As we move through time scientific research improves our understanding of the world. The resulting revelations often point to changes that could lead to progress. However, these changes are rarely painless.
Shifting away from the use of antibiotics on livestock and the agricultural use of pesticides are not small adjustments. They underpin current farming methods on many Swiss farms. And using these substances has clear short term advantages at the production level.
However, a number of studies suggest that these advantages come at a cost to environmental and human health, and some in Switzerland have decided the cost is too high.
Where the line should be drawn on using farm chemicals has been thrust into the political limelight in Switzerland by two votes on 13 June 2021 to phase out the use of certain chemicals on farms.
Finding a compromise is messy. Some believe organic and agro-chemical based farming can coexist alongside each other. However, the complex interconnected fabric of nature means these chemicals end up in shared waterways and get moved around in animal manure, by the wind and by insects, making it difficult to compartmentalise different farming methods. Vote organisers recognise these interconnections and are pushing for change. For them the health and environmental costs are too high.
Many others, a large number of farmers in particular, see the phasing out of pesticides and antibiotics as a poor tradeoff, especially given they will be left with the pain of change and potentially lower production.
So what research is there to support the dangers of these substances to human health?
The development of low cost DNA sequencing has turbocharged our understanding of the billions of tiny microorganisms in the human gut microbiome and how damage to them is associated with diseases such obesity, cancer, depression, dementia and autoimmune diseases. Research on endocrine interrupters that upset human hormones continue to progress too.
Obesity is one of the biggest health concerns of our time. The percentage of the population suffering from obesity has risen dramatically. Between 1975 and 2016, Obesity rose from 5% to nearly 20% of Switzerland’s population.
Some research suggests a link between the agricultural use of antibiotics and unhealthy waistlines. A US study suggests that its obesity and type II diabetes epidemic may be driven by population-wide chronic exposures to low-residue antibiotics that have increasingly entered the American food chain and environment over the same time period. Antibiotic residue was found in meat, but also in water and plants. Much of the antibiotics given to animals ends up in their manure, which ends up in waterways and sprayed on plants as fertiliser. Switzerland’s large imports of animal feed mean it has an oversized quantity of animal poop, which is often spread around as fertiliser.
Other studies suggest a link between pesticides and obesity. One possible causal link is endocrine interruption. These substances, which are contained in some pesticides may interfere with this part of the human hormone system, either directly or via the gut microbiome. There might also be an epigenetic effect, that would allow the problem to be passed on directly to future generations via alterations in how genes are expressed.
Rates of cancer have been rising for some time. Since 1990, rates have risen across all age groups in Switzerland. Here too research suggests links with some pesticides and cancer. In 2015, the International Agency for Research on Cancer (IARC) classified five pesticides as probably or possibly carcinogenic. But questions remain.
It is also possible that allergies and food intolerances are associated with pesticides and antibiotics via disturbances to the human gut microbiome. A study finds an association between rising gluten intolerance (and Hodgkin’s lymphoma) and glyphosate use. A causal hypothesis is that glyphosate, a known antimicrobial agent, is damaging the gut microbiome and reducing its ability to fully digest gluten.
A man today has around half the sperm count of his grandfather. A study in the US that looked at male fertility found a strong correlation between pesticide exposure and low sperm count. The causal link here is likely to be hormonal.
Much remains to be discovered and these studies have their limitations. Many of the people studied in the research on the links between pesticides and cancer had higher than average exposure to pesticides.
There are other research challenges too. The use of some chemicals is now so widespread, it is now difficult to find control groups completely unexposed to them. In addition, there are the many confounders, things that occurs alongside the thing studied that might be the true cause of the outcome rather than the thing studied.
None of this research is perfect. But it is attempting to find answers to important questions, such as why obesity has risen, why more people have cancer, dementia, autoimmune diseases, allergies and lower fertility. Evidence continues to emerge around links between the use of these chemicals and disturbances in our hormone systems and the trillions of important microbes in our digestive systems.
The two votes in Switzerland on 13 June 2021 shine a light on this difficult topic.
Some see these chemicals as harmful and want to be able to avoid them and spare the environment from their effects. They argue that the interconnected nature of the ecosystem means these substances cannot be avoided unless they are phased out everywhere.
Others are more focused on the short term advantages of using these chemicals and believe they are relatively harmless. Some on this side of the debate also believe that the compartmentalisation of organic or non-organic farming is effective.
At some point science is likely to provide greater clarity. In the meantime, expect sparks to fly.