In the paper “Hallmarks of environmental insults” published in 2021, researchers set out eight distinct ways in which the things we are exposed to in our environments can have effects on our health.
1. Oxidative stress and inflammation
Many environmental pollutants contain extremely aggressive chemicals called reactive oxygen species. These can overwhelm our natural antioxidant defences and cause inflammation, cell death and organ damage.
2. Genomic alterations and mutations
Mutagens in pollutants damage DNA and trigger cancer and other chronic diseases.
3. Epigenetic alterations
Air pollution, pesticides and heavy metals have been shown to induce harmful changes in gene expression during our lifetimes through effects such as DNA methylation and histone modification, which are known to be linked to the process of ageing.
4. Mitochondrial dysfunction
Mutagens and reactive oxygen species can also damage the genome and epigenome of mitochondria, our cells’ power packs. Such damage seems to increase the risk of conditions such as type 2 diabetes and breast cancer.
5. Endocrine disruption
Many chemicals found in the environment, food and consumer products disrupt the regulation of hormones, something that might be associated with type 2 diabetes and age-related thyroid dysfunction.
6. Altered cell communication
Some pollutants directly interfere with cell-to-cell communication, and prematurely aged cells can become dysfunctional communicators. The result can be “inflammaging”, or system-wide chronic inflammation that is a hallmark of ageing.
7. Altered microbiome communities
Toxic environmental substances reaching the gut can alter its microbial communities, increasing susceptibility to allergies and infections.
8. Impaired nervous system function
Noise pollution can disrupt the autonomic nervous system, leading to hikes in blood pressure and cardiovascular disease. Microscopic particles in air pollution reach the brain through the olfactory nerve and interfere with cognition.
© Climate Response Ireland, Celbridge, Kildare, Ireland 2021