This study was aimed at determining whether an increase of 5 portions of fruits and vegetables in the form of soups and beverages has a beneficial effect on markers of oxidative stress and cardiovascular disease risk factors. The study was a single blind, randomized, controlled, crossover dietary intervention study. After a 2-wk run-in period with fish oil supplementation, which continued throughout the dietary intervention to increase oxidative stress, the volunteers consumed carotenoid-rich or control vegetable soups and beverages for 4 wk. After a 10-wk wash-out period, the volunteers repeated the above protocol, consuming the other intervention foods. Both test and control interventions significantly increased the % energy from carbohydrates and decreased dietary protein and vitamin B-12 intakes. Compared with the control treatment, consumption of the carotenoid-rich soups and beverages increased dietary carotenoids, vitamin C, alpha-tocopherol, potassium, and folate, and the plasma concentrations of alpha-carotene (362%), beta-carotene (250%) and lycopene (31%) (P < 0.01) and decreased the plasma homocysteine concentration by 8.8% (P < 0.01). The reduction in plasma homocysteine correlated weakly with the increase in dietary folate during the test intervention (r = -0.35, P = 0.04). The plasma antioxidant status and markers of oxidative stress were not affected by treatment. Consumption of fruit and vegetable soups and beverages makes a useful contribution to meeting dietary recommendations for fruit and vegetable consumption.
The average UK adult consumes less than three portions of fruit and vegetables daily, despite evidence to suggest that consuming five portions daily could help prevent chronic diseases. It is recommended that fruit juice should only count as one of these portions, as juicing removes fibre and releases sugars. However, fruit juices contain beneficial compounds such as vitamin C and flavonoids and could be a useful source of dietary phytochemicals. Two randomised controlled cross-over intervention studies investigating the effects of chronic and acute consumption of commercially-available fruit-and vegetable-puree-based drinks (FVPD) on bioavailability, antioxidant status and CVD risk factors are described. Blood and urine samples were collected during both studies and vascular tone was measured using laser Doppler imaging. In the chronic intervention study FVPD consumption was found to significantly increase dietary carotenoids (P = 0 . 001) and vitamin C (P = 0 . 003). Plasma carotenoids were increased (P = 0 . 001), but the increase in plasma vitamin C was not significant. There were no significant effects on oxidative stress, antioxidant status and other CVD risk factors. In the acute intervention study FVPD were found to increase total plasma nitrate and nitrite (P = 0 . 001) and plasma vitamin C (P = 0 . 002). There was no effect on plasma lipids or uric acid, but there was a lower glucose and insulin peak concentration after consumption of the FVPD compared with the sugar-matched control. There was a trend towards increased vasodilation following both chronic and acute FVPD consumption. All volunteers were retrospectively genotyped for the eNOS G298T polymorphism and the effect of genotype on the measurements is discussed. Overall, there was a non-significant trend towards increased endothelium-dependent vasodilation following both acute and chronic FVPD consumption. However, there was a significant time · treatment effect (P < 0 . 05) of acute FVPD consumption in individuals with the GG variant of the eNOS gene. Carotenoids: Flavonoids: CVD: Laser Doppler imagingCVD is one of the major causes of death in Europe and is responsible for 4 . 3 · 10 6 deaths each year across the continent (1) . One of the emerging risk factors for CVD is dysfunction of the endothelium (2,3) , which is characterised by a reduction in the bioavailability of vasodilators, predominantly NO, endothelium-derived hyperpolarizing factor and prostacyclin, and an increase in endothelium-derived vasoconstrictors, e.g. thromboxane A 2 , PGH 2 and endothelin 1 (2) . Endothelial dysfunction can be assessed by measuring enhanced and maintained endothelial activation and impaired endothelium-dependent vasodilation (4) .Endothelial activation is determined by an increase in the plasma concentrations of soluble cell adhesion molecules, such as intercellular adhesion molecule-1, vascularAbbreviations: atRA, all-trans-retinoic acid; eNOS, endothelial NO synthase; FVPD, fruit-and vegetable-puree-based drinks.
Epidemiological studies indicate that diets rich in fruits and vegetables (F&V) are protective against CVD. Puréed F&V products retain many beneficial components, including flavonoids, carotenoids, vitamin C and dietary fibres. The present study aimed to establish the physiological effects of acute ingestion of a F&V purée-based drink (FVPD) on vasodilation, antioxidant status, phytochemical bioavailability and other CVD risk factors. A total of twenty-four subjects, aged 30-70 years, completed the randomised, single-blind, controlled, crossover test meal study. Subjects consumed 400 ml of the FVPD, or a fruit-flavoured sugar-matched control, after following a low-flavonoid diet for 5 d. Blood and urine samples were collected throughout the study day, and vascular reactivity was assessed at 90 min intervals using laser Doppler iontophoresis. The FVPD significantly increased plasma vitamin C (P¼ 0·002) and total nitrate/nitrite (P¼ 0·001) concentrations. There was a near significant time by treatment effect on ex vivo LDL oxidation (P¼ 0·068), with a longer lag phase after consuming the FVPD. During the 6 h after juice consumption, the antioxidant capacity of plasma increased significantly (P¼ 0·003) and there was a simultaneous increase in plasma and urinary phenolic metabolites (P,0·05). There were significantly lower glucose and insulin peaks after ingestion of the FVPD compared with control (P¼0·019 and 0·003) and a trend towards increased endothelium-dependent vasodilation following FVPD consumption (P¼ 0·061). Overall, FVPD consumption significantly increased plasma vitamin C and total nitrate/nitrite concentrations, with a trend towards increased endothelium-dependent vasodilation. Puréed F&V products are useful vehicles for increasing micronutrient status, plasma antioxidant capacity and in vivo NO generation, which may contribute to CVD risk reduction.
Scope: Diets low in fruits and vegetables (FV) are responsible for 2.7 million deaths from cardiovascular diseases (CVD) and certain cancers annually. Many FV and their juices contain flavonoids, some of which increase endothelial nitric oxide synthase (eNOS) activity. A single nucleotide polymorphism in the eNOS gene, where thymine (T) replaces guanine (G) at position 894 predicting substitution of glutamate for aspartate at codon 298 (Glu298Asp), has been associated with increased CVD risk due to effects on nitric oxide synthesis and subsequently vascular reactivity. Individuals can be homozygous for guanine (GG), thymine (TT) or heterozygous (GT). Methods and results:We investigated the effects of acute ingestion of a FV-puree-baseddrink (FVPD) on vasodilation and antioxidant status in subjects retrospectively genotyped for this polymorphism. Healthy volunteers (n = 24; 11 GG, 11 GT, 2 TT) aged 30-70 were recruited to a randomized, controlled, crossover, acute study. We showed that acute consumption of 400 mL FVPD differentially affected individuals depending on their genotype. There was a significant genotype interaction for endothelium-dependent vasodilation measured by laser Doppler imaging with iontophoresis (P < 0.05) and ex vivo low-density lipoproteins (LDL) oxidation (P = 0.002). GG subjects had increased endothelium-dependent vasodilation 180 min (P = 0.028) and reduced ex vivo LDL oxidation (P = 0.013) after 60 min after FVPD compared with control, no differences were observed in GT subjects. Conclusion: eNOS Glu298Asp genotype differentially affects vasodilation and ex vivo LDL oxidation after consumption of FV in the form of a puree-based drink.
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