Researchers from the Poznań University of Medical Sciences presented their arguments in Frontiers in Environmental Science.

The One Health concept began to take shape at the beginning of the 21st century and is now developed jointly by the World Health Organization (WHO), the Food and Agriculture Organization of the United Nations (FAO), the United Nations Environment Programme (UNEP) and the World Organisation for Animal Health (WOAH).

It is based on the idea that human health is closely linked to animal health and the state of the environment. Problems such as zoonotic diseases, antimicrobial resistance and ecosystem degradation should therefore be considered together.

According to the Polish scientists, these issues have so far been at the centre of the concept, while too little attention has been paid to what they have in common: food production.

‘In our work, we propose including a plant-based diet in the One Health framework, because it can simultaneously support achieving almost all of its goals: support human health and animal welfare, and reduce antibiotic resistance, the risk of zoonotic diseases and pressure on the environment’, says Anna Choręziak from the Poznań University of Medical Sciences Doctoral School, the first author of the publication.

She says the issue is not only about the well-known links between diet and cardiovascular disease, diabetes and obesity. The connections begin at the stage of food production.

On industrial farms, for example, many animals are kept in confined spaces. ‘Sows and hens are kept in cages so tight that they cannot turn around. Chronic stress, bad conditions and numerous wounds can weaken their immunity, making them more susceptible to infections’, Choręziak says.

The risk of infections spreading is also increased by workers' contact with large numbers of animals, the transfer of microorganisms between farms and the environment by wild birds, rodents and insects, and the transport of animals over long distances.

According to the researchers from Poznań, the scale of the problem is reflected in the fact that approximately 75 percent of human infectious diseases that have emerged in recent decades are of zoonotic origin.

Intensive animal production also involves high antibiotic use. According to data cited by the authors, animal production accounts for almost three-quarters of global antibiotic use and contributes to the development of antibiotic resistance.

Meat production also has a major impact on the climate and on land and water resources. Red meat provides one of the clearest examples.

‘The average water footprint of the production of a kilogram of beef is approx. 15.4 thousand litres; in the case of a kilogram of lentils it is only 1.25 thousand litres’, Choręziak says.

Reducing demand for meat could also reduce pressure for forest clearing and the degradation of other natural ecosystems. Currently, more than 75 percent of global soy production is used for animal feed, while only about 6 percent goes directly to human consumption.

Reducing livestock production would therefore reduce demand for both pasture and land used to grow animal feed. The author also points to the large carbon footprint of ruminant farming, linked, among other things, to methane emissions during digestion. Emissions from egg, dairy and pork production are lower, but still higher than those associated with the production of legumes and other plant foods.

‘In turn, chickens are among the most commonly farmed animals in the world, so their total environmental impact also remains very large. And we should not forget about fish – the pressure here concerns aquatic ecosystems, feed use in aquaculture and the risk of spreading diseases’, Choręziak says.

She says this does not mean that the entire population should become vegan.

‘There is no need for that. For some people, a vegan diet may be a good choice. It is important that it is properly balanced, then it can be used at various ages and stages of life, also by pregnant and breastfeeding women, children, the elderly and athletes. However, an equally important direction is to simply reduce the consumption of animal products and increase the share of plant food in the diet’, she says.

‘Global recommendations suggest that a weekly intake of 300–600 g of meat is sufficient, yet in Europe, we consume up to 1.5 kg – 2.5 times that amount. Studies indicate that halving the proportion of animal-based products in one's diet can reduce associated greenhouse gas emissions by 30–50%’, she adds.

Such a change can also benefit health, although what replaces meat, dairy and eggs is crucial. According to the researchers, well-planned plant-based diets can lower the risk of cardiovascular disease, type 2 diabetes and certain cancers, while helping to maintain healthy body weight, blood pressure, glucose levels and lipid profiles.

However, the ‘plant-based’ label alone does not guarantee that a product is healthy. The diet should be based on legumes, vegetables, fruits, whole grains, nuts and seeds, while providing adequate amounts of vitamins B12 and D, calcium, iron, iodine, zinc and omega-3 fatty acids.

‘If our primary choices are highly processed meat-free products, or if we simply eliminate animal protein sources without replacing them with suitable plant-based alternatives, the diet will be neither healthy nor balanced’, Choręziak says.

She adds that it is also important to remember that plant-based foods can contribute to deforestation, excessive water use and biodiversity loss. The overall impact depends not only on the type of product but also on where and how it is produced.

The authors therefore do not want the entire responsibility for transforming the food system to fall on consumers. They say changes are needed in official dietary guidelines and institutional catering, alongside education, support for farmers growing high-protein crops, and investment in new protein sources and technologies, including cell-cultured meat.

These changes do not need to be identical in every country and should take into account local food production, prices, availability and culinary traditions.

‘The most important shift is to stop viewing dietary habits solely as a private matter for the consumer. If the food system impacts chronic and infectious diseases, antibiotic resistance, the climate, water resources, biodiversity, and animal welfare, then food policy effectively becomes health policy’, study co-author Professor Piotr Rzymski says.

Katarzyna Czechowicz (PAP)

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