In this article, our expert Dr Kate Edwards – Associate Professor in Exercise and Sport Science at the University of Sydney – reviews Fruit and vegetable intake is inversely associated with perceived stress across the adult lifespan by Radavelli-Bagatini et al. 2021, and breaks it down to give us the vital parts we need to know.
1) What was the high-level summary of the research?
The study found that reported perceived stress levels were associated with fruit and vegetable intake in adult Australians, with those people eating the most fruit and vegetables (>473g/day) reporting lower perceived stress than those eating the least (≤243 g/day). The World Health Organisation recommends eating 400g/day of fruit and vegetables. When looking at the effect across the different age groups, it was found that the positive associations were greatest in adults between the ages of ≥45-<65 years.
2) How was the study undertaken & what was it trying to measure?
The data came from a large study, the Australian Diabetes, Obesity and Lifestyle (AusDiab) Study. AusDiab is a national population-based survey of Australian adults aged ≥25 years, recruited in 1999–2000 (AusDiab1), they also included data from the 5-year follow up in 2004-2005. This study included 8689 adults at baseline and 5031 at 5 years follow up.
3) What did the study find?
First the study looked at the cross-sectional association (looking at the data at a single time point) and found that fruit and vegetable intake was associated with perceived stress. They then added into their model other factors that might also be associated with stress and that could attenuate the effects, like overall energy intake, physical activity, smoking, age, sex, BMI, relationship status, socio-economic index and chronic disease. Even accounting for all those factors, fruit and vegetable intake was still associated with perceived stress. Interestingly, when they looked at the change in fruit and vegetable intake over time, perceived stress was not associated, which the authors suggest means that fruit and vegetables might reduce perceived stress rather than stress leading to reduced fruit and vegetable intake.
4) Is there any other research out there that supports these findings or contradicts it?
This data is similar in findings to other studies but is much more representative of the whole population. Prior studies have found similar associations in pregnant women and students and have included smaller numbers of people. The data is 20 years old, but Australian Bureau of Statistics suggests there has been little change in fruit and vegetable intake between 2007-2018.
5) What’s the key takeaway for us to take from this research?
Public health messaging about fruit and vegetable consumption might be well targeted to middle-aged adults, as the association between perceived stress and fruit and vegetable intake was strongest in that group, and if the effect can be confirmed the messaging of anti-stress effects could be powerful.
6) Will you be doing anything differently because of this research?
This study suggests accounting for diet and in particular fruit and vegetable intake in stress research is important, and suggests that work examining the effect of diet interventions should be considered.