Ruminant-produced trans-fatty acids raise plasma HDL particle concentrations in intact and ovariectomized female Hartley guinea pigs.

Cardiovascular disease (CVD) is the leading cause of death among women worldwide, and risk for developing CVD increases postmenopause. Consumption of trans-fatty acids (tFA) has been positively associated with CVD incidence and mortality. The current study was designed to assess the effects of diets high in industrially produced (IP)-tFA, from partially hydrogenated vegetable oils (PHVO), and ruminant-produced (RP)-tFA, from butter oil (BO), on risk factors for CVD. Thirty-two female Hartley guinea pigs, one-half of which were ovariectomized (OVX) to mimic the postmenopausal condition, were fed hypercholesterolemic diets containing 9% by weight PHVO or BO (n = 8/diet and ovariectomy) for 8 wk. The plasma and hepatic lipids did not differ between IP- and RP-tFA groups or between intact and OVX guinea pigs. The BO diet resulted in higher concentrations of plasma total and small HDL particle subclass concentrations than the PHVO diet regardless of ovariectomy status. The intact BO group had higher concentrations of large HDL particles than the intact PHVO group. HDL mean particle size tended to be larger (P = 0.07) in the PHVO groups compared with the BO groups regardless of ovariectomy status. There was a trend toward an interaction between diet and ovariectomy status for LDL mean particle size, which tended to be larger in OVX guinea pigs fed PHVO (P = 0.07). In summary, consumption of IP- and RP-tFA resulted in differential effects on HDL particle subclass profiles in female guinea pigs. The effect of tFA consumption and hormonal status on HDL particle subclass metabolism and the subsequent impact on CVD in females warrants further investigation.

Ruminant-produced trans-fatty acids raise plasma total and small HDL particle concentrations in male Hartley guinea pigs.

Although trans-fatty acid (tFA) intake has been positively associated with coronary heart disease (CHD), the relative effect of consuming industrially produced (IP)- compared with ruminant-produced (RP)-tFA on CHD risk factors is unclear. This study was designed to examine the effects of feeding partially hydrogenated vegetable oil (PHVO), IP-tFA source, and butter oil (BO), RP-tFA source, on the development of atherosclerosis and risk factors associated with CHD. Forty-eight male Hartley guinea pigs were fed a hypercholesterolemic diet containing (9% by weight) PHVO, BO, coconut oil (CO; positive control), or soybean oil (SO; negative control) for 8 or 12 wk (n = 6/group). Morphological analysis revealed that none of the groups developed atherosclerosis. Plasma and hepatic lipids did not differ between the tFA groups, but total and small HDL particles were significantly higher in the BO group than in the PHVO group and mean HDL particle size was significantly smaller in the BO group than in the PHVO group. Compared with the other treatment groups, the SO treatment resulted in significantly lower total cholesterol (TC) and LDL cholesterol in plasma, whereas hepatic TC was significantly higher in the SO group than in the other treatment groups. Plasma and hepatic cholesterol concentrations did not differ between the tFA and CO treatments. These results demonstrate that when fed at a high dose, IP- and RP-tFA had the same effect on established CHD risk factors in male Hartley guinea pigs. The effects of RP-tFA on HDL particle sizes and concentrations warrant further investigation.