Bitter taste sensitivity, cruciferous vegetable intake, obesity, and diabetes in American adults: a cross-sectional study of NHANES 2013–2014

Objective: To examine the associations between bitter taste sensitivity, cruciferous vegetable consumption, and likelihood of obesity and diabetes among American adults. Research design and method: Cross-section observation of 2129 adults aged 40-80 years of the National Health and Nutrition Examination Survey (NHANES) 2013-2014. Bitter taste sensitivity was estimated by the generalized labeled magnitude scale (gLMS) rating for bitterness (non-tasters: the lowest 25%, the others were tasters). Consumption of cruciferous vegetables was recorded by the 2 day 24 hours dietary records. Obesity was defined as body mass index (BMI) ≥30 kg m-2. Diabetes was defined as self-reported physician-diagnosed diabetes, or who reported taking diabetes medication or individuals with a fasting plasma glucose (FPG) ≥ 126 mg dL-1 or Hemoglobin A1c ≥ 6.5%. Results: The proportion of participants who ate cruciferous vegetables over the two days was 29.5% among bitter tasters, significantly lower than that (35.7%) among non-tasters (P = 0.04) after adjustment of age, gender, race/ethnicity, dietary energy intake, physical activity, education, smoking and income levels. Among participants who ate cruciferous vegetables, bitter tasters on average consumed 15.5 g (±7.0) grams less cruciferous vegetables per day compared to non-tasters. The multi-variates adjusted odds ratio of obesity was 1.29 (95% confident interval (CI): 0.76-2.17), 1.40 (95% CI: 0.90-2.18) and 1.68 (95% CI: 1.05-2.67) among bitter tasters who ate cruciferous vegetables, among non-tasters who did not ate cruciferous vegetables, and among bitter tasters who did not eat cruciferous vegetables, respectively, as compared with non-tasters who ate cruciferous vegetables. The prevalence of diabetes was 17.3% and 13.0% among bitter tasters and non-tasters, respectively, with a multi-adjusted odds ratio of 1.32 (95% CI: 1.02-1.69, P = 0.033) for diabetes comparing bitter tasters with non-tasters, which was attenuated to 1.26 (95% CI: 0.95-1.67, P = 0.108) by further adjustment of cruciferous vegetables consumption and obesity, with a mediation effect of 17.8% (95% CI: 2.9%-60.9%; P = 0.069). Conclusion: Bitter taste sensitivity was associated with less consumption of cruciferous vegetables and a high likelihood of obesity, which may mediate its association with diabetes.