Should You Be Eating Fish?


Many people equate eating fish with doing something good for their health. But is it really? Dr. Sofia Pineda Ochoa discusses this largely misunderstood topic.

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“[TMAO is] a really good predictor, because it’s more than just a risk factor. It actually is causative, that is it does blood vessel damage, creates plaque, makes it more likely that the plaque is going to rupture.”

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“The weight of evidence for fish pain is strong enough today that it has the support of venerable institutions — among them, the American Veterinary Medical Association…. Not only is the scientific consensus squarely behind consciousness and pain in fishes, consciousness probably evolved first in fishes.”

Dr. Sofia Pineda Ochoa:

Hi, I’m Sofia and today I’m going to talk about fish.

Recently, I was at a yoga studio, and when I was changing in the locker room, all of a sudden I smelled a strong stench of fish. It smelled really strong like tuna fish. So, I looked around to see where the smell was coming from and saw that the yoga teacher, who had just taught the class, was opening up and eating a little can of tuna — just with a fork straight out of the can.

She told me that she tries to always eat a little can of tuna fish right after she teaches yoga. She believes that’s pretty much the best thing she can do for her body. And like her most people equate eating fish with doing something good for their health. But is it really?

There are some very important considerations I think we need to keep in mind. And these have to do both with some intrinsic characteristics of the fish themselves, as well as with some environmental issues of what the fish are exposed to.

Fish are frequently contaminated with things like mercury, PCB’s, dioxins, as well as pesticides like DDT. A recent study that sampled fish from around the world actually found that eighty four percent of them had unsafe levels of mercury. Eighty four percent of them!

And what’s the problem with mercury? Well, it’s a heavy metal that’s very difficult to eliminate from the body once it’s ingested. It can cause problems depending on where it accumulates. For example, it can accumulate in our nervous system and cause a wide variety of neurologic problems, or it can accumulate in the heart, in the actual heart muscle, and alter the normal cardiac physiology and conduction.

And another highly concerning issue is that mercury can also cross the placenta barrier in pregnant women and accumulate in the body of a developing fetus. So, it can cause nervous system damage or other problems in the body of an unborn baby before it’s even born.

Fish today are also contaminated with a lot of plastic. This wasn’t a problem fifty or a hundred years ago, but now it is.

We have turned the oceans into nothing short of a plastic dump in the last few decades. And now, over eight million metric tons of plastic end up in the ocean every year. That’s the equivalent of more than one thousand garbage trucks filled with plastic going into the ocean every single day.

And all this plastic doesn’t go away either. It just breaks into smaller and smaller pieces which the fish eat, and then people end up eating that plastic too when they eat fish, even though we don’t taste it, or see it, or smell it.

According to a recent study from the University of Belgium, seafood loving Europeans are estimated to be eating about 11,000 tiny pieces of plastic per person per year. The scary thing is we don’t really know how eating all this plastic will affect human health. We’re just now starting to study it.

In some fish however, we’ve seen plastic can cross cell membranes and accumulate in the fish’s livers, brains and testicles, and cause problems with their behavior, immune system, and reproduction. And if it’s affecting fish, I don’t know how we can be so comfortable that it’s not also going to affect us.

But moving on from environmental issues. Let’s pretend I had a time machine and could go back in time two hundred years or so and could get a perfectly clean fish. Would it be a heath food then?

Well it’s important to remind ourselves that even if we could hypothetically get a perfectly uncontaminated fish, they are still animals. And just like flesh of any other animal, fish contains animal protein.

But, so what if it contains animal protein, right? Well, animal protein contains a higher proportion of essential amino acids. And when we eat animal protein – including that from fish – with a higher proportion of essential amino acids, it causes our bodies to produce increased levels of the hormone IGF-1, or insulin like growth factor 1.

And IGF-1 stimulates cell division and growth and is associated with increased cancer proliferation and malignancy. The role of IGF-1 in cancer promotion is well understood, and animal protein (including from fish) is associated with increased circulating levels of this hormone and therefore is associated with increased risk of cancer development.

While fish are frequently touted for containing long chain omega-3 fatty acids, it is important to note that fish don’t produce omega-3 fatty acids. They don’t make them themselves. They get them from the plants they eat. And we can easily get our omega-3s directly from plants like nuts, seeds, and many vegetables. And, while some fish contain omega-3 fatty acids from the plants they eat, most of the remaining fats in fish are saturated fats and cholesterol, which are associated with increased risk of cardiovascular disease. For example, three ounces of sea bass has about seventy-four milligrams of cholesterol, about the same as the seventy-five milligrams of cholesterol found in the same amount of beef.

And if that wasn’t enough, eating animal foods in general, including fish, increases our levels of TMAO, which is a vasculotoxic substance that injures the lining of our blood vessels and makes them more prone to develop atherosclerosis or to build up cholesterol plaques in the blood vessels.

Not one single fish anywhere in the world contains even one gram of fiber, which in itself makes it a poor choice as a health promoting food. Fiber deficiencies are pretty ubiquitous in this country because most people don’t get near enough fiber in their diet. So when we eat fish, it displaces other more beneficial foods that we could be eating, like legumes or fruits or vegetables, that do have fiber along with many other phytonutrients and antioxidants.

In some respects, fish has appeared to be less disadvantageous to health than other animal foods like red meat. But just because one food is less bad than another food that’s even worse, it doesn’t mean it’s necessarily a health food. And, in the case of fish, it’s not a health food for being less bad than red meat.

In conclusion, consumption of fish should not be encouraged from a health perspective, given not only it’s unacceptable levels of environmental contaminants like mercury, dioxins, PCB’s and plastic fibers, but also because of the cholesterol and saturated fat content, and the inherent increased cancer and cardiovascular risk associated with animal protein in general due to IGF-1 and TMAO.

The ideal or “gold standard” diet from a health standpoint remains a whole food plant-based diet, which means eating unprocessed, or minimally processed, vegetables, grains, legumes, nuts, fruits and seeds, while excluding animal foods like fish.

And this is a fortuitous fact too, because we are currently overfishing our oceans, and in a big way.

The United Nations FAO publishes a report on the health of the world’s fisheries every two years called the SOFIA report. And of course I remember this report very well, because my name is Sofia as well, but the report actually stands for State of World Fisheries and Aquaculture, and the last one had some very alarming figures – reporting that a whopping 89.5 percent of fish stocks are already “fully fished” or “overfished”.

This is totally unsustainable, no matter how you spin it, especially with our growing human population, which is increasing by 1.5 million people every single week. So, every week we have 1.5 million new food eaters and plastic users, which make all these matters even more challenging.

For those of us with access to food options, if we just stopped eating fish we could end this unsustainable fishing assault on the ocean life.

And of course, last but not least, the animals themselves would benefit. Fish, like any animal, can and do feel pain. Fishes may look different, with their adaptations for living in water. They may not scream like a human, dog, or cow when they’re hurt. And we may not find them cuddly or as relatable, due to characteristics like not having eyelids, which are not needed in water. But fishes do have all the hallmarks of pain, both physiologically and behaviorally.

For all these reasons, please leave fish or other animals off your plate. For your own health, for the environment, and for the animals.

This transcript is an approximation of the audio in above video. To hear the audio and see the accompanying visuals, please play the video.

This video was written and narrated by Sofia Pineda Ochoa, MD and Bob Rapfogel.

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  • Photographs of (1) cover image of fish and pristine ocean image by Bob Rapfogel from Bob Rapfogel Photography; (2) yoga class at gym from under Wikipedia Commons license; (3) open can of tuna from “jules” on Flickr under Creative Commons Attribution 2.0 Generic license; (4) “embryo week 9-10” by lunar caustic under Creative Commons Attribution Sharealike 2.0 Generic license and other pregnant women images from Pixabay under CC0 Creative Commons license; (5) Dump Truck Dumping Toxic Medical Waste by “Averyaudio” under Creative Commons Attribution-Share Alike 4.0 International license; (6)  heart muscle by Bruce Blaus under Creative Commons Attribution-Share Alike 4.0 International license; (7) coffee cups overflowing trash by Hat4Rain under Attribution 2.0 Generic license; (8) Back to the Future DeLorean Time Machine by Oto Godfrey and Justin Morton under Creative Commons Attribution-Share Alike 4.0 International license; (9) Salmon Leaping at the Locks by Ingrid Taylar under Creative Commons Attribution 2.0 Generic license; (10) drawing of black sea bass from NOAA Fish Watch in public domain; (11) drawing of cow by LadyofHats in public domain; (12) Artery image from staff (2014), “Medical gallery of Blausen Medical 2014, WikiJournal of Medicine 1(2); DOI:10.15347/wjm/2014.010. ISSN 2002-4436; (13) assortment of legumes from Pixabay under Creative Commons Zero license; (14) assortment of fruits by Bill Ebbesen under Attribution 3.0 Unported; (15) assortment of vegetables by Joanna Poe under Attribution-ShareAlike 2.0 Generic; (16) plastic in fish by David M. Lawrence via National Geographic, “Ocean Garbage Patch Not Growing—Where’s ‘Missing’ Plastic?”; (17) Mexico City sprawl by Pablo Lopez Luz; and (18) large crowd of people in Paris by James Cridland under Attribution 2.0 Genericlicense.