The Nutrition Examination Research Digest (NERD) aims to provide rigorous, unbiased analysis of the latest and most important nutrition and supplementation studies. Click here to subscribe or login if already a subscriber .

In this article

Something smells fishy: is your fish oil oxidized?

Previous research found that a lot of fish oil being sold in New Zealand was subpar. Newer research out of Australia says otherwise.

Study under review: Australian and New Zealand Fish Oil Products in 2016 Meet Label Omega-3 Claims and Are Not Oxidized.

Introduction

In 2015, a research group published a study[1] examining the quality of fish oil supplements sold in New Zealand. We reviewed this study way back in ERD #5’s Fish Oil or Snake Oil. The results were startling. Out of 32 fish oil products tested, 90% tested below the stated label claims for omega-3 content and two-thirds contained less than 70% of listed omega-3 amounts. More concerning, over 50% were considered rancid according to their TOTOX values, a measure of oil oxidation.

Fish oil oxidation and inaccurate dosage labeling can be a big issue for consumers. If the amount of DHA+EPA in a fish oil supplement is considerably lower or higher than what the label claims, you could end up over- or underdosing. With regard to oxidation, there is little research in humans on the effects of consuming poor quality fish oil. This makes it hard to say if they are safe for consumption or what safe levels of consumption may be.

As could be expected from such a startling negative finding about one of the world’s most beloved supplements, media outlets howled with headlines about consumers being misled about their purchases of fish oil supplements. However, the study was not without controversy. Several experts from authoritative groups on lipids and omega-3 fatty acids claimed that the 2015 paper had several flaws, such as not using an accredited laboratory or industry-standard testing protocols. In the study under review, some of these same researchers attempted to replicate the 2015 study with a new batch of fish oil supplements common to Australia and New Zealand.

A 2015 study on fish oil quality on New Zealand fish oil supplements showed that most did not contain the amounts omega-3 claimed on the label and were heavily oxidized. Another research group claimed that the 2015 study used improper testing methodology. The study under review is an attempted replication of the 2015 study investigating label claims and rancidity of a new batch of fish oil products from Australia and New Zealand.

Who and what was studied?

Become a subscriber to the Nutrition Examination Research Digest to read the full article.

Becoming a member will keep you updated on the most important nutrition studies every month, and give you access to our back catalog of over 500 other articles.

NERD also includes access to Examine Personalized, which includes 150+ monthly summaries on the most important recent studies and access to our database of 10,000+ studies across 600+ health topics.

Stop wasting time and energy — we make it easy for you to stay on top of nutrition research

Try free for a week

Already a member? Please login to read this article.

What were the findings?

Subscribe to the Nutrition Examination Research Digest to unlock this article.

Free 7-day trial!

Already a member? Please login to read this article.

What does the study really tell us?

Subscribe to the Nutrition Examination Research Digest to unlock this article.

Already a member? Please login to read this article.

The big picture

Subscribe to the Nutrition Examination Research Digest to unlock this article.

Already a member? Please login to read this article.

Frequently asked questions

Subscribe to the Nutrition Examination Research Digest to unlock this article.

Already a member? Please login to read this article.

What should I know?

Subscribe to the Nutrition Examination Research Digest to unlock this article.

Already a member? Please login to read this article.

Other Articles in Issue #36 (October 2017)