Quantitative Analysis of Trans‐Fatty Acids in Human Plasma

To assess the relationship between plasma trans-fatty acids (TFAs) levels and leucocyte telomere length (TL) in a US adult population sample. National Health and Nutrition Examination Survey (NHANES) database was used for this study. Gas chromatography was used to separate derivatised fatty acids (Four major TFAs [palmitelaidic acid (C16:1n-7t), trans vaccenic acid (C18:1n-7t), elaidic acid (C18:1n-9t), and linoelaidic acid (C18:2n-6t,9t)]) which were then quatified using negative chemical ionization mass spectrometry. Data analyses used multivariable linear regressions, while accounting for the survey design. A total of 5446 eligible participants, with 46.8% (n = 2550) being men, were included. Their average age was 47.1 years for the total sample, and 47.8 and 46.5 years in men and women respectively (p = 0.085 for men vs. women difference). Concentrations of palmitelaidic acid and linolelaidic acid decreased with increasing length of the telomere (p < 0.05). Univariable linear regressions revealed a significant negative association between levels of the palmitelaidic acid, elaidic acid, vaccenic acid, and linolelaidic acid with TL. However when models were adjusted for age, sex, ethnicity, education, marital status, sub-clinical inflammation, body mass index, and smoking, only palmitelaidic acid and linolelaidic acid remained significant (p < 0.05). TFAs levels and particularly palmitelaidic and linolelaidic acids, are likely negatively associated with telomere lenght. Future studies should explore the potential implications of these associations.

ObjectiveUnsaturated fatty acids (UFA) may be related to glycometabolism. While associations between UFA intake (especially their subtype) and prediabetes or type 2 diabetes mellitus (T2DM) need to be further studied. In this study, we aimed to evaluate the potential relation of UFA with prediabetes and T2DM.MethodsA total of 16,290 adults aged older than 18 years from the National Health and Nutrition Examination Survey (NHANES) from 2005 to March 2020 were included in the present analysis. Dietary intake was assessed by two day, 24-hour dietary recalls and daily intake of total monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA); four specific fatty acids of MUFA and seven specific fatty acids of PUFA were calculated. Prediabetes and T2DM were diagnosed by fasting glucose, glycohemoglobin, and self-reported medication or insulin. Rao–Scott modified chi-square tests, the Taylor series linearization method, and multivariable logistic regression analyses were applied to analyze the associations of dietary MUFA and PUFA intake with diabetes risk.ResultsOf the participants, 44.34% had prediabetes and 13.16% had T2DM patients. From multivariate analysis, we found that intake of MUFA, PUFA, and some subtypes was negatively associated with the risk of prediabetes and T2DM in Americans. Compared with adults in the lowest tertile, those in the highest MUFA (PUFA) tertile had an approximately 50% (49%) and 69% (68%) lower risk of prediabetes and T2DM, respectively. Moreover, the effects of the subtypes of MUFA and PUFA on prediabetes and T2DM were different. Higher intakes of MFA 18:1, MFA 20:1, PFA 18:2, and PFA 18:3 and higher tertile intakes of MFA 16:1 and PFA 20:4 were related to a lower risk of prediabetes and T2DM. Similarly, the effects of MUFA, PUFA, and subtype on prediabetes and T2DM varied among different age groups, being weakened along with age.ConclusionOur study suggested that total MUFA and PUFA intake might be essential in preventing prediabetes and T2DM, especially in Americans. However, this protective effect may decrease with age. Moreover, the effects of the specific UFA on prediabetes and T2DM need further consideration.

High dietary consumption of trans fatty acids decreases brain docosahexaenoic acid but does not alter amyloid-β and tau pathologies in the 3xTg-AD model of Alzheimer's disease

Changes in Mean Intake of Fatty Acids and Intake of Saturated and trans Fats from Potatoes: NHANES 2005–2006, 2007–2008, and 2009–2010

Epidemiological studies suggest that chronic consumption of trans MUFA may alter muscle insulin sensitivity. The major sources of dietary trans MUFA (dairy fat vs. industrially hydrogenated oils) have different isomeric profiles and thus probably different metabolic consequences. These effects may involve alterations in muscle mitochondrial oxidative capacity, which may in turn promote insulin resistance if fatty acid oxidation is reduced. We report that in Wistar rats, an 8 week diet enriched (4% of energy intake) in either dairy, industrial, or control MUFA did not alter insulin and glucose responses to an intraperitoneal glucose tolerance test (1g/kg). In C2C12 myotubes, vaccenic and elaidic acids did not modify insulin sensitivity compared with oleic acid. Furthermore, the ex vivo total, mitochondrial and peroxisomal oxidation rates of [1-(14)C]oleic, vaccenic, and elaidic acids were similar in soleus and tibialis anterior rat muscle. Finally, an 8 week diet enriched in either dairy or industrial trans MUFA did not alter mitochondrial oxidative capacity in these two muscles compared with control MUFA but did induce a specific reduction in soleus mitochondrial ATP and superoxide anion production (P<0.01 vs. control). In conclusion, dietary trans MUFA of dairy or industrial origin have similar effects and do not impair muscle mitochondrial capacity and insulin sensitivity.

Given that the effects of trans fatty acids (TFA) may be associated with the type of TFA isomer and the proportion of n‐3/n‐6/n‐9 fatty acids (FA), this work aimed to investigate the influence of different oils on the following parameters: content, incorporation, and retention of TFA; conversion of vaccenic acid (VA) to rumenic acid (RA) in different tissues; and hepatic output of TFA by VLDL. Another objective was to assess relative conversion rates of key FA and the potential alteration of FA composition induced by TFA in tissues. Male CF1 mice were fed (30‐days) diets containing 7% olive, corn or rapeseed oils either supplemented with 0.75% of TFA or without added TFA. FA composition of liver, epididymal adipose tissue, gastrocnemius muscle, brain, and serum was assessed. With the exception of the brain, TFAs were incorporated into the analyzed tissues and serum. TFA retention and RA bioconversion from VA depended on the dietary unsaturated FA proportions. The higher levels of hepatic RA in the liver of mice fed an olive oil+TFA diet could be associated with a raised Δ9‐desaturase index. The FA composition of tissues was scarcely modified by the consumption of partially hydrogenated vegetable oils containing similar proportions of t9‐, t10‐, and t11‐18:1.Practical applications: The present study evaluates the interaction of hydrogenated vegetable oils with different edible oils and the impact on the FA profile and, specifically, TFA incorporation and retention in the tissues. Since the characterization of FA present in tissues might be determining the biological effects of edible fats, this study is relevant for elucidation of existing controversial findings associated with the intake of TFA and its effects on human metabolic alterations.The levels of trans fatty acids (TFA) in a particular tissue might be related to different variables including: type and level of the dietary TFA isomer; uptake, metabolization and release from the tissue, and interference with different dietary fatty acids.

BackgroundSeveral epidemiological studies have investigated the association between dietary fat intake and cardiovascular disease. However, dietary recommendations based on systematic review and meta-analysis might be more credible.Methods and resultsPubmed, Embase and Cochrane library were searched up to July 1st 2018 for cohort studies reporting associations of dietary fat intake and risk of CVDs. By comparing the highest vs. the lowest categories of fat or fatty acids intake, we found that higher dietary trans fatty acids (TFA) intake was associated with increased risk of CVDs [RR:1.14(1.08–1.21)]. However, no association was observed between total fat, monounsaturated fatty acids (MUFA), saturated fatty acids (SFA), and polyunsaturated fatty acids (PUFA), and risk of CVDs. Subgroup analysis found a cardio-protective effect of PUFA in the studies that has been followed up more than 10 years [0.95(0.91–0.99), I2 = 62.4%]. Dose-response analysis suggested that the risk of CVDs increased 16% [1.16 (1.07–1.25), Plinearity = 0.033] for an increment of 2% energy/day of TFA intake.ConclusionsThis current meta-analysis of cohort studies suggested that total fat, SFA, MUFA, and PUFA intake were not associated with the risk of cardiovascular disease. However, we found that higher TFA intake is associated with greater risk of CVDs in a dose-response fashion. Furthermore, the subgroup analysis found a cardio-protective effect of PUFA in studies followed up for more than 10 years.

Dietary intake and serum levels of trans fatty acids and risk of breast cancer: A systematic review and dose-response meta-analysis of prospective studies

A large body of data from epidemiologic, clinical trial, animal, and in vitro studies demonstrate adverse consequences of industrially synthesized trans fatty acids (TFAs) on the risk of coronary heart disease (CHD). A growing database of more recent research from virtually all experimental models demonstrates evidence of detrimental consequences of TFAs on the risk of diabetes. Evidence is accumulating about the physiological and cellular mechanisms of action that account for the many adverse effects TFAs have on CHD and diabetes. In a relatively short period of time (i.e., from around the early 1990s to the present time, or almost 20 years), we have gained a good understanding of the health effects of TFAs from epidemiologic studies, clinical trials/studies, animal research, and in vitro experiments that collectively justify current dietary recommendations made by numerous government agencies and health organizations to consume a diet with as little TFAs as possible. Public policy actions have been impl...

Background and Aims: The association of fatty acids with coronary heart disease (CHD) has been examined, mainly through dietary measurements, and has generated inconsistent results due to measurement error. Large observational studies and randomized controlled trials have shown that plasma phospholipid fatty acids (PL-FA), especially those less likely to be endogenously synthesized, are good biomarkers of dietary fatty acids. Thus, PL-FA profiles may better predict CHD risk with less measurement error. Methods: We performed a matched case-control study of 2428 postmenopausal women nested in the Women’s Health Initiative Observational Study. Plasma PL-FA were measured using gas chromatography and expressed as molar percentage (moL %). Multivariable conditional logistic regression was used to calculate odds ratios (95% CIs) for CHD associated with 1 moL % change in PL-FA. Results: Higher plasma PL long-chain saturated fatty acids (SFA) were associated with increased CHD risk, while higher n-3 polyunsaturated fatty acids (PUFA) were associated with decreased risk. No significant associations were observed for very-long-chain SFA, monounsaturated fatty acids (MUFA), PUFA n-6 or trans fatty acids (TFA). Substituting 1 moL % PUFA n-6 or TFA with an equivalent proportion of PUFA n-3 were associated with lower CHD risk. Conclusions: Higher plasma PL long-chain SFA and lower PUFA n-3 were associated with increased CHD risk. A change in diet by limiting foods that are associated with plasma PL long-chain SFA and TFA while enhancing foods high in PUFA n-3 may be beneficial in CHD among postmenopausal women.

Prior research suggests polyunsaturated fatty acids (PUFA) may prevent gallstones, but evidence on saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) is limited. This study aims to explore the associations between fatty acids and gallstones using a large sample of American population and Mendelian randomization (MR) methods. The cross-sectional study involved 6,629 participants from the National Health and Nutrition Examination Survey (NHANES) 2017-2020. Logistic regression and restricted cubic spline (RCS) analysis were conducted after stratifying by gender subgroups. Two-sample MR analysis was used to explore the causal relationship between fatty acids and gallstones without confounding factors. In females, higher SFA intake was positively associated with gallstone risk, while higher intake of n-3 and n-6 PUFA was negatively associated. No significant associations were found in males. No nonlinear correlations were found in any group by RCS analysis. MR analysis indicated that SFA, n-3, and n-6 PUFA could reduce gallstone risk. The influence of dietary fatty acid composition on gallstone development differs by gender, providing insights into dietary prevention and treatment of gallstones.

Developing countries are undergoing rapid nutrition transition concurrent with increases in obesity, the metabolic syndrome, and type 2 diabetes mellitus (T2DM). From a healthy traditional high-fiber, low-fat, low-calorie diet, a shift is occurring toward increasing consumption of calorie-dense foods containing refined carbohydrates, fats, red meats, and low fiber. Data show an increase in the supply of animal fats and increased intake of saturated fatty acid (SFAs) (obtained from coconut oil, palm oil, and ghee [clarified butter]) in many developing countries, particularly in South Asia and South-East Asia. In some South Asian populations, particularly among vegetarians, intake of n-3 polyunsaturated fatty acids (PUFAs) (obtained from flaxseed, mustard, and canola oils) and long-chain (LC) n-3 PUFAs (obtained from fish and fish oils) is low. Further, the effect of supplementation of n-3 PUFAs on metabolic risk factors and insulin resistance, except for demonstrated benefit in terms of decreased triglycerides, needs further investigation among South Asians. Data also show that intake of monounsaturated fatty acids (MUFAs) ranged from 4.7% to 16.4%en in developing countries, and supplementing it from olive, canola, mustard, groundnut, and rice bran oils may reduce metabolic risk. In addition, in some developing countries, intake of n-6 PUFAs (obtained from sunflower, safflower, corn, soybean, and sesame oils) and trans-fatty acids (TFAs) is increasing. These data show imbalanced consumption of fats and oils in developing countries, which may have potentially deleterious metabolic and glycemic consequences, although more research is needed. In view of the rapid rise of T2DM in developing countries, more aggressive public health awareness programs coupled with governmental action and clear country-specific guidelines are required, so as to promote widespread use of healthy oils, thus curbing intake of SFAs and TFAs, and increasing intake of n-3 PUFAs and MUFAs. Such actions would contribute to decelerating further escalation of “epidemics” of obesity, the metabolic syndrome, and T2DM in developing countries.

Some studies have demonstrated the transfer of trans fatty acids (TFA) across the human placenta. It was suggested that TFA might disturb the metabolism of essential fatty acids (EFA) in fetus and consequently might affect intrauterine human growth more or less according to the TFA intake level of the mother. In this context, the objective of this study was to assess, for French pregnant women, possible impact of their TFA intake on parameters of their term infants: 1/ TFA composition of the umbilical cord (plasma lipids and parietal phospholipids), 2/ birth weight and head circumference. The TFA composition of maternal and umbilical plasma lipids, and parietal phospholipids of umbilical cord were determined by gas chromatography, associated with a thin-layer chromatography for the phospholipids. Because TFA content of adipose tissue is a reliable biochemical indicator of the usual TFA intake level, maternal adipose tissue was also analyzed. Trans fatty acid (TFA) percentage was significantly higher (p = 0.001) in maternal (0.9% of total fatty acids) than in umbilical plasma total lipids (0.6%) thus confirming their placental passage. Moreover, trans isomer pattern of cord plasma lipids was different from the maternal’s one, especially regarding trans isomers of linoleic acid (9c,12c-18:2). Percentage values of 9c,13t + 9t,12t and 9t,12c isomers were respectively, 2 and 3 times higher (p < 0.001) in umbilical than in maternal plasma (Except trans 16:1 acids). All trans isomers observed in umbilical plasma lipids were detected in both parietal and vessel (vein and arteries) phospholipids of umbilical cord. Nevertheless, 9c13t + 9t12t isomer mix level was significantly higher (p < 0.001) in artery than in vein TPL. Moreover, in artery TPL, percentage value of 9c13t+9t12t isomer mix was inversely correlated (r = - 0.703, p = 0.003) with arachidonic acid content. Nevertheless, for this French population, there was no relation between either weight or head circumference of newborn and the TFA levels in both adipose tissue and plasma lipids of their mother.

The association between fatty acid intake and breast cancer based on the NHANES and Mendelian randomization study

Dietary fat composition may modulate energy expenditure and body weight. Little is known about the relationship between fatty acid intake and body weight at a population level. The purposes of this study were to compare intakes of energy, macronutrients, and individual fatty acids across BMI categories (1) for the US adult population and, (2) by sociodemographic groups. Reported dietary intake data from the National Health and Nutrition Examination Survey (NHANES) and What We Eat in America (WWEIA) surveys in the years 2005–2012 were analyzed. Overall, we found that the reported intake of carbohydrate, protein, total fat, total saturated fat (as well as long-chain saturated fatty acids 14:0–18:0), and monounsaturated fatty acids (MUFAs) were positively associated with BMI; while lauric acid (a medium-chain saturated fatty acid, 12:0) and total polyunsaturated fatty acids (PUFAs) (as well as all individual PUFAs) were not associated with BMI. Non-Hispanic black individuals demonstrated a negative association between BMI and energy intake and a positive association between total PUFAs, linoleic acid (LA), α-linolenic acid (ALA) and BMI. Individuals with less than a high school education showed a negative association between BMI and DHA. Mexican-Americans reported intakes with no association between BMI and energy, any macronutrient, or individual fatty acids. These findings support those of experimental studies demonstrating fatty acid-dependent associations between dietary fatty acid composition and body weight. Notably, we observed divergent results for some sociodemographic groups which warrant further investigation.