Protein: Are You Getting Enough?

Nutrition facts labels prominently display information about protein. But of the three macronutrients in food – protein, fat, and carbohydrates -- protein may be the one most of us know least about.

How much protein do you need to stay healthy? What’s the best source of protein?

Protein requirements are complicated because the amount we need changes with age.

• Infants require about 10 grams a day.
• Teenage boys need up to 52 grams a day.
• Teenage girls need 46 grams a day.
• Adult men need about 56 grams a day.
• Adult women need about 46 grams a day.

One important exception is pregnant or lactating women, when the recommended intake rises to 71 grams of protein a day.

Another way to count protein requirements is as a percentage of calories. The USDA’s MyPyramid plan suggests that protein make up between 17% to 21% percent of total calories. The Institute of Medicine recommends we get at least 10% and no more than 35% of calories from protein.

Are You Getting Enough Protein?

Many of us might do well to add a few additional sources of protein.

A 2008 analysis of data from the National Health and Nutrition Examination Survey conducted in 2003-2004 found that 7.7% of adolescent females and about 8% of older adult women weren’t hitting the minimum recommended amount of protein.

As a proportion of total calories, the median intake of protein in children was 13.4%, below the ideal range. Men aged 51 to 70 consumed 16% of their calories in protein, also a little below the recommended amount.

The Risks of Too Little Protein

That shortfall could mean trouble. Protein is important to many physiological functions, from building muscle and bone to keeping cells in good working order.

Recent studies suggest that protein makes a meal more satiating, which in turn could help people maintain a healthy weight. Indeed, a 2005 study published in the American Journal of Clinical Nutrition found that increasing protein from 15% to 30% of total calories -- and reducing fat from 35% to 20% of calories -- resulted in sustained weight loss.

Choosing the Healthiest Source of Protein

A wide variety of foods contain protein, from meat, fish, and diary to beans, whole grains, nuts, eggs, and vegetables. A meat-eater can easily get all the protein he or she needs. But even vegetarians can meet their requirements if they choose with a little care.

How healthy a protein-rich food is typically depends on what else it contains. For example:

• Meat is one of the leading sources of protein in the American diet. Some meat is also loaded with saturated fat, which is unhealthy. The healthiest choice is lean meat low in saturated fat. 
• Fish is an excellent source of protein, since the oils contained in fish help protect against heart disease.
   
• Eggs are also abundant in protein, although they also contain dietary cholesterol, which can raise the risk of heart disease in people with elevated blood cholesterol levels. 
• Plants such as beans and nuts are a particularly wise choice of protein, since so many Americans fall short on fiber. Both beans and nuts are rich in fiber and plant-based phytochemicals that may help lower heart disease and cancer risk.