Protein 411

June 28, 2010

Proteins are part of every cell, tissue, and organ in our bodies; and are constantly being broken down and replaced.

Proteins are part of every cell, tissue, and organ in our bodies; and are constantly being broken down and replaced. Protein is made up of amino acids that are later used for tissue repair and maintenance in the body. There are twenty different amino acids that join together to make the different proteins; some are made in the body, others are not. The amino acids that can not be made by the body are called essential amino acids; it is essential that our diet provide these.

Dietary protein sources are evaluated according to how many essential amino acids they provide. Complete proteins are those that provide all of the essential amino acids. Animal-based foods for example, meat, poultry, fish, milk, eggs, and cheese are considered complete protein sources. Incomplete proteins on the other hand, are those that are low in one or more of the essential amino acids. Complementary proteins are two or more incomplete protein sources that together provide adequate amounts of all the essential amino acids; an example includes tofu and brown rice.

Although some protein is needed for muscle growth, most people overemphasize protein needs. The average American eats about three times the amount of protein he or she actually needs. Here are some guidelines you can use to determine how much protein you should strive to consume and what foods provide it:

Look at Your Overall Food Intake: next time you are at the grocery store start by noting the variety of foods, or lack thereof, in your cart. Eating a variety of foods provides a greater opportunity to take in nutrients, such as protein, carbohydrates and fat, which your body needs to stay healthy. 
How much do you need? In general, it's recommended that 10–35% of your daily calories come from protein. The Recommended Dietary Allowances (RDA) vary by different age groups vary. Generally women aged 14+ require about 46 grams and men 14+ require at least 52 grams a day. 
Shop Carefully: Look for protein-rich lean meats, poultry and fish as well as dairy products, legumes, tofu, nuts and nut-butter. Cereals, breads, beans and vegetables are also good sources of protein. 
Get Help: If you have any specific health conditions that may alter your daily nutritional requirements, would like more information about RDA’s, or need to determine your total daily caloric intake, contact your health care provider. For more information visit the CDC.

Note* Consumer Reports recently reported on the heavy metal testing (arsenic, cadmium, lead and mercury) of 15 readily available protein powders. Levels in several of the products tested exceeded the United States Pharmacopeia (USP) limits- and at three servings a day, could result in daily exposure to arsenic, cadmium, or lead.