The National Institutes of Health sets the daily target for omega-3 at 1.6 grams for adult men and 1.1 grams for adult women.
The two long-chain forms found in fish, EPA and DHA, do not have their own recommended intake, but federal guidelines and the American Heart Association point to about 250 milligrams a day combined.
The average American adult falls well short of that. A NHANES analysis of US adults found mean daily intake from food of just 23 milligrams of EPA and 63 milligrams of DHA. Fish rich in omega-3 made up only about a fifth of an ounce a day.
True clinical omega-3 deficiency is rare in the United States, according to the NIH Office of Dietary Supplements.
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But a chronic low intake can still leave a fingerprint on how the body functions.
Here are 7 signs that may point to a low-omega-3 diet, and the foods that can push your intake in the right direction.
7 signs to look out for
1. Rough, scaly or flaky skin. This is the one sign the NIH factsheet names outright.
A shortage of essential fatty acids can cause rough, scaly skin and dermatitis.
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The 2022 review in the Journal of Preventive Medicine and Hygiene describes a dry, scaly rash and slower wound healing among the classic clinical signs.
2. Dry or irritated eyes. Omega-3 fatty acids feed the tear film. A 2023 systematic review and meta-analysis of randomized trials found that omega-3 supplementation significantly improved dry eye symptoms and tear stability, which suggests the tear film is sensitive to intake.
3. Joint stiffness and slower recovery. EPA and DHA feed anti-inflammatory pathways in the body.
Low intake is associated with a more inflammatory tone, which can show up as stiff joints or a longer soreness window after exercise.
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4. Dull or brittle hair. Fatty acids sit in the cell membranes that build the hair shaft.
When intake stays low, hair can lose shine and feel more fragile, alongside the skin changes flagged by the NIH.
5. Low mood. EPA in particular has been studied for its role in depressive symptoms.
A meta-analysis published in Translational Psychiatry found an overall benefit of omega-3 supplementation for major depressive disorder, especially with EPA-heavy formulas.
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6. Trouble concentrating. DHA is the most abundant omega-3 in the brain and sits in the membranes of nerve cells.
A steady shortfall in the diet has been linked in observational studies to poorer cognitive performance, though the evidence is not as clear-cut as it is for cardiovascular endpoints.
7. Fatigue. Tiredness is not a specific omega-3 sign, and other causes should always be ruled out first.
But a diet low in fatty fish often runs low in several nutrients tied to energy and iron status, and low omega-3 status is one factor worth considering with a doctor.
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If any of these signs persist, talk to your doctor before making big diet changes or reaching for a supplement. Symptoms like fatigue, low mood or dry eyes have many possible causes.
What to eat to close the gap
Fatty fish is the most concentrated source of the long-chain omega-3s the body can use directly.
According to the NIH factsheet, a 3-ounce cooked serving of Atlantic salmon (farmed) delivers about 1.24 grams of DHA and 0.59 grams of EPA.
Atlantic mackerel provides 0.59 grams of DHA and 0.43 grams of EPA per 3-ounce serving, and canned sardines around 0.74 grams of DHA and 0.45 grams of EPA. Two servings of fatty fish a week is the standard federal recommendation.
Plant foods deliver ALA, which the body can convert to EPA and DHA, though only a small share is converted.
A 1-ounce serving of chia seeds contains about 5.06 grams of ALA, though, as we have covered, the body only uses a small fraction of chia's plant-form omega-3.
A 1-ounce serving of English walnuts provides 2.57 grams of ALA, and a tablespoon of whole flaxseed about 2.35 grams.
Any one of these alone meets the daily ALA target for an adult woman.
For readers who eat little or no fish, a mix of walnuts, ground flaxseed and chia seeds across the day is the simplest way to reach the ALA target without a supplement, while keeping fatty fish, canola oil or algae-based DHA in mind for the EPA and DHA the body uses most efficiently.
This article is made and published by Mie Hermansen, who may have used AI in the preparation.