Protein

Then there's protein. How much do you really need? Can you get too much? You'll find answers to these questions and more by visiting this section.

What do you think about when you hear the word protein? Maybe it's an ad for some protein shake that promises massive muscles? Or is it the last high-protein diet craze you read about? With all this talk about protein, you might think Americans were at risk for not eating enough. In fact, most of us eat more protein than we need. Protein is in many foods that we eat on a regular basis.

This section will help you learn more about protein. You'll find information about what foods have protein and what happens when we eat more protein than we need.

What is Protein?

Proteins are part of every cell, tissue, and organ in our bodies. These body proteins are constantly being broken down and replaced. The protein in the foods we eat is digested into amino acids that are later used to replace these proteins in our bodies.

Protein is found in the following foods:

meats, poultry, and fish

legumes (dry beans and peas)

tofu

eggs

nuts and seeds

milk and milk products

grains, some vegetables, and some fruits (provide only small amounts of protein relative to other sources)

As we mentioned, most adults in the United States get more than enough protein to meet their needs. It's rare for someone who is healthy and eating a varied diet to not get enough protein.

What are the types of protein?

Proteins are made up of amino acids. Think of amino acids as the building blocks. There are 20 different amino acids that join together to make all types of protein. Some of these amino acids can't be made by our bodies, so these are known as essential amino acids. It's essential that our diet provide these.

In the diet, protein sources are labeled according to how many of the essential amino acids they provide:

Protein is found in the following foods:

A complete protein source is one that provides all of the essential amino acids. You may also hear these sources called high quality proteins. Animal-based foods; for example, meat, poultry, fish, milk, eggs, and cheese are considered complete protein sources.

An incomplete protein source is one that is 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.

For example, rice contains low amounts of certain essential amino acids; however, these same essential amino acids are found in greater amounts in dry beans. Similarly, dry beans contain lower amounts of other essential amino acids that can be found in larger amounts in rice. Together, these two foods can provide adequate amounts of all the essential amino acids the body needs.

Is it true that complementary proteins must be eaten together to count as a complete protein source?

In the past, it was thought that these complementary proteins needed to be eaten at the same meal for your body to use them together. Now studies show that your body can combine complementary proteins that are eaten within the same day.

How much protein do I need?

Maybe you've wondered how much protein you need each day. In general, it's recommended that 10–35% of your daily calories come from protein. Below are the Recommended Dietary Allowances (RDA) for different age groups.

Here are examples of amounts of protein in food:

1 cup of milk has 8 grams of protein

A 3-ounce piece of meat has about 21 grams of protein

1 cup of dry beans has about 16 grams of protein

An 8-ounce container of yogurt has about 11 grams of protein

Added together, just these four sources would meet the protein needs of an adult male (56 grams). This doesn't count all the other foods that add smaller amounts of protein to his diet.

Rather than just focusing on your protein needs, choose an overall healthy eating plan that provides the protein you need as well as other nutrients.

Vitamins and Minerals

Vitamins and minerals are nutrients your body needs to grow and develop normally. The NIH Vitamin and Mineral Supplement Fact Sheets provide information about the role of vitamins and minerals in health and disease.

Vitamins are organic substances (made by plants or animals), minerals are inorganic elements that come from the earth; soil and water and are absorbed by plants. Animals and humans absorb minerals from the plants they eat. Vitamins and minerals are nutrients that your body needs to grow and develop normally.

Vitamins and minerals, have a unique role to play in maintaining your health. For example Vitamin D helps your body absorb the amount of calcium (a mineral) it needs to form strong bones. A deficiency in vitamin D can result in a disease called rickets (softening of the bones caused by the bodies inability to absorb the mineral calcium.) The body cannot produce calcium; therefore, it must be absorbed through our food. Other minerals like chromium, copper, iodine, iron, selenium, and zinc are called trace minerals because you only need very small amounts of them each day. The best way to get enough vitamins is to eat a balanced diet with a variety of foods. You can usually get all your vitamins from the foods you eat.

Related Information

CDC, Calcium and Bone Health

Bones play many roles in the body. They provide structure, protect organs, anchor muscles, and store calcium. Adequate calcium consumption and weight bearing physical activity build strong bones, optimizes bone mass, and may reduce the risk of osteoporosis later in life.

CDC, Folic Acid

Folic acid is a B vitamin. It is used in our bodies to make new cells. If a woman has enough folic acid in her body before she is pregnant, it can help prevent major birth defects of her baby's brain and spine.

CDC, Iron and Iron Deficiency

Iron is a mineral needed by our bodies. Iron is a part of all cells and does many things in our bodies. For example, iron (as part of the protein hemoglobin) carries oxygen from our lungs throughout our bodies. Having too little hemoglobin is called anemia. Although anemia has a number of causes, iron deficiency anemia is the most common type of anemia.

Salt

Most of the sodium we consume is in the form of salt, and the vast majority of sodium we consume is in processed and restaurant foods. Too much sodium is bad for your health. It can increase your blood pressure and your risk for a heart attack and stroke.

Sodium and Potassium

Nearly all Americans eat too much salt (sodium). Most of the salt comes from eating processed foods (75%), or adding salt to food while cooking and using the salt shaker at meals (5% to 10%). On average, the more salt a person eats, the higher his or her blood pressure.