Food sources of individual plasma phospholipid trans fatty acid isomers: the Cardiovascular Health Study

Abstract

Background: The overall consumption of trans fatty acids (TFAs) increases the risk of coronary artery disease. However, multiple TFA isomers exist, each with potentially different health effects. Different food sources of these specific TFA isomers are not well established.

Objective: Our objective was to determine the major independent food sources of specific TFA isomers.

Design: We investigated relations of major potential food sources of TFAs, as assessed by serial food-frequency questionnaires, with 10 plasma phospholipid TFA isomers [5 trans (t-) 18:1, 3 t-18:2, and 2 t-16:1] in 3330 older adults in the Cardiovascular Health Study, a community-based multicenter cohort. Stepwise regression was used to identify independent major food sources of individual plasma phospholipid TFA isomers, which were adjusted for demographic, lifestyle, and dietary factors.

Results: All 5 t-18:1 isomers were similarly associated with foods commonly made with partially hydrogenated vegetable oils (PHVOs), including biscuits (0.51 higher SD of total 18:1 fatty acid concentrations per serving/d, P < 0.01), chips and/or popcorn (0.33 higher SD per serving/d, P = 0.02), margarine (0.32 higher SD per serving/d, P < 0.001), fried foods (0.32 higher SD per serving/d, P = 0.04), and bakery foods (0.23 higher SD per serving/d, P = 0.02). Each of the t-18:2 isomers were associated only with bakery foods (0.50 higher SD of total 18:2 fatty acid concentrations per serving/d, P < 0.001). Ruminant foods were major correlates of t-16:1n-7, including red meats (0.72 higher SD per serving/d, P < 0.001), butter (0.43 higher SD per serving/d, P < 0.001), and higher-fat dairy (0.37 higher SD per serving/d, P < 0.001). In contrast, t-16:1n-9 were derived mainly from margarine (0.31 higher SD per serving/d, P < 0.001).

Conclusions: t-18:1 Isomers are similarly derived from multiple PHVO-containing foods. In contrast, t-18:2 and t-16:1n-9 isomers are derived from more-specific types of PHVO-containing foods. Ruminant foods are major sources of t-16:1n-7. Different TFA isomers and dietary sources should be considered when investigating health effects and interventions to lower TFAs.

FIGURE 1

Representative selection of fatty acid peaks from gas chromatographic analysis in one participant, including the 10 trans fatty acid isomers (*). U1 represents an unknown fatty acid peak.

FIGURE 2

Multivariable-adjusted relations between consumption of specific food groups and plasma phospholipid concentrations of trans fatty acid (TFA) isomers in 3330 men and women in the Cardiovascular Health Study. Values represent SD differences in plasma phospholipid fatty acid concentrations for each serving per day of each food with corresponding CIs based on separate stepwise multivariable regression analyses. Positive relations with P < 0.05 are shown, including between total t-18:1 and biscuits (0.51 higher SD per serving/d, P < 0.01), chips and/or popcorn (0.33 higher SD per serving/d, P = 0.02), margarine (0.32 higher SD per serving/d, P < 0.001), fried foods (0.32 higher SD per serving/d, P = 0.04), and bakery foods (0.23 higher SD per serving/d, P = 0.02); total t-18:2 and bakery foods (0.50 higher SD per serving/d, P < 0.001); t-16:1n−7 and red meats (0.72 higher SD per serving/d, P < 0.001), butter (0.43 higher SD per serving/d, P < 0.001), and higher-fat dairy (0.37 higher SD per serving/d, P < 0.001); and t-16:1n−9 and margarine (0.31 higher SD per serving/d, P < 0.001). In multivariable-adjusted analyses, total processed meats, total lower-fat dairy, and pizza were not associated with any of the plasma phospholipid TFAs. Potential covariates included all food groups shown in the figure and age (y), sex, race (white, nonwhite), education (<high school, high school, >high-school), income (<$16,000/y, $16,000–$34,999/y, ≥$35,000/y), enrollment site (4 sites), self-reported health (3 categories), smoking (never, past, current), alcohol consumption (drinks/wk), leisure-time physical activity (kcal/wk), total energy intake (kcal/d), BMI (in kg/m²), prevalent coronary artery disease, stroke, diabetes, and treated hypertension (yes/no for each). Age, sex, race, education, and total energy consumption were forced in the model.