The Nutritive Value of Meat
Elizabeth Boyle, Ph.D.
Department of Animal Sciences and Industry
Kansas State University
Meat is an excellent source of many nutrients, especially protein, B vitamins, iron and zinc. As a nutrient dense food, meat provides major nutritive contributions to your diet relative to the amount of calories it contains. For example, a 3 ounce cooked portion of lean beef containing 195 calories would provide 25 grams of protein, 9 grams of fat, over one-third of your daily requirement for zinc and nearly fifteen percent of your daily iron needs.
In addition to having a high protein content, meat provides high quality protein. To understand this concept, some fundamental knowledge about the composition of proteins is needed. Compounds called amino acids are the basic building blocks that form proteins. There are essential and non-essential amino acids. Essential amino acids cannot be made in adequate quantities by the body and must be supplied through your diet. Meat, eggs and milk supply all of the essential amino acids, making them complete, high quality protein sources.
Meat is a major dietary source of thiamin, riboflavin, niacin, vitamin B6 and vitamin B12. A 3 ounce cooked portion of pork provides more thiamin than most other foods commonly consumed. Thiamin, however, is a water soluble vitamin that is easily lost during cooking. To retain as much thiamin as possible, it is recommended that meat be cooked using dry heat rather than moist heat cooking methods.
Dietary iron is present in food as heme or nonheme iron. The human body absorbs heme iron at a rate about five to ten times higher than it absorbs nonheme iron. Heme iron accounts for fifty to sixty percent of the iron in beef, lamb and chicken and thirty to forty percent of that in pork, liver and fish. All remaining iron in meat is in the nonheme form. Scientists have established that ascorbic acid can aid in the absorption of nonheme iron. By drinking a glass of orange juice with a meal containing meat, you can enhance nonheme iron absorption by a substantial amount.
Other components in food such as tannins in tea and polyphenols in coffee can inhibit the absorption of nonheme iron. Consuming coffee one hour before a meal will not effect nonheme iron absorption. If coffee is consumed with a meal, or one hour after a meal, nonheme iron absorption can be reduced nearly forty percent. The absorption of heme iron has not been found to be affected by these foods.
Meat, liver, eggs and seafoods, especially oysters, are excellent sources of highly available zinc. In general, zinc is more readily available from animal sources than from vegetable sources. There are, however, many dietary and physiological factors that affect the absorption and bioavailability of dietary zinc.
Remember to consume a variety of foods in moderation and include meat as part of your healthy, balanced diet.