Here are a few candidates:
1) Environmental contaminants in water, food, and air https://slimemoldtimemold.com/2021/07/13/a-chemical-hunger-p...
2) Xenoestrogens in plastics, pesticides, toiletries, perfumes, polyester and nylon clothing https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3947648/
3) Mass consumption of pharmaceutical drugs
4) Vegetable seed oils https://chriskresser.com/how-industrial-seed-oils-are-making...
5) Sugar and hyper palatable foods https://slatestarcodex.com/2017/04/25/book-review-the-hungry...
6) Endemic pathogens like toxoplasmosis https://www.hardtowrite.com/pathogens/