Impact of a Municipal Policy Restricting Trans Fatty Acid Use in New York City Restaurants on Serum Trans Fatty Acid Levels in Adults.

OBJECTIVES: To estimate the impact of the 2006 policy restricting use of trans fatty acids (TFAs) in New York City restaurants on change in serum TFA concentrations in New York City adults. METHODS: Two cross-sectional population-based New York City Health and Nutrition Examination Surveys conducted in 2004 (n = 212) and 2013-2014 (n = 247) provided estimates of serum TFA exposure and average frequency of weekly restaurant meals. We estimated the geometric mean of the sum of serum TFAs by year and restaurant meal frequency by using linear regression. RESULTS: Among those who ate less than 1 restaurant meal per week, geometric mean of the sum of serum TFAs declined 51.1% (95% confidence interval [CI] = 42.7, 58.3)-from 44.6 (95% CI = 39.7, 50.1) to 21.8 (95% CI = 19.3, 24.5) micromoles per liter. The decline in the geometric mean was greater (P for interaction = .04) among those who ate 4 or more restaurant meals per week: 61.6% (95% CI = 55.8, 66.7) or from 54.6 (95% CI = 49.3, 60.5) to 21.0 (95% CI = 18.9, 23.3) micromoles per liter. CONCLUSIONS: New York City adult serum TFA concentrations declined between 2004 and 2014. The indication of greater decline in serum TFAs among those eating restaurant meals more frequently suggests that the municipal restriction on TFA use was effective in reducing TFA exposure. Public Health Implications. Local policies focused on restaurants can promote nutritional improvements.

Dietary Sources of Plasma trans Fatty Acids among Adults in the United States: NHANES 2009-2010.

BACKGROUND: Intake of trans fatty acids (TFAs) increases LDL cholesterol, decreases HDL cholesterol, and increases the risk of heart disease morbidity and mortality. Many food products potentially contain industrially produced or ruminant TFAs. However, little is known about the dietary sources of plasma TFA concentrations. OBJECTIVE: The objective of this study was to examine associations between foods consumed and plasma TFA concentrations using 24-h dietary recall data and plasma TFA measures among adults aged ≥20 y who participated in the NHANES 2009-2010 in the United States. METHODS: Over 4400 food products in the dietary interview data were categorized into 32 food and beverage groups/subgroups. Four major plasma TFAs (palmitelaidic acid, elaidic acid, vaccenic acid, linolelaidic acid) and the sum of the 4 TFAs (sumTFAs) were analyzed using GC-MS. Multivariable linear regression analyses were conducted to identify associations of plasma TFAs with all 32 food and beverage groups/subgroups, controlling for the potential confounding effects of 11 demographic, socioeconomic, behavioral, lifestyle, and health-related variables. RESULTS: Consumption of the following food groups/subgroups was significantly associated with elevated plasma TFA concentrations: cream substitutes (P < 0.001 for palmitelaidic acid, elaidic acid, vaccenic acid, and sumTFAs); cakes, cookies, pastries, and pies (P < 0.001 for elaidic acid, vaccenic acid, and sumTFAs; P < 0.05 for linolelaidic acid); milk and milk desserts (P < 0.01 for palmitelaidic acid and vaccenic acid; P < 0.05 for linolelaidic acid and sumTFAs); beef/veal, lamb/goat, and venison/deer (P < 0.01 for vaccenic acid; P < 0.05 for sumTFAs); and butters (P < 0.001 for palmitelaidic acid and vaccenic acid; P < 0.05 for sumTFAs). CONCLUSIONS: The findings suggest that the above 5 food groups/subgroups could be the main dietary sources of plasma TFAs among adults in the United States in 2009-2010.

Cost assessment of a program for laboratory testing of plasma trans-fatty acids in Thailand.

Objectives: Intake of trans fatty acids (TFA) increases the risk of cardiovascular disease. Assessment of TFA exposure in the population is key for determining TFA burden and monitoring change over time. One approach for TFA monitoring is measurement of TFA levels in plasma. Understanding costs associated with this approach can facilitate program planning, implementation and scale-up. This report provides an assessment of costs associated with a pilot program to measure plasma TFA levels in Thailand. Study design: Cost analysis in a laboratory facility in Thailand. Methods: We defined three broad cost modules: laboratory, personnel, and facility costs, which were further classified into sub-components and into fixed and variable categories. Costs were estimated based on the number of processed plasma samples (100-2700 in increments of 50) per year over a certain number of years (1-5), in both USD and Thai Baht. Total cost and average costs per sample were estimated across a range of samples processed. Results: The average cost per sample of analyzing 900 samples annually over 5 years was estimated at USD186. Laboratory, personnel, and facility costs constitute 67%, 23%, and 10% of costs, respectively. The breakdown across fixed costs, such as laboratory instruments and personnel, and variable costs, such as chemical supplies, was 60% and 40%, respectively. Average costs decline as more samples are processed: the cost per sample for analyzing 100, 500, 1500, and 2500 samples per year over 5 years is USD1351, USD301, USD195; and USD177, respectively. Conclusions: Laboratory analysis of plasma TFA levels has high potential for economies of scale, encouraging a long-term approach to TFA monitoring initiatives, particularly in countries that already maintain national biometric repositories.

Ascorbic acid promotes detoxification and elimination of 4-hydroxy-2(E)-nonenal in human monocytic THP-1 cells.

4-Hydroxy-2(E)-nonenal (HNE), a reactive aldehyde derived from oxidized lipids, has been implicated in the pathogenesis of cardiovascular and neurological diseases, in part by its ability to induce oxidative stress and by protein carbonylation in target cells. The effects of intracellular ascorbic acid (vitamin C) on HNE-induced cytotoxicity and protein carbonylation were investigated in human THP-1 monocytic leukemia cells. HNE treatment of these cells resulted in apoptosis, necrosis, and protein carbonylation. Ascorbic acid accumulated in the cells at concentrations of 6.4 or 8.9 mM after treatment with 0.1 or 1 mM ascorbate in the medium for 18 h. Pretreatment of cells with 1.0 mM ascorbate decreased HNE-induced formation of reactive oxygen species and formation of protein carbonyls. The protective effects of ascorbate were associated with an increase in the formation of GSH-HNE conjugate and its phase 1 metabolites, measured by LC-MS/MS, and with increased transport of GSH conjugates from the cells into the medium. Ascorbate pretreatment enhanced the efflux of the multidrug resistant protein (MRP) substrate, carboxy-2',7'-dichlorofluorescein (CDF), and it prevented the HNE-induced inhibition of CDF export from THP-1 cells, suggesting that the protective effect of ascorbate against HNE cytotoxicity is through modulation of MRP-mediated transport of GSH-HNE conjugate metabolites. The formation of ascorbate adducts of HNE was observed in the cell exposure experiments, but it represented a minor pathway contributing to the elimination of HNE and to the protective effects of ascorbate.

Quantitation of trans-fatty acids in human blood via isotope dilution-gas chromatography-negative chemical ionization-mass spectrometry.

Trans-fatty acids (TFA) are geometric isomers of naturally occurring cis-fatty acids. High dietary TFA intake has been associated with risk factors for cardiovascular disease. However, little is known about TFA levels in humans. To address this data need, we developed and validated a new isotope dilution-gas chromatography-negative chemical ionization-mass spectrometry (ID-GC-NCI-MS) method for quantitation of 27 fatty acids (FA) including 4 major TFA in human plasma, serum, and red blood cells (RBC) from 66 donors. Quantitation was performed with 18 isotope labeled internal standards and results are presented in µM and % of total FA. This method has high sensitivity and specificity due to use of pentafluorobenzyl-bromide derivatization combined with NCI-MS and a 200m column to optimize positional and geometric FA isomer separation. The four major TFA, palmitelaidic acid, elaidic acid, trans-vaccenic acid, and linoelaidic acid, were detected in all samples, with median total TFA concentrations of 17.7µM in plasma, 19.6µM in serum, and 21.5µM in RBC. The % of total FA for the TFA was 0.20% in plasma, 0.20% in serum, and 0.30% in RBC. Patterns for % FA are similar to those reported in other studies. We developed a highly specific, ID-GC-NCI-MS method to quantitate TFA and other FA in humans.

Plasma trans-fatty acid concentrations in fasting adults declined from NHANES 1999-2000 to 2009-2010.

Background: The consumption of trans fatty acids (TFAs) is associated with an increased risk of cardiovascular disease, and reducing their consumption is a major public health objective. Food intake studies have provided estimates for TFA concentrations in the US population; however, there is a need for data on TFA blood concentrations in the population.Objective: The objective of this study was to determine plasma TFA concentrations in a nationally representative group of fasted adults in the US population in NHANES samples from 1999-2000 and 2009-2010.Design: 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)] were measured in plasma in 1613 subjects from NHANES 1999-2000 and 2462 subjects from NHANES 2009-2010 by gas chromatography-mass spectrometry. Geometric means and distribution percentiles were calculated for each TFA and their sum by age, sex, and race/ethnicity (non-Hispanic white, non-Hispanic black, Mexican American), and covariate-adjusted geometric means were computed by using a model that included these demographic and other dietary factors, as well as survey year and any significant interaction terms.Results: These nationally representative data for the adult US population show that TFA concentrations were 54% lower in NHANES 2009-2010 than in NHANES 1999-2000. Covariate-adjusted geometric means for the sum of the 4 TFAs were 81.4 µmol/L (95% CI: 77.3, 85.6 µmol/L) and 37.8 µmol/L (95% CI: 36.4, 39.4 µmol/L) in NHANES 1999-2000 and 2009-2010, respectively. Even with the large decline in TFA concentrations, differences between demographic subgroups were comparable in the 2 surveys.Conclusion: The results indicate an overall reduction in TFA concentrations in the US population and provide a valuable baseline to evaluate the impact of the recent regulation categorizing TFAs as food additives.

LC-MS/MS quantitation of mercapturic acid conjugates of lipid peroxidation products as markers of oxidative stress.

Oxidative stress-induced lipid peroxidation (LPO) leads to the formation of cytotoxic and genotoxic 2-alkenals. LPO products such as 4-hydroxy-2(E)-nonenal (HNE) and 4-oxo-2(E)-nonenal (ONE) have been the subject of many studies due to their association with the development of cardiovascular and neurodegenerative diseases, as well as cancer. LPO products are excreted in the urine after conjugation with glutathione (GSH) and subsequent metabolism to mercapturic acid (MA) conjugates. Urinary LPO-MA metabolites are stable end-product metabolites and have gained interest as non-invasive in vivo biomarkers of oxidative stress. This protocol describes a method for the quantitative analysis of LPO-MA metabolites in urine using isotope-dilution liquid chromatography coupled with electrospray tandem mass spectrometry (LC-MS/MS). Included are protocols for preparation of labeled LPO-MA conjugates from unlabeled LPO products and deuterium labeled MA.

Vitamin C supplementation lowers urinary levels of 4-hydroperoxy-2-nonenal metabolites in humans.

The lack of suitable biomarkers of oxidative stress is a common problem for antioxidant intervention studies in humans. We evaluated the efficacy of vitamin C supplementation in decreasing biomarkers of lipid peroxidation in nonsmokers and in cigarette smokers, a commonly studied, free-living human model of chronic oxidative stress. Participants received ascorbic acid (500mg twice per day) or placebo for 17 days in a double-blind, placebo-controlled, randomized crossover design study. The urinary biomarkers assessed and reported herein are derived from 4-hydroperoxy-2-nonenal (HPNE) and include the mercapturic acid (MA) conjugates of 4-hydroxy-2(E)-nonenal (HNE), 1,4-dihydroxy-2(E)-nonene (DHN), and 4-oxo-2(E)-nonenol(ONO). Vitamin C supplementation decreased the urinary concentrations of both ONO-MA (p=0.0013) and HNE-MA (p=0.0213) by ~30%; however, neither cigarette smoking nor sex affected these biomarkers. In contrast, vitamin C supplementation decreased urinary concentrations of DHN-MA (three-way interaction p=0.0304) in nonsmoking men compared with nonsmoking women (p<0.05), as well as in nonsmoking men compared with smoking men (p<0.05). Vitamin C supplementation also decreased (p=0.0092) urinary total of metabolites by ~20%. Thus, HPNE metabolites can be reduced favorably in response to improved plasma ascorbic acid concentrations, an effect due to ascorbic acid antioxidant function.

Quantitation of mercapturic acid conjugates of 4-hydroxy-2-nonenal and 4-oxo-2-nonenal metabolites in a smoking cessation study.

The breakdown of polyunsaturated fatty acids (PUFAs) under conditions of oxidative stress results in the formation of lipid peroxidation (LPO) products. These LPO products such as 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE) can contribute to the development of cardiovascular and neurodegenerative diseases and cancer. Conjugation with glutathione, followed by further metabolism to mercapturic acid (MA) conjugates, can mitigate the effects of these LPO products in disease development by facilitating their excretion from the body. We have developed a quantitative method to simultaneously assess levels of 4-oxo-2-nonen-1-ol (ONO)-MA, HNE-MA, and 1,4-dihydroxy-2-nonene (DHN)-MA in human urine samples utilizing isotope-dilution mass spectrometry. We are also able to detect 4-hydroxy-2-nonenoic acid (HNA)-MA, 4-hydroxy-2-nonenoic acid lactone (HNAL)-MA, and 4-oxo-2-nonenoic acid (ONA)-MA with this method. The detection of ONO-MA and ONA-MA in humans is significant because it demonstrates that HNE/ONE branching occurs in the breakdown of PUFAs and suggests that ONO may contribute to the harmful effects currently associated with HNE. We were able to show significant decreases in HNE-MA, DHN-MA, and total LPO-MA in a group of seven smokers upon smoking cessation. These data demonstrate the value of HNE and ONE metabolites as in vivo markers of oxidative stress.

Mercapturic acid conjugates of 4-hydroxy-2-nonenal and 4-oxo-2-nonenal metabolites are in vivo markers of oxidative stress.

Oxidative stress-induced lipid peroxidation leads to the formation of cytotoxic and genotoxic 2-alkenals, such as 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE). Lipid-derived reactive aldehydes are subject to phase-2 metabolism and are predominantly found as mercapturic acid (MA) conjugates in urine. This study shows evidence for the in vivo formation of ONE and its phase-1 metabolites, 4-oxo-2-nonen-1-ol (ONO) and 4-oxo-2-nonenoic acid (ONA). We have detected the MA conjugates of HNE, 1,4-dihydroxy-2-nonene (DHN), 4-hydroxy-2-nonenoic acid (HNA), the lactone of HNA, ONE, ONO, and ONA in rat urine by liquid chromatography-tandem mass spectrometry comparison with synthetic standards prepared in our laboratory. CCl(4) treatment of rats, a widely accepted animal model of acute oxidative stress, resulted in a significant increase in the urinary levels of DHN-MA, HNA-MA lactone, ONE-MA, and ONA-MA. Our data suggest that conjugates of HNE and ONE metabolites have value as markers of in vivo oxidative stress and lipid peroxidation.