You may encounter black kingfish, Pacific kingfish and yellowtail kingfish, but they’re not related to plain kingfish. Kingfish, which is more commonly called king mackerel, thrives in the Atlantic Ocean along the American coast. Even though it's low in total fat, kingfish is a rich source of healthy omega-3 fatty acids. It’s also packed with protein, vitamin B-12 and selenium. But be aware that it has high levels of mercury.
Extra Lean Protein
Kingfish is more than just a lean protein. It easily meets the standard for an extra lean protein, according to requirements established by the U.S. Department of Agriculture’s Food Safety and Inspection Service. A 3-ounce serving of kingfish contains 114 calories and 22 grams of protein, or 44 percent of your daily value for protein based on a 2,000-calorie-a-day diet. The same portion has just 2 grams of total fat and 58 milligrams of cholesterol.
Omega-3s for Your Heart
The omega-3 fatty acids fill a number of essential roles, from regulating inflammation to supporting the structure and function of cells, but they’re best known for their potential to lower your risk of cardiovascular disease. The omega-3s in fish oil -- eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA -- help lower blood pressure and reduce the amount of triglycerides in your blood, according to the Harvard School of Public Health. The Institute of Medicine established a recommended daily intake for total omega-3 fatty acids of 1.1 grams for women and 1.6 grams for men. Three ounces of kingfish contain 0.34 grams of combined EPA and DHA.
B Vitamins for Energy
As a group, the B vitamins support your metabolism through their role converting food into energy. Your body also uses niacin to make hormones, while vitamins B-6 and B-12 are essential for synthesizing red blood cells and DNA. Kingfish contains a significant amount of all three vitamins. Based on a 2,000-calorie-a-day diet, a 3-ounce serving provides 44 percent of your daily value of niacin and 22 percent of vitamin B-6. The same portion also supplies 255 percent of your daily value for vitamin B-12.
Rich Source of Selenium
Your thyroid gland can’t produce hormones that regulate your metabolism if you don’t get enough selenium in your diet. Selenium also strengthens your immune system and helps produce antioxidants that protect cell membranes from damage caused by free radicals. A 3-ounce serving of kingfish supplies 57 percent of your daily value for selenium if you eat 2,000 calories daily. You may get a little more or less according to the number of calories you consume. Kingfish also provides 10 percent of the daily value of iron and potassium.
Kingfish, or king mackerel, is on the list of fish to avoid due to its high levels of mercury. The Environmental Defense Fund states that adult men should eat less than one serving of kingfish a month. The U.S. Food and Drug Administration warns that women who might become pregnant, anyone who is pregnant or nursing, and young children should not eat king mackerel.