Fun fact: Omega-3 fatty acids were discovered fewer than 100 years ago! It was only in 1930 that husband-and-wife research team George and Mildred Burr identified these essential lipids while studying fat deficiency in rats. From there, scholarly curiosity in omega-3s grew gradually, eventually triggering the public interest that has made them a common supplement today.

Not surprisingly, given their relatively short history in our scientific lexicon, we’re still learning a lot about these fats found in fish, walnuts, flaxseed, and other foods. They’ve been researched for their effects on heart health and babies’ developing brains, but, increasingly, it appears they may serve other important functions in the body as well, from promoting eye health to boosting mood.

The National Academy of Medicine has set an Adequate Intake level for omega-3s of 1.6 grams per day for adult men, 1.1 grams per day for adult women, and 1.4 and 1.3 grams for pregnancy and lactation, respectively. But since nutrition labels aren’t required to list amounts of omega-3s, it can be tough to know if you’re getting enough for good health.

Not sure whether your diet is providing enough of those all-important omega-3s? Look out for the following signs you’re falling short.   

1. You’re Experiencing Low Mood

Omega-3s are known for supporting babies’ neurological development, but their effects on the brain don’t seem to stop after infancy. It’s possible that an omega-3 deficiency could contribute to mental illnesses like depression, anxiety, bipolar disorder, and attention deficit hyperactivity disorder (ADHD).

Read More: 5 Healthful Ways to Ward Off Mild Depression

In a 2016 study, researchers analyzed the omega-3 content of blood samples from 130 people with treatment-resistant mood or anxiety disorders. The results: Seventy-five percent of them had low omega-3 levels. Subsequently, the researchers noted that increasing omega-3 levels effectively supported the mental well-being of the study participants. 

2. Your Eyes Are Dry 

Nothing quite compares to the stinging discomfort (and, sometimes, inexplicable and uncontrollable watering) of dry eye syndrome. Besides being a major pain, this could also be an indicator that you could use more omega-3s. “There is some evidence that suggests that a diet rich in omega-3 fatty acids may help reduce dry eyes,” says culinary nutritionist Laura M. Ali, R.D. “The thought is that omega-3s help your tear glands produce the oily part of the tear, which helps keep your eyes moist. These fats also help balance the body’s inflammatory response as well as swelling that can make dry eyes worse.”

Per one large study from 2019, women who consumed more omega-3 fatty acids had a significantly lower risk for dry eyes. So, if your dry eyes are driving you crazy, consider whether a diet lacking in omega-3s could be part of the problem. 

3. Your Skin Is Irritated 

Just like omega-3s might help moisturize eyes, they could also moisturize skin. Without enough of these healthy fats in your system, you could end up with unsightly dryness and flakiness.  

Read More: 10 Products That Could Save Your Flaky Skin

Omega-3s’ benefits for healthy, glowing skin have to do with their impact on the skin’s natural barrier. “Omega-3 essential fatty acids are critical for maintaining healthy skin barrier function, which keeps moisture locked in (a.k.a. protects our hydration from literally evaporating from our body!) and protects our body from free radicals and other inflammatory factors in our environment,” explains Butner. Studies have shown that ample omega-3s could help increase your resistance to sunburn and decrease skin irritation and sensitivity. 

4. You’re in a Mental Fog

Brain fog is one of those vague issues that can have many hard-to-pin-down culprits—but, nonetheless, it’s a very real struggle for those experiencing it. If your thoughts are feeling fuzzy or you can’t seem to focus, bumping up your omega-3 intake might help bring back some much-needed mental precision.

Specifically, the omega-3 docosahexaenoic acid (DHA)—rather than other omegas EPA or ALA—could clear the clouds of brain fog. “DHA helps to increase blood flow and circulation in your brain and has been researched in various studies,” Butner says. “Results were generally positive in just how much benefit DHA can have on cognition and focus.” Cold-water fatty fish like salmon, tuna, herring, and sardines are particularly good sources of DHA.

5. Your Breastfed Baby’s Weight Is Low

The recommended omega-3 intake for breastfeeding women is more than a pie-in-the-sky suggestion. If you’ve got a nursing babe, reaching your target omega-3s could make a real difference to your little one’s weight. “The most obvious sign of a breastfeeding woman not getting adequate essential fatty acids (EFAs) is their baby’s weight,” says Dr. Lana Butner, N.D., board-certified naturopathic doctor and founder of Dr. Lana Wellness. This often manifests as a baby who struggles to gain weight, begins to lose weight, or, in more extreme cases, cannot maintain sufficient body heat.

If your breastfeeding infant is struggling to gain pounds, consider its mother’s diet—and particularly her intake of omega-3-rich foods like salmon, sardines, mackerel, and chia seeds—to ensure she’s consuming enough (and thus producing enough) of the nutrients the baby needs. A consultation with a dietitian who specializes in maternal nutrition could be a helpful step if you’re unsure about how to craft the best diet for breastfeeding. 

How to Get More Omega-3s 

Fortunately, when it comes to getting enough omega-3s in your diet, there are plenty of fish in the sea (and other foods to choose from, too)! Some of the best sources include:

• Salmon
• Sardines
• Trout
• Tuna
• Herring
• Mackerel
• Seaweed
• Walnuts
• Chia seeds
• Flax seeds
• Edamame
• Brussels sprouts

You can even mix and match these foods for an even bigger omega-3 boost. Try salmon sushi wrapped in seaweed, walnut-crusted tuna steaks, or Brussels sprouts roasted in flaxseed oil.

Omega-3 supplements are always a supportive option if your diet doesn’t provide enough (or, of course, if your healthcare provider recommends them). Supplements can be particularly helpful if you eat a vegetarian or otherwise highly restricted diet, Ali says. (Not sure which omega-3 supplement is right for you? Read our guide.)