Correspondence between total whole grain intake and whole grain intake surrogate estimats in the Finnish adult population

Background and objectives: Whole grain is considered one of the core components in diets promoting health and environmental sustainability. However, inconsistencies in the current whole grain intake estimation possibly weaken the associations between whole grain intake and health outcomes. For example, surrogate estimates (e.g., whole grain bread) have been frequently applied instead of total whole grain intake. Yet, research of these estimates in relation to total whole grain intake is largely missing. We aimed at examining the correspondence of two potential surrogate estimates, dietary fiber and rye bread intake, with total whole grain intake in Finnish adults. Methods: The data comprised 5094 adults aged 18−74 years participating in the population-based FinHealth 2017 Study. Subgroup analyses were implemented by sex, age (median as cut-off) and education (low/medium vs. high). Dietary intake was assessed by a validated 134-item FFQ. Food, nutrient, energy and whole grain intakes were calculated utilizing the Finnish Food Composition Database Fineli®. Results: Daily total whole grain intake was 61 g (7.7 g/MJ) in women and 71 g (7.2 g/MJ) in men. The partial (energy-adjusted) Spearman's rank correlation coefficients were 0.68 between total whole grain and dietary fiber intake and 0.83 between total whole grain and rye bread intake. Total whole grain had a higher correlation with dietary fiber in men than women (0.75 vs. 0.64, p< 0.0001) and in low/medium educated than high educated participants (0.70 vs. 0.66, p