Search

Background: Low rates of incident ischemic heart disease (IHD) and cardiac death occur in Spain despite a high prevalence of cardiovascular risk factors. High consumption of unsaturated fatty acid--rich foods, such as olive oil, nuts, and seafood, might underlie this paradox. Objective: We investigated whether serum phosphatidylcholine enrichment in oleic, linoleic, [alpha]-linolenic, and n-3 (omega-3) longchain polyunsaturated fatty acids (as biomarkers of olive oil, seed oil, walnut, and fish intake, respectively) relate to carotid atherosclerosis in Spanish subjects at risk of IHD. Design: In a cross-sectional study, we measured fatty acid concentrations in serum phosphatidylcholine and measured carotid intimamedia thickness (IMT) by using ultrasound in 451 asymptomatic subjects (261 men, 190 women; mean age: 45 y) with primary dyslipidemia. Main and secondary outcomes were mean and maximum IMT in the common carotid artery (CCA) and other carotid segments, respectively. Results: Phosphatidylcholine fatty acid composition was similar to that reported for other Spanish populations. Multiple regression analyses showed that proportions of oleic and docosahexaenoic acids were inversely related to mean CCA IMT (P < 0.02, all) after adjustment for several confounders. In similar models, [alpha]-linolenic acid related inversely to mean and maximum internal carotid artery IMT (P < 0.05 for all). Linoleic and eicosapentaenoic acids were unrelated to IMT. Conclusions: Higher phospholipid proportions of oleic, [alpha]-linolenic, and docosahexaenoic acids showed inverse associations with IMT at specific carotid segments in subjects with primary dyslipidemia. High intakes of healthy fats might explain, in part, the Spanish paradox of low IHD rates in the face of a high burden of cardiovascular risk factors. Am J Clin Nutr 2010;92:186-93. doi: 10.3945/ajcn.2009.28807.

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. Am J Clin Nutr 2010;91:883-93. doi: 10.3945/ajcn.2009.28877.

Background: Plausible biological mechanisms underlie possible associations between fatty acids in blood and risk of prostate cancer; epidemiologic evidence for an association, however, is inconsistent. Objective: The objectives were to assess the association between plasma phospholipid fatty acids and risk of total prostate cancer by stage and grade. Design: This was a nested case-control analysis of 962 men with a diagnosis of prostate cancer after a median follow-up time of 4.2 y and 1061 matched controls who were taking part in the European Prospective Investigation into Cancer and Nutrition. The fatty acid composition of plasma phospholipids was measured by gas chromatography, and the risk of prostate cancer was estimated by using conditional logistic regression with adjustment for lifestyle variables. Results: We found a positive association between palmitic acid and risk of total, localized, and low-grade prostate cancer. The risk of prostate cancer for men in the highest quintile compared with the lowest quintile of palmitic acid was 1.47 (95% CI: 0.97, 2.23; P for trend = 0.032). We found an inverse association between stearic acid and the risk of total, localized, and low-grade prostate cancer; men in the highest quintile of stearic acid had a relative risk of 0.77 (95% CI: 0.56, 1.06; P for trend = 0.03). There were significant positive associations between myristic, [alpha]-linolenic, and eicosapentaenoic acids and risk of high-grade prostate cancer. Conclusion: The associations between palmitic, stearic, myristic, [alpha]-linolenic, and eicosapentaenoic acids and prostate cancer risk may reflect differences in intake or metabolism of these fatty acids between the precancer cases and controls and should be explored further.

To characterize the time course of plasma and red blood cell (RBC) changes after n-3 polyunsaturated fatty acid (PUFA) supplementation, 20 healthy male volunteers were randomly assigned to receive either four 1-g capsules of n-3 PUFA ethyl esters or four 1-g capsules of olive oil (as placebo) for a period of 4 mo, followed by a 3-mo washout period. Fatty acids of plasma and RBC phospholipid fractions were analyzed at 0, 2, and 4 mo of treatment and at 1, 2, and 3 mo of washout. During n-3 PUFA supplementation, accumulations of eicosapentaenoic (EPA), docosapentaenoic (DPA), and docosahexaenoic (DHA) acids were marked after 2 mo with differences among different fractions of plasma and RBCs in further accumulation up to 4 mo. During the first and second months of the washout, slight differences were observed in changes of various fatty acids among different phospholipid fractions, but after 3 mo of washout, only minor alterations were still detectable with respect to pretreatment values. These data confirm the complex relations among different fatty acid pools after n-3 PUFA supplementation. Am J Clin Nutr 1996;63:925-32.

This study was undertaken to examine the effects that consumption of eggs from hens fed diets containing flaxseed would have on plasma and platelet lipids of male volunteers. Feeding diets containing 0%, 10%, and 20% ground flaxseed to Leghorn pullets provided a marked progressive increase in n - 3 fatty acid content as [alpha]-linolenic acid ([alpha]-LNA) (28, 261, and 527 mg/egg) and docosahexaenoic acid (DHA) (51, 81, and 87 mg/egg) but no alteration in the cholesterol concentration of the egg yolk. Twenty-eight male volunteers, divided into three groups, were fed four eggs per day for 2 wk according to a cyclic Latin-square design. No statistically significant changes were observed in total cholesterol, high-density-lipoprotein cholesterol, or plasma triglyceride concentrations. Significant increases in total n - 3 fatty acids and in DHA content (which rose from 1.5 to 2.0 % by wt or 33% overall), and a significant decrease in ratio of n - 6 to n - 3 fatty acids were found in platelet phospholipids of subjects consuming eggs from flaxseed-fed hens. Health and Welfare Canada in 1990 set recommended intakes for dietary n - 3 fatty acids and for the ratio of n - 6 to n - 3 fatty acids, which are not being met currently by the overall population. Eggs modified by the inclusion of flaxseed in the laying hens' diet could provide an important nutritional source of n - 3 fatty acid.