to be tailored to population subgroup. While reducing dietary carbohydrates, and particularly sugars like sucrose, may be beneficial for treating GERD symptoms in EA women, other dietary strategies may be more beneficial for AA women.