High dietary sodium reduces brachial artery flow-mediated dilation in humans with salt-sensitive and salt-resistant blood pressure

Abstract

Recent studies demonstrate that high dietary sodium (HS) impairs endothelial function in those with salt-resistant (SR) blood pressure (BP). The effect of HS on endothelial function in those with salt-sensitive (SS) BP is not currently known. We hypothesized that HS would impair brachial artery flow-mediated dilation (FMD) to a greater extent in SS compared with SR adults. Ten SR (age 42 ± 5 yr, 5 men, 5 women) and 10 SS (age 39 ± 5 yr, 5 men, 5 women) healthy, normotensive participants were enrolled in a controlled feeding study consisting of a run-in diet followed by a 7-day low dietary sodium (LS) (20 mmol/day) and a 7-day HS (300 mmol/day) diet in random order. Brachial artery FMD and 24-h BP were assessed on the last day of each diet. SS BP was individually assessed and defined as a change in 24-h mean arterial pressure (MAP) of >5 mmHg between the LS and HS diets (ΔMAP: SR -0.6 ± 1.2, SS 7.7 ± 0.4 mmHg). Brachial artery FMD was lower in both SS and SR individuals during the HS diet (P < 0.001), and did not differ between groups (P > 0.05) (FMD: SR LS 10.6 ± 1.3%, SR HS 7.2 ± 1.5%, SS LS 12.5 ± 1.7%, SS HS 7.8 ± 1.4%). These data indicate that an HS diet impairs brachial artery FMD to a similar extent in adults with SS BP and SR BP.

More evidence that salt increases blood pressure and risk of kidney disease from the Science of Salt: A regularly updated systematic review of salt and health outcomes (April–July 2016)

“…These studies are summarized in Table . The outcomes examined were diverse: one study assessed mortality outcomes (category I), two studies assessed morbidity outcomes (category II), two studies assessed outcomes related to symptoms/quality of life/functional status (category III), six studies assessed BP outcomes (category IV), seven studies assessed other clinically relevant surrogate outcomes (category V), and 10 studies assessed physiologic outcomes (category VI) …”

“…No primary research studies in the physiologic category (category VI) met the minimum methodological criteria. A range of outcomes were captured by the studies considered to be of lower quality, including all‐cause mortality, headaches/migranes, BP, cognitive function, acne, obesity and ghrelin, multiple sclerosis, BMD, gastric cancer, flow‐mediated dilatation, pulse wave velocity, markers of the renin‐angiotensin‐aldosterone system, heart rate, insulin resistance and the metabolic syndrome, brain tissue white matter hyperintensity, uric acid, and urinary albumin . Most of these studies found adverse effects of dietary salt on health, except for three that were neutral and one that found an inverse relationship between salt intake and headaches/migranes …”

ETBreceptor contribution to vascular dysfunction in postmenopausal women

“…Women lay supine for~20 -30 min, and a venous blood sample was obtained from an antecubital vein to assess sex steroids and plasma ET-1. Conduit artery endothelial function was assessed in the brachial artery using FMD as previously described (11,37). Briefly, a longitudinal image of the brachial artery was obtained via ultrasound (GE P5; Healthcare, Waukesha, WI).…”

Dietary sodium and nocturnal blood pressure dipping in normotensive men and women

“…Another secondary analysis was performed to determine whether individuals classified as “salt-sensitive” had impaired nocturnal dipping during the HS diet. Salt-sensitivity was defined as a 5 mmHg or more change in 24h mean arterial pressure from LS to HS, as previously described (22). Ten participants were classified as salt-sensitive (Δ mean arterial pressure = 9±1 mmHg).…”