A Cross-Sectional Study of Food Insecurity, Mediterranean Diet Adherence, and Gut-Derived Metabolites and Their Associations with Glycemic Control and Macrovascular Complications in Adults with Type 2 Diabetes.
Ozcaliskan Ilkay H & Ozdamar Karaca Z • Nutrients • 2026
Combined food insecurity-Mediterranean diet adherence patterns showed suggestive but imprecise differences in HbA1c category membership, while serum TMAO and L-carnitine concentrations differed significantly according to food insecurity and macrovascular complication status in adults with type 2 diabetes.
Key Findings
Results
In multinomial logistic regression, no combined food insecurity-Mediterranean diet adherence patterns were significantly associated with intermediate or highest HbA1c tertiles after multivariable adjustment.
Primary analysis used multinomial logistic regression on data-derived HbA1c tertiles.
Food insecurity with high MDA adherence showed a point estimate of AOR = 3.41 (95% CI: 0.76–15.25) for the intermediate HbA1c tertile, which was not statistically significant.
Food insecurity with low MDA adherence showed a point estimate of AOR = 4.74 (95% CI: 0.66–34.16) for the highest HbA1c tertile, also not statistically significant.
The authors noted these estimates were 'imprecise' and confidence intervals were wide, spanning both below and above 1 (or close to 1 on the lower bound).
Sensitivity analyses using separate binary logistic regression models yielded stronger associations but were flagged for cautious interpretation.
Results
Participants with macrovascular complications had significantly higher serum TMAO and L-carnitine concentrations compared to those without macrovascular complications.
TMAO concentrations were significantly higher in participants with macrovascular complications (p = 0.026).
L-carnitine concentrations were also significantly higher in participants with macrovascular complications (p = 0.039).
Comparisons were adjusted using ANCOVA.
These findings suggest a potential link between gut-derived metabolites and macrovascular complication status in T2DM.
Results
Food-insecure participants had significantly lower serum TMAO and L-carnitine concentrations compared to food-secure participants.
TMAO concentrations were significantly lower in food-insecure participants (p = 0.009).
L-carnitine concentrations were significantly lower in food-insecure participants (p = 0.018).
Food insecurity was assessed using the Food Insecurity Experience Scale.
The direction of the association (lower metabolites with food insecurity) contrasts with the higher metabolites seen with macrovascular complications, suggesting complex relationships between dietary access, diet quality, and metabolite profiles.
Results
Higher dietary fiber and plant protein intakes were cross-sectionally associated with lower serum TMAO concentrations.
Both dietary fiber intake and plant protein intake were inversely associated with TMAO concentrations.
Associations were cross-sectional and described as exploratory.
The study used ELISA to quantify serum TMAO concentrations.
The authors cautioned that these should be interpreted as 'exploratory cross-sectional associations rather than evidence of causal or mechanistic effects.'
Results
L-carnitine concentrations were positively associated with dietary fiber intake and inversely associated with plant protein intake.
Higher dietary fiber intake was associated with higher serum L-carnitine concentrations.
Higher plant protein intake was associated with lower serum L-carnitine concentrations.
This pattern differs from the associations seen with TMAO, where both fiber and plant protein were inversely associated.
L-carnitine concentrations were quantified using ELISA.
These associations were cross-sectional and flagged as exploratory.
Methods
The study used a cross-sectional design assessing food insecurity, Mediterranean diet adherence, gut-derived metabolites, glycemic control, and macrovascular complications in adults with type 2 diabetes.
Food insecurity was assessed using the Food Insecurity Experience Scale.
Mediterranean diet adherence was evaluated with the 14-item Mediterranean Diet Adherence (MDA) Scale.
Serum TMAO and L-carnitine concentrations were quantified using ELISA.
Primary analysis used multinomial logistic regression on HbA1c tertiles; sensitivity analyses used separate binary logistic regression models.
ANCOVA was used for adjusted comparisons of continuous outcomes.
Conclusions
The authors concluded that larger prospective studies are needed to confirm the suggestive associations between combined food insecurity-MDA patterns and HbA1c category membership.
Point estimates for HbA1c tertile associations were described as 'imprecise' due to wide confidence intervals.
The primary multinomial analysis did not yield statistically significant findings for the food insecurity-MDA combinations.
Authors explicitly framed all findings as 'exploratory cross-sectional associations rather than evidence of causal or mechanistic effects.'
The study highlights the need for prospective designs with larger sample sizes to draw firmer conclusions.
What This Means
This research suggests that among adults with type 2 diabetes, the combination of food insecurity (difficulty accessing enough food) and poor adherence to a Mediterranean-style diet may be linked to worse blood sugar control, but the study could not confirm this statistically due to imprecise estimates and wide uncertainty ranges. When researchers looked at blood markers called TMAO and L-carnitine—substances produced when gut bacteria break down certain foods—they found that people with cardiovascular complications had higher levels of both, while people who were food insecure had lower levels of both. Diet composition, specifically fiber and plant protein intake, was also linked to these metabolite levels in different ways.
The finding that food-insecure individuals had lower TMAO and L-carnitine levels, while those with macrovascular complications had higher levels, highlights the complexity of how diet access, diet quality, and disease interact. Higher TMAO has previously been associated with cardiovascular risk, so the lower levels in food-insecure individuals may reflect different dietary patterns rather than better health outcomes—this study cannot determine which direction the relationships run.
This research suggests that gut-derived metabolites may serve as markers of both dietary patterns and cardiovascular disease status in people with type 2 diabetes, and that food insecurity could affect these biological pathways. However, because the study was conducted at a single point in time and some analyses were underpowered, the findings are exploratory and cannot establish cause and effect. Future larger, longer-term studies would be needed to understand whether addressing food insecurity or improving diet quality could meaningfully alter these metabolite levels or improve diabetes outcomes.
Ozcaliskan Ilkay H, Ozdamar Karaca Z. (2026). A Cross-Sectional Study of Food Insecurity, Mediterranean Diet Adherence, and Gut-Derived Metabolites and Their Associations with Glycemic Control and Macrovascular Complications in Adults with Type 2 Diabetes.. Nutrients. https://doi.org/10.3390/nu18162695