In Fishy Business: Why Fish Oils Can Do More Harm Than Good, Youri Kruse, alongside notable contributors Raymond Peat, PhD, and Petr Grúz, PhD, delivers a provocative and meticulously argued critique of the widespread enthusiasm for fish oil supplements. Marketed as a panacea for heart health, inflammation, and even cognitive function, fish oils—rich in omega-3 fatty acids like EPA and DHA—have become a multi-billion-dollar industry. Yet, Kruse’s book challenges this narrative, urging readers to reconsider the science and rethink the risks.
The central thesis of Fishy Business is that fish oils, far from being the miracle cure they’re often portrayed as, may actually pose significant health risks due to their chemical instability and biological effects. Kruse argues that the polyunsaturated fatty acids (PUFAs) in fish oils are highly prone to oxidation. These oxidized compounds have been linked to inflammation, immune suppression, and a host of chronic diseases—ironically, the very conditions fish oils are supposed to prevent.
Kruse doesn’t stop at biochemistry. He traces the historical rise of fish oil supplementation. The book highlights how early studies linking fish consumption (not supplements) to cardiovascular benefits were misinterpreted, leading to an overzealous push for isolated omega-3s.
Kruse backs his claims with scientific references. The book compellingly argues that the body doesn’t need supplemental fish oils and that whole foods, not capsules would do.
Fishy Business is a valuable cautionary tale. It’s not a call to demonize fish itself—eating fatty fish like salmon or sardines remains an option. Kruse questions that as well and favors less fatty fish.