Healthy Dietary Pattern Cycling Affects Gut Microbiota and Cardiovascular Disease Risk Factors: Results from a Randomized Controlled Feeding Trial with Young, Healthy Adults

Abstract

Background: Previous research demonstrates that adopting, abandoning, and re-adopting (i.e., cycling) a healthy dietary pattern (HDP) improved, reverted, and re-improved cardiovascular disease (CVD) risk factors. In addition, changes in CVD risk factors are associated with dietary modifications of gut microbiota.

Objective: We sought to assess the effects of cycling an HDP on gut microbiota and CVD risk factors.

Methods: Retrospectively, we used data from a randomized controlled, crossover trial with three 3-week controlled dietary interventions, each separated by a 5-week period of participant-chosen, uncontrolled food intake. Seventeen participants (10 males, 7 females, age 26 ± 4 years old, BMI 23 ± 3 kg/m²) all consumed intervention diets that followed healthy U.S.-style dietary patterns. Gut microbiota composition and cardiovascular risk factors were measured before and after each HDP.

Results: Repeatedly adopting and abandoning an HDP led to a cycling pattern of changes in the gut microbial community and taxonomic composition. During the HDP cycles, relative abundances of several bacterial taxa (e.g., Collinsella, Mediterraneibacter, Romboutsia, and Dorea) decreased and returned to baseline repeatedly. Similar HDP cycling occurred for multiple CVD risk factors (i.e., serum total cholesterol and LDL-C concentrations). Consistent negative associations were observed between changes in Mediterraneibacter or Collinsella and serum total cholesterol/HDL-C ratio.

Conclusions: These results support previous findings that HDP cycling affected multiple CVD risk factors and expand the HDP cycling phenomenon to include several bacterial taxa. Young adults are encouraged to adopt and sustain a healthy dietary pattern to improve cardiovascular health, potentially through modifying gut microbiota composition.

Keywords: dietary adherence; gut microbiome; healthy eating pattern.

Figure 1

Schematic of study design and measurements. HDP, healthy dietary pattern. The HDP interventions are indicated in dark grey. The assessment timepoints before and after the three HDPs (Pre-1, Post-1, Pre-2, Post-2, Pre-3, and Post-3) are underlined for the corresponding study weeks.

Figure 2

The CONSORT flow diagram of study enrollment (HDP, healthy dietary pattern; N, sample size; F, female; M, male).

Figure 3

A cycling pattern of changes in diet quality from baseline 1 to healthy dietary pattern 3. Results are presented using group means and standard deviations.

Figure 4

Gut microbiota community composition before and after each HDP over time. A total of 112 OTUs with at least 0.1% of abundance, representing 41 genera, are included and colored by phylum. The rest of the OTUs with less than 0.1% of relative abundance are categorized into “Others”. OTU, operational taxonomic unit.

Figure 5

Cycling of bacterial genera that were (a) increased and (b) decreased by the prescribed healthy dietary pattern, and OTUs that were (c) increased and (d) decreased by the prescribed healthy dietary pattern, using group means and standard deviations with data pooled from the three HDPs. OTU, operational taxonomic unit.

Figure 6

Changes in (a) serum lipids, (b) TC/HDL-C ratio, (c) serum glucose, and (d) blood pressures over time using unadjusted group means and standard deviations. TC, total cholesterol; TAG, triglycerides; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol.