Trans Fatty Acids and Mortality
There are numerous reports about trans-fatty acids (TFAs) of industrial origin being hazardous to human health. What is the association of TFA intake with mortality in the LURIC (Ludwigshafen Risk and Cardiovascular Health) study?
The LURIC study population was comprised of 3,316 Caucasians hospitalized for coronary angiography in southwestern Germany between 1997 and 2000. The individual FAs measured included trans isomers of C16:1, C18:1, and C18:2. The fatty acid composition of erythrocyte membranes was analyzed using the HS-Omega-3 Index®. Association of TFA with clinical outcome was investigated with Cox proportional hazards regression.
The average German TFA intake in the 1990s was 2.4 g/d, which is below 1% of total energy intake; 79% of this TFA intake was derived from milk and ruminant fat. During a median of 10.0 years of follow-up, a total of 975 (29.9%) study participants died, 614 (18.8%) from cardiovascular causes including 254 (7.8%) sudden cardiac deaths (SCDs). Total TFAs were inversely associated with mortality due to cardiovascular causes or SCD. This was mainly driven by the naturally occurring TFA C16:1n-7t (trans-palmitoleic acid). The reduced risk of SCD associated with C16:1n-7t persisted after multivariate adjustment with a hazard ratio of 0.63 (0.46-0.86) for the third tertile compared with the first tertile. There was no association of any TFA subgroup with an increased risk of adverse outcomes.
In contrast to previous findings, the low concentrations of total TFAs found in LURIC were inversely associated with adverse cardiac outcomes. While the naturally occurring TFAC16:1n-7t was associated with reduced risk, no increased risk was found for industrially produced TFAs.
The findings are not generalizable. TFA concentrations in erythrocyte membranes of study participants were low compared to concentrations reported in the United States at a similar time period. In Europe, the major source of TFAs are dairy ruminents, and intake of industrially produced TFA (hydrogenation of PUFAs) has traditionally been lower than the United States, where major sources are margarines, manufactured cooking oils used in fried foods, and refined carbohydrate products such as pastries.
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