The market in this prized commodity is worth billions – but are the supposed benefits worth the cost to global ecosystems?

• Revealed: many common omega-3 fish oil supplements are ‘rancid’

Scanning the shelves and internet for fish oil is a dizzying task. There are dozens of brands available and, although the typical consideration for the popular supplement is that quality matters most, it is not the only factor.

These prized products travel a long way before being labelled as “pure” and “fresh” – starting with the industrial-scale grinding down of a tiny fish that is crucial for healthy ocean and food systems.