Dietary treatment of blood pressure in kidney disease

Effects of water soaking and/or sodium polystyrene sulfonate addition on potassium content of foods

In this study, we determined, by atomic absorption spectrophotometry, the potassium amount leached by soaking or boiling foods identified by children suffering from chronic renal failure as "pleasure food" and that they cannot eat because of their low-potassium diet, and evaluated whether addition of sodium polystyrene sulfonate resin (i.e. Kayexalate®) during soaking or boiling modulated potassium loss. A significant amount of potassium content was removed by soaking (16% for chocolate and potato, 26% for apple, 37% for tomato and 41% for banana) or boiling in a large amount of water (73% for potato). Although Kayexalate® efficiently dose-dependently removed potassium from drinks (by 48% to 73%), resin addition during soaking or boiling did not eliminate more potassium from solid foods. Our results therefore provide useful information for dietitians who elaborate menus for people on potassium-restricted diets and would give an interesting alternative to the systematic elimination of all potassium-rich foods from their diet.

The effects of fish oil supplementation on markers of inflammation in chronic kidney disease patients

OBJECTIVE

One prevalent characteristic of all stages of chronic kidney disease (CKD) is excessive production of proinflammatory cytokines. Fish oil (FO) supplementation has been reported to lower levels of proinflammatory cytokines. The benefits of FO for an extensive range of populations and a variety of health concerns are apparent, yet the anti-inflammatory benefits for nondialysis CKD patients are not as well documented. Therefore, the purpose of this study was to investigate the effects of the daily consumption of FO (1,400 mg eicosapentaenoic acid + 1,000 mg docosahexaenoic acid) on interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) for 8 weeks in nondialysis CKD patients.

DESIGN, SETTING, AND SUBJECTS

In this double-blind, randomized, placebo-controlled intervention, the effect of 8 weeks of FO administration on IL-1β, IL-6, and TNF-α levels in nondialysis CKD patients were evaluated.

INTERVENTION

Thirty-one nondialysis CKD patients (17 = FO; 14 = placebo) randomly received either FO dietary supplementation 2.4 g/day (1,400 mg eicosapentaenoic acid + 1,000 mg docosahexaenoic acid) or placebo (safflower oil) for 8 weeks.

MAIN OUTCOME MEASURES

IL-1β, IL-6, and TNF-α were all measured as markers of inflammation.

RESULTS

One-way analysis of variance revealed no significant differences in IL-6 (P = .06), IL-1β (P = .18), and TNF-α (P = .20) between groups in pretest values. Additionally, no pretest differences existed between groups for age (P = .549), weight (P = .324), waist circumference (P = .086), gender (P = .591), and ethnicity (P = .875). Covariance was calculated using compliance, age, gender, ethnicity, body weight, and waist circumference as covariates. No significant differences were discovered between groups after FO supplementation for IL-6 (P = .453) and TNF-α (P = .242). A significant difference was discovered for IL-1β (P = .050) with lower levels in the FO group.

CONCLUSIONS

The results of this study are in agreement with some previous studies that suggest that FO supplementation has no effect on plasma proinflammatory cytokines TNF-α or IL-6, but does have an effect on IL-1β in nondialysis CKD patients.