Cod Liver Oil, Fermented

Description

Cod liver oil, fermented rather than heat refined, with the vitamin A and vitamin D amounts both printed on the panel. This is the traditional preparation, and the reason the processing is named is that it changes what is in the bottle. A refined cod liver oil has its vitamins stripped during deodorising and then added back as synthetic concentrates; a fermented oil keeps what the liver held.

What is in the bottle

The vitamin A figure is the one to read first

This is the most important sentence on the page. Cod liver oil is a concentrated source of preformed vitamin A, retinol, and preformed retinol has an upper intake level of 3,000 micrograms RAE a day for adults. That limit exists because excess retinol accumulates, and it matters more during pregnancy, where high intakes are specifically cautioned against.

So the amount per serving is printed rather than described as naturally occurring and left there. Anyone already taking a multivitamin with retinol, or a separate vitamin A capsule, needs to add the figures together. The NIH vitamin A fact sheet gives the limits and the conversions.

Fermented against refined, and the oxidation question

Fermentation avoids the high temperatures of industrial refining, which is the case for it. The case against it, made publicly in independent testing over the years, is that unrefined fish oils can carry higher oxidation markers than refined ones, and fermented cod liver oil has been at the centre of that argument more than once.

We are not going to settle it in a product description. What we can do is publish the peroxide value, the anisidine value and the composite TOTOX figure for your lot against the GOED limit of 26, and withdraw anything that fails. A number beats a position, which is the argument in why we publish the batch that failed.

Cod liver oil against a fish body oil

They come from different tissue and they carry different things. Body oil from anchovy or sardine is pressed from muscle and arrives with EPA and DHA and almost no vitamin A or D. Liver oil carries both vitamins, because the liver is where a fish stores them. A cod liver oil is therefore a vitamin product as much as an omega-3 product, which is why it needs a different reading than the softgels beside it.

Anyone who wants the fatty acids without the retinol should buy a body oil concentrate instead. Anyone who wants the traditional preparation with its vitamins intact is in the right place, provided the figures get added up rather than admired.

Why the vitamins are not standardised

Vitamin content in a natural liver oil moves with the fish, the season and the catch, so a fermented oil cannot promise an identical figure in every bottle. That is a genuine disadvantage against a refined oil with added concentrates, and the honest response is to assay each lot and print what it actually holds.

EPA and DHA, in proportion

A cod liver oil is not a concentrate, so the EPA and DHA content per spoonful is modest compared with a re-esterified triglyceride concentrate. Both amounts are listed separately and as a combined total, priced per gram of the two, which is how everything on the omega and fats page is quoted.

Storage, which matters more here

Keep it in the refrigerator once opened and use it within the window stated on the label. An unrefined oil has no added antioxidant from a refining step, so time, warmth and air do more to it than they would to a processed concentrate.

Testing

Every lot of cod liver oil is assayed by an independent laboratory for vitamin A, vitamin D, EPA and DHA, and screened for mercury, lead, cadmium, arsenic, dioxins, PCBs and oxidation markers. Lots outside specification are withdrawn and their certificates stay published. The assay covering the bottle you receive is linked on this page.