Sodium and Potassium Intake from Food Diaries and 24-h Urine Collections from 7 Days in a Sample of Healthy Greek Adults

Meta-analysis guided development of a standard artificial urine

In this study, we present the first meta-analysis of human urine reported in the literature, drawing data from a total of 35 articles with a combined participant count of 14,021. Through this analysis, we have developed an artificial urine (AU) composition that can be adjusted within typical physiological parameters for in vitro applications. Our findings demonstrate the utility of this AU in determining the solubility of nitrofurantoin, particularly in the context of crystalluria. Notably, we observe that in saline, nitrofurantoin solubility, within the framework of its urinary pharmacokinetics, suggests a risk of crystalluria. However, in AU, this risk is mitigated due to complexation with urea. More broadly, we anticipate that our developed formulation will serve as a foundation for translational studies across biomedical and pharmaceutical sciences.

Sodium, potassium intake, and all-cause mortality: confusion and new findings

BACKGROUND

The World Health Organization (WHO) has established recommended daily intakes for sodium and potassium. However, there is currently some controversy regarding the association between sodium intake, potassium intake, the sodium-to-potassium ratio, and overall mortality. To assess the correlations between sodium intake, potassium intake, the sodium-to-potassium ratio, and overall mortality, as well as the potential differences in sodium and potassium intake thresholds among different population groups, we analyzed data from NHANES 2003-2018.

METHODS

NHANES is an observational cohort study that estimates sodium and potassium intake through one or two 24-h dietary recalls. Hazard ratios (HR) for overall mortality were calculated using multivariable adjusted Cox models accounting for sampling design. A total of 13855 out of 26288 participants were included in the final analysis. Restricted cubic spline analyses were used to examine the relationship between sodium intake, potassium intake, and overall mortality. If non-linearity was detected, we employed a recursive algorithm to calculate inflection points.

RESULTS

Based on one or two 24-h dietary recalls, the sample consisted of 13,855 participants, representing a non-institutionalized population aged 40-80 years, totaling 11,348,771 person-months of mean follow-up 99.395 months. Daily sodium intake and daily potassium intake were inversely associated with all-cause mortality. Restrictive cubic spline analysis showed non-linear relationships between daily sodium intake, potassium intake, sodium-potassium ratio, and total mortality. The inflection point for daily sodium intake was 3133 mg/d, and the inflection point for daily potassium intake was 3501 mg/d, and the inflection point for daily sodium-potassium ratio intake was 1.203 mg/mg/d. In subgroup analyses, a significant interaction was found between age and high sodium intake, which was further confirmed by the smooth curves that showed a U-shaped relationship between sodium intake and all-cause mortality in the elderly population, with a inflection point of 3634 mg/d.

CONCLUSION

Nonlinear associations of daily sodium intake, daily potassium intake and daily sodium-potassium ratio intake with all-cause mortality were observed in American individuals. The inflection point for daily sodium intake was 3133 mg/d. And the inflection point for daily sodium intake was 3634 mg/d in elderly population. The inflection point for daily potassium intake was 3501 mg/d. The inflection point for daily sodium-potassium ratio intake was 1.203 mg/mg/d, respectively, A healthy diet should be based on reasonable sodium intake and include an appropriate sodium-to-potassium ratio.

Assessment of 24 h Sodium and Potassium Urinary Excretion in Normotensive and Hypertensive Dominican Adults

Higher salt (sodium) intake has been associated with higher blood pressure (BP). The degree of association may be influenced by factors such as age, origin, and dietary components. This study aimed to evaluate the 24 h urinary sodium (Na) and potassium (K) excretion in normotensive and hypertensive Dominican adults and estimate their salt intake. 163 volunteers (18-80 years old) participated in a cross-sectional study. The 24 h Na and K urinary excretion were measured using an ion-selective electrode technique. Na and K urinary excretion (99.4 ± 46.5 and 35.0 ± 17.5 mmol/24 h) did not correlate with BP, except in the normotensive group, in which K correlated with SBP (0.249, p = 0.019). Na and K excretion were similar in normotensive and hypertensive subjects. When considering two age groups (18-45, 46-80 years), the Na-to-K molar ratio (3.1 ± 1.3) was higher in younger subjects (p = 0.040). Na-to-K ratio was associated with DBP in the total group (r = 0.153, p = 0.052), in the hypertensive group (r = 0.395, p < 0.001), and in the older group with SBP (0.350, p = 0.002) and DBP (0.373, p < 0.001). In the older group, Na-to-K ratio and DBP correlated after controlling for subjects with hypertension controlled by treatment (r = 0.236, p = 0.041). The Na-to-K ratio correlated, when salt intake was over 5 g/day (52.2%), with SBP (rho = 0.219, p = 0.044) and DBP (rho = 0.259, p = 0.017). Determinants of BP in the total sample were age (SBP, beta: 0.6 ± 0.1, p < 0.001; DBP, beta: 0.2 ± 0.1, p < 0.002), sex (SBP, beta: 11.2 ± 3.5, p = 0.001), body mass index (BMI) (SBP, beta: 1.0 ± 0.3, p < 0.001; DBP, beta: 0.4 ± 0.2, p = 0.01), and Na-to-K ratio (SBP, beta: 3.0 ± 1.1, p = 0.008; DBP, beta: -12.3 ± 4.0, p = 0.002). Sex and BMI were determinants in the younger group. Na-to-K molar ratio was determinant in the older group (SBP, beta: 6.7 ± 2.4, p = 0.005; DBP, beta: 3.8 ± 1.1, p < 0.001). The mean Na and salt intakes (2.3 and 5.8 g/day) were slightly higher and the K intake lower (1.4 g/day) than WHO recommendations.

Potassium intake is associated with nutritional quality and actual diet cost: a study at formulating a low sodium high potassium (LSHP) healthy diet

Increasing potassium and reducing sodium intake have been identified as a priority intervention to reduce non-communicable diseases. A low sodium high potassium (LSHP) healthy diet can be a predictor of overall dietary quality and is associated with higher diet costs. The present study was a randomised controlled-feeding trial, formulating menus of low sodium and potassium-rich healthy diet and comparing with usual diet (a control diet based on typical Indonesian diet) to assess the association of potassium intake in the menus with other nutritional contents and diet cost. Totally seventy menus, which consisted of LSHP diets and the usual diets for a 7-d cycle, were composed from the analysis of the Indonesian food composition database. The correlation coefficient of the potassium content of all menus with nutritional quality and diet cost was analysed using the Pearson test. Multiple linear regression analysis was performed to determine the most important nutrient in determining diet cost. A comparison of nutrition quality and diet cost from the two menus was analysed using the independent t-test. LSHP diet had significantly higher carbohydrate, protein, fibre, magnesium, calcium, vitamin C, potassium density and diet cost but lower total fat, saturated fat and energy density than the usual diet (P < 0⋅05). Furthermore, there was a strong positive correlation between fibre, potassium and diet cost (coefficient correlation of >0⋅8). Potassium is a nutrient that is closely related to diet quality although the cost of the diet often may inhibit its intake. A targeted and effective strategy is required to provide affordable food for achieving a sustainable nutrient-rich diet.

Measuring sodium intake: research and clinical applications

Although most current guidelines recommend a daily sodium intake of less than 2.3 g/day, most people do not have a reliable estimate of their usual sodium intake. In this review, we describe the different methods used to estimate sodium intake and discuss each method in the context of specific clinical or research questions. We suggest the following classification for sodium measurement methods: preingestion measurement (controlled intake), peri-ingestion measurement (concurrent), and postingestion measurement. On the basis of the characteristics of the available tools, we suggest that: validated 24-h recall methods are a reasonable approach to estimate sodium intake in large epidemiologic studies and individual clinical counselling sessions, methods (such as single 24-h urine collection, single-time urine collection, or 24-h recall methods), are of value in population-level estimation of mean sodium intake, but are less suited for individual level estimation and a feeding-trial design using a controlled diet is the most valid and reliable method for establishing the effect of reducing sodium to a specific intake target in early phase clinical trials. By considering the various approaches to sodium measurement, investigators and public health practitioners may be better informed in assessing the health implications of sodium consumption at the individual and population level.

Trend in potassium intake and Na/K ratio in the Italian adult population between the 2008 and 2018 CUORE project surveys

BACKGROUND AND AIMS

Low potassium intake, in addition to high sodium, has been associated with higher risk of hypertension and CVD. The Study assessed habitual potassium intake and sodium/potassium ratio of the Italian adult population from 2008 to 2012 to 2018-2019 based on 24-h urine collection, in the framework of the CUORE Project/MINISAL-GIRCSI/MENO SALE PIU' SALUTE national surveys.

METHODS AND RESULTS

Data were from cross-sectional surveys of randomly selected age-and-sex stratified samples of resident persons aged 35-74 years in 10 (out of 20) Italian regions. Urinary electrolyte and creatinine measurements were performed in a central laboratory. Analyses considered 942 men and 916 women, examined in 2008-2012, and 967 men and 1010 women, examined in 2018-2019. In 2008-2012, the age-standardized mean of potassium intake (urinary potassium accounts for 70% of potassium intake) was 3147 mg (95% CI 3086-3208) in men and 2784 mg (2727-2841) in women, whereas in 2018-2019, it was 3043 mg (2968-3118) and 2561 mg (2508-2614) respectively. In 2008-2012, age-adjusted prevalence of persons with an adequate potassium intake (i.e. ≥ 3510 mg/day) was 31% (95% CI 28-34%) for men and 18% (16-21%) for women; in 2018-2019, it was 26% (23-29%) and 12% (10-14%) respectively. The sodium/potassium ratio significantly decreased both in men and women.

CONCLUSIONS

The average daily potassium intake of the Italian general adult population remains lower than the WHO and EFSA recommended level. These results suggest the need of a revision to strengthen initiatives for the promotion of an adequate potassium intake at the population level.

Nutritional Characteristics of Prepacked Feta PDO Cheese Products in Greece: Assessment of Dietary Intakes and Nutritional Profiles

Feta cheese, a protected designation of origin (PDO) food, is one of the most important Mediterranean food products. Although it is the cheese with the highest consumption in Greece, the nutritional characteristics of products available in the market, as well as their contribution to the Greek diet, have not been evaluated in detail. In the present study, the basic nutritional content of 81 prepacked feta cheese products available in the Greek market were recorded based on their labels. This was combined with consumption data to provide an overall picture of feta cheese’s contribution to the Greek diet. The nutrient contents per 100 g ranged as follows. Energy: 221–343 kcal, total fat: 20–29 g, saturated fat: 12.8–20.3 g, carbohydrates: 0–3.1 g, sugars: 0–3 g, proteins: 13.1–21.0 g and salt: 1.2–5.1 g. The median feta daily individual consumption was found to be 39 g, ranging from 20 g to 100 g (fifth and 95th percentiles, respectively). The nutritional intake analysis as a percentage of dietary reference intake (DRI) showed that saturated fat and salt are ranked on the top of the list, with intakes reaching 101.5% and 85% respectively. The products were also evaluated against five nutrient profile models and their potential use under statutory requirements and policy development are discussed.

Dietary Intake and Sources of Potassium in a Cross-Sectional Study of Australian Adults

A diet rich in potassium is important to reduce the risk of cardiovascular disease. This study assessed potassium intake; food sources of potassium (including NOVA level of processing, purchase origin of these foods); and sodium-to-potassium ratio (Na:K) in a cross-section of Australian adults. Data collection included 24-h urines (n = 338) and a 24-h diet recall (subsample n = 142). The mean (SD) age of participants was 41.2 (13.9) years and 56% were females. Mean potassium (95%CI) 24-h urinary excretion was 76.8 (73.0–80.5) mmol/day compared to 92.9 (86.6–99.1) by 24-h diet recall. Na:K was 1.9 (1.8–2.0) from the urine excretion and 1.4 (1.2–1.7) from diet recall. Foods contributing most to potassium were potatoes (8%), dairy milk (6%), dishes where cereal is the main ingredient (6%) and coffee/coffee substitutes (5%). Over half of potassium (56%) came from minimally processed foods, with 22% from processed and 22% from ultraprocessed foods. Almost two-thirds of potassium consumed was from foods purchased from food stores (58%), then food service sector (15%), and fresh food markets (13%). Overall, potassium levels were lower than recommended to reduce chronic disease risk. Multifaceted efforts are required for population-wide intervention—aimed at increasing fruit, vegetable, and other key sources of potassium intake; reducing consumption of processed foods; and working in supermarket/food service sector settings to improve the healthiness of foods available.

Nutrition Transition in the Post-Economic Crisis of Greece: Assessing the Nutritional Gap of Food-Insecure Individuals. A Cross-Sectional Study

Food insecurity has risen by 40% in Europe’s post-economic crisis, linked to the economic turmoil and austerity. Despite the intensification of efforts to fight all forms of poverty, including the implementation of programs targeted to the most deprived, the study of individuals at risk of food insecurity has been largely neglected. This study aimed to map the nutritional habits and needs of the most deprived in Greece, one of the countries most affected by the economic crisis. Individuals classified as most deprived under the Fund for the European Aid to the Most Deprived (FEAD) criteria (n = 499) from across Greece and an age matched control from the general population (n = 500) were interviewed between December 2017 and December 2019. Participants provided information about demographic characteristics, and self-reported anthropometric measures and nutritional intake of the past month via a food frequency questionnaire (FFQ). Protein and energy malnutrition were defined as daily intake <1.950 kcal and ≤0.75 g/kg body-weight accordingly. Protein and energy malnutrition were high among FEAD recipients (52.3% and 18.6% respectively, p < 0.001), alongside a high prevalence of overweight and obesity (BMI > 25: 68.4% versus 55.1%; p < 0.001). The diet of FEAD recipients included higher amounts of carbohydrates, lower amounts of monounsaturated fat (MUFA) and polyunsaturated fat (PUFA; p < 0.001 compared to control), larger amounts of plant-based proteins (5.81 ± 1.7 versus 4.94 ± 1.3% E respectively, p < 0.001) and very limited intake of fish (0.07 portions/day). Despite being enrolled in a food assistance program, protein and energy malnutrition is prevalent among Greece’s most deprived who experience not only lower diet quality but also the double burden of malnutrition.