Australian diets are nutritionally imbalanced, with diets low in fruit and vegetables and high in salt among the top risk factors (1). It is estimated that only 5% of Australians are meeting the recommended guideline of 2 or more serves of fruit and 5 or more serves of vegetables per day, with just over half of Australian adults meeting the fruit guideline alone and only 7.5% meeting the vegetable guideline alone (2). For salt, Australians are consuming almost double (3) the recommended daily maximum amount of 5 grams (4), placing them at increased risk of developing high blood pressure (5). Low consumption of fruit and vegetables, and high salt intakes, increase population risk of cardiovascular diseases (CVDs), diabetes, kidney disease and some cancers (1). Together, these three dietary risk factors account for more than 11,500 deaths and almost 192,000 disability-adjusted life years in Australia each year (1).
Strategies to improve Australian diets, by increasing fruit and vegetable intake and decreasing salt intake, offer an opportunity to reduce Australia’s disease burden. Strategies should include interventions to improve the food environment, through food reformulation and nutrition standards in public settings (6, 7), supplemented by programs to raise consumer awareness and positively shift consumer behaviours (8). The consumer strategy should be informed by a comprehensive understanding of the population’s knowledge, attitudes and behaviours (KABs) relating to healthy diets, including fruit, vegetable and salt intakes (9). This includes whether KABs differ by population subgroups such as sex, age, location and socioeconomic background, and if specific strategies are needed to reach different groups.
Self-reported fruit and vegetable intake data are routinely collected in national health surveys, however, these data are only disaggregated by age and sex (2, 10, 11). One study in young adults aged 18–34 years determined fruit and vegetable intake differed by selected socio-demographic factors (e.g. sex, age, location) (12). It is possible these differences exist across all age groups. Another study found no difference in fruit and vegetable score by levels of socioeconomic disadvantage, education level or household income when using a using a dietary guidelines index (13). Given the varying results in past studies, further research to determine if there are socio-demographic differences in fruit and vegetable intakes in Australia is necessary.
Several studies have investigated salt-related KABs in Australia. However, most surveys have not been administered to a nationally representative sample (14–21), and many have only included questions about two discretionary salt behaviours, adding salt at the table or during cooking/meal preparation (15–17, 21). The most recent national salt-related KAB survey, which was conducted in 2007 and comprised 23 questions, was one of only a few studies that have asked a more extensive set of questions about salt-related KABs and the only comprehensive survey in a nationally representative sample (22). Given the time elapsed since the last nationally representative survey, an update on current salt-related KABs is warranted and would be useful in informing a future national consumer campaign. When comparing the results from more recent subnational studies (14–21), large variations in participant responses were evident, likely due to the differences in sample characteristics and sampling methods. For example, the proportion of participants frequently adding salt during meal preparation varied from 46% (19) to 84% (21) and at the table from 36% (16) to 68% (14). Given the variability in participant responses between subnational studies, differences in salt-related KABs between population subgroups should be considered. In a large Victorian study, differences in salt-related KABs were identified by socio-demographic factors, including sex, age and socioeconomic status (18), and this may be true across Australia, though no study has yet investigated this.
In a nationally representative sample of Australians, this study aimed to describe self-reported intake of fruit and vegetables and knowledge, attitudes and behaviours related to salt intake, and determine if these measures differed between socio-demographic population subgroups (i.e. sex, age, location, educational attainment, language, Indigenous status, weight category and area-level disadvantage).