Fish oil, also known as omega-3 supplements, often makes the list of supplements everyone should be taking. And in fact, U.S. health surveys indicate fish oil is the most common non-vitamin supplement taken by adults and children. But what are the real benefits of fish oil? Is this a supplement everyone should take, or does it mainly benefit the supplement companies that make them?
What is Fish Oil?
Fish oil comes from fatty fish, like salmon, sardines, or anchovies. It's especially high in two fats that humans need, but can’t make – instead, you have to get them from your diet. That's why they’re known as essential fats (or fatty acids).
Those two essential fats in fish and fish oil supplements are DHA and EPA. They’re classified as omega-3 fats because of their chemical structure. You need a steady supply of EPA and DHA because these essential fats are used for
- Forming healthy, strong cell membranes
- Making hormones that regulate blood clotting
- Regulating blood vessel contraction and relaxation
- Controlling your body’s response to inflammation
Most people aren’t deficient in these omega-3 essential fats because in addition to DHA and EPA, there’s another one – called ALA. You still have to get this one from your diet, but it’s more widespread and found in foods like chia and flaxseeds, walnuts, leafy greens, canola, and soybean oil. Your body can use ALA to make DHA and EPA, but the process isn’t very efficient. Thus, even though most people aren’t actually deficient, you might be lower in EPA and DHA than desired.
What’s Better: Fish or a Supplement?
Hands down, the best option is to eat more fish. Virtually all research shows that people who eat fish regularly – as in two or more times each week – have higher levels of omega-3 fats in their blood. They also have less heart disease, diabetes, breast and colorectal cancer, dementia, and depression, among other health problems. Fish is a major part of the Mediterranean diet, and quite possibly one of the reasons for the health benefits associated with that eating pattern.
However, the evidence on fish oil supplements is kind of mixed. It’s not clear why, but the health benefits are probably not just from the oil in fish. The various nutrients and compounds in foods work together as a package to provide health benefits. So, it’s not unusual to see health benefits from eating certain foods, or groups of foods, but not from taking individual supplements.
Still, I’m one of those people in the pro-fish oil camp. I recommend omega-3 supplements often (along with eating more fish) because I’ve read many positive studies about potential fish oil benefits. The thing to remember is that fish oil supplements play more of a supporting role in your health.
Taking an omega-3 supplement alone probably won’t make a huge difference on their own, but it may enhance other positive things you’re doing for your health.
Fish Oil Benefits
Most of the research on omega-3 supplements has centered on their role in heart health. They help to reduce the inflammation that’s associated with clogged arteries and heart disease. They also help keep your blood vessels more flexible.
And, yes, some studies have found that omega-3 supplements reduce the risk of heart disease and stroke. But – other studies have found that they don’t make much difference at all. It might depend on what else you’re doing to reduce your risk.
The current statement from the National Institutes of Health is: “If you’re taking medications to reduce the risk of heart attacks, such as statin drugs to treat high cholesterol, omega-3s may not offer extra benefits beyond those of modern drug treatment.”
However, if you’re not on medications and you want to try lifestyle modifications first (please do!) I do recommend an omega-3 supplement along with a healthy, Mediterranean-style diet, increased exercise, and stress reduction. There’s some pretty convincing evidence that taking 1,000-3,000 mg/day can reduce triglycerides (a type of fat in your blood) and high blood pressure. Both are risk factors for heart disease and/or stroke.
Insulin resistance and pre-diabetes
If you have diabetes or are at risk, studies suggest taking an omega-3 fish oil supplement along with a healthier, lower carb diet, may help to reduce your fasting glucose, and A1C levels. (1) Fish oil may also help to reduce fasting insulin levels and improve insulin resistance (2) – both high insulin levels and insulin resistance are linked to prediabetes.
Depression and anxiety
Omega-3 essential fats are especially concentrated in your brain, so it makes sense that taking a fish oil supplement might be helpful for brain health. Research is looking at the possible benefits of maintaining age-related cognitive function and preventing or slowing Alzheimer’s disease. Animal studies suggest omega-3 supplements might be helpful here, but the jury’s still out.
Omega-3 supplements (and especially eating fish) do seem to be helpful for mood disorders like anxiety and depression. The International Society for Nutritional Psychiatric Research recommends adding an omega-3 supplement to enhance the effects of antidepressant medications in those with major depressive disorder. Although fish oil supplements usually contain both EPA and DHA, it seems EPA is the essential fat that’s most helpful for both depression and anxiety.
Autoimmune diseases happen when something triggers your own immune system to attack healthy cells and organs in your body. Examples include
- Hashimoto’s or Grave’s disease, which affect your thyroid gland
- Celiac, Crohn’s, or colitis, which affect your digestive tract
- Rheumatoid arthritis which affects your joints
- Psoriasis, which affects your skin
Often, autoimmune diseases are triggered by an inflammatory response to food sensitivities, environmental or toxin exposure, infections, or any combination of those. Because fish oil has anti-inflammatory properties, it can help to calm the inflammatory response that triggers these diseases. It’s also been shown to reduce symptoms of some autoimmune diseases, like rheumatoid arthritis and psoriasis.
Side Effects and Cautions
Fish oil supplements are safe for most people to take at moderate doses – usually 1,000-3,000 mg/day. Side effects are usually minimal but can include stomach upset and burping. Some people notice a fishy taste from some brands.
It’s important to look for a quality brand with high purity standards. I often recommend Nordic Naturals because they test every batch for toxins and contaminants. They also come in flavors, like lemon and strawberry which means no fishy taste!
Check with your doctor if you take medications, especially a blood thinner medication like Coumadin. Fish oil supplements can thin your blood and make it less likely to clot, so they might intensify the effects of blood thinners.
The Bottom Line
Just like any other supplement, omega-3 or fish oil supplements are not a magic bullet. You can’t solve all of your health problems with a pill. However, if you add them to your overall health routine that includes eating more fish (check this list for the ones that are highest in omega-3 fats) you’ll probably get an additional health boost. That makes them OK in my book!
Do you take fish oil supplements? Or do you try to eat more fish?
- Effect of Combined Use of a Low-Carbohydrate, High-Protein Diet With omega-3 Polyunsaturated Fatty Acid Supplementation on Glycemic Control in Newly Diagnosed Type 2 Diabetes: A Randomized, Double-Blind, Parallel-Controlled Trial. https://pubmed.ncbi.nlm.nih.gov/30101332/
- DHA-enriched fish oil reduces insulin resistance in overweight and obese adults. https://www.sciencedirect.com/science/article/abs/pii/S0952327820301125
- International Society for Nutritional Psychiatry Research Practice Guidelines for Omega-3 Fatty Acids in the Treatment of Major Depressive Disorder. https://pubmed.ncbi.nlm.nih.gov/31480057/
- Dietary omega-3 fatty acids aid in the modulation of inflammation and metabolic health. https://pubmed.ncbi.nlm.nih.gov/24860193/