Sole Fish: Benefits, Nutrition, Mercury & How to Cook It

Dr. Josh Axe · Free quiz

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A grown sole lives flat on the sea floor, brown on top and white underneath, with both eyes on one side of its head.89 That flat body gives you thin, delicate fillets with a mild, sweet taste, and one of the lowest mercury levels at the fish counter.83

Sole is on the list of fish to eat in The Biblio Diet, which I co-wrote with Jordan Rubin,10 and wild-caught fish is number one on my list of 10 biblical superfoods.11 Wild-caught sole meets the standard I follow: wild, ocean-caught fish with fins and scales.10 The goal is more fish, not less,12 and a mild, low-mercury fish like sole makes that easy.

The name is old, too. English borrowed it in the 1200s from Old French, which took it from the Latin solea, a sandal, because the fish looks like a flat shoe.13

Did you know?

• Young petrale sole drift in open water for their first 5 to 6 months before they settle to the bottom and take on their flat adult shape.9

• Dover sole are nicknamed "slippery sole" because they coat their skin and scales in mucus, which makes them hard to pick up.8

• In 2024, U.S. boats landed 197 million pounds of wild yellowfin sole, all of it from Alaska's waters.14

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What is sole fish?

If you've ever wondered whether sole is just flounder, for the five soles caught in U.S. waters, it is: NOAA places all five in the right-eyed flounder family.89141718 FDA's Seafood List lets Pacific Dover sole and English sole carry the market name "sole," while petrale, rex and yellowfin sole may be sold as either sole or flounder.15 "Dover sole" covers two different fish: the common sole of the eastern Atlantic and the Mediterranean, also called European Dover sole, and a Pacific flounder caught from Alaska to California. FDA accepts the market name "sole" for both.15198

USDA does the same thing in its nutrition data, combining flounder and sole species in a single record, so the numbers below cover the flatfish you'll find sold as sole.1

Sole tastes mild and slightly sweet. NOAA describes Dover sole as dense and firm, petrale sole as sweet, delicate and nutty with a fine texture, and yellowfin sole as firm and delicate with small flakes.8914 Its thin fillets cook in minutes, and its gentle flavor makes it an easy first fish for people who think they don't like fish.

Sole and the fins-and-scales standard

The fins-and-scales standard goes back to Leviticus: "These shall ye eat of all that are in the waters: whatsoever hath fins and scales in the waters, in the seas, and in the rivers, them shall ye eat" (Leviticus 11:9).20 Scripture never names sole, but sole clearly meets that standard. The common sole's body is covered in ctenoid scales, the kind with tiny teeth along the edge, and NOAA notes that yellowfin sole have rough scales on both sides of the body.1914 A kosher fish list published in the Orthodox Union's guide, which covers fish with fins and scales, includes the true soles and the Pacific flounders sold as Dover, English, petrale, rex, rock and yellowfin sole.16

The same standard is why I leave shellfish, catfish and eel off the plate.10 The biblical diet guide shows how the whole way of eating fits together.

Sole fish nutrition facts

Calculated from USDA FoodData Central FDC ID 174197, flatfish (flounder and sole species) cooked with dry heat, at 85 grams. % Daily Value uses FDA reference values.12

Sodium varies by source: NOAA's panel for U.S. wild soles lists 81 milligrams per 100 grams of raw fish, while USDA's raw flatfish record lists 296.821 On packaged fillets, check the label.

On my show, I've explained that the best way to get omega-3s is from fish, with a high-quality omega-3 supplement as the backup when you can't.11 It's personal for me, too: genetic testing showed that my body doesn't convert the plant omega-3s in walnuts, flax and chia as well as many people's do, so I need to eat a lot of wild-caught fish myself.22

What is sole fish good for?

How sole works in your body

Sole's value comes down to three things your body uses: complete protein, selenium for your antioxidant enzymes, and ready-made omega-3s.

• Complete protein, very little fat. Wild-caught fish is a source of complete protein that also supplies EPA and DHA directly.32 In sole, that protein comes with only 2 grams of fat per fillet.1

• Selenium runs your antioxidant enzymes. Your body builds selenium into 25 to 30 selenium-dependent enzymes, including ones that protect the brain from oxidative damage.33 The mercury section below shows why that matters for fish.

• Omega-3s your cells can use as-is. Sole's EPA and DHA arrive ready-made, about 255 milligrams per serving, so your body doesn't have to convert them from plant sources.132

Sole fish benefits, ranked by evidence

In order of how strong the research is, sole's best-supported benefits are for getting selenium, B12 and protein into your diet, weight loss, triglycerides and metabolic health, a healthy pregnancy, insulin sensitivity and lower inflammation markers. Each card names the fish and the people studied.

Is sole high in mercury?

Mercury in the environment collects in water and sediment, where it turns into methylmercury, the form found in fish, and the highest levels show up in large, long-lived fish such as swordfish, shark and king mackerel.39 The rule of thumb from the fish you should never eat guide is simple: if a fish is big, old and eats other fish, it doesn't belong in your weekly rotation.12 Sole sits at the other end of FDA's monitoring data.

Average mercury in fish as sold (FDA monitoring)

Source: FDA Mercury Levels in Commercial Fish and Shellfish (1990–2012); FDA/EPA Advice about Eating Fish.34

Selenium is the mineral mercury goes after in your body, and sole carries plenty of it. Researchers at the University of North Dakota have proposed that the ratio of selenium to mercury in a fish may say more about its risk than the mercury alone, and they point out that typical ocean fish carry much more selenium than mercury.3340

Put together with FDA's numbers, the mercury picture for sole is about as reassuring as it gets for fish. For the signs of real overexposure, see mercury poisoning.

Is sole safe during pregnancy and for kids?

Pregnancy is a time to eat more of the right fish. Eating too little fish during pregnancy carries a real cost of its own.12 In a British cohort study of 11,875 pregnant women, children whose mothers ate no seafood in pregnancy had 48% higher odds of scoring in the lowest quarter for verbal IQ than children whose mothers ate more than 340 grams (12 ounces) a week, and lower intakes were also linked to poorer social, communication and fine-motor scores.30 That study measured seafood of all kinds; the cod trial in the ranked list above is the direct test of a lean white fish in pregnancy.29

For children, FDA and EPA recommend 2 servings a week from the Best Choices list, with a serving of about 1 ounce at ages 1 to 3, 2 ounces at ages 4 to 7, 3 ounces at ages 8 to 10 and 4 ounces at age 11.4 Sole is also on the shorter list of Best Choices that are even lower in mercury, the list FDA and EPA point to for children who eat fish at the higher amounts in the Dietary Guidelines.4 Its mild taste and soft flakes make it an easy fish to start with. For the rest of the plate, see the pregnancy diet guide.

How much sole should you eat?

A serving of fish is about the size of the palm of your hand, or 4 ounces before cooking.4 The Dietary Guidelines call for at least 8 ounces of seafood a week for adults eating about 2,000 calories a day and 8 to 12 ounces from lower-mercury choices during pregnancy and breastfeeding.4 In the weight-loss trial above, people ate 150 grams of cod, a little over 5 ounces, three times a week.5

Rotate sole with other low-mercury fish that have fins and scales, such as wild salmon, sardines, anchovies, pollock, haddock and cod, so you get the range of fats and minerals different fish carry. Halibut carries more mercury and sits in FDA and EPA's Good Choices group, so schedule it about once a week.4 The best fish to eat guide has more ideas.

How to buy and store sole

When you're buying fish, make sure it's wild-caught,11 and with sole that's easy: the Dover, petrale, rex, English and yellowfin sole caught in U.S. waters are wild fish. NOAA calls each of them a smart seafood choice because it's sustainably managed and responsibly harvested under U.S. regulations, and their assessed stocks are not overfished.89141718 Bottom trawls bring them in, and NOAA reports that trawling for them over soft, sandy or muddy bottoms causes minimal damage to habitat.814 Common sole is also raised on fish farms,19 so if a label just says "sole," ask whether it's wild-caught.

Ask for the species and the country, and skip any fish you can't trace.12 At the counter, that tells you whether your "sole" is Pacific Dover, petrale or the European fish, and where it came from.

When you shop, these checks from FDA39 help you pick a good fillet:

• Smell it. Fresh fish should smell fresh and mild, not fishy, sour or like ammonia.

• Press it. Fresh fillets should have firm flesh that springs back when pressed, with no darkening or drying around the edges.

• Check frozen packages. Skip any package that's open, torn or crushed at the edges, or that shows frost or ice crystals, a sign the fish was stored a long time or thawed and refrozen.

• Store it cold. Refrigerate at 40°F or below and use within 2 days, or wrap it tightly and freeze it.

• Thaw it slowly. Move frozen sole to the refrigerator the night before you cook it.

How to cook sole

Bake, broil or pan-sear sole, and skip the deep fryer. Broiled fish has a long history at the table: when the risen Jesus asked his disciples for something to eat, "they gave him a piece of a broiled fish, and of an honeycomb" (Luke 24:42).20

I put fried or breaded fish on the avoid side of my food list,10 and research on how fish is cooked points the same way. In a U.S. cohort study of 3,910 adults aged 65 and older, followed for 9.3 years, those who ate tuna or other broiled or baked fish three or more times a week had a 49% lower risk of dying of ischemic heart disease than those who ate it less than once a month, while fried fish and fish sandwiches showed no such benefit and trended toward higher risk.41

Cook sole in extra virgin olive oil, the fat you can use liberally, and save butter or ghee for a small pat at the end for flavor. Sole is thin, so it cooks in minutes. FDA's standard is an internal temperature of 145°F; without a thermometer, the flesh should separate easily with a fork.39

Simple lemon-herb baked sole

1. Heat the oven to 400°F and brush a baking dish with olive oil.
2. Lay 1 pound of sole fillets (four 4-ounce servings) in the dish, brush them with a tablespoon of olive oil and season with sea salt, pepper and minced garlic.
3. Scatter a handful of cherry tomatoes around the fish and add a few thin slices of lemon.
4. Bake until the fish flakes easily with a fork and reaches 145°F, usually 8 to 12 minutes depending on thickness.
5. Finish with chopped fresh parsley or dill and a squeeze of lemon.

How does sole compare with other fish?

Sole sits with salmon, haddock and pollock among the lowest-mercury fish FDA has measured, and it meets the fins-and-scales standard.3410

Sources: FDA mercury monitoring; FDA/EPA Advice about Eating Fish; Dr. Axe's list of fish to eat; Orthodox Union kosher fish list.341016

Cod is a lean white fish like sole, with about twice its mercury and the same Best Choice rating.34

Who should be careful with sole?

Interaction check: Low. No medication interactions are documented for fish eaten as food.

Fish allergy

About 0.9% of U.S. adults have a convincing fish allergy, according to a national survey of 40,443 adults.42 The main fish allergens, called parvalbumins, are similar across many species, so a person allergic to one fish can react to others; some people react only to certain species.43 If you've reacted to any fish, don't eat sole and don't assume another fish is safe for you either; decide with a practitioner who knows your food allergy history. Hives, swelling of the lips or throat, wheezing or trouble breathing after eating fish need emergency care right away: call 911.

Raw or undercooked sole

Cook sole to 145°F.39 Skip raw seafood, including sole in ceviche or sushi, if you're pregnant, for young children and older adults, and if you have liver disease or a weakened immune system.1239 For more on raw fish, see is sushi healthy.

Flatfish caught by family or friends

Recreational anglers catch flounder too. For fish caught by family or friends, check your local fish advisory; if there isn't one, FDA and EPA advise eating only one serving of that fish and no other fish that week.4

The bottom line

Sole fish: frequently asked questions

References

1. U.S. Department of Agriculture, Agricultural Research Service. Fish, flatfish (flounder and sole species), cooked, dry heat. FoodData Central, SR Legacy, FDC ID 174197. Published April 1, 2019.
2. U.S. Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts Labels.
3. U.S. Food and Drug Administration. Mercury Levels in Commercial Fish and Shellfish (1990-2012).
4. U.S. Food and Drug Administration, U.S. Environmental Protection Agency. Advice about Eating Fish. Revised October 2021.
5. Thorsdottir I, Tomasson H, Gunnarsdottir I, Gisladottir E, Kiely M, Parra MD, et al. Randomized trial of weight-loss-diets for young adults varying in fish and fish oil content. Int J Obes (Lond). 2007;31(10):1560-6. doi:10.1038/sj.ijo.0803643. PMID:17502874
6. Ouellet V, Marois J, Weisnagel SJ, Jacques H. Dietary cod protein improves insulin sensitivity in insulin-resistant men and women: a randomized controlled trial. Diabetes Care. 2007;30(11):2816-21. doi:10.2337/dc07-0273. PMID:17682120
7. Ouellet V, Weisnagel SJ, Marois J, Bergeron J, Julien P, Gougeon R, et al. Dietary cod protein reduces plasma C-reactive protein in insulin-resistant men and women. J Nutr. 2008;138(12):2386-91. doi:10.3945/jn.108.092346. PMID:19022962
8. NOAA Fisheries. Dover Sole (Microstomus pacificus). FishWatch species profile. Last updated July 10, 2026.
9. NOAA Fisheries. Petrale Sole (Eopsetta jordani). FishWatch species profile. Last updated September 28, 2026.
10. Axe J, Rubin J. The Biblio Diet. Hachette Book Group; 2025. ISBN 9781546008439.
11. Axe J. 10 Biblical Superfoods That Can Add Years to Your Life. The Dr. Josh Axe Show, Episode 393. September 28, 2026 (at 6:25, 7:33, 9:46 and 10:24; also on YouTube as "The Bible's Grocery List: 10 Foods That Slow How Fast You Age," https://www.youtube.com/watch?v=9AnNi1umufc).
12. Axe J. Fish You Should Never Eat: 12 to Skip & Safer Choices. DrAxe.com. 2026.
13. Harper D. sole (n.2). Online Etymology Dictionary.
14. NOAA Fisheries. Yellowfin Sole (Limanda aspera). FishWatch species profile. Last updated June 30, 2026.
15. U.S. Food and Drug Administration. The Seafood List: acceptable market names for sole and flounder species.
16. Atz JW. Kosher and Non-Kosher Fish. Orthodox Union Kosher Guide (1991), reprinted by Kashrut.com with permission of the Orthodox Union.
17. NOAA Fisheries. Rex Sole (Glyptocephalus zachirus). FishWatch species profile. Last updated September 28, 2026.
18. NOAA Fisheries. English Sole (Parophrys vetulus). FishWatch species profile. Last updated June 30, 2026.
19. Froese R, Pauly D, editors. Solea solea, Common sole. FishBase.
20. The Holy Bible, King James Version. Project Gutenberg eBook #10. Verses quoted from this text.
21. U.S. Department of Agriculture, Agricultural Research Service. Fish, flatfish (flounder and sole species), raw. FoodData Central, SR Legacy, FDC ID 174196. Published April 1, 2019.
22. Axe J. Proven Ways To Prevent Alzheimer's Before It's Too Late. The Dr. Josh Axe Show. November 17, 2025.
23. Tørris C, Molin M, Småstuen MC. Lean Fish Consumption Is Associated with Beneficial Changes in the Metabolic Syndrome Components: A 13-Year Follow-Up Study from the Norwegian Tromsø Study. Nutrients. 2017;9(3):247. doi:10.3390/nu9030247. PMID:28282859
24. Qin ZZ, Xu JY, Chen GC, Ma YX, Qin LQ. Effects of fatty and lean fish intake on stroke risk: a meta-analysis of prospective cohort studies. Lipids Health Dis. 2018;17(1):264. doi:10.1186/s12944-018-0897-z. PMID:30470232
25. Tou JC, Gucciardi E, Young I. Lipid-modifying effects of lean fish and fish-derived protein consumption in humans: a systematic review and meta-analysis of randomized controlled trials. Nutr Rev. 2021;80(1):91-112. doi:10.1093/nutrit/nuab003. PMID:33942085
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27. Ramel A, Martinez JA, Kiely M, Bandarra NM, Thorsdottir I. Effects of weight loss and seafood consumption on inflammation parameters in young, overweight and obese European men and women during 8 weeks of energy restriction. Eur J Clin Nutr. 2010;64(9):987-93. doi:10.1038/ejcn.2010.99. PMID:20551965
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29. Kvestad I, Hysing M, Kjellevold M, Næss S, Dahl L, Markhus MW. Maternal Cod Intake during Pregnancy and Infant Development in the First Year of Life: Secondary Analyses from a Randomized Controlled Trial. J Nutr. 2021;151(7):1879-1885. doi:10.1093/jn/nxab083. PMID:33847344
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31. Rosendahl-Riise H, Karlsson T, Drevon CA, Apalset EM, Nygård OK, Tell GS, et al. Total and lean fish intake is positively associated with bone mineral density in older women in the community-based Hordaland Health Study. Eur J Nutr. 2019;58(4):1403-1413. doi:10.1007/s00394-018-1665-6. PMID:29541909
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34. Axe J. Healthy Weight & Metabolic Reset: The 90-Day Healing Protocol. DrAxe.com protocol. 2026: p. 8.
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36. Markhus MW, Hysing M, Midtbø LK, Nerhus I, Næss S, Aakre I, et al. Effects of Two Weekly Servings of Cod for 16 Weeks in Pregnancy on Maternal Iodine Status and Infant Neurodevelopment: Mommy's Food, a Randomized-Controlled Trial. Thyroid. 2021;31(2):288-298. doi:10.1089/thy.2020.0115. PMID:32746774
37. Helland A, Bratlie M, Hagen IV, Mjøs SA, Sørnes S, Ingvar Halstensen A, et al. High intake of fatty fish, but not of lean fish, improved postprandial glucose regulation and increased the n-3 PUFA content in the leucocyte membrane in healthy overweight adults: a randomised trial. Br J Nutr. 2017;117(10):1368-1378. doi:10.1017/S0007114517001234. PMID:28606215
38. Schwab US, Lankinen MA, de Mello VD, Manninen SM, Kurl S, Pulkki KJ, et al. Camelina Sativa Oil, but not Fatty Fish or Lean Fish, Improves Serum Lipid Profile in Subjects with Impaired Glucose Metabolism-A Randomized Controlled Trial. Mol Nutr Food Res. 2018;62(4):e1700503. doi:10.1002/mnfr.201700503. PMID:29272068
39. U.S. Food and Drug Administration. Selecting and Serving Fresh and Frozen Seafood Safely.
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Dr. Josh Axe, DC, DNM, CNS

Doctor of Natural Medicine · Founder, DrAxe.com

Dr. Axe is a certified doctor of natural medicine, clinical nutritionist, and multiple New York Times bestselling author. He has spent 20+ years in clinical practice helping people heal at the root cause and founded one of the most-visited natural-health platforms in the world.

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