A new analysis of the data from the Melbourne Collaborative Cohort Study has warned that the amount of highly processed food being consumed by Australians could be negatively impacting their mental health.
After adjusting for sociodemographic characteristics and lifestyle and health-related behaviours, participants with the highest relative intake of ultra-processed food had a significantly higher risk of psychological distress compared to participants with the lowest intake.
Lead author, Dr Melissa Lane, who completed the research as part of her PhD studies at Deakin University’s Food and Mood Centre, explained that Australians who ate the most ultra-processed food had about a 23% higher risk of depression compared to those who ate the least.
“Our study comprised people who were initially not taking any medication for depression and anxiety and followed them over 15 years,” Dr Lane said.
“Even after accounting for factors like smoking and lower education, income and physical activity, which are linked to poor health outcomes, the findings show greater consumption of ultra-processed food is associated with a higher risk of depression.”
Participants in the top quartile of ultra-processed food consumption appeared to be more likely to be born in Australia or New Zealand and live alone, were less likely to have completed tertiary education, and more likely to be classed as ‘disadvantaged.’
The study also found no evidence for any impact of gender, age, or existing BMI with ultra-processed food intake.
“While Australians eat a lot of ultra-processed foods, the link with depression has never been assessed in a group of Australians until now,” Dr Lane said.
“Depression is one of the most common mental disorders across the globe and it is a major health problem because it negatively affects daily living and well-being through lasting low energy, changes in appetite and sleep, loss of interest or pleasure, sadness, and sometimes thoughts of suicide.
“Identifying a critical level of consumption that may increase the risk of depression will help consumers, healthcare professionals and policymakers make more informed decisions around dietary choices, interventions and public health strategies.”
Ultra-processed foods are not limited to typical junk and fast foods. They also include mass-produced and highly refined products that might be considered relatively ‘neutral’ or even ‘healthy’ like diet soft drink, some fruit juices and flavoured yoghurts, margarine, packet preparations of foods like scrambled egg and mashed potato and many ready-to-heat and-eat pasta dishes.
And concerningly, food insecurity, already linked to depression amongst a host of negative outcomes, has seen a surge in the number of people forced to consume a diet largely composed of ultra-processed foods.
According to the Australian Institute of Family Studies, certain groups in Australia are more susceptible to food insecurity – including unemployed people, single parent households, low-income earners, rental households, and young people – a situation exacerbated by the impact of the current housing crisis.
“Economic barriers to food security are common and low-income families often experience challenges in purchasing adequate quantities of food, as well as appropriately healthy food,” the Institute said.
Food insecurity was associated with lower household income, increased use of healthcare, poorer general health as well as depression, with vulnerable groups and people on low incomes most likely to display health risk factors such as poor nutrition.
“Welfare dependent families needed to spend at least 33% of their weekly income to eat according to public health recommendations if they bought generic brands.”
The issue has become such crucial aspect of Australia’s economic landscape that a Senate Inquiry into the Extent and Nature of Poverty in Australia was launched on 7 December 2022, which noted that data produced by Australia’s largest hunger-relief charity, the “Foodbank Hunger Report 2022” estimated that around 21% families are deeply food insecure, going without food for at least one day, having been unable to afford it in the past 12 months.
The Inquiry held sessions in Perth on 4 April 2023 and heard evidence from Adjunct Professor Tony Pietropiccolo AM, representing both Centrecare and The Equity Project, that children and young people living in the 20% least well-off households are four times more likely to experience severe mental health problems than those in the highest income thresholds.
“For households, this can start for children in utero, as the mother is undernourished and stressed,” Mr Pietropiccolo said.
The Equity Project’s submission stated that “families affected by poverty often resort to diverse survival strategies, which include, but are not limited to skipping meals or reducing food portions and substituting fresh and/or nutritionally dense food for cheap, highly processed and inferior quality food.”
As the Australian Unemployed Workers’ Union told the Inquiry in February 2023, “Eating healthy costs a lot of money,” a reflection echoed by ‘Kerry,’ a 60-year-old recipient of the Disability Support Pension.
“I’m living on a shoestring, and my health is suffering as well. The doctor says to me, ‘Your diabetes is high, you’ve got to eat better.’ And I said, ‘Well, I can’t eat better because there’s no money.’ If I had the money, of course you can buy better food … and I would go to the gym as well, but I can’t do that because there’s no money,” Kerry shared.
“He wanted to send me to a dietitian, and I said, ‘Well, you’re wasting your time. I know what to eat, the problem is I can’t.’”