1.
Dietary intervention with cooking instructions and self-monitoring of the diet in free-living hypertensive men.
Kitaoka, K, Nagaoka, J, Matsuoka, T, Shigemura, C, Harada, K, Aoi, W, Wada, S, Asano, H, Sakane, N, Higashi, A
Clinical and experimental hypertension (New York, N.Y. : 1993). 2013;(2):120-7
Abstract
The control of blood pressure (BP) is important in the prevention of cardiovascular diseases. This study was conducted to evaluate the effect of a dietary educational program for free-living, high-normal, and stage 1 or 2 hypertensive men. The participants were volunteers aged 40-75 years who agreed to the intervention. They were divided into two groups: 39 men for the intervention group and 32 men for the control group. BP, urinary sodium and potassium excretion, dietary and lifestyle data, and nonfasting venous blood sample were collected at baseline and after the intervention period. The intervention was designed to decrease sodium level with an emphasis on a decrease in the consumption of salted foods and to increase potassium level with an emphasis on an increase in the consumption of fruit and vegetables through cooking instructions and self-monitoring of the diet. At the baseline, there were no significant differences observed between the groups, except the diastolic BP. In the intervention group, a greater decrease in the urinary sodium-to-potassium excretion ratio was observed, compared with the control group (net difference 0.6, P = .029). The systolic and diastolic BP (mm Hg) decreased in the intervention group (149.0-143.0, P = .073; 93.0-87.0, P = .002), but no changes were observed in the control group (145.0-143.0, P = .231; 84.9-85.3, P = .381). In the intervention group, the urinary sodium-to-potassium excretion ratio was significantly improved by focusing on cooking instructions and self-monitoring of the diet.
2.
Dietary sodium restriction and beta2-adrenergic receptor polymorphism modulate cardiovascular function in humans.
Eisenach, JH, Schroeder, DR, Pike, TL, Johnson, CP, Schrage, WG, Snyder, EM, Johnson, BD, Garovic, VD, Turner, ST, Joyner, MJ
The Journal of physiology. 2006;(Pt 3):955-65
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Abstract
Dietary Na+ intake influences beta2-adrenergic receptor (beta2AR) responsiveness. While receiving a normal Na+ diet (150 mmol day(-1)), subjects homozygous for glycine at amino acid 16 (Gly16) have greater forearm beta2AR-mediated vasodilatation than subjects homozygous for arginine (Arg16), an effect that is mediated by endothelial NO. We tested the hypothesis that dietary Na+ restriction eliminates genotype differences in forearm and systemic beta2AR-mediated dilatation in these groups. We measured heart rate, mean arterial pressure and cardiac output (CO, acetylene breathing) responses to administration of intravenous terbutaline (TRB) before and after 5 days of low dietary Na+ intake (10 mmol day(-1)) in healthy Gly16 (n = 17; age, 31 +/- 7 year) and Arg16 homozygotes (n = 15; age, 29 +/- 8 year). After the low-Na+ diet, a catheter was placed in the brachial artery to measure forearm blood flow (FBF, plethysmography) responses to administration of isoprenaline (isoproterenol) before and after NO inhibition with NG-mono-methyl-L-arginine (L-NMMA). In the Gly16 group, the low-Na+ diet decreased baseline CO from 6.4 +/- 1.4 to 5.5 +/- 1.2 l min(-1) (P = 0.003, paired t test), tended to decrease stroke volume from 97.0 +/- 20.6 to 86.9 +/- 21.7 ml (P = 0.06) and increased peripheral resistance from 1106 +/- 246 to 1246 +/- 222 dynes s cm(-5) (P = 0.02); significant effects of the low-Na+ diet were not observed in Arg16 subjects. In a repeated measures ANOVA, the responses of all cardiovascular measures to systemic administration of TRB were not influenced by genotype or diet. Additionally, the FBF response to incremental doses of isoprenaline did not differ between genotype groups before or after administration of L-NMMA. We conclude that dietary Na+ restriction blunted the increased forearm NO-mediated beta2AR responsiveness in Gly16 homozygotes observed in a previous study after normal dietary Na+ intake, while baseline CO decreased and peripheral resistance increased in this group. This study provides evidence that dietary Na+ modulates effects of the Arg16Gly polymorphism on cardiovascular function.
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Persistence of normotension after discontinuation of lifestyle intervention in the trial of TONE. Trial of Nonpharmacologic Interventions in the Elderly.
Kostis, JB, Wilson, AC, Shindler, DM, Cosgrove, NM, Lacy, CR
American journal of hypertension. 2002;(8):732-4
Abstract
BACKGROUND Weight loss and sodium reduction programs are effective in treating hypertension, but there is little information about the persistence of the benefit after discontinuation of the intervention. METHODS The Trial of Nonpharmacologic Interventions in the Elderly (TONE) was a four-center controlled clinical trial of weight loss, reduced sodium intake, or both in maintaining normotension after withdrawal of antihypertensive drug therapy in older men and women whose hypertension was controlled with a single antihypertensive medication. Information on maintenance of normotension without need for drug therapy was obtained on 222 of 223 participants at the Robert Wood Johnson Medical School clinical center on average of 48.4 months (range 45 to 54 months) after the end of TONE. RESULTS At the end of TONE follow-up, 43% of participants in the combined intervention group were off medication compared with 25% in the usual care group (P = .011). At 48 months after the end of TONE and discontinuation of contact of the participants with the clinical center, 23% of the combined intervention group v 7% in the usual care group were off medication (P = .012). CONCLUSIONS Some benefits of structured dietary intervention appears to persist long term in a significant number of patients after discontinuation of the intervention.