Potassium-Enriched Salt Substitutes: A Review of Recommendations in Clinical Management Guidelines.

Excess dietary sodium intake and insufficient dietary potassium intake are both well-established risk factors for hypertension. Despite some successful initiatives, efforts to control hypertension by improving dietary intake have largely failed because the changes required are mostly too hard to implement. Consistent recent data from randomized controlled trials show that potassium-enriched, sodium-reduced salt substitutes are an effective option for improving consumption levels and reducing blood pressure and the rates of cardiovascular events and deaths. Yet, salt substitutes are inconsistently recommended and rarely used. We sought to define the extent to which evidence about the likely benefits and harms of potassium-enriched salt substitutes has been incorporated into clinical management by systematically searching guidelines for the management of hypertension or chronic kidney disease. We found incomplete and inconsistent recommendations about the use of potassium-enriched salt substitutes in the 32 hypertension and 14 kidney guidelines that we reviewed. Discussion among the authors identified the possibility of updating clinical guidelines to provide consistent advice about the use of potassium-enriched salt for hypertension control. Draft wording was chosen to commence debate and progress consensus building: strong recommendation for patients with hypertension-potassium-enriched salt with a composition of 75% sodium chloride and 25% potassium chloride should be recommended to all patients with hypertension, unless they have advanced kidney disease, are using a potassium supplement, are using a potassium-sparing diuretic, or have another contraindication. We strongly encourage clinical guideline bodies to review their recommendations about the use of potassium-enriched salt substitutes at the earliest opportunity.

The Joint Effects of Diet and Dietary Supplements in Relation to Obesity and Cardiovascular Disease over a 10-Year Follow-Up: A Longitudinal Study of 69,990 Participants in Australia.

It is unknown whether a healthy diet or unhealthy diet combined with specific supplements may jointly contribute to incidence of obesity and cardiovascular disease (CVD). We included 69,990 participants from the 45 and Up Study who completed both baseline (2006-2009) and follow-up (2012-2015) surveys. We found that compared to participants with a long-term healthy diet and no supplement consumption, those with a long-term healthy diet combined with multivitamins and minerals (MVM) or fish oil consumption were associated with a lower incidence of CVD (p < 0.001); whilst those with an unhealthy diet and no MVM or fish oil consumption were associated with a higher risk of obesity (p < 0.05). Compared to participants with a long-term healthy diet and no calcium consumption, the combination of a long-term healthy diet and calcium consumption was linked to a lower risk of CVD (IRR = 0.87, 95% CI: 0.78; 0.96). In conclusion, a long-term healthy diet combined with MVM or fish oil was associated with a lower incidence of CVD. Participants who maintained a healthy diet and used calcium supplements were associated with a lower incidence of obesity. However, these associations were not found among those with an unhealthy diet, despite taking similar supplements.

The Association of Measures of the Micro- and Macro-Vasculature with Selenium and GPx Activity in a Young Bi-Ethnic Population: The African-PREDICT Study.

Objective: Selenium plays an important physiological role as component for antioxidant selenoproteins such as glutathione peroxidase (GPx). Since oxidative stress contributes to hypertension development, it is likely that selenium deficiency may contribute to the burden of cardiovascular disease. To better understand the involvement of selenium and GPx in the early development of cardiovascular disease, we investigated in young, healthy black and white African men and women whether measures of the micro- and macrovasculature are related to selenium and GPx activity. Methods: In young adults (N = 394; aged 20-30 years) we determined serum selenium, GPx activity, microvascular measures (central retinal artery equivalent, central retinal vein equivalent, arteriolar-to-venular ratio [AVR], and estimated glomerular filtration rate [eGFR]), and macrovascular measures (pulse wave velocity, 24-hour pulse pressure [PP] and augmentation index [Aix]). Results: In multivariable-adjusted regression analyses, there were vasculoprotective associations between serum selenium and a microvascular measure (AVR [ß = 0.23; p = 0.036]) in black African women and with a macrovascular measure (24-hour PP [ß = -0.15; p = 0.048]) in white African women. In turn, GPx activity also showed a protective association with a microvascular measure (eGFR) in white African men (ß = 0.23; p = 0.035), as well as with macrovascular measures (AIx, PP) in the black (ß = -0.25; p = 0.027) and white African men (ß = -0.22; p = 0.035), and black African women (ß = -0.32; p = 0.001). Conclusions: Collectively the findings suggest a protective role for the micronutrient selenium and GPx on both the micro- and macrovasculature in a young, healthy bi-ethnic population.

How will South Africa's mandatory salt reduction policy affect its salt iodisation programme? A cross-sectional analysis from the WHO-SAGE Wave 2 Salt & Tobacco study.

OBJECTIVE: The WHO's global targets for non-communicable disease reduction recommend consumption of<5 g salt/day. In 2016, South Africa was the first country to legislate maximum salt levels in processed foods. South Africa's salt iodisation fortification programme has successfully addressed iodine deficiency but information is dated. Simultaneous monitoring of sodium reduction and iodine status is required to ensure compatibility of the two public health interventions. DESIGN/SETTING/PARTICIPANTS: A nested cohort design within WHO's 2015 Study on global AGEing and adult health (n=2887) including individuals from households across South Africa. Randomly selected adults (n=875) provided 24-hour and spot urine samples for sodium and iodine concentration analysis (the primary and secondary outcome measures, respectively). Median 24-hour urinary iodine excretion (UIE) and spot urinary iodine concentrations (UIC) were compared by salt intakes of <5g/day, 5-9g/dayand >9 g/day. RESULTS: Median daily sodium excretion was equivalent to 6.3 g salt/day (range 1-43 g/day); 35% had urinary sodium excretion values within the desirable range (<5 g salt/day), 37% had high values (5-9 g salt/day) and 28% had very high values (>9 g salt/day). Median UIC was 130 µg/L (IQR=58-202), indicating population iodine sufficiency (≥100 µg/L). Both UIC and UIE differed across salt intake categories (p<0.001) and were positively correlated with estimated salt intake (r=0.166 and 0.552, respectively; both p<0.001). Participants with salt intakes of <5 g/day were not meeting the Estimated Average Requirement for iodine intake (95 µg/day). CONCLUSIONS: In a nationally representative sample of South African adults, the association between indicators of population iodine status (UIC and UIE) and salt intake, estimated using 24-hour urinary sodium excretion, indicate that low salt intakes may compromise adequacy of iodine intakes in a country with mandatory iodisation of table salt. The iodine status of populations undergoing salt reduction strategies needs to be closely monitored to prevent re-emergence of iodine deficiency.

Vitamin K Dependent Protection of Renal Function in Multi-ethnic Population Studies.

BACKGROUND: Following activation by vitamin K (VK), matrix Gla protein (MGP) inhibits arterial calcification, but its role in preserving renal function remains unknown. METHODS: In 1166 white Flemish (mean age, 38.2 years) and 714 South Africans (49.2% black; 40.6 years), we correlated estimated glomerular filtration (eGFR [CKD-EPI formula]) and stage of chronic kidney disease (CKD [KDOQI stages 2-3]) with inactive desphospho-uncarboxylated MGP (dp-ucMGP), using multivariable linear and logistic regression. RESULTS: Among Flemish and white and black Africans, between-group differences in eGFR (90, 100 and 122 mL/min/1.73 m(2)), dp-ucMGP (3.7, 6.5 and 3.2 µg/L), and CKD prevalence (53.5, 28.7 and 10.5%) were significant, but associations of eGFR with dp-ucMGP did not differ among ethnicities (P ≥ 0.075). For a doubling of dp-ucMGP, eGFR decreased by 1.5 (P = 0.023), 1.0 (P = 0.56), 2.8 (P = 0.0012) and 2.1 (P < 0.0001) mL/min/1.73 m(2) in Flemish, white Africans, black Africans and all participants combined; the odds ratios for moving up one CKD stage were 1.17 (P = 0.033), 1.03 (P = 0.87), 1.29 (P = 0.12) and 1.17 (P = 0.011), respectively. INTERPRETATION: In the general population, eGFR decreases and CKD risk increases with higher dp-ucMGP, a marker of VK deficiency. These findings highlight the possibility that VK supplementation might promote renal health.

Cardiovascular effects of oral Supplementation of vitamin C, E and folic acid in young healthy males.

Numerous observational studies showed associations of antioxidants (vitamins C and E) and folate intake with a reduced risk of cardiovascular disease, but randomized controlled clinical trials have generally not supported this hypothesis. The objective of this study was to investigate the effects of a daily dosage of 1000 mg vitamin C, 800 mg vitamin E, and 10 mg folate on markers of vascular function in 31 young healthy male adults. Cardiovascular values after a 12-week vitamin (14 subjects) or placebo (17 subjects) intervention were compared to baseline values. Cardiovascular parameters (blood pressure, stroke volume, heart rate, cardiac output, vascular resistance, arterial compliance) were measured continuously after an overnight fast under controlled circumstances with a Finometer device. Our main finding was a significant decrease (p = 0.03) in systolic blood pressure in the experimental group. No statistically significant changes were observed within other cardiovascular variables of the experimental group, but possible beneficial decreases in diastolic blood pressure and increases in arterial compliance after 12 weeks of vitamin supplementation were indicated. In conclusion, beneficial effects of antioxidants and folate were observed probably because the supplementation was used by young healthy subjects under carefully controlled conditions.