Omega-3 Fatty Acids for Your Health

Conflicting reports may be confusing about omega-3s. Here’s what you need to know about these important nutrients.

By Linda Rath | Updated Dec. 8, 2022

You’ve probably heard of omega-3 fatty acids, especially if you have an inflammatory type of arthritis. They help reduce pain and inflammation throughout the body, and some studies have also shown benefits for heart health, brain function and diabetes, not to mention ACL injuries.

Omega-3 Overview

Over the past couple of decades, omega-3 fatty acids have fallen in and out of favor. Claims have varied that they’re either good or bad for the brain, they do or don’t prevent heart disease and cancer, and they may curb arthritis pain a little or a lot.

What gets lost in the flurry of conflicting studies is that omega-3 fatty acids are essential nutrients. 
  • They are key components in your retina and brain (and are so crucial for early development they’re included in baby formulas).
  • They play a role in blood clotting.
  • They improve blood vessel function.
  • They influence gene expression.
Despite the fact that these fats are critical, your body doesn’t make them; you need to get them from food. Top sources are fatty fish like salmon, herring, mackerel and sardines, algae, a type of seaweed, and fish oil or algal oil supplements.

There are several types of omega-3 fatty acids, but the three main ones are:
  • Eicosapentaenoic acid (EPA)
  • Docosahexaenoic acid (DHA)
  • Alpha-linolenic acid (ALA), which your body partially converts to EPA and DHA and, depending on the source, may be less healthy.
Fish Oil for Arthritis

Although omega-3 fats from fish oil have probably been most extensively studied for heart disease, researchers are increasingly looking at their benefits for rheumatoid arthritis (RA) and lupus.

For example, a 2021 analysis of 70 studies of fish oil and other dietary supplements found that fish oil significantly reduced disease activity, pain and morning stiffness in people with RA. Patients taking fish oil supplements also had a better response to disease-modifying antirheumatic drugs (DMARDs) and achieved remission sooner.

Doses of fish oil in these studies ranged from less than 1 gram (1,000 milligrams) to 10,000 milligrams a day. Higher doses (more than 2.6 grams a day) lowered inflammatory biomarkers like C-reactive protein and erythrocyte sedimentation rate and squelched inflammatory immune cells and proteins. Patients taking higher doses were able to discontinue nonsteroidal anti-inflammatory drugs (NSAIDs) and had reductions in disease activity lasting nearly eight months.

When it comes to lupus, almost all published trials showed some benefits from fish oil, including reduced disease activity and a decrease in inflammatory markers, such as interleukin (IL)-12 and IL-13. In one small study, very low daily doses of fish oil led to complete remission in 10 lupus patients. This is an old study, however, and it’s wise to be wary of research with so few patients. In a different twist, researchers studying the blood of people with lupus found far lower levels of omega-3 fats compared to their healthy counterparts. In similar studies, lupus patients had lower levels of omega-3 fats than people with heart disease did.

Other Conditions

Heart Health. Omega-3s have had their ups and downs relative to heart health, hailed as a cardiac miracle at one point and a disappointment at others. A recent meta-analysis of 13 trials conducted by researchers at Brigham and Women’s Hospital and Harvard Medical School elevated them again. They concluded that fish oil supplements significantly lowered the risk of most heart-related conditions, including heart attack, coronary heart disease (CHD) and cardiovascular disease (CVD) as well as CHD- and CVD-related death. The amount of omega-3s varied among trials, from 376 mg to 4,000 mg a day. Higher doses were associated with better outcomes.

These findings were reinforced by a large 2020 study involving nearly half a million people who were followed for eight or nine years. It, too, found that regular use of fish oil supplements led to lower rates of cardiovascular disease, heart attack and death.  Fish oil was even more protective for people with high blood pressure.

Whether fish oil benefits heart health remains controversial. Another 2020 trial found that fish oil didn’t improve heart health in high-risk patients. And a 2021 analysis of seven clinical trials found higher doses of fish oil might increase the risk of atrial fibrillation or irregular heartbeat. So the debate continues.

Cognitive Health. Aging brings a greater risk of cognitive impairment. Omega-3s, particularly DHA, have been found to lower the risk of dementia as well as improve Alzheimer’s disease symptoms. In some studies, food sources of omega-3s, such as salmon and other oily fish, were more effective than supplements in people who carry a gene that increases the risk of Alzheimer’s. This may be due to difficulty converting DHA from supplements into forms that can cross easily into the brain.

Diabetes. Although arthritis and diabetes are not directly related, they often coexist. The Centers for Disease Control and Prevention (CDC) found that more than half of people with diabetes also have arthritis. Some older research reported that omega-3s might be able to stave off type 1 diabetes if given early enough to infants and young children. And one of the largest and most recent adult trials to date — a prospective, observational study of nearly 400,000 people in the U.K.  — found that those who ate oily fish at least once or twice a week had a 22% reduced risk of diabetes compared to those who didn’t. People taking fish oil supplements had a 9% lower risk.

Food vs. Pills

Although most research has focused on fish oil supplements, some studies, including the diabetes and Alzheimer’s studies referenced above, have reported better results from fish as a food. The U.S. Department of Agriculture recommends at least two servings a week (3.5-ounce portions) of fish to get full omega-3 benefits.

There are some problems with sourcing omega-3s from food, though. For instance, not everyone likes, has access to or can afford fresh or frozen fish, especially wild-caught salmon, which is particularly high in omega-3s. Herring and sardines, also rich in DHA and EPA, are sold in tins in most grocery stores and are relatively inexpensive, but aren’t to everyone’s taste. In these cases, supplements are an important option.

Vegetarian and Vegan Sources

Vegetarians and vegans — a growing portion of the population — are often left out of omega-3 discussions. Some plant foods, including Brussels sprouts, kale, spinach, flaxseeds, chia seeds and walnuts, contain alpha-linolenic acid. But ALA is a pipsqueak compared to DHA and EPA. To be effective, it must be converted into its two cousins, usually with poor results. About 5% of ALA is converted to EPA, while less than 0.5% is converted to DHA.

One good alternative is algal oil, derived from algae. It contains both DHA and EPA and some studies have found it equivalent to fish oil from salmon, the omega-3 gold standard. Sourcing omega-3s from algae also helps preserve the sustainability of salmon stock.

If you choose fish or algal oil supplements, be sure to select a brand that has been tested for contaminants such as mercury and PCBs. ConsumerLab is a terrific online resource, with thousands of reviews of third-party tested supplements.

Also be aware that because fish oil has a blood-thinning effect, increasing your intake much beyond 3 grams a day isn’t recommended if you take a blood-thinner or aspirin.

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