3,166 research outputs found
Effect of animal and industrial trans fatty acids on HDL and LDL cholesterol levels in humans - a quantitative review
No full textBackground: Trans fatty acids are produced either by industrial hydrogenation or by biohydrogenation in the rumens of cows and sheep. Industrial trans fatty acids lower HDL cholesterol, raise LDL cholesterol, and increase the risk of coronary heart disease. The effects of conjugated linoleic acid and trans fatty acids from ruminant animals are less clear. We reviewed the literature, estimated the effects trans fatty acids from ruminant sources and of conjugated trans linoleic acid (CLA) on blood lipoproteins, and compared these with industrial trans fatty acids. Methodology/Principal Findings: We searched Medline and scanned reference lists for intervention trials that reported effects of industrial trans fatty acids, ruminant trans fatty acids or conjugated linoleic acid on LDL and HDL cholesterol in humans. The 39 studies that met our criteria provided results of 29 treatments with industrial trans fatty acids, 6 with ruminant trans fatty acids and 17 with CLA. Control treatments differed between studies; to enable comparison between studies we recalculated for each study what the effect of trans fatty acids on lipoprotein would be if they isocalorically replaced cis mono unsaturated fatty acids. In linear regression analysis the plasma LDL to HDL cholesterol ratio increased by 0.055 (95% CI 0.044-0.066) for each % of dietary energy from industrial trans fatty acids replacing cis monounsaturated fatty acids The increase in the LDL to HDL ratio for each % of energy was 0.038 (95% CI 0.012-0.065) for ruminant trans fatty acids, and 0.043 (95% CI 0.012-0.074) for conjugated linoleic acid (p = 0.99 for difference between CLA and industrial trans fatty acids; p = 0.37 for ruminant versus industrial trans fatty acids). Conclusions/Significance: Published data suggest that all fatty acids with a double bond in the trans configuration raise the ratio of plasma LDL to HDL cholesterol
Effect of a high intake of conjugated linoleic acid on lipoprotein levels in healthy human subjects
No full textBackground -Trans fatty acids are produced either by industrial hydrogenation or by biohydrogenation in the rumens of cows and sheep. Industrial trans fatty acids lower high-density lipoprotein (HDL) cholesterol, raise low-density lipoprotein (LDL) cholesterol, and increase the risk of coronary heart disease. The effects of trans fatty acids from ruminants are less clear. We investigated the effect on blood lipids of cis-9, trans-11 conjugated linoleic acid (CLA), a trans fatty acid largely restricted to ruminant fats. Methodology/Principal Findings - Sixty-one healthy women and men were sequentially fed each of three diets for three weeks, in random order, for a total of nine weeks. Diets were identical except for 7% of energy (approximately 20 g/day), which was provided either by oleic acid, by industrial trans fatty acids, or by a mixture of 80% cis-9, trans-11 and 20% trans-10, cis-12 CLA. After the oleic acid diet, mean (± SD) serum LDL cholesterol was 2.68±0.62 mmol/L compared to 3.00±0.66 mmol/L after industrial trans fatty acids (
The cholesterol-raising diterpenes from coffee beans increase serum lipid transfer protein activity levels in humans
No full textCafestol and kahweol–diterpenes present in unfiltered coffee— strongly raise serum VLDL and LDL cholesterol and slightly reduce HDL cholesterol in humans. The mechanism of action is unknown. We determined whether the coffee diterpenes may affect lipoprotein metabolism via effects on lipid transfer proteins and lecithin:cholesterol acyltransferase in a randomized, double-blind cross-over study with 10 healthy male volunteers. Either cafestol (61–64 mg/day) or a mixture of cafestol (60 mg/day) and kahweol (48–54 mg/day) was given for 28 days. Serum activity levels of cholesterylester transfer protein, phospholipid transfer protein and lecithin:cholesterol acyltransferase were measured using exogenous substrate assays. Relative to baseline values, cafestol raised the mean (±S.D.) activity of cholesterylester transfer protein by 18±12% and of phospholipid transfer protein by 21±14% (both P<0.001). Relative to cafestol alone, kahweol had no significant additional effects. Lecithin:cholesterol acyltransferase activity was reduced by 11±12% by cafestol plus kahweol (P=0.02). It is concluded that the effects of coffee diterpenes on plasma lipoproteins may be connected with changes in serum activity levels of lipid transfer proteins
Effects of fats and fatty acids on blood lipids in humans: an overview.
No full textEffects of fats and fatty acids on blood lipids in humans: an overview. Katan MB, Zock PL, Mensink RP. Department of Human Nutrition, Wageningen Agricultural University, Netherlands. Differences in dietary fatty acid structure induce marked differences in lipid and lipoprotein concentrations in plasma from fasting subjects. Under metabolic-ward conditions, replacement of carbohydrates by lauric, myristic, and palmitic acids raise both low-density-lipoprotein (LDL) and high-density-lipoprotein (HDL) cholesterol whereas stearic acid has little effect. Oleic and linoleic acids raise HDL and slightly lower LDL; all fatty acids lower fasting triglycerides when substituted for carbohydrates. Trans monounsaturates lower HDL and raise LDL and lipoprotein(a). The fatty acids in unhydrogenated fish oil potently lower triglycerides, with variable effects on LDL. Of the commercial fats, palm-kernel and coconut oil are the most hypercholesterolemic, followed by butter and palm oil. Replacement of hard fats rich in lauric, myristic, or palmitic acids or trans fatty acids by unsaturated oils will lower LDL, but replacement by carbohydrates will in addition decrease HDL and increase triglycerides. In free-living subjects, high-oil diets could lead to obesity, undoing the favorable effects on HDL and triglyceride
Replacement of dietary saturated fatty acids by trans fatty acids lowers serum HDL cholesterol and impairs endothelial function in healthy men and women
No full textWe tested whether trans fatty acids and saturated fatty acids had different effects on flow-mediated vasodilation (FMD), a risk marker of coronary heart disease (CHD). Consumption of trans fatty acids is related to increased risk of CHD, probably through effects on lipoproteins. Trans fatty acids differ from most saturated fatty acids because they decrease serum high-density lipoprotein (HDL) cholesterol, and this may increase the risk of CHD. We fed 29 volunteers 2 controlled diets in a 2x4-week randomized crossover design. The "Trans-diet" contained 9.2 energy percent of trans fatty acids; these were replaced by saturated fatty acids in the "Sat-diet." Mean serum HDL cholesterol after the Trans-diet was 0.39 mmol/L (14.8 mg/dL), or 21␕ower than after the Sat-diet (95␌I 0.28 to 0.50 mmol/L). Serum low density lipoprotein and triglyceride concentrations were stable. FMD SD was 4.4±2.3fter the Trans-diet and 6.2±3.0fter the Sat-diet (difference -1.8°95␌I -3.2 to -0.4). Replacement of dietary saturated fatty acids by trans fatty acids impaired FMD of the brachial artery, which suggests increased risk of CHD. Further studies are needed to test whether the decrease in serum HDL cholesterol caused the impairment of FMD
High-oil compared with low-fat, high carbohydrate diets in the prevention of ischemic heart disease.
No full textReducing the intake of saturated fatty acids reduces the risk of coronary disease. This paper reviews the merits of two types of diets reduced in saturated fat. Low-fat, high-carbohydrate diets lower plasma low-density lipoprotein (LDL) but also lower high-density lipoprotein (HDL) concentrations and raise plasma very-low-density lipoprotein. The predicted net effect on coronary risk is zero. Weight loss with low-fat diets is modest and insufficient to offset the fall in HDL. Evidence for other beneficial effects of low-fat diets in incomplete. In contrast, diets low in saturated fat but high in unsaturated oils improve the ratio of HDL to LDL in plasma and thus reduce the predicted coronary risk. Recommendations to reduce total fat intake are therefore too imprecise; guidelines should aim specifically at saturated and probably also at trans fatty acids, whereas recommendations for restriction of cis-unsaturated fatty acids are not supported by firm scientific evidence
Underestimation of energy intake by 3-d records compared with energy intake to maintain body weight in 269 nonobese adults.
No full textUnderestimation of energy intake by 3-d records compared with energy intake to maintain body weight in 269 nonobese adults. de Vries JH, Zock PL, Mensink RP, Katan MB. Department of Human Nutrition, Wageningen Agricultural University, Netherlands. We assessed how accurately participants in dietary trials reported their free-living energy intake. We compared self-reported energy intake, calculated from 3-d food records, with actual intakes needed to maintain body weight during controlled trials lasting 6-9 wk. In 269 free-living healthy male (n = 119) and female (n = 150) adults with mean body weights close to ideal values (mean +/- SD body mass index in kg/m2, 22.1 +/- 2.4), energy intake reported in food records was 1.2 +/- 1.6 MJ/d (277 +/- 378 kcal/d) lower than actual energy requirements during the experiments. The relative bias was significantly smaller (P = 0.01) for men (-8.0 +/- 13.4%) than for women (-12.2 +/- 13.7%). Body mass index, daily energy intake, and age were not significantly related to the extent of underestimation. We conclude that food records systematically underestimate energy needs in young, nonobese well-educated adult
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