Protein is made up of amino acids. Depending on which source you read, there are 20 to 22 different amino acids. One of the most familiar proteins in the human body is hemoglobin, found in red blood cells, which carries oxygen from your lungs throughout your whole body.
The protein in the foods you eat do not directly supply your body with protein. It supplies the amino acids needed by your body to make its own proteins like hemoglobin. There are eight essential amino acids needed for adults and nine for infants. Without these amino acids, your body would not be able to make its own proteins.
Sources of Protein
Most foods with the exception of sugar and fats provide protein. Some foods are better sources than others providing all or most of the essential amino acids.
Ideally, you want to eat foods containing high quality protein with the essential amino acids in the right proportions needed by your body. Like carbohydrates, there are high quality proteins analogous to complex carbohydrates and low quality proteins analogous to process sugars.
One example of a high quality protein is eggs. Egg protein has been designated as a reference protein and assigned a value of 100 by the Food and Agricultural Organizations of the United Nations which sets world standards. An international measure of food protein is its biological value (BV). Egg protein has a BV of 100, rice 86, fish fillets 75-90 and corn 40. As you can see from these numbers, meat protein has a higher value than plant protein. For this reason, it is essential for people on a strict vegetarian diet to eat foods containing the essential amino acids to meet their bodies needs.
What Roles Do Proteins Play?
What roles do proteins play in your body?
Proteins maintain fluid balance, they are antibodies which protect you against dieses and hormones like insulin which regulates the glucose concentration in your blood. Proteins act as transport mechanisms for moving nutrients in and out of your cells. Fibrin is a protein that forms to produce a clot when you cut yourself preventing you from bleeding to death. Proteins make scar tissue, bones, and teeth. They are in the light sensitive pigments in your retina. And the list goes on.
For a growing child, protein is needed to sustain growth. For an adult, protein is needed to maintain body tissues. The debate is usually over how much protein you should include in your diet.
How Much Protein Does Your Body Need
Some weight loss diets recommend eating large amounts of protein rich foods while other recommend the opposite. The amount of protein you need depends on the amount of lean tissue in your body. Fat tissue requires very little protein whereas your muscles, blood, and other highly active tissues need a constant supply of the amino acids in protein.
How much protein do you need? Most adults need about 0.36 grams of protein per pound of body weight. That is the Recommended Daily Allowance. At that level, a person weighing 125 pounds needs about 45 grams per day while a person weighing 195 pounds needs about 70 grams.
- 50 years old and younger – multiply your weight in pounds by 0.36 or 0.4 (Ex. 130 lbs. x 0.4 = 52 grams of protein per day.
As you age and lose muscle mass, your protein needs may have to increase. Some experts recommended getting 0.50 grams of protein per pound of body weight for men and women over 50 years old. That means:
- 63 grams if you weight 125 lbs.
- 98 grams if you weight 195 lbs.
The 0.5 gram recommendation is easier to calculate then 0.36. Just divide your weight by 2 and you have the amount of protein you should be getting from your diet.
Foods High in Protein
High protein foods include:
Four ounces of cooked chicken or turkey breast provides 34 grams of protein. One cup of milk and 1/2 cup of cooked beans have about 8 grams of protein. Vegetarians meet their protein requirements by substituting legumes for meat. Since legumes have less calories than meat you can and must eat more to meet the bodies protein requirements. It takes 2 cups of cooked legumes to provide the same amount of protein in 4 ounces of chicken or turkey breast.