What Really Happens to Your Body When You Take Fish Oil
8 things you need to know before you take fish oil supplements
Fish oil is one of the most widely used supplements in the United States. A National Institutes of Health (NIH) survey found almost 19 million adults had popped a fish oil pill within the last month — that's around one in every 17 people. There's good reason why: Many supplements are plagued by inconclusive research, but fish oil isn't one of them. A solid evidence base suggests fish oil supplements can hold benefits for your health, and may even slow down the aging process.
But before you jump on this trend, here are 8 facts you need to know to decide if fish oil is right for you.
What is fish oil?
As the name suggests, fish oil is essentially fat extracted from fish . The specific components of fish oil scientists are most interested in are omega-3 fatty acids.
The number ‘3’ stands for the position of an important double carbon bond in the compound’s molecular structure. The position of the bond singles out omega-3s' behavior in the body from other omega fatty acids, like omega-6 fatty acids, which are derived from plant sources, according to Harvard Medical School.
Omega-3s come in three main varieties: alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). Again, these three kinds of omega-3 come from different sources — EPA and DHA come from fish oil, while ALA is found in plant sources such as flaxseed.
What food contains fish oil?
If you are an adherent to a Mediterranean-style diet, or pescatarianism, then chances are your diet is already rich in omega-3s. But there are some other natural sources of this essential nutrient not to do with fish, too.
These are the best foods to consume to ensure you get enough omega-3s:
Seafood : Cold-water fatty fish are ideal. The best include tuna, mackerel, salmon, sardines, and herring.
: Cold-water fatty fish are ideal. The best include tuna, mackerel, salmon, sardines, and herring. Nuts and seeds: Walnuts, flaxseeds, and chia seeds are all excellent sources.
Walnuts, flaxseeds, and chia seeds are all excellent sources. Plant oils: Soybean oil, flaxseed oil, and canola oil all contain omega-3s.
Soybean oil, flaxseed oil, and canola oil all contain omega-3s. Fortified foods: These can include yogurt, juice, milk, soy drinks, and eggs.
Salmon has abundant omega-3s and relatively low mercury levels Enn Li Photography Getty Images
If you don't eat fish, have a nut allergy, or otherwise think you don't get enough omega-3s in your daily diet, then you may want to consider taking omega-3 supplements — typically fish oil capsules.
What are fish oil supplements?
Supplements to boost omega-3 consumption are typically made from fish oil, and most frequently cod liver oil, krill oil, or even oil from algae. Algal oil is a plant-based source of omega-3s that contains both EPA and DHA.
While scientists aren't sure whether one specific kind of omega-3 is better for you than another, there is evidence to suggest omega-3s are — at least in part — the reason why eating fish regularly, as in the Mediterranean diet, is so good for your physical and mental health.
How do omega-3s affect mental health?
Your body uses omega-3s to build cells' membranes, the basic container for all of your body's cellular processes, but some of your cells use more omega-3s than others. DHA levels are particularly elevated in brain cells, which suggests they play an important function in brain health.
Here are four key ways omega-3s may influence your brain:
Neurogenesis and brain structure:
A 2014 review found omega-3s play a role in neurogenesis, or the creation of brain cells. People who consumed more fish oil tended to have greater volumes of grey matter in their brains. It also found evidence to suggest both grey and white matter may be less prone to the affects of aging in people who consume more fish oil.
Cognition and aging:
According to the National Institutes of Health, research shows consuming more omega-3s from dietary sources, such as fish, may lower the risk for Alzheimer’s disease, dementia, and other cognitive health problems. But as the NIH researchers point out, the evidence on omega-3s and staving off cognitive decline is mixed.
A 2015 study showed two to four years of omega-3 supplementation in 4000 older participants didn't prevent cognitive decline. But the study did not test the effects of omega-3 intake from diet — a major limitation.
Depression:
Researchers have found stronger evidence omega-3 supplementation help with depression, however. In a review of multiple studies involving more than 10,000 participants, researchers found using omega-3 supplementation in conjunction with conventional treatments for depression helped alleviate symptoms significantly more than the traditional therapies alone.
Mood and behavior:
There is also evidence to suggest omega-3s may curb aggressive behavior. In Australia, researchers are testing the idea that omega-3 supplementation may reduce violent incidents in Australian prison populations. In a pilot study published in the journal PLOS ONE in 2015, the team found omega-3 levels varied between individual Australian prisoners and lower omega-3 levels were correlated with increased aggression and signs of attention deficit hyperactivity disorder, or ADHD. The jury is still out on their overarching hypothesis — a study published this year assessing the feasibility of a randomized, double-blind, placebo controlled trial of omega-3 supplements in prisoners suggests these supplements do reduce violent or aggressive behaviors among inmates — but the sample size in the feasibility study is far too small to come to any definitive conclusion.
Why are omega-3s good for the body?
In addition to being a building block of cell membranes, omega-3s play an important role in safeguarding respiratory health, the cardiovascular system, the immune system, and endocrine system function.
Here are three of the top benefits omeag-3s have for the body:
Heart health:
According to the NIH, both dietary and supplemented sources of omega-3s support cardiovascular health.
One or two servings of seafood per week is recommended by the American Heart Association (AHA) to reduce the risk of developing cardiovascular problems. And both dietary and supplemental omega-3s have been shown to reduce triglycerides — a particle in the blood that transports fat through the body.
One large clinical trial involving 26,000 people found that omega-3 supplementation reduced heart attacks by 28 percent and deaths from heart attacks by 50 percent — there is also evidence to suggest omega-3s reduce the risk of arrhythmia — a potentially deadly condition in which the heart falls into the wrong rhythm.
For heart disease patients, the AHA recommends 1 gram per day of EPA and DHA. Ideally, these fatty acids are consumed as part of one's diet, but supplements work as well. The AHA do not recommend supplementation for people who are not high-risk for cardiovascular disease, however.
Eyesight:
Just like brain cells, retinal cells in the eye have particularly high levels of DHA. People who have a high intake of omega-3s from food may lower their chances of developing age-related macular degeneration, a condition which eventually causes blindness. This condition, in which the retina deteriorates, is a leading cause of vision decline in older people. But you need to start as you mean to continue: According to the NIH, there is no evidence to suggest supplements prevent the problem from worsening once it begins.
Reproductive advantages:
Brain and retinal cells are not the only ones in the body with particularly high levels of DHA. The amount of this fatty acid is particularly high in sperm cells, too. Studies suggest omega-3 supplementation can support male reproductive health, boosting sperm fitness.
Men are not the only beneficiaries. Between 8 to 12 ounces of seafood per week during pregnancy and breastfeeding may significantly benefit the unborn child, too. Omega-3 supplements may increase birth weight and the length of gestation, both of which may be beneficial for infant health, according to the NIH.
You can get omega-3s from both food and supplements. John Lawson, Belhaven / Getty Images
Are fish oil supplements good for you?
This depends on whom you ask. The evidence in support of omega-3s is strong, but the NIH and other health research bodies say the best way to consume omega-3s is by eating fish, rather than taking fish oil supplements.
What is not a point of contention however is whether fish oil supplements boost omega-3 levels — they do.
How long do fish oil supplements take to work?
Fish oil supplements do seem to work, but it isn't clear how long they take to work, according to Carol Haggans, a nutrition scientist at the NIH Office of Dietary Supplements. Part of this is to do with the studies we have at hand to suggest fish oil supplements are of benefit at all.
"Most studies examining the health effects of fish oil for conditions like cardiovascular disease last many years, like 5 years or even longer," she tells Inverse. "The idea is to increase your intake of omega-3's to see if they have long-term health benefits."
There are some studies which have tested omega-3 supplements over shorter time frames. For instance, one 2011 study found omega-3s lowered inflammation and anxiety in a group of 68 students after just 12 weeks.
Can you take too much fish oil?
According to the NIH, there is no set recommended daily intake for DHA or EPA, the omega-3s found primarily in fish oil. But the United States Food and Drug Administration sets an upper limit of 3 grams per day of DHA and EPA combined.
You might want to talk to your doctor before you opt for omega-3 supplements, the NIH says. These supplements can interact with prescription medications, including warfarin and other anticoagulant drugs, potentially causing bleeding problems, according to the NIH.
In low doses, however, the side effects of fish oil supplements tend to be minimal. But they can include: bad breath, an unpleasant taste in the mouth, nausea, stomach discomfort, heartburn, diarrhea, headache, and smelly sweat.
What Using Fish Oil Pills Every Day Does to Your Body
Fish oil –a.k.a. the oil extracted from the fish tissue – is one of the most consumed nutritional supplements in the US. The oil is rich in omega-3 fatty acids, which have many beneficial effects on human health. Unfortunately, the human body cannot produce omega-3 fatty acids, so you'll have to rely on foods like fatty fish – such as mackerel, tuna, and herring – to get them. But if you don't eat a lot of oily fish, taking a fish oil supplement every day can help you attain your daily omega-3 fatty acid requirements. That said, omega-3 fatty acids can also be obtained from plant sources – such as walnuts and soy – but research has shown that the omega-3s gotten from fish oil are more beneficial for human health. So, how exactly do omega-3 fatty acids help you? To answer this, Eat This, Not That! Health spoke with Megan Wong, a registered dietitian at AlgaeCal, who explains what happens to your body when you take Fish oils. Read on to find out the various ways fish oil pills can benefit your health.
1
Lowers Inflammation
body inflammation
According to Wong, "not only do omega 3 fatty acids reduce the production of substances that trigger inflammation, but newer research has shown that they also increase the levels of molecules that actively fight inflammation. These are called specialized pro-resolving mediators (or SPM)."
2
Supports Bone Health
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Fish oils can also do your bones a lot of good. "Chronic inflammation is one of the underlying causes of osteoporosis," Wong says. She added that "taking omega-3 fatty acids can help to keep inflammation at bay, which in turn strengthens your bones. But this is often an overlooked way to keep bones strong and healthy."
3
Keeps Your Heart Healthy
doctor holding heart
According to Wong, "one of the latest systematic reviews on omega-3 fatty acids and heart health concluded that omega-3 fatty acids reduced cardiovascular mortality and improved cardiovascular outcomes." She noted that "this isn't surprising since we know that omega 3s are involved in regulating vasodilation, platelet aggregation, inflammation, and oxidation. Keeping these in check helps to make sure you have healthy blood pressure, cholesterol, and blood flow."
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4
Boosts Your Brain Function
Wong explains that "omega 3 fats are needed to build brain and nerve cells and are crucial for proper brain development and function. They improve communication between brain and nerve cells and protect from inflammation. If you're focusing on brain health, look for an omega-3 supplement with more docosahexaenoic acid (DHA), as DHA plays a bigger role in brain health compared to Eicosapentaenoic acid EPA, even though they're both omega-3 fatty acids."
5
Improves Eye Health
Stylish shot of surprised scared Caucasian girl with brown hair, charming blue eyes, white skin. Young female with tattoo looks lovely in her natural amusement with closed mouth, raised eyebrows.
"Studies show that omega-3 fatty acids can help improve dry eyes as well as offer protection from macular degeneration and glaucoma," Wong says. "These benefits likely stem from its anti-inflammatory properties and its ability to improve oil production in eye glands, keeping eyes lubricated," she added.
What Really Happens to Your Body When You Take Fish Oil
Fish oil is one of the most popular supplements, but you may not need to take it if you already eat seafood. Image Credit: Creative What Really Happens to Your Body When examines the head-to-toe effects of common behaviors, actions and habits in your everyday life.
Healthy fats are our friends. In fact, fat is an essential part of a nutrient-dense diet — but not all fats are one and the same.
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The omega-3 fatty acids naturally found in fish, for example, are significantly better for us than the partially hydrogenated oils found in ultra-processed and packaged foods.
But if omega-3s are so stellar, should everyone be taking fish oil supplements for optimal health? Here's what the research says about what fish oil does, who might benefit from fish oil supplements and more.
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What Is Fish Oil?
Fish oil comes from the fatty tissue of fish like salmon, sardines, mackerel, herring and lake trout. The primary fats found in fish are omega-3 fatty acids, a type of polyunsaturated fat.
The two main types of omega-3s found in fish are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
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Most fish oil supplements consist of marine-derived EPA and DHA. "The difference between products will be the EPA to DHA ratio, which can range from 0.3 to 3," explains Tyler Preston, RD, registered dietitian, performance coach and founder of the practice Preston Performance.
"If you want to simply resolve a deficiency, a more balanced EPA to DHA ratio of 1:1 would be appropriate," Preston says.
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There are different types of omega-3 supplements, including fish oil, cod liver oil and krill oil. Cod liver oil provides vitamins A and D in addition to EPA and DHA, per the National Institutes of Health (NIH).
Both EPA and DHA are essential for our health. "While DHA might have a stronger anti-inflammatory effect, EPA targets the balance between pro-inflammatory and anti-inflammatory proteins, illustrating their symbiotic relationship," Preston says.
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Tip Alpha-linolenic acid (or ALA) is an omega-3 fat found in plants, like walnuts, chia and flax seeds and canola oil. ALA can convert into EPA and DHA in the body, but not well. Some estimates say anywhere from 0 to 4 percent of ALA is converted to DHA, according to Oregon State University. Bottom line: We get much less bang for our buck with plant-based omega-3s compared to those found in fish.
The Effects of Fish Oil
Your Triglyceride Levels May Go Down
Omega-3 supplements have been shown to lower elevated triglyceride (TG) levels in the blood, per Michigan Medicine. That's pretty important as high TGs are linked to an increased risk of heart disease.
Prescription medications that supply high doses of omega-3 fatty acids (around 4 grams per day) have been found to reduce TG levels by about 30 percent in people with hypertriglyceridemia, according to August 2019 research in the journal Circulation.
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But for the average person with healthy lipid levels and no fatty acid deficiencies, fish oil supplements aren't essential as long as they're eating fish regularly. Aim for at least two 3.5-ounce servings of fatty fish per week, as is recommended by the American Heart Association.
FYI, people who ate fish twice weekly saw significantly greater reductions in their LDL cholesterol compared to those who took fish oil supplements, per a December 2017 study in Nutrition & Diabetes.
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Should I Take Fish Oil? People at risk of heart disease aren’t the only ones who might benefit from fish oil supplements. “Athletes may require a higher intake of omega-3s to account for greater systemic inflammation from exercise and training,” Preston explains. Vegetarians with low intakes of ALA may consider omega-3 supplementation given the inefficient conversion of ALA to EPA and DHA in the body. Pregnant people can also benefit from omega-3 supplements.
Your Mood Could Improve
Fish is called "brain food" for a reason.
The anti-inflammatory fats in fish help maintain the structure and function of cell membranes across the body, including those found in the brain. That may be why some studies have shown that people who eat more seafood have a decreased risk of cognitive decline, per the National Center for Complementary and Integrative Health.
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As of now, there's little evidence we should pop fish oil pills for the prevention of conditions like dementia, but the supplements may bring benefits for other neural conditions. Take depression, for example: Research suggests that fish oil supplementation, particularly EPA, is linked to reduced symptoms of depression, per an August 2019 meta-analysis in Translational Psychiatry.
One theory of the pathophysiology of depression involves imbalances in neurotransmitters in the brain. "By altering serotonin and dopamine receptor number and function, omega-3s can theoretically help correct these dysfunctional pathways in depressed people, improving their depressive status," Preston tells
Because findings on the efficacy of omega-3s for depression are mixed, experts agree that more research is needed before the capsules become a mainstay of mental health treatment. That means: If you're on anti-depressants, don't quit your meds just yet — and always talk to your doctor before starting a new supplement or if you're considering going off prescribed meds.
If you're open to eating seafood, start with the real deal instead of a fish oil supplement. For now, get your good mood food in with at least two servings of fish weekly.
Your Blood Pressure May Go Down
Omega-3 supplementation may help reduce blood pressure levels in people with hypertension.
"According to NIH research, omega-3 fatty acids work by directly activating large-conductance calcium-dependent potassium channels in the blood vessels, which lowers blood pressure," says Angela Marshall, MD, a board-certified internist and the CEO of Comprehensive Women's Health.
Fish oil supplements with a moderate amount of DHA and EPA (think: the same amount you'd get from eating two to three portions of seafood per week) were found to lower blood pressure by 5 mmHg in people with systolic hypertension, per a March 2016 study in The Journal of Nutrition. Though it might not sound like a lot, that 5-point decrease could potentially lead to a 20 percent reduction in heart disease risk, according to the researchers.
For now, the majority of the research supports a well-balanced, low-sodium diet packed with fruits, vegetables, heart-healthy fats (like fish!), lean proteins and whole grains over fish oil supplements for lowering blood pressure levels.
Your Joints Might Hurt Less
"Studies show that omega-3 fatty acids are helpful at lowering joint inflammation, which is helpful for people with inflammatory disorders like rheumatoid arthritis," Dr. Marshall says.
These healthy fats have been shown to inhibit the production of inflammatory compounds like cytokines and interleukins in the body. It's not all that surprising, then, that fish oil supplements have been associated with improvements in symptoms among people with inflammatory conditions like rheumatoid arthritis (RA), per Oregon State University.
While the reduction in pain is often modest, it may be enough to decrease one's need for pain medications like NSAIDs, according to the Mayo Clinic.
You Might Get Fishy Burps and Nausea
If you're just starting to add fish oil supplements to your regimen, beware of the potential for a fishy fragrance and aftertaste, as well as some not-so-comfy GI symptoms.
"Common side effects, though normally mild, can include heartburn, nausea and GI discomfort, which are all common issues with ingesting too much fat in one sitting," Preston says.
You could avoid the fishy aftertaste by storing your bottle in the freezer or taking the pill with meals, per the Arthritis Foundation.
And note that the higher the dose, the greater your risk for adverse reactions. The Food and Drug Administration (FDA) recommends no more than 5 grams of EPA and DHA combined per day from supplements, per the NIH. But, if your doctor prescribed fish oil for a heart condition, the dosage may be higher.
Tip Timing matters when it comes to taking omega-3 supplements. “Fish oil supplements can be taken at any time during the day, however, they can sometimes cause nausea when consumed on an empty stomach,” Preston notes. “Since fish oil is a fat-soluble supplement, we can enhance absorption by taking them with a meal.”
The Bottom Line
If you eat seafood, opt for fatty fish often before reaching for a fish oil supplement.
"I always tell people to go for the whole food instead of a supplement if they can," says William W. Li, MD, physician and author of Eat to Beat Disease. "Regular consumption of oily fish, such as salmon, sardines and anchovies is a great way to get omega-3s. Not only do you get the healthy fat, but seafood is a good source of protein as well."
While fresh, wild-caught fish is optimal, flash frozen and even tinned seafood can be just as nourishing, and, not to mention, more budget-friendly.
And if you don't eat fish and you're interested in going the supplement route, remember: "It's a good practice for anyone taking any supplements to tell their doctor to discuss the possibility of drug-supplement interactions," Dr. Li says.
Image Credit: Creative
