Extreme Variability in Urinary Sodium Excretion: Time to Stop Use of Spot Urines to Predict Clinical Outcomes

Consumption of Discretionary Salt and Salt from Bouillon among Households, Women, and Young Children in Northern Region, Ghana: A Mixed-Methods Study with the Condiment Micronutrient Innovation Trial (CoMIT) Project

Background

Information on salt consumption patterns is needed to inform the need for and design of salt reduction strategies.

Objectives

In northern Ghana, this study aimed to estimate household consumption of salt, including salt from bouillon, and compare (estimated) women and children's salt intake to global recommendations; to estimate the proportion of salt consumed from bouillon; and to identify factors, including knowledge, attitudes, and practices, associated with household salt consumption.

Methods

Employing mixed-methods methodology, we conducted a pilot survey (n = 369 households enrolled) and focus group discussions (FGDs; n = 20) in Tolon and Kumbungu districts (14 urban, 14 rural clusters) (clinicaltrials.gov registry: NCT04632771). Households reported purchases of discretionary salt (DS, "table salt") and bouillon cubes. DS and total salt (TS; DS+salt from bouillon) consumption for women (15-49 y) and children (2-5 y) were estimated using the Adult Male Equivalent method and compared with global recommendations (<5 g/d women; <3.75 g/d children). Women's salt intake was also predicted from urinary sodium excretion (INTERSALT equation). Associations between DS and TS consumption, as well as household and women's characteristics, were tested with minimally adjusted and multivariable linear mixed-effects models. Qualitative FGD themes were generated using the Framework Method.

Results

From household purchase data, estimated TS consumption exceeded global recommendations for 44% of children [median: 2.9 (IQR: 1.9, 5.2) g/d] and 60% of women [6.0 (4.0, 10.2) g/d]; 35% of children and 50% of women exceeded recommendations from DS alone. Bouillon contributed <25% of households' TS consumption. Few characteristics were associated with DS or TS consumption. Salient qualitative themes that shaped salt consumption behaviors included salt's ubiquity as a seasoning, key household members' influence on food procurement and preparation, and perceptions about health.

Conclusions

Purchase data suggest salt consumption among women and children exceeds recommendations, even when excluding salt from bouillon; food prepared outside the home likely further contributes. Salt reduction interventions may be warranted in this context.

Age differences in the impact of dietary salt on metabolism, blood pressure and cognitive function in male rats

The influence of salt consumption on physiological processes, especially blood pressure (BP), metabolism, and cognition, remains a topical concern. While guidelines endorse reduced salt diets, there are gaps in understanding the age-specific implications and challenges in adherence. The present study delved into the differential effects of salt intake on young adult and aged male rats over a 12-week period, using control, low-, and high-salt diets. Key metrics, such as BP, cognition, and general parameters, were monitored. Our findings revealed significant age-dependent effects of salt intake on survival rates, body weight, blood sodium, blood glucose, blood lipids, BP, heart rates, and cognition. Notably, young adult rats did not show significant sodium level changes on a high-salt diet, whereas aged rats experienced increased sodium levels even on a normal salt diet. Blood glucose levels decreased significantly in aged rats on a high-salt diet but remained stable in young adults. Aged rats had the highest survival rates on low-salt diets. Low-salt diets led to reduced BP in both age groups, more significantly in young adults. Young adult rats displayed increased BP variability on both high- and low-salt diets, while a decrease in BP variability was exclusive to aged rats on a low-salt diet. There were significant differences across age groups in short-term memory, but not in long-term memory. The study provides a nuanced understanding of the age-dependent physiological effects of salt intake, suggesting the necessity of age-specific guidelines for public health.

Comment on Hogas et al. Salt, Not Always a Cardiovascular Enemy? A Mini-Review and Modern Perspective. Medicina 2022, 58, 1175

Hogas et al. recently published their perspective on dietary salt in a mini review [...].

The modulatory effect of high salt on immune cells and related diseases

BACKGROUND

The adverse effect of excessive salt intake has been recognized in decades. Researchers have mainly focused on the association between salt intake and hypertension. However, studies in recent years have proposed the existence of extra-renal sodium storage and provided insight into the immunomodulatory function of sodium.

OBJECTIVES

In this review, we discuss the modulatory effects of high salt on various innate and adaptive immune cells and immune-regulated diseases.

METHODS

We identified papers through electronic searches of PubMed database from inception to March 2022.

RESULTS

An increasing body of evidence has demonstrated that high salt can modulate the differentiation, activation and function of multiple immune cells. Furthermore, a high-salt diet can increase tissue sodium concentrations and influence the immune responses in microenvironments, thereby affecting the development of immune-regulated diseases, including hypertension, multiple sclerosis, cancer and infections. These findings provide a novel mechanism for the pathology of certain diseases and indicate that salt might serve as a target or potential therapeutic agent in different disease contexts.

CONCLUSION

High salt has a profound impact on the differentiation, activation and function of multiple immune cells. Additionally, an HSD can modulate the development of various immune-regulated diseases.