European Journal of Nutrition (v.46, #8)

Protective effects of taurine on endothelial cells impaired by high glucose and oxidized low density lipoproteins by Gudrun Ulrich-Merzenich; Heike Zeitler; Hans Vetter; Ramesh R. Bhonde (431-438).
Endothelial dysfunction, common to diabetes and cardiovascular diseases, is an early step in the development of atherosclerosis and diabetic angiopathies. Deficiencies of taurine have been related to diabetes and cardiovascular diseases.We investigated whether taurine provides protective action against endothelial dysfunction induced by hyperglycemia and/or oxidized low density lipoproteins (oxLDL).Quiescent human umbilical cord venous endothelial cells were exposed for 20 h to high glucose (35 mM) and/or oxLDL (60 µg/ml) alone and in presence of taurine (0.5–2.5 mg/ml). Apoptosis, caspase-3 activity, soluble(s) and cell surface expressions of vascular cellular (VCAM-1) and intercellular (ICAM-1) adhesion molecules were determined. Results are given as a percentage of the low glucose medium control. Apoptosis, VCAM-1 and ICAM-1 expressions were related to cell number.Hyperglycemia increased apoptosis to 162.5 ± 19.2%, caspase-3 activity to 153.2 ± 10.3%, cell-surface exp ression of VCAM-1 to 125.1 ±  5.8%, the expression of ICAM-1 to 123.7 ± 2.8% and sICAM-1 to 146.5 ± 7.9%. Taurine (0.5–2.5  mg/ml) restored apoptosis, caspase-3 activity and expressions of VCAM-1 and ICAM-1. OxLDL (60 µg/ml) increased apoptosis to 114.8 ± 3.1%; taurine (2.5 mg/ml) reduced this apoptosis to 40.5 ± 4.1%. The combination of hyperglycemia and oxLDL increased apoptosis to 211.7 ±  11.6%. This increase was normalized by taurine (2.5 mg/ml) to 97.9 ± 12.8%.Taurine protects HUVECs from endothelial dysfunction induced by hyperglycemia through down-regulation of apoptosis and adhesion molecules. Counteracting the combination of oxLDL and hyperglycemia requires pharmacological concentrations of taurine.
Keywords: taurine; endothelium; oxLDL; diabetes; apoptosis; adhesion molecules

The impact of a meat- versus a vegetable-based diet on iron status in women of childbearing age with small iron stores by Inge Tetens; Karen M. Bendtsen; Marianne Henriksen; Annette K. Ersbøll; Nils Milman (439-445).
Single-meal and short-term studies have shown an enhancing effect of meat on iron absorption, but there are few interventions of longer duration comprising measurements of biomarkers of iron status. To assess the impact of a meat-based and a vegetable-based diet on iron status of women of childbearing age.For 20 weeks, 57 women aged 19–39 years with low iron stores (serum ferritin ≤30 μg/l and haemoglobin ≥120 g/l) consumed either a meat-based or a vegetable-based diet. Haemoglobin and serum ferritin concentrations were measured at baseline, after 10 and 20 weeks. Information about dietary intake before and during intervention, meat/fish intake, menstruation and contraceptive methods were recorded.The women who consumed the meat-based diet had a significantly (P < 0.001) higher intake of meat/fish, 152 (147–168) g/day (median (Q1–Q3)) compared to the women consuming the vegetable-based diet 31 (24–36) g/day, while the total iron intake was similar in the two groups (mean ± SE) 11.0 ± 0.5 and 12.3 ± 0.3/day mg/day, respectively. Serum ferritin remained unchanged in women on the meat-based diet (n = 29)(before intervention (median (Q1–Q3)): 16.3 (12.7–25.3) μg/l and after intervention: 16.5 (10.3–25.3) μg/l, but declined from 17.3 (10.9–23.7) to 11.2 (8.8–14.6) μg/l (P < 0.001) in women on the vegetable-based diet (n = 28).Our results emphasize the importance of the delicate balance between dietary iron content and iron bioavailability for the maintenance of blood indicators of iron stores in women with initially low iron status.
Keywords: bioavailability; haemoglobin; serum ferritin; meat-factor

Effects of orange juice and proline betaine on glycine betaine and homocysteine in healthy male subjects by Wendy Atkinson; Pamela Downer; Dr. Michael Lever; Stephen T. Chambers; Peter M. George (446-452).
Proline betaine (PB), a glycine betaine (GB) analogue found in citrus foods, increases urinary GB loss and plasma total homocysteine (tHcy) concentrations in rats. Its presence in human plasma is associated with increased GB excretion.To compare the effects of dietary levels of PB on GB excretion, and on plasma tHcy and GB concentrations in healthy volunteers.In a randomized crossover study, eight healthy males (18–50 years) ingested either 750 mL orange juice (containing 0.545 g PB), a PB supplement (0.545 g PB dissolved in 750 mL apple juice), or 750 mL apple juice (control). Plasma PB, GB and tHcy, and urine PB, GB and creatinine concentrations were measured hourly for 6 h and at 24 h post-treatment.Plasma tHcy concentrations were not increased (relative to control) following ingestion of either orange juice or PB supplement. Both treatments produced a significant increase in plasma PB concentrations (P < 0.001), this effect being greater following orange juice compared with PB supplement (P < 0.05, 1–2 h). Urinary excretion of PB was greater than the control following both orange juice (P < 0.001) and PB supplement (P < 0.001), from 2 to 24 h post-treatment. This increase in PB excretion was significantly greater following orange juice compared with PB supplement with higher peak excretion (C max difference, P = 0.008). GB excretion was significantly greater following ingestion of orange juice compared with PB in apple juice (P = 0.007) and apple juice control (P < 0.001) in the first 2 h post-ingestion.PB administered in dietary doses had little effect on plasma tHcy concentrations in healthy humans. Ingestion of PB in orange juice compared with PB alone resulted in greater increases in the urinary excretion of PB and GB.
Keywords: proline betaine (PB); glycine betaine (GB); total homocysteine (tHcy); orange juice; methionine load test

Both aluminum and polyphenols in green tea decoction (Camellia sinensis) affect iron status and hematological parameters in rats by Neila Marouani; Adel Chahed; Abderrazek Hédhili; Prof. Dr. Mohamed Hédi Hamdaoui (453-459).
Green tea leaves naturally contain high levels of polyphenols and aluminum (Al). Polyphenols in green tea decoction are considered to be one of the major factors responsible of low iron status. However, the effects of Al from green tea decoction on iron status and hematological parameters remained unclear.The objective was to investigate the Al absorption from green tea decoction and studied its influence on iron status and hematological parameters in rats.During the experiment period, rats were given the experimental diet + a simple dose of Al sulfate with or without graded doses of green tea decoction (25, 50 and 100 g/l). The Al absorption was evaluated in the serum; however, iron status was evaluated by the iron concentration in the liver, kidney, spleen and femur. In addition, the hemoglobin and hematocrit were evaluated.Our results showed that the serum Al significantly increased between 61.5 and 342%, as tea doses-dependant. The Al sulfate significantly decreased the reserve of iron in all studied organs between 21.7 and 17% (P < 0.05). In groups receiving green tea decoction alone or Al + graded doses of tea, the reserve of iron significantly decreased in all studied organs between 59.4 and 18.5% (P < 0.01). Al alone or associated with drinking doses of tea significantly decreased hemoglobin concentration between 23.6 and 9% (P < 0.05) and hematocrit between 12.7 and 7% (P < 0.01).Our data showed that Al from green tea decoction was more absorbed in the serum than Al sulfate. Al absorption was associated with low iron status and reduction of hemoglobin and hematocrit. Considering that Al competes with iron in different stage of erythropoiesis including transferrin binding, so we could assume that the negative effect of tea on iron status arises not only from polyphenols iron complexes but also from Al released in tea decoction.
Keywords: green tea decoction; Al absorption; iron status; hematological parameters

Impact of fish intake on oxidative stress when included into a moderate energy-restricted program to treat obesity by Dolores Parra; Narcisa M. Bandarra; Mairead Kiely; Inga Thorsdottir; Prof. J. Alfredo Martínez (460-467).
The role of some nutritional factors and hypocaloric diets on oxidative balance is a matter of debate, especially related to the prevention and treatment of obesity and co-morbidities.The aim was to investigate the antioxidant capacity of different energy restricted diets in the treatment of obesity, paying emphasis to the effect of incorporating omega-3 fatty acids with or without other seafood components.The study was a randomized 8-weeks parallel intervention trial prescribed to lose weight, which was implemented in 276 subjects aged 31.4 ± 5.4 y.o. following four different balanced hypocaloric diets (TEE-30%): fish-restricted (control), cod and salmon based diets and DHA+EPA supplemented administration. At baseline (day 0) and at the end of the trial (day 56), anthropometry, dietary intake, erythrocyte membrane fatty acid content, circulating malondialdehyde (MDA) and plasma antioxidant status (AOP) were determined.Overall, percent weight loss was −5.8 ± 3.2% (P < 0.001) and the AOP statistically increased after the energy restriction period (P = 0.015), basically due to the seafood-based diets. In contrast, MDA statistically only decreased (P = 0.026) after the cod-based diet intake with no changes after the other nutritional treatments. In fact, the cod-based intervention statistically decreased oxidative stress when expressed as the MDA/AOP ratio (P = 0.006).A moderate calorie-restricted cod-based diet was found as a useful strategy to lose weight, which was accompanied by a specific improvement on oxidative stress markers. The low saturated fat content and the seafood protein source of this diet may be important factors involved in these findings.
Keywords: obesity; oxidative stress; weight loss; PUFA; MDA

Comparison of lycopene and tomato effects on biomarkers of oxidative stress in vitamin E deficient rats by Delphine Gitenay; Bernard Lyan; Mathieu Rambeau; Andrzej Mazur; Edmond Rock (468-475).
Cohort studies suggested that individuals with higher intake of tomatoes and tomato products have a lower risk of degenerative diseases. Lycopene, an antioxidant and antiproliferative carotenoid, has been hypothesized to be responsible for the health benefits of tomatoes. However, studies demonstrated a higher potential of tomatoes compared to lycopene to reduce oxidative stress or carcinogenesis.Our study aimed at distinguishing lycopene effect from that of tomato on oxidative stress, by using yellow tomato, a tomato variety devoid of lycopene.Effects of feeding with none (control), 16% freeze-dried yellow tomato (YT), 16% freeze-dried red tomato (RT) or 0.05% lycopene beadlets (LB) were compared in a rat model with mild oxidative stress induced by low vitamin E diet (LVED). Four groups of 10 rats were fed ad libitum for 6 weeks. Physiological parameters such as ingesta, body, spleen and liver weights, cholesterol and triglycerides (TG) levels were assessed. Lycopene and vitamin E concentrations and oxidative stress biomarkers were measured in the plasma and/or liver and/or heart tissue of the rats.RT, YT, and LB had no effect on rats’ ingesta, body and spleen weights. RT, YT and LB had no effect on plasma cholesterol concentration. RT decreased TG level compared to control, YT and LB (P < 0.05). Rats fed RT or LB accumulated lycopene in plasma in contrast with rats fed YT. Heart level of thiobarbituric reactive species (TBARS) in rats fed RT or YT was lower than that in the control and the LB fed rats (P < 0.05). Despite similar concentrations of lycopene in plasma and liver, rats fed LB showed a significantly higher heart level of TBARS than rats fed tomatoes. RT increased erythrocyte superoxide dismutase (eSOD) activity compared with LB and nitric oxide (NO) level compared with control and LB. LB decreased ferric reducing ability of plasma (FRAP) level compared with control, RT and LB (P < 0.05).Our study showed for the first time that tomatoes, containing or not containing lycopene, have a higher potential than lycopene to attenuate and or to reverse oxidative stress-related parameters in a mild oxidative stress context.
Keywords: tomato; lycopene; oxidative stress; vitamin E

The inverse association of peanut consumption and risk markers of CHD (lipids) has been reported however health professionals are still concerned whether hyperlipidemic subjects advised to eat peanuts will have increased serum lipid levels. Tissue factor (TF), the major regulator of normal haemostasis and thrombosis, plays a critical role in haemostasis in all tissues.To investigate the effects of peanut consumption on lipid profile, blood Glutathione (GSH), thiobarbituric acid reactive substances (TBARS), haematologic parameters and TF activities in rats fed a high-cholesterol diet.32 Wistar Albino rats were divided into 4 groups of 8 rats each: 1-Control 2-Control+peanut 3-Hyperlipidemic and 4-Hyperlipidemic+peanut group. At the end of 12 weeks, blood samples were used to evaluate lipid profile, haemostatic parameters, GSH, TBARS and tissue samples were used for the determination of TF activities.Peanut consumption increased blood GSH both in the control and hyperlipidemic groups; increased HDL-cholesterol and decreased TBARS in the hyperlipidemic group. The addition of peanut to the diet did not change blood lipids, protrombin time, activated partial thromboplastin time or fibrinogen levels significantly both in the control and hyperlipidemic groups. It affected TF activities differently in both groups. It decreased brain and aorta TF activity but increased spleen and kidney TF activity in the control group. It led to significant increases in the TF activity of kidney, spleen and aorta and a significant decrease in the TF activity of brain in the hyperlipidemic group.Peanut consumption improved GSH and HDL-C levels and decreased TBARS, without increasing other blood lipids in experimental hyperlipidemia. Nevertheless the mechanism of the effect of peanut consumption on the TF activity of tissues remains to be determined.
Keywords: hyperlipidemia; lipids; peanut; rat; tissue factor