Study links high dietary amino acid intake to increased type 2 diabetes risk

By Vijay Kumar MalesuReviewed by Lily Ramsey, LLMNov 22 2023

In a recent study published in BMC Public Health, researchers investigated the association between dietary amino acid intake and the incidence of Type 2 diabetes (T2D) in participants of the Ravansar Non-Communicable Disease (RaNCD) Cohort Study.

Study: The association between dietary amino acid profile and the risk of type 2 diabetes: Ravansar non-communicable disease cohort study. Image Credit: Yulia Furman/Shutterstock.com

Background 

T2D is a prevalent chronic disease influenced by lifestyle, diet, and genetic factors. Amino acids, crucial dietary components, have been linked to chronic disease risk, including T2D.

Amino acids, key dietary components, play a significant role in the association between dietary protein and chronic diseases. Prior research has shown mixed results regarding the association between various amino acids and T2D risk.

Most research has focused on Western populations, with fewer studies in Asian contexts showing conflicting results. The need for further research in this area, particularly among different ethnic groups, is emphasized better to understand the dietary patterns and their relation to T2D.

About the study 

The present study utilized the RaNCD Cohort Study data, part of the Prospective Epidemiological Research Studies in IrAN (PERSIAN) Cohort. It included individuals aged 35–65 at different phases, focusing on those who developed T2D during a 6-year follow-up period.

Participants with pre-existing chronic conditions or abnormal energy intake were excluded. For each T2D case, four controls were matched for sex and age.

Dietary intake data were collected using the Iranian Food Frequency Questionnaire (FFQ), which assessed consumption frequency and portion sizes of 125 food items.

Intake of amino acids was calculated and categorized into different groups based on their chemical structure. Other variables such as demographic data, smoking status, physical activity, socioeconomic status, dietary habits, anthropometric characteristics, and comorbidities were also collected.

Statistical analysis involved chi-square, T-test, Mann-Whitney tests for comparing groups, and binary logistic regression to estimate odds ratios for T2D risk. Adjustments were made for potential confounders, including residency, socioeconomic status, education level, family history of diabetes, body mass index (BMI), waist-to-height ratio, physical activity, sleep duration, dietary patterns, comorbidities, blood pressure, and daily energy intake.

Study results 

The present study found significant associations between the risk of T2D and higher intakes of certain amino acids. In the initial unadjusted model, higher chances of T2D were observed in individuals with the highest quartile intakes of branched-chain, sulfuric, alkaline, and essential amino acids compared to those in the lowest quartile.

Specifically, the risk increased by 1.81 to 1.87 times in these individuals. However, the results varied across different amino acid groups when adjusting for various confounders.

For individuals in the highest quartile, the adjusted odds of developing T2D were 2.70 times higher for branched-chain amino acids, 2.68 times for alkaline amino acids, 2.98 times for sulfuric amino acids, 2.45 times for alcoholic amino acids, and 2.66 times for essential amino acids, compared to those in the lowest quartile.

This suggests a significant relationship between higher dietary intake of these amino acids and increased T2D risk, even after adjusting for several factors.

Despite these findings, the study did not observe a significant nonlinear association between dietary amino acid profiles and T2D risk after extensive demographic and lifestyle factors adjustment. This indicates that the relationship between amino acid intake and T2D risk is not straightforward and may be influenced by other factors.

The study highlighted branched-chain amino acids as particularly significant, aligning with previous research showing their association with T2D risk in various populations. This supports the potential role of these amino acids as biomarkers for T2D risk. However, the results were not consistent across all amino acid groups.

For instance, no significant associations were found with aromatic, non-essential, acidic amino acids, small amino acids, and proline. Additionally, glycine was not associated with T2D risk, aligning with some previous studies but contrasting with others that reported an inverse association.

The study’s findings underline the complexity of the relationship between dietary amino acids and T2D risk. It suggests that while certain amino acids are associated with increased risk, this relationship is influenced by various factors, including ethnicity, lifestyle, and measurement methods.

The study’s specific focus on an Iranian cohort adds to the understanding of these associations in Asian populations, which have been less studied compared to Western groups.

Conclusions 

In the nested case-control study within a 565-participant cohort, it was found that most dietary amino acid levels were higher in T2D patients compared to controls.

A significant link was observed between a high intake of certain amino acids (branched-chain, alkaline, sulfuric, and essential) and increased T2D risk, particularly in the highest intake quartile. These results suggest that amino acids could serve as biomarkers for T2D risk, with insulin resistance potentially playing a mediating role.

The study aligns with prior research indicating a correlation between elevated specific amino acids and higher diabetes risk across diverse populations.