Researchers at Queensland University of Technology (QUT) have identified that foods that are good for us and can help build our immune systems are also better for the environment.
Prompted by a 350 per cent rise in online searches for ‘immunity boosting foods’ during Covid, ecologist Dr Ayesha Tulloch and dietitian Professor Danielle Gallegos analysed 150 webpages from six world regions.
They found 83 per cent of the 2556 recommendations for foods that might boost immunity were plant-based.
Gallegos said, “We found a variation – from a high of Australia’s 82.5 per cent plant-based food recommendations to a low of 77.7 per cent in the UK.
“While there is no evidence that any one food provides immunity from infectious diseases, a person’s overall diet can affect their health and disease susceptibility. The only evidence-based approach to disease immunity is vaccination.”
There were 23 overall recommended food groups – both animal and plant based – with the top six all plant based:
- brassicas and leafy green vegetables;
- vitamin-C-rich fruit and vegetables;
- other vegetables;
- nuts;
- lycopene-rich fruit and vegetables such as tomatoes and capsicum; and
- onions and garlic.
Gallegos explained that while poor nutrition increased the risk of infection, nutrients such as vitamin D and Zinc, and the phytonutrients found in plants help protect against disease and can improve the body’s defence against – and resistance to – infection.
Meanwhile, Tulloch said the average environmental impact of the six top-ranked food groups were generally lower than rarely recommended food groups.
The QUT study used data from two global study to examine the agricultural production required for an average serving of 150 foods against five types of environmental degradation:
- greenhouse gas emissions;
- land use;
- scarcity-weighted freshwater use;
- acidification of soil; and
- eutrophication (two forms of nutrient pollution).
Tulloch said, “Our analysis showed that eating a serving of a more frequently recommended food over a less recommended one would result in lower impacts for greenhouse gas emissions and land use, as well as health risks,” said Tulloch.
While land environments fared better when people ate the most frequently recommended foods, it was the opposite for the aquatic environment due to the use of chemicals and freshwater during production.
The researchers also found that not all recommended foods had the joint benefit of reducing negative impacts on health and the environment.
Yoghurt, eggs, and poultry comprised the 6th, 11th and 17th most frequently recommended foods, but were in the top quartile of the worst outcomes for environmental and health impacts.
“Foods with a low land impact can have high environmental impacts if their production is dominated by water, fertiliser, and pesticide intensive methods that use large volumes of water and produce water acidification and algae growth,” said Tulloch.
Tulloch and Gallegos said the rise in consumers’ interest in health and wellbeing and the environmental impacts of what they eat was an opportunity to educate, engage, and empower them and their purchasing habits.
“Empowering the public to change eating habits and food consumption to more sustainable practices is complex and requires a combination of approaches and online information should not be disregarded in this mix.
“In times of crisis when people are more likely to seek information, the opportunity to engage with the public online and build awareness of beneficial behaviour change,” Gallegos said.
The study, Environmental and public health co-benefits of consumer switches to immunity-supporting food, was published in Ambio.
