Petrale sole is one of the healthiest fish you can eat. With only 91 calories and nearly 19 grams of protein per 100-gram serving, it delivers a high ratio of protein to calories while keeping fat and mercury levels remarkably low. It’s a smart choice whether you’re watching your weight, protecting your heart, or simply looking for a clean source of protein.
Calories, Protein, and Fat
A 100-gram serving of petrale sole (roughly a small fillet) contains 91 calories, 18.84 grams of protein, and just 1.19 grams of total fat. Cholesterol comes in at 48 milligrams. For context, that protein count is comparable to chicken breast, but with a fraction of the fat. Because petrale sole is a lean white fish rather than a fatty species like salmon or mackerel, it won’t give you a significant dose of omega-3 fatty acids. What it does give you is an extremely efficient protein source with very little else you need to worry about.
Vitamins and Minerals
Petrale sole punches above its weight in micronutrients. A single serving provides close to half your daily value of both selenium and vitamin B12, plus about 20 percent of your daily phosphorus needs. Selenium supports thyroid function and acts as an antioxidant, protecting cells from damage. B12 is essential for nerve function and red blood cell production, and many adults, particularly older adults and those eating less meat, fall short of it. Getting nearly half a day’s worth from one piece of fish is a meaningful contribution.
Heart Health Benefits
Even without the high omega-3 content of fattier fish, lean white fish like petrale sole offers measurable cardiovascular benefits. A randomized controlled trial published in The American Journal of Clinical Nutrition found that people who ate lean seafood had lower fasting triglyceride levels compared to those eating a non-seafood diet. The difference was about 0.31 mmol/L, which is clinically meaningful. The study also observed improvements in the size and concentration of VLDL particles, a type of cholesterol-carrying molecule linked to heart disease risk when elevated.
In practical terms, this means regularly eating lean fish like petrale sole can help reduce the level of fats circulating in your blood after meals and between them. This is especially relevant if you’re replacing red meat or processed protein sources with fish a few times a week.
Mercury Levels
Mercury is one of the main concerns people have about eating fish, and petrale sole scores well here. According to FDA testing data, flatfish (a category that includes sole, flounder, and plaice) average just 0.056 parts per million of mercury. That’s extremely low. For comparison, swordfish averages around 0.995 ppm and canned albacore tuna comes in around 0.35 ppm. Petrale sole contains roughly one-sixth the mercury of canned tuna.
Because mercury levels are so low, petrale sole is safe to eat multiple times per week for most adults, including pregnant women and children. Low-mercury white fish like sole, flounder, and cod carry no practical limit on weekly servings the way higher-mercury species do.
How It Compares to Other Fish
If you’re choosing between petrale sole and other white fish like cod, tilapia, or haddock, the nutritional profiles are broadly similar: high protein, low fat, low mercury. Petrale sole tends to have a slightly more delicate flavor and finer texture than cod, which makes it popular in restaurants but also means it can fall apart more easily during cooking.
Where petrale sole differs more sharply is against fatty fish like salmon. Salmon provides far more omega-3s (roughly 2 grams per serving versus a trace amount in sole), but it also has more calories and fat. Both types of fish belong in a healthy diet. If you’re eating fish several times a week, a good strategy is to mix lean options like petrale sole with fattier fish like salmon or sardines to get the full range of benefits.
Sustainability
Petrale sole is primarily caught off the U.S. Pacific coast, and the stock is in healthy shape. The most recent stock assessment, reviewed by the Pacific Fishery Management Council in 2023, found the population at about 33.6 percent of its unfished level, well above the 25 percent threshold that would trigger concern. This means you can eat petrale sole without significant worry about overfishing, though availability can be seasonal since most of the catch comes from trawl fisheries that operate during specific windows.
Best Ways to Keep It Healthy
Petrale sole’s mild flavor makes it versatile, but how you cook it matters. Pan-searing in a small amount of olive oil or butter, baking, or broiling all preserve its low-calorie profile. Breading and deep-frying, on the other hand, can triple the calorie count and add inflammatory fats that undercut the benefits of choosing fish in the first place.
A simple approach: season a fillet with salt, pepper, and lemon, then cook it in a hot pan with a teaspoon of olive oil for about three minutes per side. The fish is done when it flakes easily with a fork. Pair it with vegetables or whole grains, and you have a meal that’s under 300 calories with over 30 grams of protein, depending on your sides.