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**Dante Dellamorte** · 04-07-2005, 02:09:00

Originariamente Scritto da Drugo84

io nn ho mai detto che la dose di pro è 30g infatti, ho sempre detto secondo piano dietetico

Si, ma non c'è un "Più o meno" ? E allora uno come fa a sapere quanta prenderne?

**Shura** · 04-07-2005, 07:00:53

Io assumo 1 cpr di vitamina C time relased da 1 gr di vit C l'una!

**Dante Dellamorte** · 04-07-2005, 09:22:28

Dove le prendi?

**lupin III** · 04-07-2005, 10:32:32

Link esatti non ne ho,ho alcuni studi salvati sul PC. Domani ho esami,poi potrei postarli se vi interessano.

Byeeeee

**River** · 04-07-2005, 19:22:10

Attenzione, in un articolo recente si parlno di 90mg di RDA....

**River** · 04-07-2005, 19:26:29

<TABLE cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD>J Am Coll Nutr. 1989 Dec;8(6):636-43.</TD><TD align=right>Related Articles,<SCRIPT language=JavaScript1.2></SCRIPT><SCRIPT language=JavaScript1.2></SCRIPT> Links </TD></TR></TBODY></TABLE>

<DD>
The role of vitamin C in athletic performance.

Gerster H.

Department of Human Nutrition and Health, F. Hoffmann-La Roche and Co, Ltd, Basel, Switzerland.

There is widespread belief among athletes that special nutritional practices--in particular high-protein diets--will enhance their achievements in competition. Supplementation with vitamins, especially vitamin C, is equally popular. But because genetic predisposition, hard physical training and psychological factors play a most important role in determining performance, and because any potential difference in achievement will be small, it is almost impossible to obtain scientific evidence of a beneficial effect of a particular nutrient. There have been many investigations during the past four decades of the potential effect of high-dose vitamin C supplementation on physical performance. The variables used have included maximum oxygen uptake, blood lactic acid levels, and heart rate after exercise, and in some cases performance was assessed in competitive events. The results have been equivocal: Most studies could not demonstrate an effect. On the other hand, a suboptimal vitamin C status results in an impaired working capacity which can be normalized by restoring vitamin C body pools. Athletes, who follow irrational, unhealthy eating patterns often not including vitamin-C-containing fruit and vegetables, are in need of nutrition education.

Publication Types:

Review

</DD>

**River** · 04-07-2005, 19:28:02

<TABLE cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD>Br J Nutr. 2004 Sep;92(3):461-8.</TD><TD align=right>Related Articles,<SCRIPT language=JavaScript1.2></SCRIPT><SCRIPT language=JavaScript1.2></SCRIPT> Links </TD></TR></TBODY></TABLE>

<DD>
Antioxidant vitamin status in high exposure to oxidative stress in competitive athletes.

Rousseau AS, Hininger I, Palazzetti S, Faure H, Roussel AM, Margaritis I.

Laboratoire Nutrition, Vieillissement et Maladies Cardio-vasculaires, Universite Joseph Fourier, Domaine de la Merci, La Tronche, France.

We conducted a cross-sectional study in 118 well-trained athletes to investigate 'high exposure' to sub-deficient antioxidant status, and consequently to oxidative damage, in relation to estimated daily energy expenditure (EE) and dietary antioxidant intake. Subjects completed 7 d food and activity records. Blood samples were obtained on day 8. Of the athletes 81, 60 and 43% had intakes of vitamins E, C and beta-carotene below two-thirds of the French RDA respectively, which is adjusted for EE (FRDAa). The deficit in vitamin E intake was positively correlated with EE (r 0.51, P<0.0001). All the athletes had normal plasma vitamins E and C and 14% had marginal plasma beta-carotene. Plasma thiobarbituric acid-reactive substances (TBARS) did not increase with increased EE. As evidenced by ANOVA, EE-induced vitamin C intakes increased and consequently led to increased plasma ascorbic acid concentrations. In male athletes, plasma total carotenoids were negatively correlated with plasma TBARS concentrations (r -0.31, P<0.006). The relationship between vitamin C intakes and plasma concentrations was logarithmic (r 0.59, P< 0.0001). To summarize, it is not clear whether vitamin E requirements are overestimated with reference to EE in the FRDAa. Daily requirements for vitamin C do not exceed 200 mg. Our present results could be interpreted as meaning that carotenoids play a protective role as exogenous antioxidants. Carotenoid intakes in athletes must be considered carefully.</DD>

**River** · 04-07-2005, 19:30:56

Effects of vitamin E and C supplementation either alone or in combination on exercise-induced lipid peroxidation in trained cyclists.

Bryant RJ, Ryder J, Martino P, Kim J, Craig BW.

Human Performance Laboratory, Ball State University, Munice, Indiana 47306, USA.

Seven trained male cyclists (ate 22.3 +/- 2 years) participated in 4 separate supplementation phases. They ingested 2 capsules per day containing the following treatments: placebo (placebo plus placebo); vitamin C (1 g per day vitamin C plus placebo); vitamin C and E (1 g per day vitamin C plus 200 IU per kg vitamin E); and vitamin E (400 IU per kg vitamin E plus placebo). The treatment order (placebo, vitamin C, vitamin C and E, and vitamin E) was the same for all subjects. Performance trials consisting of a 60-minute steady state ride (SSR) and a 30-minute performance ride (PR) on Cybex 100 Metabolic cycles were performed after each trial. Workloads of 70% of the VO2max were set for the SSR and PR rides, with pedal rate maintained at 90 rpm (SSR) or self determined (PR). Blood samples (5 ml) were drawn pre- and postexercise and analyzed for malonaldehyde (MDA) and lactic acid. The results indicate that vitamin E treatment was more effective than vitamin C alone or vitamin C and E. Pre-exercise plasma levels of MDA in the vitamin E trial was 39% below the pre-exercise MDA levels of the placebo: 2.94 +/- 0.54 and 4.81 +/- 0.65 micromol per ml, respectively. Plasma MDA following exercise in the vitamin E group was also lower than teh placebo: 4.32 +/- 0.37 vs 7.89 +/- 1.0 micromol per ml, respectively. Vitamin C supplementation, on the other hand, elevated both the resting and exercise plasma levels of MDA. None of th supplemental phases had any significant effect on performance. In conclusion, the results indicate that 400 IU/day of vitamin E reduces membrane damage more effectively than vitamin C but does not enhance performance. Athletes are encouraged to include antioxidants, such as vitamin E and C, in their diet to counteract these detrimental effects of exercise. The data presented here suggests that 400 IU/day of vitamin E will provide adequate protection but supplementing the diet with 1 g per day of vitamin C may promote cellular damage. However neither of these vitamins, either alone or in combination, will enhance exercise performance.

Publication Types:

Clinical Trial
Controlled Clinical Trial

**River** · 04-07-2005, 19:33:09

Effect of vitamin C supplements on antioxidant defence and stress proteins in human lymphocytes and skeletal muscle.

Khassaf M, McArdle A, Esanu C, Vasilaki A, McArdle F, Griffiths RD, Brodie DA, Jackson MJ.

Department of Medicine, University of Liverpool, Liverpool L69 3GA, UK.

Oxidative stress induces adaptations in the expression of protective enzymes and heat shock proteins (HSPs) in a variety of tissues. We have examined the possibility that supplementation of subjects with the nutritional antioxidant, vitamin C, influences the ability of lymphocytes to express protective enzymes and HSPs following exposure to an exogenous oxidant and the response of skeletal muscle to the physiological oxidative stress that occurs during exercise in vivo. Our hypothesis was that an elevation of tissue vitamin C content would reduce oxidant-induced expression of protective enzymes and HSP content. Lymphocytes from non-supplemented subjects responded to hydrogen peroxide with increased activity of superoxide dismutase (SOD) and catalase, and HSP60 and HSP70 content over 48 h. Vitamin C supplementation at a dose of 500 mg day-1 for 8 weeks was found to increase the serum vitamin C concentration by ~50 %. Lymphocytes from vitamin C-supplemented subjects had increased baseline SOD and catalase activities and an elevated HSP60 content. The SOD and catalase activities and the HSP60 and HSP70 content of lymphocytes from supplemented subjects did not increase significantly in response to hydrogen peroxide. In non-supplemented subjects, a single period of cycle ergometry was found to significantly increase the HSP70 content of the vastus lateralis. Following vitamin C supplementation, the HSP70 content of the muscle was increased at baseline with no further increase following exercise. We conclude that, in vitamin C-supplemented subjects, adaptive responses to oxidants are attenuated, but that this may reflect an increased baseline expression of potential protective systems against oxidative stress (SOD, catalase and HSPs).

Publication Types:

Clinical Trial
Randomized Controlled Trial

**River** · 04-07-2005, 19:36:59

Effects of alpha-tocopherol, beta-carotene and ascorbic acid on oxidative, hormonal and enzymatic exercise stress markers in habitual training activity of professional basketball players.

Schroder H, Navarro E, Mora J, Galiano D, Tramullas A.

Sports Medicine Barcelona, Department of Nutrition, Spain. helmuts@teleline.es

BACKGROUND: Intense physical exercise has been associated with an increase of free radical production. When the body's natural defense systems against free radicals are overwhelmed, oxidative stress increases. AIM OF THE STUDY: This study examined the effects of a vitamin antioxidant supplement, (composed of 600 mg alpha-tocopherol, 1000 mg ascorbic acid and 32 mg beta-carotene) on oxidative, hormonal, and enzymatic exercise stress markers during habitual training activity over 35 days. METHODS: The plasma concentrations of ascorbic acid, alpha-tocopherol, beta-carotene, testosterone, cortisol and lipid peroxides and the serum activities of lactate dehydrogenase and creatine kinase were measured at four time points: pre-supplementation (PS), pre-training (PT), after training (AT) and 24 h after training (24h-AT) in 13 professional basketball players of the first Spanish Basketball League (ACB). RESULTS: Antioxidant supplementation led to a significant increase of alpha-tocopherol and beta-carotene from PS to PT. Plasma lipid peroxides decreased about 27.7% after 35 days of antioxidant treatment. A significant decrease of lactate dehydrogenase serum activity was observed during the 24 h recuperation time. During this time the anabolic/catabolic balance increased about 29.8% in the antioxidant supplemented group, although this increase did not reach statistical significance. CONCLUSIONS: The results of the present study suggest that supplementation with alpha-tocopherol, beta-carotene and ascorbic acid might partially account for the hormonal and enzymatic stress marker profile observed during habitual training activity of professional basketball players.

Publication Types:

Clinical Trial

**River** · 04-07-2005, 19:44:11

<TABLE cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD>J Nutr Sci Vitaminol (Tokyo). 1999 Apr;45(2):163-71.</TD><TD align=right>Related Articles,<SCRIPT language=JavaScript1.2></SCRIPT><SCRIPT language=JavaScript1.2></SCRIPT> Links </TD></TR></TBODY></TABLE>

<DD>
Contribution of a high dose of L-ascorbic acid to carnitine synthesis in guinea pigs fed high-fat diets.

Otsuka M, Matsuzawa M, Ha TY, Arakawa N.

Department of Nutrition & Food Science, Ochanomizu University, Tokyo, Japan. m220@cc.ocha.ac.jp

Ascorbate is a cofactor of two-enzyme hydroxylation in the pathway of carnitine biosynthesis. The purpose of this study was to investigate the contribution of ascorbate to endogenous carnitine in guinea pigs fed high-fat diets. The contents of carnitine in plasma, urine and tissues of guinea pigs supplemented with L-ascorbic acid were determined and compared with those supplemented with carnitine. Albino-Hartley guinea pigs were fed vitamin C-deficient diets containing lard throughout the experiment. They were administered orally with 5 mg L-ascorbic acid/d/animal for 14 d, and then divided into three groups and administered orally with the following supplements (/d/animal) for 14 d; L (5 mg L-ascorbic acid), LASA (100 mg L-ascorbic acid), and LCAR (10 mg carnitine plus 5 mg L-ascorbic acid). As a control, a normal group was fed vitamin C-deficient diets and administered orally with 5 mg L-ascorbic acid/d/animal for 28 d. The animals fed high-fat diets (L group) had higher free-carnitine contents in the muscle and urine than the normal group. The groups of LCAR and LASA had significantly higher contents of acid-soluble carnitine (p < 0.05) in plasma than the L group. Urinary excretion of carnitine in the LASA group was decreased to the same level as that in the normal group, although no significant difference between the groups of L and LCAR was observed. Moreover, the supplement of ascorbic acid, but not of carnitine, induced a significantly lower content of triacylglycerol in the plasma of the LASA group as compared to the L group (p < 0.05). These data suggest that high doses of ascorbic acid in guinea pigs fed high-fat diets contribute to the enhancement of carnitine synthesis and improvement of the triacylglycerol content in the plasma.
</DD>

**rodolfothebest** · 06-07-2005, 14:26:03

Originariamente Scritto da Dante Dellamorte

Quindi è la solita fregatura, prendi un integratore, ne devi prendere sei scatole al giorno, ecc.?

Ottimo è il multicentrum selecta 50+

**Dante Dellamorte** · 09-07-2005, 00:16:45

Ho preso il c tard, 500 mg per capsula... dite che due al giorno vanno bene? Non ho proprio idea di quanta prenderne...

**River** · 09-07-2005, 13:37:09

Originariamente Scritto da Dante Dellamorte

Ho preso il c tard, 500 mg per capsula... dite che due al giorno vanno bene? Non ho proprio idea di quanta prenderne...

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Vitamina C

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