The aim of this study is to conduct a comparative analysis across nations to: (1) identify the determinants influencing knowledge and attitudes related to sodium (Na) intake and (2) to analyse the association between knowledge and attitudes related to Na intake.

We utilised a secondary data from a cross-sectional study that was conducted across seven nations. Structural equation modelling (SEM) was utilised to assess the impact of socio-economic and health-related predictors on knowledge and attitudes pertaining to Na intake and further to investigate the relationship between knowledge and attitude.

Indonesia, Brazil, Thailand, Japan, France, the UK and the USA.

7090 participants aged 15 years and above were included in the study.

SEM analysis showed a strong association between knowledge about Na intake and related attitude across all countries, particularly in the UK (2·65, 95 % CI 1·48–3·82), France (2·62, 1·45–3·79) and the USA (1·97, 1·21–2·73). In Brazil, Japan and France, individuals or family members having certain health conditions such as raised blood pressure, heart diseases, strokes or other diseases exhibited a positive attitude towards reducing Na intake. Conversely, socio-economic factors like education and income demonstrated the complexity of influences on knowledge and attitudes about Na intake.

The study underscores the need for tailored public health interventions to reduce excessive Na consumption, considering the diverse cultural, social and economic factors. It highlights the complex determinants of knowledge and attitudes towards Na intake, calling for further research in varied populations.

Excessive salt intake raises blood pressure and increases the risk of non-communicable diseases (NCD), such as CVD, chronic kidney disease and stomach cancer. Reducing the Na content of food is an important public health measure to control the NCD. This study quantifies the amount of salt reduced by using umami substances, i.e. glutamate, inosinate and guanylate, for adults in the USA.

The secondary data analysis was performed using data of the US nationally representative cross-sectional dietary survey, the National Health and Nutrition Examination Survey (NHANES) 2017–2018. Per capita daily salt intake corresponding to the NHANES food groups was calculated in the four hypothetical scenarios of 0 %, 30 %, 60 % and 90 % market share of low-Na foods in the country. The salt reduction rates by using umami substances were estimated based on the previous study results.

The USA

4139 individuals aged 20 years and older in the USA

Replacing salt with umami substances could help the US adults reduce salt intake by 7·31–13·53 % (7·50–13·61 % for women and 7·18–13·53 % for men), which is equivalent to 0·61–1·13 g/d (0·54–0·98 g/d for women and 0·69–1·30 g/d for men) without compromising the taste. Approximately, 21·21–26·04 % of the US adults could keep their salt intake below 5 g/d, the WHO’s recommendation in the scenario where there is no low-Na product on the market.

This study provides essential information that the use of umami substances as a substitute for salt may help reduce the US adults’ salt intake.

To examine the association between the consumption of green tea, coffee and caffeine and depressive symptoms.

Cross-sectional study. Consumption of green tea and coffee was ascertained with a validated dietary questionnaire and the amount of caffeine intake was estimated from these beverages. Depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale. Multiple logistic regression analysis was performed to compute odds ratios and 95 % confidence intervals for depressive symptoms with adjustments for potential confounders.

Two workplaces in north-eastern Kyushu, Japan, in 2009.

A total of 537 men and women aged 20–68 years.

Higher green tea consumption was associated with a lower prevalence of depressive symptoms. Compared with participants consuming ≤1 cup/d, those consuming ≥4 cups green tea/d had a 51 % significantly lower prevalence odds of having depressive symptoms after adjustment for potential confounders, with significant trend association (P for trend = 0·01). Further adjustment for serum folate slightly attenuated the association. Coffee consumption was also inversely associated with depressive symptoms (≥2 cups/d v. <1 cup/d: OR = 0·61; 95 % CI 0·38, 0·98). Multiple-adjusted odds for depressive symptoms comparing the highest with the lowest quartile of caffeine consumption was OR = 0·57 (95 % CI 0·30, 1·05; P for trend = 0·02).

Results suggest that higher consumption of green tea, coffee and caffeine may confer protection against depression.