Protein is found in every cell, tissue and organ in the human body and is necessary for optimal functioning. Protein is a macronutrient, and therefore provides the body with energy. It is constantly being broken down, digested and replaced by dietary sources. The amount of protein you need depends on your age, gender, weight and activity level. Protein needs increase during times of growth and stress. Eating a variety of foods will help you meet your daily protein needs.
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Function of Protein
Protein is used to make amino acids, the building blocks of life. Protein is necessary for proper growth and development, muscle contractions, production of red blood cells and normal metabolism. It aids in immune function; maintain fluid and electrolyte balance; provides structure to nails, hair and teeth; and repairs tissues. Protein makes up approximately 45 percent of the body and is present primarily in bone, muscle, hemoglobin, myoglobin, hormones, enzymes and antibodies.
Recommended Dietary Allowance
There are different mechanisms for determining your protein needs. According to the Center for Disease Control and Prevention, it is generally recommended that 10 to 35 percent of your daily calories come from protein. Additionally, the Food and Nutrition Board at the Institute of Medicine established recommended dietary intake levels for protein based on age. Children ages 1 to 3 require 13 g, children ages 4 to 9 need 19 g and children ages 9 to 13 require 34 g of protein per day. These requirements increase to 46 g daily for girls ages 14 to 18 and 52 g of protein daily for boys ages 14 to 18. Women age 19 and over need 46 g of protein each day and men over the age of 19 need 56 g of protein daily.
Calculate Protein Needs
To determine your daily protein needs, you must first know your weight in kg. To convert your body weight into kg, simply divide your weight in lb by 2.2. The Centers for Disease Control and Prevention recommends 0.8 g of protein per kilogram of body weight for healthy individuals. If you are pregnant, under stress or moderately to vigorously active, use a number between 1.1 and 1.8 per day. To calculate your protein needs, multiply your weight in kg by the number of g of protein you require each day. For example, if you are a healthy individual and weight 70 kg, your protein needs would be 56 g of protein per day. If you are moderately active and weight 85 kg, you need 99 g of protein daily.
Protein is available in varying amounts in different kinds of foods. A 1 cup serving of milk is equal to 8 g of protein and an 8 oz. portion of yogurt provides 11 g of protein. On average, a 3 oz. piece of meat, poultry, fish or tofu contains 21 g of protein and a 1 cup serving of dry beans or legumes is equal to 16 g of protein. One medium egg, 1/4 cup of tuna and 2 tbsp of peanut butter provide 7 g of protein. Grain products such as whole grain bread, cereal, pasta, nuts, seeds and even some vegetables contain approximately 2 g of protein per serving. Consuming a healthy diet which emphasizes a variety of foods will help you consume the right amount of protein for your individual needs.