Bitterness as an indicator of diet quality: A secondary analysis of the Australian National Nutrition and Physical Activity Survey

Bitter foods are linked to health benefits, but a comprehensive evaluation of dietary bitterness remains limited. This study quantified dietary bitterness and examined its relationship with nutritional quality. This secondary analysis of the 2011-12 National Nutrition and Physical Activity Survey (NNPAS) combined dietary data from 8975 Australian adults with an established sensory food database. The bitterness of foods consumed was calculated by multiplying the bitterness of each food by the grams consumed (bitterness intensity), then summing to estimate the total bitterness of an individual's diet. Tertiles of bitterness were created, and ANOVA with a Bonferroni post hoc test was used to compare individual characteristics and food and nutrient intakes between groups. We hypothesized that more bitter diets might exhibit a more favorable nutritional profile. Age was the strongest predictor of dietary bitterness (β = 0.26), with older adults consuming more bitter diets (P < .001). Compared to the least bitter diets, those with the most bitter diets had higher intakes of vegetables (+30%), fruits (+34%), wholegrain cereals (+36%), and low-fat dairy (+57.2%), and lower intake of refined cereal (-18.0%) P < .001. Beverages contributed more to dietary bitterness than solid foods (87% vs 13%; P < .001), particularly in the most bitter diets (94.6% vs 79.7%; P < .001). Higher intakes of tea/coffee (+285%) and milk (+6%), and lower soft drink (-16%) and juice (-10%) consumption characterized the most bitter diets (P < .001). Dietary bitterness may serve as an indicator of diet quality. Promoting bitter diets requires consideration of both individual characteristics and preferences for bitter foods and beverages.