Effects of sodium and potassium supplementation on endothelial function: a fully controlled dietary intervention study.
High Na and low K intakes have adverse effects on blood pressure, which increases the risk for CVD. The role of endothelial dysfunction and inflammation in this pathophysiological process is not yet clear. In a randomised placebo-controlled cross-over study in untreated (pre)hypertensives, we examined the effects of Na and K supplementation on endothelial function and inflammation. During the study period, subjects were provided with a diet that contained 2·4 g/d of Na and 2·3 g/d of K for a 10 460 kJ (2500 kcal) intake. After 1-week run-in, subjects received capsules with supplemental Na (3·0 g/d), supplemental K (2·8 g/d) or placebo, for 4 weeks each, in random order. After each intervention, circulating biomarkers of endothelial function and inflammation were measured. Brachial artery flow-mediated dilation (FMD) and skin microvascular vasomotion were assessed in sub-groups of twenty-two to twenty-four subjects. Of thirty-seven randomised subjects, thirty-six completed the study. Following Na supplementation, serum endothelin-1 was increased by 0·24 pg/ml (95 % CI 0·03, 0·45), but no change was seen in other endothelial or inflammatory biomarkers. FMD and microvascular vasomotion were unaffected by Na supplementation. K supplementation reduced IL-8 levels by 0·28 pg/ml (95 % CI 0·03, 0·53), without affecting other circulating biomarkers. FMD was 1·16 % (95% CI 0·37, 1·96) higher after K supplementation than after placebo. Microvascular vasomotion was unaffected. In conclusion, a 4-week increase in Na intake increased endothelin-1, but had no effect on other endothelial or inflammatory markers. Increased K intake had a beneficial effect on FMD and possibly IL-8, without affecting other circulating endothelial or inflammatory biomarkers.
1Top Institute Food and Nutrition,Wageningen,6700 AN,The Netherlands.
Lieke
L
Gijsbers
1Top Institute Food and Nutrition,Wageningen,6700 AN,The Netherlands.
James I
JI
Dower
1Top Institute Food and Nutrition,Wageningen,6700 AN,The Netherlands.
Casper G
CG
Schalkwijk
1Top Institute Food and Nutrition,Wageningen,6700 AN,The Netherlands.
Yvo H A M
YH
Kusters
1Top Institute Food and Nutrition,Wageningen,6700 AN,The Netherlands.
Stephan J L
SJ
Bakker
1Top Institute Food and Nutrition,Wageningen,6700 AN,The Netherlands.
Peter C H
PC
Hollman
1Top Institute Food and Nutrition,Wageningen,6700 AN,The Netherlands.
Johanna M
JM
Geleijnse
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001794:Blood Pressure / Q000187:drug effects; D001916:Brachial Artery / Q000187:drug effects; D018592:Cross-Over Studies; D004032:Diet; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D019332:Endothelin-1 / Q000097:blood; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D016209:Interleukin-8 / Q000097:blood; D008297:Male; D008875:Middle Aged; D017419:Potassium, Dietary / Q000008:administration & dosage* / Q000652:urine; D012039:Regional Blood Flow / Q000187:drug effects; D012982:Sodium, Dietary / Q000008:administration & dosage* / Q000652:urine; D014664:Vasodilation / Q000187:drug effects
D015415:Biomarkers; D019332:Endothelin-1; D016209:Interleukin-8; D017419:Potassium, Dietary; D012982:Sodium, Dietary
BP blood pressure; CRP C-reactive protein; EID endothelium-independent dilation; Endothelial function; FMD flow-mediated dilation; Flow-mediated dilation; Inflammation; LDF laser Doppler flowmetry; NO nitric oxide; Potassium; Randomised controlled trials; SBP systolic blood pressure; Sodium; vWf von Willebrand factor