Flounder is type of flatfish found in the ocean and commonly eaten in the United States. A filet of flounder is an excellent source of protein and other nutrients. However, certain groups of people should limit flounder and other fish consumption due to possible toxins found in fish from waters that may be contaminated.
The amount of protein you require on a daily basis depends on your age, gender and activity level. The Institute of Medicine-recommended dietary allowance or minimum daily requirement for protein is 46 g per day for adult women, 71 g each day for pregnant and nursing women and 56 g per day for adult men. These recommendations are based on an IOM requirement of 0.8 g of protein per kilogram of body weight per day. However, according to the American Dietetic Association, athletes require slightly more protein than this, or about 1.2 to 1.7 g of protein per kilogram of body weight per day.
Protein in Flounder
The amount of protein present in flounder depends on the portion size. One fillet of flounder is typically about 3 to 4 oz., slightly larger than the size of a deck of cards. According to the U.S. Department of Agriculture Nutrient Data Laboratory, one 4-oz. fillet of flounder, or about 127 g of flounder, contains about 19 g of protein, and one 3-oz. fillet or 85 g of flounder provides about 13 g of protein.
Fish, including flounder, are a source of high-quality complete protein. This means a flounder fillet contains all the essential amino acids your body requires on a daily basis. Animal-based proteins such as meat, fish, eggs, milk and other dairy products are all considered complete proteins and most plant-based proteins, with the exception of soy protein, are considered incomplete because they are missing one or more essential amino acids.
Mercury and other contaminants are a concern if you’re eating lots of flounder to meet your protein needs. The U.S. Food and Drug Administration encourages women of childbearing age, pregnant and nursing women and children to limit fish and shellfish consumption to 12 oz. per week of low-mercury-containing fish varieties. According to the U.S. Department of Agriculture, flounder contains about 7 mcg of mercury per 4-oz. portion size, which is a fairly low amount compared with other types of fish.