Omega-3s After 40: Fish, Plant Sources and Whether You Need a Supplement

You have probably heard that fish is good for your heart, and that omega-3s are the reason. You may also have a bottle of fish oil capsules somewhere in your kitchen. But do you actually need them? And what about plant sources like flax and walnuts?

This guide explains what omega-3s do, how to get enough from food and what the research says about supplements.

What omega-3s are

Omega-3 fatty acids are a type of polyunsaturated fat. Your body cannot make them in meaningful amounts, so you need to get them from food. The NIH Office of Dietary Supplements describes three main types:

ALA (alpha-linolenic acid), found mainly in plant oils such as flaxseed, soybean and canola oils, and in walnuts and chia seeds
EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), found mainly in fish and other seafood

Your body can convert a small amount of ALA into EPA and DHA, but the conversion is limited. That is why eating fish or seafood is the most practical way to get EPA and DHA.

What omega-3s do

Omega-3s are an important part of the membranes that surround every cell in your body. DHA is especially concentrated in the brain and the retina. Omega-3s also provide energy and help make signaling molecules that affect the heart, blood vessels, lungs, immune system and hormones.

Harvard's Nutrition Source explains that polyunsaturated fats, including omega-3s, are "good fats" and that replacing saturated fats with unsaturated fats is associated with a lower risk of heart disease.

Why this matters for women in midlife

Heart disease is the leading cause of death for women in the United States, according to the CDC. After menopause, women's risk of heart disease rises, partly because of changes in cholesterol and blood pressure. A heart-healthy eating pattern that includes fish and other sources of healthy fats is one part of protecting your heart. See our guide to heart health after menopause.

How much do you need?

There is no official recommended amount for EPA and DHA alone. The Office of Dietary Supplements sets an adequate intake for ALA of 1.1 grams a day for women and 1.6 grams a day for men.

For EPA and DHA, the Dietary Guidelines for Americans recommend that adults eat about 8 ounces of a variety of seafood per week, which is about two servings. Choosing fish that are higher in omega-3s and lower in mercury is ideal.

Best food sources

Fish and seafood (EPA and DHA)

Mayo Clinic notes that fatty fish are the best sources of omega-3s. Good choices include:

Salmon
Sardines
Mackerel (Atlantic, not king mackerel)
Herring
Trout
Anchovies
Canned light tuna

Fish that are high in mercury, such as king mackerel, shark, swordfish and tilefish, are best limited.

Plant sources (ALA)

Food	Approximate ALA
Flaxseed oil, 1 tablespoon	7.3 g
Chia seeds, 1 oz	5.1 g
English walnuts, 1 oz	2.6 g
Ground flaxseed, 1 tablespoon	2.3 g
Canola oil, 1 tablespoon	1.3 g
Soybean oil, 1 tablespoon	0.9 g
Edamame, frozen, prepared, 1/2 cup	0.3 g

Values are approximate, based on NIH nutrient data.

What about fish oil supplements?

Fish oil supplements are among the most popular dietary supplements in the U.S. But research on whether they prevent heart disease in healthy people is mixed. The Office of Dietary Supplements notes that people who eat seafood regularly tend to have a lower risk of heart disease, but that the evidence for supplements is less clear. Large studies have had inconsistent results.

Some prescription omega-3 medications are used to lower very high triglyceride levels under medical supervision. These are different from over-the-counter supplements.

Research on omega-3 supplements for other conditions, such as dry eye, joint pain, mood and cognitive health, has also produced mixed results.

Safety

Omega-3 supplements are generally safe, but there are some considerations, according to the Office of Dietary Supplements:

Side effects can include a fishy aftertaste, bad breath, heartburn, nausea, digestive discomfort and diarrhea.
Bleeding risk. Omega-3s may interact with blood thinners such as warfarin, increasing the risk of bleeding.
Atrial fibrillation. Some studies have found a higher risk of atrial fibrillation (an irregular heart rhythm) in people taking high doses of omega-3 supplements, particularly those with heart disease or risk factors.
Quality. As the FDA explains, supplements are not approved for safety or effectiveness before sale. Look for products tested by independent organizations.
Allergies. People with fish or shellfish allergies should check with their clinician before taking fish oil.

If you do not eat fish, algae-based omega-3 supplements provide EPA and DHA and are suitable for vegetarians and vegans.

Putting it into practice

Aim for two servings of fish a week, choosing fatty fish lower in mercury.
Include plant sources of ALA, such as walnuts, flax and chia.
Use healthy oils like canola and olive oil instead of butter for cooking.
If you do not eat fish, talk with your clinician about whether an algae-based supplement makes sense.
Do not use supplements as a substitute for prescribed heart medications.

The bottom line

Omega-3 fats are an important part of a heart-healthy diet. The simplest and best-supported approach is to eat about 8 ounces of seafood a week, especially fatty fish, and to include plant sources like walnuts, flax and chia. Fish oil supplements have more mixed evidence for preventing heart disease in healthy people and can interact with some medications, so talk to your clinician before starting one.

Frequently asked questions

Do women over 40 need fish oil?

Most women can get enough omega-3s by eating about two servings of fish a week. Whether a supplement makes sense depends on your diet and health; ask your clinician.

What is the best source of omega-3s?

Fatty fish such as salmon, sardines, mackerel, herring and trout are the best sources of EPA and DHA. Walnuts, flaxseed and chia provide ALA.

Can I get enough omega-3s on a vegetarian diet?

You can get ALA from plant foods, but your body converts only a small amount to EPA and DHA. Algae-based supplements provide EPA and DHA for vegetarians and vegans.

Is fish oil safe with blood thinners?

Omega-3 supplements may increase bleeding risk when combined with blood thinners. Talk to your clinician before taking them together.