Grape Polyphenols Exert a Cardioprotective Effect in Pre- and Postmenopausal Women by Lowering Plasma Lipids and Reducing Oxidative Stress

Abstract

To evaluate the effects of grape polyphenols on plasma lipids, inflammatory cytokines, and oxidative stress, 24 pre- and 20 postmenopausal women were randomly assigned to consume 36 g of a lyophilized grape powder (LGP) or a placebo for 4 wk. The LGP consisted of 92% carbohydrate and was rich in flavans, anthocyanins, quercetin, myricetin, kaempferol, and resveratrol. After a 3-wk washout period, subjects were assigned to the alternate treatment for an additional 4 wk. The placebo consisted of an equal ratio of fructose and dextrose and was similar in appearance and energy content (554 kJ) to LGP. Plasma triglyceride concentrations were reduced by 15 and 6% in pre- and postmenopausal women, respectively (P < 0.01) after LGP supplementation. In addition, plasma LDL cholesterol and apolipoproteins B and E were lower due to LGP treatment (P < 0.05). Further, cholesterol ester transfer protein activity was decreased by approximately 15% with intake of LGP (P < 0.05). In contrast to these beneficial effects on plasma lipids, LDL oxidation was not modified by LGP treatment. However, whole-body oxidative stress as measured by urinary F(2)-isoprostanes was significantly reduced after LGP supplementation. LGP also decreased the levels of plasma tumor necrosis factor-alpha, which plays a major role in the inflammation process. Through alterations in lipoprotein metabolism, oxidative stress, and inflammatory markers, LGP intake beneficially affected key risk factors for coronary heart disease in both pre- and postmenopausal women.

Grapes and Cardiovascular Disease

“…Red wine consumption in healthy subjects also reduced urinary levels of prostoglandin F2-a, a marker of systemic lipid peroxidation (42). A similar effect on urinary isoprostane concentrations were observed in pre-and postmenopausal women following treatment with lyophilized grape powder for 4 wk (43). At the present time, no study, to our knowledge, has shown a relation between polyphenol consumption and reduced atherosclerosis in humans.…”

Grape products and cardiovascular disease risk factors

“…For instance, red wine or red wine polyphenol supplementation to rats increased apoA1 and reduced apoB (59,61) . Similarly, the same effects were produced by the intake of freeze-dried grapes or concentrated grape juice by menopausal women or by healthy and haemodialysed subjects respectively (24,65,68) .…”

“…In the case of LDL-cholesterol, significant reductions have been observed in studies in both animals (13,27) and in human subjects (24,29,33,65,68,69) , although other studies have reported no effect either in animals (11,70) or in human subjects (21,24,47,66,67) .…”

Grape seed proanthocyanidins correct dyslipidemia associated with a high-fat diet in rats and repress genes controlling lipogenesis and VLDL assembling in liver

“…Plasma TG and apolipoprotein B (apoB) levels are reduced by GSPE in normolipidemic rats, 12 and by lyophilized grape powder in postmenopausal women. 13 The lipoprotein profile is also improved in both healthy subjects and hemodialysis patients by concentrated red grape juice.…”