The Effects of Protein Deficiency

The Importance of Amino Acids


Verywell / Alexandra Shytsman

Protein deficiency, or hypoproteinemia, happens when you have low levels of protein in your blood, which can occur if you don't have enough protein in your diet to meet your body's needs, such as when following a diet that severely restricts protein consumption. The most severe form of protein deficiency is called kwashiorkor, and is most common in children who live in developing countries.

You may also become deficient if your body isn't able to effectively digest and absorb the proteins within the foods you eat due to another medical condition.

Most Americans consume enough protein to meet generalized nutrition guidelines.

What Does Protein Do?

When digested, protein breaks down into amino acids. These amino acids help the body's tissues function and grow. That makes this macronutrient important to having healthy and strong muscles and bones, as well as impacting your hair and nails.

There are nine essential amino acids and 11 non-essential amino acids. Essential amino acids are "essential" in that they must be consumed through the diet because our bodies cannot make them.

Unlike with carbohydrates and fats, there is no mechanism to store excess amino acids that are consumed in the diet. So a continuous supply is needed. Put simply, you need to consume protein daily to meet your body's needs.

Protein Deficiency Symptoms

When your body doesn't get the required protein amounts or isn't able to use protein efficiently, research has shown that it can lead to a number of symptoms including increased infections and illnesses and reduced muscle mass, often referred to as sarcopenia in older patients. Lack of protein also may lead to swelling in the legs, slower wound healing times, and high blood pressure during the second trimester of pregnancy, also called preeclampsia

Protein deficiency may show up differently in infants and children. For example, one study found that a child had developed silvery hair and lighter patches of skin as a result of disease-induced protein deficiency. Preterm infants born with hypoproteinemia also have a higher risk of severe neurological injury and death.

These studies reinforce why adequate protein intake is essential for maintaining proper body function at every stage in life. Going a step further, understanding the role of protein and ensuring adequate intake in your diet is critical too.

If you believe that you may have a protein deficiency, contact your doctor. While this deficiency is more common in developing countries, your doctor can test your blood to find out whether your protein levels are too low, as well as provide advice as to how to bring those levels back up.

What Causes Protein Deficiency?

Current dietary guidelines recommend that adults consume between 10% and 35% of daily calories from protein. However, some researchers believe that this may be too low and should be reconsidered.

Some studies suggest that most Americans consume about 14% to 16% of their daily calories from protein.

Another theory is that eating a vegetarian diet contributes protein deficiency. The thought is that eliminating all meat-based foods severely restricts protein intake, sometimes to unhealthy levels. While this may happen in some cases, research reveals that most vegetarian diets supply enough protein via legumes, nuts, and seeds.

Protein deficiency can also be caused by certain medical conditions, some of which include:

  • Acquired immune deficiency syndrome (AIDS)
  • Anorexia nervosa
  • Cancer
  • Chronic obstructive pulmonary disease (COPD)
  • Gastrointestinal conditions, such as amyloidosis
  • Renal failure

How Common Is Protein Deficiency?

According to a study published in the Annals of the New York Academy of Sciences, approximately one billion people worldwide have inadequate protein intake. This is largely due to limited access to food in general.

Because protein sources are so widely available in the United States, the Physician's Committee for Responsible Medicine reports that eating enough protein is hardly an issue stateside. This infers that deficiency due to medical conditions may be more common in this area of the world.

Yet, some pieces of research have found that approximately one-third of adults over age 50 are failing to meet the recommended daily allowance (RDA) for protein intake. People following a restrictive diet can also become protein deficient.

How Much Protein Do You Need?

In order to maintain a steady flow of amino acids, adequate protein intake is essential. Therefore, it is recommended that you eat enough protein to support your cell's structure and function. This requirement will be different for each person based on factors like age, sex, and physical activity levels.

The 2020-2025 U.S. Department of Agriculture (USDA) guidelines recommend that most adults consume 5.5 ounces of protein each day, or 38.5 ounces per week. Roughly 26 of these weekly ounces should be meat, poultry, or eggs. Eight ounces should be seafood and five ounces of nuts, seeds, and soy products.

For those following a vegetarian diet, the USDA recommends 3.5 to 5.5 ounces of protein daily depending on total caloric intake. This is split fairly evenly between beans, peas, and lentils; soy products; and nuts and seeds, with approximately 3 to 4 ounces per week of eggs.

For comparison purposes, 3 ounces of protein is roughly the size of the palm of your hand. Another way to visualize this amount is that it is about the same size as a deck of cards.

How to Increase Protein Intake

Protein is available in a wide variety of animal and plant foods. Choosing nutritious protein sources is recommended for optimal health and fitness. This includes foods such as:


6 Tips for Getting More Protein in Your Diet

A Word From Verywell

Protein is essential for all cells and body tissue and when in short supply can impair body function. While diet-related protein deficiency is rare in the United States, it exists for some at marginal levels. Certain medical conditions can also increase this risk.

Regardless, some people will benefit from increasing their protein intake. Thankfully, adding protein to your diet is simple and can be achieved by incorporating a wide variety of foods from either plant or animal sources.

23 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Darla Leal
Darla Leal is a Master Fitness Trainer, freelance writer, and the creator of Stay Healthy Fitness, where she embraces a "fit-over-55" lifestyle.