An Assessment of Usual Salt Intake among Older Normotensive Adults in Atonsu, a Suburb of Kumasi in the Ashanti Region of Ghana

BACKGROUND

Globally, sodium intake has been found to be far above the normal level required by the body. Within countries, variations in salt intake exist between rural communities and urban communities. Experimental and epidemiological studies as well as studies involving clinical trials show the existence of adverse effect of salt consumption on the blood pressure of adults. The study evaluated salt intake among older normotensive adults in Atonsu, a suburb of Kumasi in the Ashanti region of Ghana.

METHODS

Participants were randomly selected from five churches which constituted cluster samples. A questionnaire was administered to participants for demographic information and dietary and lifestyle assessments. The study targeted 100 participants, twenty from each of the five churches. Eighty-two individuals gave their informed consent. Out of the 82 who gave their informed consent, 15 withdrew and 67 completed the course. The 67 participants comprised 36 (53.7%) men and 31 (46.3%) women. Systolic and diastolic blood pressure, BMI, urinary sodium, urinary potassium, serum creatinine, serum sodium, and serum potassium concentrations were also measured.

RESULTS

Participants' mean age was 52.3 ± 8.7 years. Participants had 24 hr urinary sodium excretion of 153.0 ± 26.9 mmol/day. All participants indicated that they consume foods high in salt even though none of them added salt to their diet at table. Mean 24 hr urinary potassium was 52.5 ± 12.9 mmol/day. Mean systolic blood pressure was 119.9 ± 10.8 mmHg and mean diastolic blood pressure was 72.5 ± 7.3 mmHg. Their mean BMI was 23.7 ± 3.5 kg/m2.

CONCLUSION

The participants who can be described as quite old and normotensive were high salt consumers, indicated by their dietary assessment and urinary sodium excretion, even though they had normal blood pressure.

Characterization of Traditional Croatian Household-Produced Dry-Fermented Sausages

Characterization of five types of traditional Croatian dry-fermented sausages produced by family farms was performed via identification of superficial mycobiota, physicochemical, sensory, instrumental color, fatty acids & fat quality indices. Detailed characterization of these sausages aimed to achieve standardization of their production and composition and to establish and/or improve their specification protocols. Traditional sausages varied significantly (p < 0.05) in all analyzed parameters except for the number of mold isolates. Sausages coming from eastern Croatia had a greater mold species diversity, with the highest number of isolated mycotoxigenic species in Slavonian domestic sausage. Sensory evaluation showed good acceptability of all sausages. According to health recommendations, Kulenova Seka showed the most representable values for most of fat quality indices. The results suggest the need for certain modifications in fat & fatty acid composition and, to a lesser extent, in salt content, however not at the expense of product safety, quality and acceptability.

Quality, functionality, and microbiology of fermented fish: a review

Fermentation is a traditional food preservation method and is widely used for improving food safety, shelf life, and organoleptic and nutritional attributes. Fermented fish are produced and consumed in different parts of the world and are an integral part of many food cultures. Furthermore, fermented fish are a source of interesting microbes and are an important industry in many countries. This review tries to update the types and manufacturing processes for fermented fish around the world. The emphasis is on this work related to fermented fish and their health benefits, as well as the contribution of microorganisms to their fermentation. A variety of different approaches have been used to determine and understand microbial composition and functionality. Moreover, some challenges and future research directions regarding fermented fish are also discussed in this review. Further research into fermented fish products is of crucial importance not only for the food industry but also for human health. However, extensive in vivo and toxicological studies are essential before the application of bioactive-rich fermented fish products for human health benefits.

Characterisation of "Catalão" and "Salsichão" Portuguese traditional sausages with salt reduction

The present study evaluated the effect of salt reduction on traditional dry-cured sausages' safety, quality and product acceptance, comprising physicochemical and microbiological parameters, biogenic amines, fatty acids, texture profile and sensory analysis. According to our results, salt content had a major effect on microbiological counts, although not compromising the products' safety. Marked differences were identified regarding biogenic amines, in particular for histamine, tyramine and cadaverine, which were detected in larger amounts in products with 3%. Moreover, significant differences in the fatty acids profile have also been found, but only in less abundant components such as linoleic, lauric and heneicosanoic acids. Texture profile analysis of low-salt products, revealed a decrease in hardness and chewiness, along with an increase in adhesiveness values. Sensory evaluations revealed that despite the less intense aroma, products with 3% salt, had a more balanced salt perception. Our results suggest that salt content may be reduced to 50% in dry-cured products, with the obvious health-related advantages.

A study on sensory properties of sodium reduction and replacement in Asian food using difference-from - control test

This study examined the effects of sodium reduction and flavor enhancers on the sensory profile of two types of hawker foods commonly consumed in Singapore, namely chicken rice and mee soto broth. The ‘difference‐from‐control’ test was the method adopted in this study involving 24–29 trained panelists. Combinations included blind control, two levels of sodium reduction, and two levels of flavor enhancers in sodium‐reduced recipes. In the sodium‐reduced recipes, two levels of NaCl, 0.48% and 0.55%, for chicken rice, and 0.76% and 0.86% for mee soto (equivalent to 31% and 22% reduction in NaCl), were used. Monosodium glutamate (MSG) or Ajiplus^® (a blend of MSG and nucleotides) at 0.20% and 0.40% were added to the recipes comprising a reduction of 40% in NaCl (equivalent to 31% and 22% reduction in sodium, respectively) compared with the control. It was found that the inclusion of MSG or Ajiplus^® in 40% NaCl‐reduced recipe resulted in a significant increase in perception of umami taste (P < 0.05) when compared to the control. By adding flavor enhancers into the 40%‐reduced salt chicken rice recipes, the perception of saltiness was significantly increased when compared to 22% and 31% sodium reduced recipes. Similarly for mee soto broth, there was a significant increase in perception of chicken flavor, umami taste, mouthfeel sensation, and sweet taste (P < 0.05) with a decrease in the perception of sour and bitter taste when compared to control. By adding 0.40% MSG into the 40%‐reduced salt recipes, the perception of saltiness was maintained when compared with control.

Study on lipolysis-oxidation and volatile flavour compounds of dry-cured goose with different curing salt content during production

The effect of dry-curing salt content (4% low salt (LS), 8% high salt (HS)) on lipolysis, lipid oxidation and volatile compounds in dry-cured goose was investigated in our study. The activities of acid lipase and neutral lipase increased during dry-curing, while phospholipase reached its maximum at the end of marinating. Lipoxygenase (LOX) and thiobarbituric acid reactive substances (TBARS) values increased during dry-curing and marinating then decreased during dry-ripening. Total free fatty acids (TFFA) increased at dry-curing and dry-ripening points and decreased during marinating. Total peak area of lipids derived volatile compounds (TPALDVC) and total peak area increased during entire stages. Compared to LS, HS group has higher lipolytic and LOX activities, TBARS, TFFA, unsaturated fatty acids and TPALDVC. The higher TPALDVC in HS could be attributed to higher lipid hydrolysis and oxidation during processing.

Angiotensin II- and salt-induced kidney injury through Rac1-mediated mineralocorticoid receptor activation

Experiments with hyperaldosteronemic animals suggest that, despite lowering plasma aldosterone, salt worsens renal injury by paradoxical activation of the mineralocorticoid receptor (MR). Salt and aldosterone synergistically contribute to renal impairment through Rac1-mediated activation of the MR, but whether angiotensin II also promotes renal injury through this mechanism is unknown. Here, we placed angiotensin II-overproducing double transgenic Tsukuba hypertensive mice on a low- or high-salt intake for 6 weeks and treated some animals with adrenalectomy, the MR antagonist eplerenone, the Rac inhibitor EHT1864, or hydralazine. High-salt intake, but not low-salt intake, led to hypertension and prominent kidney injury. Adrenalectomy prevented angiotensin II/salt-induced nephropathy in mice receiving high-salt intake, which was recapitulated by aldosterone supplementation, suggesting the involvement of aldosterone/MR signaling. Plasma aldosterone levels, however, were lower in high- than low-salt conditions. Instead, angiotensin II/salt-evoked MR activation associated with Rac1 activation and was not dependent on plasma aldosterone level. Both EHT1864 and eplerenone repressed the augmented MR signaling and mitigated kidney injury with partial but significant reduction in BP with high-salt intake. Hydralazine similarly reduced BP, but it neither suppressed the Rac1-MR pathway nor ameliorated the nephropathy. Taken together, these results show that angiotensin II and salt accelerate kidney injury through Rac1-mediated MR activation. Rac inhibition may be a promising strategy for the treatment of CKD.

Low-sodium meat products: retaining salty taste for sweet health

There is a positive correlation between excessive intake of sodium and incidence of hypertension. As diet is the main source of sodium, awareness among people regarding its possible role upon health has driven demand for various low sodium foods including meat products. Meat products contribute a significant amount of dietary sodium, thus maligning their own image. However, this is not an easy task as common salt affects taste and flavor, functional attributes, stability, and food safety of meat products. The various properties such as taste and flavor, binding, as well as microbiological characteristics should be given due care while developing low salt meat products and accordingly different approaches have been proposed for processing of such products. Potassium chloride has been mostly used to replace sodium; however, a number of other salts, flavor enhancers, bitter blockers and water, as well as fat binders have also been attempted either alone or in different combinations. A number of low sodium meat products have been developed but their economy and consumer acceptability are the major concerns needing proper attention. In future it is anticipated that these challenges would be overcome to provide well acceptable and cost-effective healthier meat products to the consumers.

Estimation of salt intake by 24 h urinary sodium excretion in a representative sample of Spanish adults

The present study reports the Na intake of a representative sample of Spanish young and middle-aged adults aged 18–60 years (n418, 53·1 % women, selected from the capitals of fifteen provinces and the surrounding semi-urban/rural area), measured with a 24 h urinary Na excretion method. To validate the paper collection of 24 h urine, the correlation between fat-free mass determined by electrical bioimpedance (50·8 (sd11·3) kg) and that determined via urinary creatinine excretion (51·5 (sd18·8) kg) was calculated (r0·633,P < 0·001). Urinary Na excretion correlated with systolic and dyastolic blood pressure data (r0·243 and 0·153, respectively). Assuming that all urinary Na (168·0 (sd78·6) mmol/d) comes from the diet, Na excretion would correspond with a dietary salt intake of 9·8 (sd4·6) g/d, and it would mean that 88·2 % of the subjects had salt intakes above the recommended 5 g/d. Logistic regression analysis, adjusted for sex, age and BMI, showed male sex (OR 3·678, 95 % CI 2·336, 5·791) and increasing BMI (OR 1·069, 95 % CI 1·009, 1·132) (P < 0·001) to be associated with excreting >200 mmol/d urinary Na – a consequence of the higher salt intake in men and in participants with higher BMI. The present results help us to know the baseline salt intake in the Spanish young and middle-aged adult population, and can be used as the baseline to design policies to reduce salt consumption.

Relative transcription of Listeria monocytogenes virulence genes in liver pâtés with varying NaCl content

Quantitative real time polymerase chain reaction (qRT PCR) was used to compare the relative transcription of prfA, inlA, sigB and clpC for three Listeria monocytogenes strains after incubation in i) a standard liver pâté versus brain heart infusion (BHI) broth and ii) the standard liver pâté versus three liver pâtés with reduced NaCl content of which one also has been supplied with organic acids (Ca-acetate and Ca-lactate). The three strains (EGD-e: reference strain; O57: more NaCl sensitive; 6896: more NaCl tolerant) were selected out of twelve strains based on their growth in BHI broth adjusted to 6%, 8%, 10% (w/v) NaCl. The three strains were spiked into the liver pâtés (10(9) cfu/g) and the BHI (10(9) cfu/ml) and incubated for 48 h at 7 degrees C; all incubation conditions supported growth of the strains. Extraction of intact listerial RNA from the liver pâtés was complicated by the complexity of the liver pâté matrix. However, a method has been optimized and described, and the quality of RNA extracted from liver pâtés was equal to the quality of RNA extracted from BHI. The amplification efficiencies of the six genes used for the transcription analyses (the four target genes and two reference genes, gap and rpoB) were within the acceptable range from 90% to 110% for all three strains in both liver pâté and BHI. Comparison of the three strains after incubation in the standard liver pâté and BHI showed that the relative transcription of prfA for O57 and the relative transcription of inlA and sigB for both O57 and 6896 were significantly higher when the strains were grown in BHI compared to the standard liver pâté. Reducing the NaCl content of the standard liver pâté did not change relative transcription levels of prfA, inlA, sigB or clpC (except for prfA in O57 and sigB in 6896). However, the presence of Ca-acetate and Ca-lactate induced relative transcription of the stress response gene, clpC, for all three strains. This study demonstrates that relative microbial gene transcription can be measured in complex food matrices and points to the need for designing experimental set-ups in real food matrices to replace the laboratory model systems. With respect to L. monocytogenes, it seems that the NaCl content of liver pâté can be lowered within the investigated range without significant changes in relative virulence gene transcription while more caution should be taken when adding organic acids such as acetate and lactate.

Salt and high blood pressure

HBP (high blood pressure) is the leading risk of death in the world. Unfortunately around the world, blood pressure levels are predicted to become even higher, especially in developing countries. High dietary salt is an important contributor to increased blood pressure. The present review evaluates the association between excess dietary salt intake and the importance of a population-based strategy to lower dietary salt, and also highlights some salt-reduction strategies from selected countries. Evidence from diverse sources spanning animal, epidemiology and human intervention studies demonstrate the association between salt intake and HBP. Furthermore, animal studies indicate that short-term interventions in humans may underestimate the health risks associated with high dietary sodium. Recent intervention studies have found decreases in cardiovascular events following reductions in dietary sodium. Salt intake is high in most countries and, therefore, strategies to lower salt intake could be an effective means to reduce the increasing burden of HBP and the associated cardiovascular disease. Effective collaborative partnerships between governments, the food industry, scientific organizations and healthcare organizations are essential to achieve the WHO (World Health Organization)-recommended population-wide decrease in salt consumption to less than 5 g/day. In the milieu of increasing cardiovascular disease worldwide, particularly in resource-constrained low- and middle-income countries, salt reduction is one of the most cost-effective strategies to combat the epidemic of HBP, associated cardiovascular disease and improve population health.

Salt intakes around the world: implications for public health

BACKGROUND

High levels of dietary sodium (consumed as common salt, sodium chloride) are associated with raised blood pressure and adverse cardiovascular health. Despite this, public health efforts to reduce sodium consumption remain limited to a few countries. Comprehensive, contemporaneous sodium intake data from around the world are needed to inform national/international public health initiatives to reduce sodium consumption.

METHODS

Use of standardized 24-h sodium excretion estimates for adults from the international INTERSALT (1985-87) and INTERMAP (1996-99) studies, and recent dietary and urinary sodium data from observational or interventional studies--identified by a comprehensive search of peer-reviewed and 'grey' literature--presented separately for adults and children. Review of methods for the estimation of sodium intake/excretion. Main food sources of sodium are presented for several Asian, European and Northern American countries, including previously unpublished INTERMAP data.

RESULTS

Sodium intakes around the world are well in excess of physiological need (i.e. 10-20 mmol/day). Most adult populations have mean sodium intakes >100 mmol/day, and for many (particularly the Asian countries) mean intakes are >200 mmol/day. Possible exceptions include estimates from Cameroon, Ghana, Samoa, Spain, Taiwan, Tanzania, Uganda and Venezuela, though methodologies were sub-optimal and samples were not nationally representative. Sodium intakes were commonly >100 mmol/day in children over 5 years old, and increased with age. In European and Northern American countries, sodium intake is dominated by sodium added in manufactured foods ( approximately 75% of intake). Cereals and baked goods were the single largest contributor to dietary sodium intake in UK and US adults. In Japan and China, salt added at home (in cooking and at the table) and soy sauce were the largest sources.

CONCLUSIONS

Unfavourably high sodium intakes remain prevalent around the world. Sources of dietary sodium vary largely worldwide. If policies for salt reduction at the population level are to be effective, policy development and implementation needs to target the main source of dietary sodium in the various populations.

Twelve-year trends and correlates of dietary salt intakes for the general adult population of Geneva, Switzerland

BACKGROUND/OBJECTIVES

Investigate dietary salt intake trends by gender, and their associations with risk factors for cardiovascular diseases in Geneva, Switzerland.

SUBJECTS/METHODS

Continuous surveillance of the Geneva general adult (35-74 years) population for 12 years (1993-2004) using a validated, semi-quantitative food frequency questionnaire (FFQ) in random, cross-sectional, representative samples (6688 men, 6647 women). Dietary salt intake assessment by FFQ excluded discretionary salt, but was calibrated on total salt intake using an independent validation substudy of 100 volunteers who additionally provided 24-h urine collections.

RESULTS

Quartiles (mean) of calibrated dietary salt intake (g per day) were 9.9, 10.5, 11.2 (10.6) in men, and 7.0, 7.8, 8.9 (8.1) in women and were above current recommendations. Quartiles (mean) of salt density (g MJ(-1)) were 0.99, 1.16, 1.39 (1.23) in men, and 0.98, 1.12, 1.30 (1.17) in women. Both measures were stable during the 12-year surveillance period, regardless of hypertension treatment. Salt-density differences between cardiovascular disease risk factor subgroups were moderate. Salt density increased with age and body mass index. The main dietary non-discretionary salt food sources (men/women: 47/48%) were breads (17/17%), cheeses (11/10%), meat and meat products (8/7%), soups (6/9%) and ready-to-eat foods (5/5%).

CONCLUSIONS

Salt intakes from all sources for the Geneva, and perhaps the Swiss adult population are above current recommendations. The quantitative and qualitative data provided in this paper could be used to develop and implement strategies for salt-intake reduction in Switzerland.

Pathophysiological Mechanisms of Salt-Dependent Hypertension

Changes in salt intake are associated in general with corresponding changes in arterial blood pressure. An exaggerated increment in blood pressure driven by a salt load is characteristic of salt-sensitive hypertension, a condition affecting more than two thirds of individuals with essential hypertension who are older than 60 years. In the last decade, significant insight was gained about the role of the kidney in the increment in blood pressure induced by sodium retention. The present review focuses on the pathophysiological characteristics of the blood pressure increase driven by expansion of extracellular fluid and the increment in plasma sodium concentration. In addition, we discuss systemic and renal conditions that result in decreased urinary sodium excretion and were implicated in the development of salt-sensitive hypertension.

Reducing salt: A challenge for the meat industry

Intake of dietary sodium has been linked to hypertension and consequently increased risk of cardiovascular disease (CVD). The estimated cost of CVD to both the EU and US economies is €169B and $403B, respectively. Currently the daily sodium adult intake is approximately three times the recommended daily allowance (Ireland and UK) and therefore public health and regulatory authorities are recommending reducing dietary intake of sodium to 2.4g (6g salt) per day. Processed meat products comprise one of the major sources of sodium in the form of sodium chloride (salt). Salt has an essential function in meat products in terms of flavour, texture and shelf-life. Apart from lowering the level of salt added to products there are a number of approaches to reduce the sodium content in processed foods including the use of salt substitutes, in particular, potassium chloride (KCl) in combination with masking agents, the use of flavour enhancers which enhance the saltiness of products when used with salt and finally optimising the physical form of salt so that it becomes more functional and taste bioavailable. The ultimate goal of ingredient suppliers and meat processors is to produce reduced sodium meat products that consumers can enjoy as part of an ongoing healthier diet and lifestyle. This article reviews some of the technological aspects of reduced salt meat products and how the meat and food ingredient industries are responding to this current health issue.

Salt and Blood Pressure: Time to Challenge

Hypertension is a worldwide epidemic and its control is costly, but still inadequate. The mechanisms underlying the development of primary hypertension remain elusive. Several observations point to the kidney as a primary actor and sodium as the main culprit for development of hypertension. Over the last few decades, experimental, observational and clinical data have continuously indicated that excess salt intake is positively associated with elevated blood pressure and that blood pressure can be significantly reduced with substantial reductions in dietary sodium. This review highlights the pathophysiological mechanisms linking sodium to elevated blood pressure, synthesizes available evidence for the effect of reducing salt intake in controlling blood pressure. It specifically analyzes 6 recent meta-analyses and dietary approaches to stop hypertension.

Blood pressure and urinary sodium in men and women: the Norfolk Cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk)

BACKGROUND

Abundant evidence indicates that a high sodium intake is causally related to high blood pressure, but debate over recommendations to reduce dietary sodium in the general population continues. A key issue is whether differences in usual sodium intake within the range feasible in free-living populations have clinical or public health relevance.

OBJECTIVE

We examined the relation between blood pressure and urinary sodium as a marker of dietary intake.

DESIGN

This was a study of 23104 community-living adults aged 45-79 y.

RESULTS

Mean systolic and diastolic blood pressure increased as the ratio of urinary sodium to creatinine increased (as estimated from a casual urine sample), with differences of 7.2 mm Hg for systolic blood pressure and 3.0 mm Hg for diastolic blood pressure (P < 0.0001) between the top and bottom quintiles. This trend was independent of age, body mass index, urinary potassium:creatinine, and smoking and was consistent by sex and history of hypertension. The prevalence of those with systolic blood pressure >/= 160 mm Hg halved from 12% in the top quintile to 6% in the bottom quintile; the odds ratio for having systolic blood pressure >/= 160 mm Hg was 2.48 (95% CI: 1.90, 3.22) for men and 2.67 (95% CI: 2.08, 3.43) for women in the top compared with the bottom quintile of urinary sodium. Estimated mean sodium intakes in the lowest and highest quintiles were approximately 80 and 220 mmol/d, respectively.

CONCLUSIONS

Within the usual range found in a free-living population, differences in urinary sodium, an indicator of dietary sodium intake, are associated with blood pressure differences of clinical and public health relevance. Our findings reinforce recommendations to lower average sodium intakes in the general population.

Sodium and potassium handling by the aldosterone-sensitive distal nephron: the pivotal role of the distal and connecting tubule

Sodium reabsorption and potassium secretion in the distal convoluted tubule and in the connecting tubule can maintain the homeostasis of the body, especially when dietary sodium intake is high and potassium intake is low. Under these conditions, a large proportion of the aldosterone-regulated sodium and potassium transport would occur in these nephron segments before the tubular fluid reaches the collecting duct. The differences between these two segments and the collecting duct would be more quantitative than qualitative. The collecting duct would come into play when the upstream segments are overloaded by a primary genetic defect that affects sodium and/or potassium transport or by a diet that is exceedingly poor in sodium and rich in potassium. It is likely that the homeostatic role of the distal convoluted and connecting tubules, which are technically difficult to study, has been underestimated, whereas the role of the more easily accessible collecting duct may have been overemphasized.