The clam, a type of mollusk, is an excellent source of protein, vitamin B-12 and iron.

Serving Size and Calories

A serving of steamed clams is 3 oz, which is about 10 small clams. A 3 oz. serving of steamed clams provides 126 calories.

Protein

Clams are a good source of complete protein, meaning they provide all nine essential amino acids your body cannot make on its own. Protein in your diet is important to support the growth and repair of all your organs, tissues and cells. A 3 oz. serving of steamed clams provides 21.7g of protein.

Vitamins

Steamed clams are a good source of vitamin B-12, which your body needs for nerve function and DNA synthesis. A 3 oz. serving of steamed clams provides 84mcg of vitamin B-12. Clams also provide niacin, a B vitamin necessary for the function of more than 200 enzymes involved in energy metabolism.

Minerals

Steamed clams are rich in iron, a mineral necessary for the production of red blood cells. A 3 oz. serving of steamed clams has 23.8mg of iron. Steamed clams also provide zinc, a mineral that promotes immune function and essential for energy metabolism.

Fat and Cholesterol

Steamed clams have a small amount of fat, most of which is heart-healthy polyunsaturated fat. A 3 oz. serving of steamed clams has 1.66g of fat.

Selection and Storage

Steamed clams are prepared with live clams in the shell. When purchasing live hard-shell clams, the shells should be closed tightly. If a hard shell clam is slightly open, tap it lightly and make sure it snaps shut, otherwise discard. Live soft-shell clams will have the neck sticking out of the shell, which should move when touched. Live clams may be stored for up to two days in a 40 degree F refrigerator.

【Reference】

http://www.livestrong.com/article/315890-nutritional-value-of-steamed-clams/