Plasma lipid changes in young adult couples consuming polyunsaturated meats and dairy products

Cholesterol-lowering potential in human subjects of fat from pigs fed rapeseed oil

The possibility of achieving blood-lipid-lowering characteristics of pig fat by increasing the content of unsaturated fat in pig feed was evaluated. Three pig feeding regimens were applied: basal feed (no added fat or vitamin E), basal feed + rapeseed oil (60 g/kg feed), and basal feed + rapeseed oil (60 g/kg) + vitamin E (200 mg/kg). Meat and meat products from the three pig groups were incorporated into diets providing 86 g pig fat/10 MJ. The diets were served to twelve healthy human male subjects for 3 weeks each in a randomised crossover design. The diets prepared from pigs fed rapeseed oil had a lower content of saturated fatty acids (approximately 9 v. 11 % of energy) and a higher content of polyunsaturated fatty acids (approximately 6 v. 4 % of energy) than the diet prepared from pigs fed the basal feed. Diets based on fat from pigs fed the rapeseed oil resulted in significantly lower (approximately 4 %, P = 0·019) total serum cholesterol concentration compared with the diet from pigs fed the basal feed. No differences were observed in LDL-, HDL- or VLDL-cholesterol, or in triacylglycerol or VLDL-triacylglycerol concentrations. Addition of vitamin E to the pig feed resulted in only a minor increase in vitamin E content in the human subjects' diet and the vitamin E content was low in all three pig diets. Plasma vitamin E concentration in the human subjects at the end of the period with diets from pigs fed rapeseed oil without vitamin E was significantly lower (P = 0·04) than in the other two diet periods. In conclusion, an increased content of rapeseed oil in pig feed changes the fatty acid composition of the pig fat in a way that has a potential to reduce blood cholesterol concentrations in human subjects. However, intake of pig fat with a higher content of unsaturated fatty acids needs to be matched by a higher dietary intake of vitamin E.

Efficacy of a Novel Whey Protein Gel Complex to Increase the Unsaturated Fatty Acid Composition of Bovine Milk Fat

A novel whey protein emulsion gel (WPEG) complex was developed to protect dietary unsaturated fatty acids from rumen biohydrogenation with the goal of modifying the fatty acid composition of milk fat. Three experiments were conducted with WPEG complexes made from either whey protein concentrate containing 80% crude protein, whey protein isolate, or whey protein concentrate high-gel capacity. Each experiment lasted 3 wk. All cows received a basal total mixed ration (TMR). During wk 1 and 3, all cows received only the TMR. During wk 2, 3 control cows received 330 g/d of soybean oil added to the TMR, and the other 3 cows received 330 g/d of soybean oil in one of the WPEG complexes. During wk 2, C18:2 increased from 3.29 to 5.88 g/100 g of fat in Experiment 1, 2.91 to 7.42 g/100 g of fat in Experiment 2, and 3.57 to 6.56 g/100 g of fat in Experiment 3 for WPEG cows. Fatty acid C18:3 increased from 0.51 to 0.84, 0.52 to 1.15, and 0.51 to 0.97 g/100 g of fat for Experiments 1, 2, and 3, respectively, for WPEG cows. Higher proportions of C18:1 trans-9 in milk fat of control cows compared with WPEG cows were seen in all experiments. The proportion of C18:1 trans-11 was also higher in control cows in Experiments 1 and 2, but not in Experiment 3. The WPEG complexes successfully protected unsaturated fatty acids from rumen biohydrogenation and resulted in an increase in the unsaturated fatty acid composition of milk fat produced by Holstein cows without increasing the trans 18-carbon monoenes.

Lipid-lowering effects of a modified butter-fat: a controlled intervention trial in healthy men

OBJECTIVE

To investigate the lipid-lowering potential of a butter-fat modified through manipulations in bovine feeding to increase the unsaturated:saturated fatty acid ratio.

DESIGN

Double-blind, randomised, cross-over intervention trial.

SETTING

University of Auckland Human Nutrition Unit, New Zealand.

SUBJECTS

Twenty healthy, male subjects.

INTERVENTION

A residential trial in which all foods and beverages were provided during two intervention periods, comprising 3 weeks of high unsaturated 'modified' vs. 3 weeks of saturated 'control' butter feeding separated by a 4 week washout. Diets were of typical composition of 39 percentage energy (en%) fat (20 en% butter-fat), 48 en% CHO, 13 en% protein.

RESULTS

There was a significant decrease in both total (P<0.05, -7.9%) and LDL-cholesterol (P<0.01, -9.5%) during modified butter feeding. There was no significant effect of treatment on a range of other risk factors including HDL-cholesterol, triglyceride, apolipoprotein A or B, nonesterified fatty acids (NEFA), haemostatic clotting factor VII and fibrinogen or glucose (P>0.05). Subjects were maintained in energy balance and there was no significant change in body weight during intervention. Butter-fat composition alone differed between treatments.

CONCLUSIONS

A significant improvement in cardiovascular risk can be achieved by moderate changes in dietary fatty acid profile, achieved through a common and well accepted food source, butter-fat.

Fatty acid and triglyceride composition of milk fat from lactating Holstein cows in response to supplemental canola oil

The objective was to determine the influence of dietary lipid on total and sn-2 fatty acid composition and triglyceride structure of milk fat in lactating Holstein cows. Five primiparous Holstein cows surgically fitted with ruminal and duodenal cannulas were used in a 4 x 5 incomplete Latin square. All cows received a basal diet. Treatments consisted of a basal diet with no supplemental canola oil (control), basal diet with canola oil added to the concentrate portion of the diet to provide 1.6% fat, basal diet with 330 g of canola oil infused directly into the rumen, and basal diet with 330 g of canola oil infused directly into the abomasum. Canola oil treatments decreased palmitic acid and increased oleic acid content of milk fat compared with the control. Stearate was higher when canola oil was rumen available compared with control and abomasal infusion. Abomasal infusion increased linoleic and linoleic acids in milk fat compared with the other treatments. The sn-2 fatty acid composition reflected total fatty acid composition. All canola oil treatments reduced palmitic acid and increased oleic acid content at the sn-2 position. Changes in sn-2 composition reflect specificity of the acyl transferases and substrate concentration. Triglyceride composition reported as carbon number was altered by canola oil. Triglycerides in carbon number C50, C52, and C54 were increased while C32, C34, and C36 were decreased.

Fatty acid composition of serum lipid fractions in relation to gender and quality of dietary fat

The fatty acid compositions of serum lipid fractions are believed to reflect the quality of dietary fat, but only a few cross-sectional studies have examined these relationships in a representative free-living population. We related the composition of dietary fat obtained by 7-day food records from 84 free-living middle-aged married couples, on their habitual diets, to gas chromatographic analyses of the percentage compositions of fatty acids in three lipid fractions of fasting sera. Dietary polyunsaturated fat had Pearson's correlation coefficients of 0.63, 0.73 and 0.44 with n-6 polyunsaturated fatty acids in serum cholesteryl esters, triglycerides and phospholipids, respectively. Intake of fish showed correlations of 0.60, 0.36 and 0.52 with the percentage of eicosapentaenoate in the respective fractions. Dietary saturated fat had correlations of 0.57 and 0.54 with saturated fatty acids in serum cholesteryl esters and triglycerides, respectively. Dietary monounsaturated fat did not correlate positively with monounsaturated fatty acids in any serum lipid fraction. There were some small but significant gender differences in the serum fatty acid compositions.

CONCLUSIONS

of the three serum lipid fractions, triglycerides appear to be the best reflectors of dietary polyunsaturated and saturated fat, but the intake of monounsaturated fat is poorly reflected in all serum lipid fractions. Intake of fish is mirrored in all serum lipid fractions, best in cholesteryl esters and phospholipids.

Effects of gene-environment interactions on cardiovascular risk factors in Chinese adolescent twins

A population-based sample of 73 male and 77 female monozygotic (MZ), and 41 male and 33 female dizygotic (DZ) Chinese adolescent twin pairs were studied to assess effects of gene-environment interactions of systolic blood pressure (SBP), diastolic blood pressure (DBP), serum cholesterol and triglyceride levels. Intrapair concordance in BP levels was found to be significantly associated with the interaction of zygosity and salty foods preference and also with that of zygosity and vegetable preference. A consistently positive and statistically significant association was observed between the intrapair difference in serum cholesterol and the interaction of zygosity and animal organ preference; while intrapair concordance in serum cholesterol was associated with the interaction of zygosity and milk consumption. Intrapair difference in serum triglycerides was associated with the interaction of zygosity and fish preference, and a significant association was also found between the intrapair concordance in serum triglycerides and the interaction of zygosity and sweets preference. These observations suggest that the impact of these environmental agents may be influenced by the genotype.