Plasma coagulation factor VII activity and its corrlates in healthy men

Objective: The aim of this study was to investigate the plasma coagulation factor VII activity and its correlates in healthy Australian men.
Design: Cross-sectional study.
Setting: Free living subjects.
Subjects: A total of 139 healthy Australian males aged 20–55 y with widely varying intakes of individual fatty acids.
Outcome measures: The concentration of phospholipid fatty acids and the parameters of biochemistry were analysed by standard methods. Citrated plasma factor VII activity was measured by using the ACL 200 system with commercially available kits.
Results: In the stepwise multiple regression, controlled for age, body mass index and dietary groups, the two most important variables of factor VII activity were selected in the forward entry model with R2¼0.474 and Po0.0001 from 19 independent variables, which were significantly correlated with plasma factor VII activity in age-adjusted bivariate analysis where significance was considered at Po0.01. Plasma factor VII activity was strongly negatively correlated with prothrombin time (PT) (Std. Coeff. -0.550), and significantly positively correlated with plasma phospholipid (PL) stearic acid (Std. Coeff. 0.285).
Conclusions: Increased factor VII activity was associated with shortening of PT. All types of fatty-acid concentrations of PLs were
significantly positively correlated with factor VII activity; however, stearic acid was more potent than other fatty acids in healthy Australian men.
Sponsorship: Meat Research Corporation of Australia.

Effects of dietary constituents on coronary heart disease risk factors

Coronary Heart Disease (CHD) is a major cause of death in Western countries. Mediterranean and Asian populations have a lower risk of death from CHD compared to Westernised population, as do vegetarian versus omnivorous populations. Dietary constituents of traditional diets consumed by these populations are thought to influence both the classical risk factors for CHD, and the more recently identified risk factors, such as oxidative modification of low density lipoprotein (LDL), LDL particle size, arterial compliance and haemostatic factors. The aim of this thesis was to examine the effects of several food components, particularly soybean and monounsaturated fat (MUFA), on CHD risk factors through 3 carefully controlled dietary interventions, and a cross-sectional study. A randomised crossover dietary intervention study was conducted in 42 healthy males to investigate the effect on CHD risk factors of replacing lean meat with tofu, a soybean product regularly consumed by Asian populations, while controlling all other dietary factors. The tofu diet resulted in significantly lower total cholesterol and triacylglycerol levels compared to the lean meat diet, and LDL particles that were more resistant to in vitro oxidative modification. However, insulin, fibrinogen, factor VII, and lipoprotein (a) were not significantly different on the 2 diets. A postprandial study was subsequently conducted to investigate any acute effects of a tofu test meal on the oxidative modification of LDL in 16 male subjects. There was no significant difference between the susceptibility of LDL to oxidative modification before and after the tofu meal. Twenty eight healthy subjects completed a separate randomised crossover dietary intervention comparing a high MUFA fat diet, using an Australian high oleic sunflower oil, with a low fat, high carbohydrate diet on CHD risk factors. The high MUFA oil diet significantly increased high density lipoprotein cholesterol compared to the low fat diet as well as producing LDL that were more resistant to oxidative modification. Neither the size of the LDL particle nor arterial compliance were significantly different on the 2 diets. Twelve matched pairs of vegetations and omnivores were also studies to compare the habitual diet of a low and higher risk population group, to compare their risk factors and identify dietary constituents that may explain the differences. The vegetarians consumed less saturated fat (SFA) and dietary cholesterol while consuming more polyunsaturated fat, dietary fibre and vitamin E compared to omnivores. The vegetarians had lower total cholesterol, LDL cholesterol and triacylglycerol levels compared to the omnivores and had LDL particles that were more resistant to in vitro oxidation. These findings contribute to our knowledge about the dietary constituents that can alter some CHD risk factors in healthy subjects, and which could reduce the risk of developing CHD. Investigations in high risk groups might reveal even more benefits.