A diet rich in n-3 fatty acids (fish oils) is associated with reduced risks of cardiovascular and metabolic diseases, but the mechanisms remain incompletely understood. Sympathoadrenal activation is postulated to be involved in the pathogenesis of these diseases, and may be inhibited by n-3 fatty acids. We therefore evaluated the effects of a diet supplemented with n-3 fatty acids on the stimulation of the sympathetic nervous system and of stress hormones elicited by a mental stress.
Seven human volunteers were studied on two occasions, before and after 3 weeks of supplementation with 7.2 g/day fish oil. On each occasion, the concentrations of plasma cortisol, and catecholamines, energy expenditure (indirect calorimetry), and adipose tissue lipolysis (plasma non esterified fatty acid concentrations) were monitored in basal conditions followed by a 30 min mental stress (mental arithmetics and Stroop's test) and a 30 min recovery period.
In control conditions, mental stress significantly increased heart rate, mean blood pressure, and energy expenditure. It increased plasma epinephrine from 60.9 +/- 6.2 to 89.3 +/- 16.1 pg/ml (p<0.05), plasma cortisol from 291 +/- 32 to 372 +/- 37 micromol/l (p<0.05) and plasma non esterified fatty acids from 409 +/- 113 to 544 +/- 89 micromol/l (p<0.05). After 3 weeks of a diet supplemented with n-3 fatty acids, the stimulation by mental stress of plasma epinephrine, cortisol, energy expenditure, and plasma non esterified fatty acids concentrations, were all significantly blunted.
Supplementation with n-3 fatty acids inhibits the adrenal activation elicited by a mental stress, presumably through effects exerted at the level of the central nervous system.
7 osobom badano poziom kortyzolu i katecholamin (adrenalini i noradrenaliny) w 2 okazjach
-pozniej 7,2g oleju rybiego (1.1g EPA + 0.7g DHA) przez okres 3 tygodni
uczestniczyli w 30 minutowym tescie aby wywolac stres
katecholaminy (noradrenalina i adrenalina)
czarne kwadarty - po suplementacji 03
biale kwadraty - placebo
po 3 tygodniowej suplementacji 0-3 odpowiedz kortyzolu na stres byla nizsza niz przed suplemetacją
Effects of supplemental fish oil on resting metabolic rate, body composition, and salivary cortisol in healthy adults
To determine the effects of supplemental fish oil (FO) on resting metabolic rate (RMR), body composition, and cortisol production in healthy adults.
A total of 44 men and women (34 ą 13y, mean+SD) participated in the study. All testing was performed first thing in the morning following an overnight fast. Baseline measurements of RMR were measured using indirect calorimetry using a facemask, and body composition was measured using air displacement plethysmography. Saliva was collected via passive drool and analyzed for cortisol concentration using ELISA. Following baseline testing, subjects were randomly assigned in a double blind manner to one of two groups: 4 g/d of Safflower Oil (SO); or 4 g/d of FO supplying 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA). All tests were repeated following 6 wk of treatment. Pre to post differences were analyzed using a treatment X time repeated measures ANOVA, and correlations were analyzed using Pearson's r.
Compared to the SO group, there was a significant increase in fat free mass following treatment with FO (FO = +0.5 ą 0.5 kg, SO = -0.1 ą 1.2 kg, p = 0.03), a significant reduction in fat mass (FO = -0.5 ą 1.3 kg, SO = +0.2 ą 1.2 kg, p = 0.04), and a tendency for a decrease in body fat percentage (FO = -0.4 ą 1.3% body fat, SO = +0. 3 ą 1.5% body fat, p = 0.08). No significant differences were observed for body mass (FO = 0.0 ą 0.9 kg, SO = +0.2 ą 0.8 kg), RMR (FO = +17 ą 260 kcal, SO = -62 ą 184 kcal) or respiratory exchange ratio (FO = -0.02 ą 0.09, SO = +0.02 ą 0.05). There was a tendency for salivary cortisol to decrease in the FO group (FO = -0.064 ą 0.142 μg/dL, SO = +0.016 ą 0.272 μg/dL, p = 0.11). There was a significant correlation in the FO group between change in cortisol and change in fat free mass (r = -0.504, p = 0.02) and fat mass (r = 0.661, p = 0.001).
6 wk of supplementation with FO significantly increased lean mass and decreased fat mass. These changes were significantly correlated with a reduction in salivary cortisol following FO treatment.
badano wplyw 0-3/placebo na 44osoby przez okres 6tygodni
-grupa przyjmujaca 0-3 w ilosci 2,4g epa/dha
-placebo (przed/po/zmiana):0.305/0.321/ +0.016 (μg/dL)
-0-3(przed/po/zmiana):0.270/0.206/ -0.064 (μg/dL)
poziom kortyzolu byl mniejszy u grupy przyjmującej epa/dha
Zmieniony przez - solaros w dniu 2011-05-22 04:33:37