- Sustainability of fish stocks.
- Contamination with pesticides, heavy metals and other pollutants.
- How it is treated and stored to prevent oxidation.
(Please click on the diagram to enlarge)
Now, I am not quite sure about the sustainability of Peruvian fish stocks; but I do believe that these smaller fish are less stressed than larger fish, like Tuna, and their ability to recover from over-fishing is better.
Contamination from pollutants - heavy metals is a huge issue that could become as great a threat to human existence as global warming. For a billion or so years, there has been a steady drawing of mercury and other heavy metals out of the environment and sequestering them in coal deposits. This process is rapidly being undone with these highly toxic poisons being concentrated in the brains and other organs of creatures. The main culprits are countries like China, Australia and the USA - and many others including NewZealand. Burning coal releases heavy metals into the environment where it steadily concentrates in the food chain. Sadly for us, we are at the top of the "eating order". Mercury contamination is implicated in the soaring rates of diabetes, mental retardation and dementia to name a few. So, when choosing fish oil, it does pay to favour small fish that a low in the food chain. Then is pays to favour an oil that is carefully refined to ensure that any contaminants are removed.
Finally, we have the issue of oxidation of the oil once it is on the shop shelf or in your cupboard. These are delicate oils that go off quickly when exposed to oxygen and sunlight. Once rancid oxidised, these oils become harmful, rather than healthful. Oxidisation is prevented by storing the oil in dark bottles and any air in the bottle is nitrogen. The oil is stabilised by the addition of anti-oxidants such as vitamin E. Fish and flax oil that is packaged this way will last for a very long time, not requiring refrigeration. Once opened, the oil should be used quite quickly, rather than left lying around for months and should be stored in a dark refrigerator.
Rather than relying on fish oil alone for your Omega3 oils, get them from a variety of sources, including olive oil and flax oil - both of which should be contaminant free and sustainable when grown organically. I always think it is best to go for heaps of variety in everything you eat because that way you are better ensured that you are getting all the nutrients you need.
Email Gary: gary at myotec.co.nz (Replace the "at" with @ and remove spaces). Please include any relevant background information to your question.