Role of dietary diversity in type 2 diabetes prevention

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Created On: 15/10/2026

Dietary patterns impact metabolic health, but whether dietary diversity itself is linked with the development of type 2 diabetes (T2D) remains uncertain.

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Key take away

Higher dietary diversity is associated with a 29% lower risk of incident type 2 diabetes, with beneficial gut bacteria and metabolites potentially contributing to this association.

Background

Dietary patterns impact metabolic health, but whether dietary diversity itself is linked with the development of type 2 diabetes (T2D) remains uncertain. Moreover, the biological mechanisms potentially linking dietary diversity to T2D, particularly through the gut microbiota and circulating metabolites, are not fully understood.

This study aimed to evaluate the prospective association between the Dietary Diversity Score (DDS) and incident T2D while clarifying the regulatory roles of the gut microbiota and plasma metabolome.

Method

The study incorporated 10,123 adults aged 18–80 years from two Chinese cohorts.

WELL-China cohort: 8,103 volunteers constituted the discovery cohort.
Lanxi cohort: 2,020 volunteers constituted the validation cohort.

Dietary diversity was assessed via a validated food frequency questionnaire, from which an overall DDS was calculated. Participants were classified into high-, medium-, or low-DDS groups. The key endpoint ascertained was incident T2D during a median follow-up of 6.2 years. Associations between DDS and T2D were evaluated via Cox proportional hazards regression. To examine the potential biological mechanisms, researchers executed:

16S ribosomal ribonucleic acid (16S rRNA) sequencing to characterize gut microbial composition.
Untargeted metabolomics to identify differences in circulating plasma metabolites.

The discovery findings were subsequently examined in the independent Lanxi cohort.

Result

Compared with volunteers in the low-DDS group, those with a high DDS had a lower risk of developing T2D (hazard ratio: 0.71, 29% lower risk). The multi-omics analysis identified 15 metabolites and 11 bacterial genera that differed between the low- and high-DDS groups. Among these findings:

Two bacterial genera, including Blautia, and four metabolites, including L-pipecolic acid, were enriched in the high-DDS group and exhibited negative associations with incident T2D.
Conversely, two bacterial genera and two metabolites that were depleted in the high-DDS group illustrated positive associations with T2D.
Most metabolites enriched among volunteers with higher dietary diversity were positively related to high-DDS-enriched bacterial genera.
These metabolite–microbiota relationships were linked to potentially protective metabolic pathways, including vitamin B6 metabolism.
Metabolites depleted in the high-DDS group exhibited opposite connections and were related to steroid hormone biosynthesis, a pathway whose dysregulation has been connected with insulin resistance.

Together, these findings suggest that the association between dietary diversity and T2D may involve coordinated changes in the gut microbiome–metabolite axis, rather than dietary diversity acting through a single biological pathway.

Conclusion

Higher dietary diversity was independently associated with a lower incidence of T2D, potentially through favorable gut microbiota–metabolite interactions, including enrichment of beneficial bacteria such as Blautia and metabolites linked to vitamin B6 metabolism. These findings support dietary diversity as a simple, modifiable lifestyle factor for T2D prophylaxis.