Changes in Plasma Choline and the Betaine-to-Choline Ratio in Response to 6-Month Lifestyle Intervention Are Associated with the Changes of Lipid Profiles and Intestinal Microbiota: The ICAAN Study

Abstract

Trimethylamine N-oxide (TMAO) and its precursors, including choline, betaine, and L-carnitine, are gut microbiota-related metabolites associated with the risk of obesity. We aimed (1) to comprehensively examine whether the changes in plasma TMAO and its precursors induced by lifestyle intervention are associated with the improvements in plasma metabolic parameters; and (2) to identify the fecal microbiome profiles and nutrient intakes associated with these metabolites and metabolic index. Data from 40 participants (obese children and adolescents) having the plasma metabolites data related to the changes in BMI z-scores after 6-month lifestyle intervention were analyzed. In this study, we observed that choline and the betaine-to-choline ratio (B/C) showed different patterns depending on the changes in BMI z-scores by the response to lifestyle intervention. During the 6 months, an increase in choline and a decrease in B/C were observed in non-responders. We also found that changes in choline and B/C were associated with the improvements in plasma lipid levels. Individuals who showed reduced choline or increased B/C from the baseline to 6 months had a significant decrease in LDL-cholesterol over 6 months compared to those with increased choline or decreased B/C, respectively. In addition, the increase in choline or decrease in B/C was associated with the increase in plasma triglycerides. The distribution of gut microbiota belonging to the Firmicutes, such as Clostridia, Clostridiales, Peptostreptococcaceae, Romboutsia, and Romboutsia timonensis was altered to be lower during the 6 months both as choline decreased and B/C increased. Moreover, the decrease in choline and the increase in B/C were associated with reduced fat intake and increased fiber intake after the 6-month intervention. Finally, lower abundance of Romboutsia showed the association with lower LDL-cholesterol and higher intake of fiber. In summary, we demonstrated that reduced choline and increased B/C by lifestyle intervention were associated with the improvements of LDL-cholesterol and triglycerides, low-fat and high-fiber intakes, and low abundance of Firmicutes. These indicate that changes to circulating choline and B/C could predict individuals' changes in metabolic compositions in response to the lifestyle intervention.

Keywords: Firmicutes; betaine; choline; gut microbiota; metabolic parameters; metabolite.

Figure 1

Changes in metabolic parameters by target metabolites group after lifestyle intervention. p-values were calculated using ANCOVA after adjustment for age, sex, baseline BMI z-score, values for the respective outcome traits at baseline to compare differences of between-groups at 6 months. Paired t-test was used to compare difference between pre-intervention (0 M) and post-intervention (6 months) within each group, and p-values less than 0.05 are marked with asterisks (* p < 0.05, ** p < 0.01, *** p < 0.001). DC, decreased choline group; IC, increased choline group; DBC, decreased betaine/choline group IBC, increased betaine/choline group.

Figure 2

Intestinal microbiota taxa that discriminate between change groups (decrease vs. increase) in choline and B/C ratio after 6 months. Linear discriminant analysis with effect size (LEfSe) was performed using relative abundance data. Data shown are the log 10 linear discriminant analysis (LDA) scores following LEfSe analysis and the hierarchy of discriminating taxa visualized as cladograms for class comparisons between change groups of (A) choline, (B) betaine/choline, and (C) both choline and betaine/choline. DC, decreased choline group; IC, increased choline group; DBC, decreased betaine/choline group IBC, increased betaine/choline group.

Figure 3

The association between dietary intake changes and target metabolites groups of (A) Choline, (B) Betaine/Choline, and (C) both choline and betaine/choline over a period of baseline to 6 months (Δ). In the paired t-test between pre-intervention (baseline) and post-intervention (6 months) values within each group, p-values less than 0.05 are marked with asterisks (*). DC, decreased choline group; IC, increased choline group; DBC, decreased betaine/choline group IBC, increased betaine/choline group.

Figure 4

The correlation between changes in Romboutsia and (A) LDL-cholesterol and (B) dietary fiber over a period of baseline to 6 months (Δ). Spearman’s partial correlation analyses adjusted for age, sex, and baseline BMI z-score were performed.