Something Fishy about Fish
It is often said that fish oil is good for your heart and brain due to the omega-3 fatty acids. While it is true that omega-3 fatty acids are beneficial for heart health, studies are mixed on if fish oil overall helps with reducing heart disease and dementia. Here is a study by the New England Journal of Medicine on fish oil capsules given to people with various risk factors. I suggest reading the article before taking my word, but the study suggests that there was no benefit in taking fish oil. Now they used fish oil rather than fish, so there may be other factors like mercury, cholesterol, that would have affected results.
Now in terms of brain function, here is a study showing the lack of benefit of fish oil on brain function in the http://www.neurology.org/content/81/17/1484
These articles are primarily talking about fish oil, which is where the omega-3 fatty acids are concentrated. But most people eat whole fish, and thus there are other factors to take it. Fish, for example is high in cholesterol. Now not all fish are the same, so let's look at salmon.
Okay, let's look at another fish, tuna, and look at a smaller serving size
As 3oz is slightly more than half of 5oz, the cholesterol level is, more or less, about the same. Now let's look at another popular fish...tilapia. And since grams and ounces are not easy to understand, let's look at one fillet since that is what people typically eat or conceive of.
And now let's look at mackerol. Wow a quarter of the USRDA for cholesterol, and almost 150% of the USRDA for sodium.
So regardless of how you look at it, a serving of fish can be about one fifth to almost 40% of the USRDA for cholesterol. As our body produces all of the cholesterol we need, and most Americans have cholesterol that is too high, there doesn't seem to be benefit in getting all of this cholesterol. Also, on top of that, fish contain lead, cadmium, and other toxic metals.
While many people will choose wild-caught fish, believing it to be healthier and less likely to have mercury or other toxic metals, toxic metals are in wild-caught fish as well, especially those higher on the food chain. Now to try to be unbiased, I will include this article from the Mayo Clinic, which is a very respectable organization. http://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-blog/farmed-vs-wild-fish/bgp-20146479 The Centers for Disease Control (CDC) has an article on food poisoning caused by various types of fish, and these are wild caught, not farm-raised. They were tropical reef fish. Feel free to read the study before letting me draw conclusions for you, but the artice says ciguatera fish poisoning "is characterized by various gastrointestinal, cardiovascular, and neurologic symptoms. A prolonged period of acute illness can result, and the neurologic symptoms can last months, with variable asymptomatic and symptomatic periods." https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6204a1.htm?s_cid=mm6204a1_x While coal plants are one source of mercury, fish are another source. Now one might wonder why single out fish? Isn't it possible to get mercury from the air, drinking water, eating plants, etc? According to the National Wildlife Federation, "large predator fish such as walleye and trout can have mercury levels over one million times that of the surrounding water. In turn, people and wildlife who consume fish or other species with high mercury levels are at risk of serious health problems." http://www.nwf.org/Wildlife/Threats-to-Wildlife/Pollutants/Mercury-and-Air-Toxics.aspx
And what is the risk of of mercury poisoning? Here is what the EPA has to say. https://www.epa.gov/mercury/health-effects-exposures-mercury While many plant sources of omega-3 fatty acids do not have DHA like fish, algae does have DHA. Despite many studies showing fish oil has no benefit for some people, there are many studies that do in fact show fish oil having benefits, and they should not be dismissed. While the mercury and cholesterol have a counteractive effect, the omega-3 fatty acids themselves still have heart-healthy benefits. Plant fats do not compare in terms of EPA and DHA. However, fish-farming and even catching wild fish is unsustainable. Fish often consume algae as well as other fish. Algae is the primary source of omega-3 fatty acids under the sea. Algae provides DHA without the cholesterol, and it is more sustainable. http://www.mdpi.com/2072-6643/5/4/1301/htm Luckily, there are algae oil supplements to conveniently get algae oil. http://astore.amazon.com/healthphiloso-20/detail/B00QCR00SW?