Healthy Nordic diet and associations with plasma concentrations of metabolites in the choline oxidation pathway: a cross-sectional study from Northern Sweden

BACKGROUND: The choline oxidation pathway and metabolites involved have been linked to diseases including cardiovascular disease, type 2 diabetes and cancer. A healthy Nordic diet is a recently defined dietary pattern associated with decreased risk for these diseases. Our aim was to explore associations between adherence to a healthy Nordic diet and plasma concentrations of metabolites of the choline oxidation pathway. METHODS: The Healthy Nordic Food Index (HNFI) and Baltic Sea Diet Score (BSDS) were applied to cross-sectional data (n = 969) from the Västerbotten Intervention Programme in Northern Sweden to score adherence to a healthy Nordic diet. Data included responses to a dietary questionnaire and blood sample analyses (1991–2008). Associations of diet scores with plasma concentrations of metabolites of the choline oxidation pathway and total homocysteine (tHcy), seven metabolites in total, were evaluated with linear regression, adjusting for age, BMI, education and physical activity. RESULTS: HNFI scores showed linear relationships with plasma choline (β = 0.11), betaine (β = 0.46), serine (β = 0.98) and tHcy (β = − 0.38), and BSDS scores with betaine (β = 0.13) and tHcy (β = − 0.13); unstandardized beta coefficients, all significant at P < 0.05. The regression models predicted changes in plasma metabolite concentrations (± 1 SD changes in diet score) in the range of 1–5% for choline, betaine, serine and tHcy. No other statistically significant associations were observed. CONCLUSIONS: A healthy Nordic diet was associated with plasma concentrations of several metabolites of the choline oxidation pathway. Although relationships were statistically significant, effect sizes were moderate. Further research is warranted to explore the underlying mechanisms and associations with health outcomes. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12937-023-00853-w.