4 Things Fish Oil Can Do For Your Health & 2 Things It Can't

If you've been in the habit of taking any kind of supplement, it's worth taking a moment to do some research into what it can and can't do for your health. Take fish oil supplements, for example: One of the main benefits of taking fish oil is getting your omega-3 fatty acids, which are found in fish like salmon as well as in nuts and seeds. These are known to be broadly good for your health in appropriate quantities. But believing that omega-3s, or other nutrients found in fish oil supplements, can solve all your health problems isn't really sensible. There are things that omega-3s can help, but in other areas science says it doesn't have an effect — or that it can actually make things worse.

We first discovered what omega-3s were in 1929, and since then they've been the focus of a lot of science to see what purpose they serve in human diets and how they help our bodies. You can't actually produce omega-3s on your own, so they need to be obtained via your diet, and when they're in the body they help form and maintain cell membranes, particularly in places like the brain and heart. But there are limits to their powers, so that shelf full of supplements might not do what you hoped. Here are four things fish oil can do for your health, and two things it definitely can't.

They May Help Your Brain's Aging

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Research in 2017 found that dietary intake of omega-3 fatty acids, which are known as polyunsaturated fats, is linked to healthy brain aging, with fewer signs of cognitive decline, intelligence problems or degeneration. Elderly people with a higher concentration of various omega-3s — yes, there are several types, and you get a variety depending on what fish or nuts you're eating — did better on cognitive tests, and tended to have more matter in a particular area of their brain, the left frontoparietal cortex. That specific bit of the brain is related to our ability to make decisions and pay attention to things.

They Could Help Fight Asthma

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People with asthma, according to research in 2017, should be taking omega-3 fatty acids in fish oil, because it seems to reduce their symptoms. Why? Because, at least in people with moderate asthma, omega-3s stop the production of antibodies that cause the immune system to go trigger asthma attacks. In people who are on steroids to combat their asthma, this approach doesn't work, because the steroids interfere with the fish oil. But for people with mild to medium asthma, it could help to take a supplement.

They Can Boost The Immune System

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In 2013, the Federation of American Societies for Experimental Biology released research showing that asthma was only one element of the ways in which fish oil doses can help your immune system. It not only reduces inflammation, according to their studies; it also boosts the production of a particular kind of white blood cell which really helps immune system function. So while it may help stop the immune system overreacting in cases like asthma, it also seems to have a boosting function for white blood cells that fight off infections.

They Help Blood Flow To The Brain

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We've known for quite a long time that omega-3 supplements in particular seem to boost brain health. And a 2011 study showed that there might be a practical reason for this: omega-3 doses appear to help blood flow to the brain, increasing mental performance and efficiency. This, researchers think, is why omega-3 may also provide lifelong brain help, because it's regularly boosting our brain's mechanisms and building up white matter that will help us to preserve brain function later in life.

...But They Can't Help Your Heart Health

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A massive, new study on omega-3 supplements and heart health in 2018 found that, when it comes to cardiovascular health, those supplements in your cupboard are basically useless. Having a normal supply of omega-3 sources like fish and nuts in your life, according to the study of 112,059 people around the world, is good for your heart, but taking extra supplements doesn't seem to improve heart function at all and is a waste of time and money.

And They Don't Help Your Dry Eyes

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You may have heard that omega-3 fatty acids will help with your body's functioning in places like your eyes, but it turns out, according to studies from 2018, that this isn't the case at all. In research, omega-3 fish oil supplements were shown to do nothing for peoples' dry eye conditions, where the eye doesn't produce enough moisture to coat its surface. Placebos worked just as well.

Getting the right amount of omega-3s is important, but they're also not miracle workers and can't constitute the total sum of your diet — and it seems pretty clear that too much of a good thing is bad news for your body. So, as with any supplement, make sure you do your research before picking up a bottle of fish oil.