Ethnic- and sex-specific associations between plasma fatty acids and markers of insulin resistance in healthy young adults

Abstract

BackgroundAlthough evidence indicates that fatty acids (FA) can affect insulin resistance (IR), not all FA contribute equally to the process. Indeed, monounsaturated FA (MUFA) and polyunsaturated FA (PUFA) are reported to reduce IR, whereas saturated FA (SFA) and trans FA appear to increase IR. However, it is not yet clear how individual FA are associated with markers of IR, and whether these relationships are influenced by ethnicity and/or sex. Therefore, the goal of this study was to examine the ethnic- and sex-specific relationships between plasma FA and markers of IR in a cohort of healthy young Caucasian, East Asian, and South Asian adults.MethodsGas chromatography was used to quantify fasting plasma FA from young Canadian adults (22.6 ± 0.1 yrs) of Caucasian (n = 461), East Asian (n = 362), or South Asian (n = 104) descent. Linear regression models were used to investigate associations between plasma FA and markers of IR (i.e. fasting insulin, glucose, and HOMA-IR) according to ethnicity and sex.ResultsNumerous significant associations (P < 0.05, adjusted for multiple testing) were identified between individual FA and markers of IR, with the majority identified in Caucasians. For SFA, positive associations were found between 14:0 and fasting insulin and HOMA-IR in Caucasian and East Asian populations, and 18:0 and fasting glucose in Caucasians only. Several positive associations were also found for specific MUFA (18:1t11 and 18:1t6-8 with HOMA-IR, and 18:1c9 with fasting glucose) and PUFA (18:2n6 with fasting glucose and 18:2c9t11 with HOMA-IR) in Caucasian adults only. Most of the aforementioned associations were stronger in males compared to females. Interestingly, no significant associations were found between FA and markers of IR in South Asian adults.ConclusionsWe report numerous associations between plasma FA and markers of IR in Caucasian and East Asian populations, but not in South Asian individuals. Furthermore, these associations appeared to be more robust in men. This demonstrates the importance of investigating associations between FA and markers of IR in an ethnic- and sex-specific manner in order to better understand the contribution of plasma FA to the development of IR and type-2 diabetes.

Plasma Cholesteryl Ester Fatty Acids do not Mediate the Association of Ethnicity with Type 2 Diabetes: Results From the HELIUS Study

“…suggested that odd‐chained SFA may be negatively associated with T2D, our results indicate this as well . To our knowledge, only one previous study investigated the association between individual FAs and T2D or metabolic markers of T2D in a multiethnic population and this study was conducted in Canada . Ralston et al.…”

“…The association of plasma CEFA levels with T2D in the overall population and per ethnic group was investigated using logistic regression and presented as odds ratios with their corresponding 95% confidence interval (OR [95% CI]). We investigated whether the association between CEFA and T2D differed by sex by adding an interaction term between CEFA and sex in our models, due to indications that the association between FAs and T2D may be sex specific . No evidence for interaction by sex was found (data not shown).…”

“…A 5‐day experimental high‐fat, high‐calorie diet showed for instance reduced insulin sensitivity, increased fasting glucose, and insulin concentrations in South Asians but not in Caucasians . Moreover, previous work among Caucasians, East Asians, and South Asians living in Canada suggested that associations between FAs and markers of insulin resistance differ across ethnic groups . Our study set out to further investigate the ethnic differences in plasma FAs and the association with T2D among the largest ethnic groups living in Amsterdam, the Netherlands, and to study whether these may explain ethnic disparities in prevalence of T2D.…”

Palmitoleic acid (n-7) increases white adipocyte lipolysis and lipase content in a PPARα-dependent manner

“…This dose of fatty acids was found to have no cytotoxic or deleterious effects on cell viability, as evaluated by membrane integrity and DNA fragmentation (data not shown). Importantly, we chose for the in vitro experiments a dose of palmitoleic acid higher than that found in plasma of humans and/or rodents (8,26,31,32), because, in contrast to regular adipocytes, palmitoleic acid is the most abundant fatty acid in differentiated 3T3-L1 cells (11,35). Thus, a higher dose of palmitoleic acid is required to challenge these cells.…”

Acculturation and Insulin Resistance Among US Chinese Immigrant Women

“…6 Lee et al 7 found that Taiwanese immigrants who lived in Australia for >5 years had higher insulin and HOMA compared with immigrants who had lived in Australia <5 years. Similarly, among immigrants to Canada, Chiu et al 8 found poorer risk factor profiles, including diabetes as an indicator, with longer dura-Acculturation and Insulin Resistance -Tseng and Fang these are potentially associated with both acculturation 7 and insulin resistance 33 and may suggest an alternative mechanism linking the two.…”