cardio brucia grassi.. e..

[max_power]

Hai letto bene:

These results differ with reported results, which found significant increases in caffeine half-life in vivo. The reasons for the differences between the two studies may be due to a number of different factors, including methodology and subject population.

Sì, ho visionato anche l'ultima parte.

[Gawain]

Ho letto bene ?

Hai letto bene:

These results differ with reported results, which found significant increases in caffeine half-life in vivo. The reasons for the differences between the two studies may be due to a number of different factors, including methodology and subject population.

[max_power]

No, si riferisce allo studio del 2006



Dr. Vukovich hypothesized that a caffeine/naringin combined dosage would increase the half-life of caffeine and further alter metabolic markers and hemodynamic variables. The parameters of interest included oxygen consumption, respiratory exchange ratio, resting energy expenditure, heart rate and blood pressure.
Methodology Caffeine-naïve subjects were studied before and after the ingestion of caffeine (C, 200mg) with and without naringin (100mg or 200mg). Data was collected for 8 hours every half-hour. Parameters measured included resting metabolic rate, heart rate, blood pressure, blood levels of caffeine.
Results The consumption of caffeine significantly increased resting metabolic rate or calories burned at rest. However, the addition of naringin did not further enhance energy expenditure. Furthermore, blood levels of caffeine were not influenced by the co-consumption of naringin. Conclusions Their findings suggest that naringin, when taken in conjunction with caffeine, does not significantly alter caffeine metabolism. This is evidenced by the lack of significance among the trials with all of the predetermined variables. These results differ with reported results, which found significant increases in caffeine half-life in vivo. The reasons for the differences between the two studies may be due to a number of different factors, including methodology and subject population.

Ho letto bene ?

[richard]

No, si riferisce allo studio del 2006



Dr. Vukovich hypothesized that a caffeine/naringin combined dosage would increase the half-life of caffeine and further alter metabolic markers and hemodynamic variables. The parameters of interest included oxygen consumption, respiratory exchange ratio, resting energy expenditure, heart rate and blood pressure.
Methodology Caffeine-naïve subjects were studied before and after the ingestion of caffeine (C, 200mg) with and without naringin (100mg or 200mg). Data was collected for 8 hours every half-hour. Parameters measured included resting metabolic rate, heart rate, blood pressure, blood levels of caffeine.
Results The consumption of caffeine significantly increased resting metabolic rate or calories burned at rest. However, the addition of naringin did not further enhance energy expenditure. Furthermore, blood levels of caffeine were not influenced by the co-consumption of naringin. Conclusions Their findings suggest that naringin, when taken in conjunction with caffeine, does not significantly alter caffeine metabolism. This is evidenced by the lack of significance among the trials with all of the predetermined variables. These results differ with reported results, which found significant increases in caffeine half-life in vivo. The reasons for the differences between the two studies may be due to a number of different factors, including methodology and subject population.

Grazie.

[richard]

Non ci sono review su questi studi.

Richard, di cosa ti occupi ?

max_power

Sono un ricercatore in fisica matematica con una immensa passione per le scienze naturali e la loro applicazione allo sport.

[Gawain]

Chiedo scusa, mi era sfuggito questo post.

Questo commento si riferisce, quindi, esplicitamente allo studio del 1993

"Br J Clin Pharmacol. 1993 Apr;35(4):431-6" ?

No, si riferisce allo studio del 2006



Dr. Vukovich hypothesized that a caffeine/naringin combined dosage would increase the half-life of caffeine and further alter metabolic markers and hemodynamic variables. The parameters of interest included oxygen consumption, respiratory exchange ratio, resting energy expenditure, heart rate and blood pressure.
Methodology Caffeine-naïve subjects were studied before and after the ingestion of caffeine (C, 200mg) with and without naringin (100mg or 200mg). Data was collected for 8 hours every half-hour. Parameters measured included resting metabolic rate, heart rate, blood pressure, blood levels of caffeine.
Results The consumption of caffeine significantly increased resting metabolic rate or calories burned at rest. However, the addition of naringin did not further enhance energy expenditure. Furthermore, blood levels of caffeine were not influenced by the co-consumption of naringin. Conclusions Their findings suggest that naringin, when taken in conjunction with caffeine, does not significantly alter caffeine metabolism. This is evidenced by the lack of significance among the trials with all of the predetermined variables. These results differ with reported results, which found significant increases in caffeine half-life in vivo. The reasons for the differences between the two studies may be due to a number of different factors, including methodology and subject population.

[max_power]

Chiedo scusa, mi era sfuggito questo post.

Questo commento si riferisce, quindi, esplicitamente allo studio del 1993

"Br J Clin Pharmacol. 1993 Apr;35(4):431-6" ?

Non ci sono review su questi studi.

Richard, di cosa ti occupi ?

max_power

[max_power]

Gli studi in questione sono del 1993 e del 2006, rispettivamente: sarebbe interessante sapere se lo studio del 1993 appare citato in bibliografia nello studio del 2006 e possibilmente cosa dicono gli autori riguardo questa eventuale o apparente discordanza.

Già.

max_power

[richard]

Per quanto riguarda le conclusioni dello studio che mi hai postato:

...

These results differ with reported results, which found significant increases in caffeine half-life in vivo. The reasons for the differences between the two studies may be due to a number of different factors, including methodology and subject population.

Chiedo scusa, mi era sfuggito questo post.

Questo commento si riferisce, quindi, esplicitamente allo studio del 1993

"Br J Clin Pharmacol. 1993 Apr;35(4):431-6" ?

[richard]

Gli studi in questione sono del 1993 e del 2006, rispettivamente: sarebbe interessante sapere se lo studio del 1993 appare citato in bibliografia nello studio del 2006 e possibilmente cosa dicono gli autori riguardo questa eventuale o apparente discordanza.

[max_power]

Ti pare poco un aumento dell'emivita di più del 30% ?

Secondo lo stesso studio da te postato sì. Guarda che l'emivita non è l'unico parametro da prendere in considerazione per valutare la potenza della sostanza, ergo alla fine è l'effetto clinico che conta.
Poi comunque, opinioni diverse.

max_power

[Gawain]

Esistono altri studi, in cui si sottolineano le note attività della naringina sulla caffeina, ma andiamo OT

Lacking effect of grapefruit juice on theophylline pharmacokinetics.Fuhr U, Maier A, Keller A, Steinijans VW, Sauter R, Staib AH.
Department of Clinical Pharmacology, University Hospital Frankfurt am Main, Germany.
Grapefruit juice inhibits the biotransformation of several drugs, including caffeine (23% clearance reduction), which is metabolized by the cytochrome P450 isoform CYP1A2. Since CYP1A2 also participates in theophylline biotransformation, a randomized change-over study on a possible interaction between grapefruit juice and theophylline was conducted. Twelve healthy young male nonsmokers were included (median 26 (range 23-30) years, weight 73 (65-85) kg). Theophylline was given as a single dose of 200 mg in solution (Euphyllin 200), diluted by 100 ml of either water or grapefruit juice (751 mg/l naringin). Subsequently, additional fractionated 0.91 of water or juice were administered until 16 hours postdose. Theophylline concentrations in plasma withdrawn up to 24 hours postdose were measured by HPLC, and its pharmacokinetics were estimated using compartment model independent methods. To compare between the 2 treatments, ANOVA based point estimates and 90% confidence intervals (given in parentheses) were calculated for the test (= grapefruit coadministration) to reference (= water coadministration) ratios (Tmax: differences). These were: Cmax 0.90 (0.81-1.00), AUC 1.02 (0.95-1.11), Cmax/AUC 0.88 (0.81-0.95), T 1/2el 1.03 (0.98-1.09), Tmax 0.15 h (-0.11h-0.41 h). Thus, no pharmacokinetic interaction between grapefruit juice and theophylline was observed. This finding is in contrast to the effect of grapefruit juice reported on caffeine metabolism and may be due to the contribution of enzymes other than CYP1A2 to primary theophylline metabolism or to differences in naringin and/or naringenin kinetics between studies.
PMID: 7582380 [PubMed - indexed for MEDLINE]

[Gawain]

.

Lo stesso tuo studio dice che in vivo l'effetto sulla clearance della caffeina è molto piccolo e difatti io stesso ne avevo tenuto conto.

max_power

Ti pare poco un aumento dell'emivita di più del 30% ?

[Gawain]

Per quanto riguarda le conclusioni dello studio che mi hai postato:

Conclusions Their findings suggest that naringin, when taken in conjunction with caffeine, does not significantly alter caffeine metabolism. This is evidenced by the lack of significance among the trials with all of the predetermined variables.

These results differ with reported results, which found significant increases in caffeine half-life in vivo. The reasons for the differences between the two studies may be due to a number of different factors, including methodology and subject population.

[Gawain]

In vivo grapefruit juice (1.2 l day-1 containing 0.5 g l-1 naringin, the glycone form of naringenin) decreased the oral clearance of caffeine by 23% (95% CI: 7%-30%) and prolonged its half-life by 31% (95% CI: 20%-44%) (n = 12). 4.