Is My Fish Oil Supposed to Smell FISHY??

I had an interesting conversation with a regular patient of mine yesterday which I think all of you would be interested in.


While my regular patient was waiting for her prescription, she asked me whether I have watched the most recent episode of “The Check-Up” from TV One.


Unfortunately, I haven’t been watching much TV in a long time. Life has taken its toll on me and I’m still trying to find the sweet spot between work and leisure. So I said to her that I hadn’t even heard of that show!


Anyway, she went on saying she will never take fish oil again after watching the show!


That got my curiosity going and I said to myself…Okay, now I’ve got an excuse to watch some TV tonight..yahooooo!!!


So, I went home immediately after work, took off my shoes, said hello to my wife and jumped straight in front of my computer. I went to the TVNZ on demand site to watch the recent episode of “The Check-Up”.


I fast-forwarded to the segment where it talked about omega 3 fish oil. The scientist on the show discussed how they have tested 36 products on the New Zealand market and 90% of them exceeded at least one of the limits of oxidation that they tested. Also, they found out that most of the products tested contained less than the amount of omega 3 specified on the label and only 3 products had as much as what it claimed to have or more.


Before I move on, we need to make sense of what fish oil oxidation is.


Have you ever come across that old bottle of fish oil capsules that was sitting in your cupboard for years and when you open the lid, there was this strong fishy smell? This is because the fish oil you’ve got is off! Normal fish oil should not have a fishy smell or taste to it. So, this led to the next questions why many fish oil products do not smell nice when they are off? Well, this comes from an element with which we are all quite familiar with: Oxygen.


Fish oil in its raw form is very sensitive to oxygen. If the fish oil is exposed to oxygen over a significant period, it will most likely undergo oxidation and turn rancid. After some research, I found out that when fish oil is wild-caught and harvested, it is usually transported to a factory to be refined and bottled. This process is usually short to prevent oxidation. Some manufacturers will also add antioxidants to prevent the fish oil from being oxidised.


Now going back to the show.


The findings were a huge shock to me. No wonder my patient said she will never take fish oil again! However, my curious mind didn’t stop here. I kept asking myself…” surely there’s more to this”. So, I started searching on the web trying to find out more about oxidation in fish oil and I came across a more recent study that tested 47 fish oil supplements purchased at retail in New Zealand. The study shows that 91% met the amount of DHA & EPA claimed on the label, according to strict Global Organization for EPA and DHA Omega-3s (GOED) standards, while most also met regulatory limits for oxidation.


The results are in stark contrast to findings from the scientist featured in the show, which was published in 2015, which claimed that only 9% of the fish oils in New Zealand market met label claims for EPA and DHA, and 17% were below the oxidation limits.


The author of the new study indicates a high level of confidence in the accuracy of the obtained test results because multiple accredited laboratories tested the samples were able to obtain similar results on oxidative status and omega-3 content.


The author of the new study also suggests that the replication study results show that fish oil supplements in the New Zealand market contain the correct content of EPA and DHA are not excessively oxidised. Hence, consumers can feel confident that fish oils they can purchase are quality products.


The purpose of me sharing my findings with all of you is not to undermine the “The Check-Up” programme. But, what I truly believe is that we should consider all the evidence available before we make our judgement or decision.


So if you ask me is it still worth taking omega fish oil. My answer would be …. Based on available evidence, fresh oily fish such as salmon, mackerel, and sardines are always the best sources of omega 3. According to the heart foundation, it is recommended to eat fish at least twice a week.


For people who are unable or dislike fish then taking omega 3 supplements seems to be a reasonable alternative. Some plants are rich in another type of omega 3 fatty acid, alpha-linolenic acid, which the body can convert to DHA and EPA. Good examples of these are flaxseeds, chia seeds, walnuts, pumpkin seeds, canola oil.


So, shall I ditch the fish oil I’ve got? I’ve had it in my cupboard for at least 6 months


I always ask my patients to do a “sniff test”. The most obvious sign that your fish oil supplement has gone off is when it starts to smell fishy (rancid). If you are still not sure, then another trick is to touch the bottle. Sticky residue is usually a sign of advanced rancidity and could indicate the contents inside are starting to turn on you. The last test you could do is pour out a little oil between your fingers and check for tackiness. If it feels sticky, toss it.


One trick to keep your fish oil supplements for longer is to keep them in the fridge after opening because cold temperature can slow down oxidation.


I hope you are not put off by fish oil. I do believe if it is used correctly, it can be beneficial.


To you and your family’s health