8 things you need to know before taking fish oil supplements

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Fish oil is one of the most widely used nutritional supplements in the United States. A survey by the National Institutes of Health (NIH) found that nearly 19 million adults had taken a fish oil pill in the last month – that’s roughly one in 17 people. There are good reasons for this: many supplements are plagued by inconclusive research, but fish oil is not one of them. A solid evidence base suggests that fish oil supplements can be beneficial to health and may even slow down the aging process.

Before you dive into this trend, however, there are 8 facts you should know to help you decide if fish oil is right for you.

What is fish oil?

As the name suggests, fish oil is essentially fat that is extracted from fish. The specific components of fish oil scientists that 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 molecular structure of the compound. The position of the bond differentiates the behavior of omega-3 fatty acids in the body from other omega-fatty acids such as omega-6 fatty acids, which Harvard Medical School says come from plant sources.

Omega-3 fatty acids come in three main types: alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA). Again, these three types of omega-3s come from different sources – EPA and DHA come from fish oil, while ALA is found in plant sources like flaxseed.

Which foods contain fish oil?

If you are sticking to a Mediterranean diet or pescatarianism, your diet is likely already high in omega-3s. However, there are several other natural sources of this essential nutrient that are not related to fish.

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These are the best foods to consume to make sure you are getting enough omega-3 fatty acids:

  • seafood: Cold water oily fish are ideal. The best are tuna, mackerel, salmon, sardines, and herring.
  • Nuts and seeds: Walnuts, flax seeds, and chia seeds are excellent sources.
  • Vegetable oils: Soybean oil, flaxseed oil, and rapeseed oil all contain omega-3 fatty acids.
  • Fortified foods: These can be yogurt, juice, milk, soy drinks, and eggs.

Salmon is rich in omega-3 fatty acids and relatively low in mercury. Enn Li Photography Getty Images

If you don’t eat fish, have a nut allergy, or otherwise believe that you are not getting enough omega-3s in your daily diet, consider taking omega-3 supplements – usually fish oil capsules.

What are fish oil supplements?

Supplements to increase omega-3 consumption are typically made from fish oil and most commonly from cod liver oil, krill oil, or even algae oil. Algae oil is a vegetable source of omega-3 fatty acids that contains both EPA and DHA.

While scientists aren’t sure if a certain type of omega-3 is better for you than another, there is evidence that omega-3s are – at least in part – why they eat 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-3 fatty acids to build cell membranes, the basic receptacle for all of your body’s cellular processes. However, some of your cells use more omega-3 fatty acids than others. DHA levels are particularly elevated in brain cells, suggesting that they play an important role in brain health.

Here are four key ways omega-3 fatty acids can affect your brain:

  • Neurogenesis and brain structure:

A 2014 review found that omega-3 fatty acids play a role in neurogenesis, or the formation of brain cells. People who consumed more fish oil tended to have larger amounts of gray matter in their brains. Evidence has also been found that both gray and white matter are less prone to the effects of aging in people who consume more fish oil.

According to the National Institutes of Health, consuming more omega-3 fatty acids from food sources like fish can lower your risk of Alzheimer’s, dementia, and other cognitive health problems. But as the NIH researchers point out, the evidence for omega-3 fatty acids and cognitive decline defense is mixed.

A 2015 study showed that two to four years of omega-3 supplementation did not prevent cognitive decline in 4,000 older participants. However, the study did not test the effects of dietary omega-3 intake – a major limitation.

However, researchers have found stronger evidence that omega-3 supplementation helps with depression. In a review of multiple studies involving more than 10,000 participants, researchers found that using omega-3 supplementation in conjunction with conventional treatments for depression helped relieve symptoms significantly more than conventional therapies alone.

There is also evidence that omega-3 fatty acids can curb aggressive behavior. In Australia, researchers are testing the idea that omega-3 supplementation can reduce violent incidents in Australian prison populations. In a pilot study published in 2015 in the journal PLOS ONE, the team found that omega-3 levels were different between individual Australian prisoners, and lower omega-3 levels were associated with increased aggression and signs of attention deficit hyperactivity disorder (ADHD ) correlated. The jury is still unaware of their overall hypothesis – a study published earlier this year evaluating the feasibility of a randomized, double-blind, placebo-controlled trial of omega-3 dietary supplements in prisoners suggests that these dietary supplements were violent or aggressive Reduce behavior in inmates – but the feasibility study sample size is far too small to reach a definitive conclusion.

Why Are Omega-3 Fatty Acids Good For The Body?

Omega-3 fatty acids are not only a building block of cell membranes, they also play an important role in maintaining the health of the respiratory tract, the cardiovascular system, the immune system and the functioning of the endocrine system.

Here are three of the most important benefits Omeag-3 have for the body:

Both dietary and supplemented omega-3 sources are beneficial for cardiovascular health, according to the NIH.

One or two servings of seafood per week is recommended by the American Heart Association (AHA) to help reduce the risk of cardiovascular problems. Both dietary and supplemental omega-3 fatty acids have been shown to reduce triglycerides – a particle in the blood that carries fat around the body.

A large clinical study of 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 that omega-3s reduce the risk of arrhythmia – a potentially fatal disease in which the heart falls out of rhythm.

For patients with heart disease, the AHA recommends 1 gram of EPA and DHA per day. Ideally, these fatty acids are consumed as part of your own diet, but dietary supplements also work. However, the AHA does not recommend supplementation for people who are not at high risk for cardiovascular disease.

Retinal cells in the eye, like brain cells, have a particularly high level of DHA. People who have a high dietary intake of omega-3 fatty acids can reduce their chances of developing age-related macular degeneration, which eventually leads to blindness. This condition, in which the retina deteriorates, is a major cause of vision deterioration in the elderly. But you have to start like you plan to continue: According to the NIH, there is no evidence that dietary supplements prevent the problem from getting worse once it starts.

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. Studies suggest that omega-3 supplementation can support male reproductive health and improve sperm fitness.

Men aren’t the only beneficiaries. Between 8 and 12 ounces of seafood per week during pregnancy and breastfeeding can also be of significant benefit to the unborn baby. According to the NIH, omega-3 supplements can increase birth weight and length of pregnancy, which, according to the NIH, can be beneficial for the health of the child.

You can get omega-3 fatty acids from both foods and supplements. John Lawson, Belhaven / Getty Images

Are Fish Oil Supplements Good For You?

It depends on who you ask. The evidence to support omega-3s is strong, but the NIH and other health research institutions say the best way to consume omega-3s is to eat fish instead of taking fish oil supplements.

What is not controversial, however, is whether fish oil supplements increase omega-3 levels – they do.

How long does it take for fish oil supplements to work?

Fish oil supplements seem to work, but it’s not clear how long it takes for them to work, according to Carol Haggans, a nutritionist at the NIH Office of Dietary Supplements. Part of this has to do with the available studies suggesting that fish oil supplements are of any use at all.

“Most studies examining the health effects of fish oil on conditions such as cardiovascular disease take many years, for example 5 years or even more,” she tells Inverse. “The idea is to increase your omega-3 fatty acid intake to see if they have long-term health benefits.”

There are some studies that have tested omega-3 supplements over shorter periods of time. For example, a 2011 study found that omega-3 fatty acids reduced inflammation and anxiety in a group of 68 college students after just 12 weeks.

Can You Take Too Much Fish Oil?

According to the NIH, there is no recommended daily intake for DHA or EPA, the omega-3 fatty acids found primarily in fish oil. However, the US Food and Drug Administration sets an upper limit of 3 grams of DHA and EPA combined per day.

You may want to speak to your doctor before choosing omega-3 supplements, says the NIH. These supplements can interact with prescription drugs like warfarin and other anticoagulants and potentially cause bleeding problems, according to the NIH.

However, at low doses, the side effects of fish oil supplements tend to be minimal. But they can include: bad breath, bad taste in the mouth, nausea, stomach upset, heartburn, diarrhea, headache, and smelly sweat.

The Reverse Analysis – Ultimately, the evidence for fish oil supplements mirrors the evidence for a Mediterranean diet high in fatty fish, nuts, and plants. While this diet isn’t for everyone, the evidence is good enough to suggest that sticking to this type of eating will ultimately benefit your health – from your brain to your gut, to your heart.

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