Common Signs and Symptoms of Protein Deficiency

Protein deficiency is not consuming enough protein to support your body’s needs. Protein is an essential macronutrient—a nutrient the body needs and uses in large amounts. It helps your body make and repair cells. Protein also helps children, teenagers, and pregnant people with growth and development.

A protein deficiency can lead to conditions like kwashiorkor and marasmus. Kwashiorkor is a severe protein deficiency accompanied by edema (swelling) in the arms and legs. Marasmus is severe malnutrition (a lack of or imbalance in food or nutrient intake) caused by not consuming enough calories.

A lack of protein in the diet can greatly affect health. Signs and symptoms of protein deficiency include swelling, stunted growth, and a weakened immune system.

1. Edema (Swelling)

Low protein intake may cause edema. One of the main signs of kwashiorkor is swelling on both sides of the body.

People with kwashiorkor have low levels of a substance called albumin. Albumin helps to keep fluid inside the blood vessels. A lack of albumin can make it difficult for the body to balance fluid in blood vessels. As a result, the body tries to hold onto more water and sodium, which causes swelling.

2. Stunted Growth

Protein is essential for growth. Growth stunting, or impaired growth and development, can occur when children don’t get enough protein. This is one of the symptoms of kwashiorkor. Growth stunting can affect health and well-being in multiple ways, including:

• Poor performance in school
• Impaired cognitive development
• Increased risk of nutrition-related chronic health conditions

It is important to treat protein deficiency early, especially in children. Early treatment can reduce the risk of complications like permanent physical disabilities.

3. Weakened Immune System

A severe protein deficiency can impair your immune system. Protein helps make antibodies that protect you from infection and other illnesses. Protein deficiency leads to fewer antibodies, which can increase your risk of developing an infection.

Low protein intake often means lower intake of other nutrients. For example, one meta-analysis of over 11,000 adults aged 51 and older found that adults who didn’t meet the estimated average requirement (EAR) of protein were more likely to fall below the EAR for a number of vitamins and minerals.

A lack of nutrients is associated with inflammation and oxidative stress, which can affect the immune system. Oxidative stress happens when there are more free radicals in the body than there are antioxidants available to remove them. Free radicals are produced during digestion. They can damage cells, trigger changes in genes, accelerate aging, and increase the risk of various conditions like heart disease and diabetes.

4. Changes in Skin and Hair

Protein is a major component of skin and hair, which is why protein deficiency can greatly affect skin and hair health.

A lack of protein can cause your skin to appear paler, as well as drier or flakier. Your hair may appear more brittle and may break more easily. You may also experience hair loss or graying.

Symptoms of kwashiorkor include:

• Dry, thin, or peeling skin
• Skin folds due to weight loss
• Skin lesions or dermatitis on ears, armpits, groin, and genitals
• Hair that's dry or falls out easily

Hair and skin changes do not usually occur with marasmus.

5. Decreased Bone Development and Density

Protein is an essential component of muscles and bones. A protein deficiency can decrease muscle and bone mass, leading you to feel tired and weak.

Protein from calcium-rich foods is required for bone growth, especially for young children. Bone mass, or bone mineral density (BMD) is largely genetic. Consuming adequate protein helps children reach their optimum genetic potential for bone mass.

Protein is also important for bone maintenance in older adults who have or are at a higher risk of osteoporosis, a condition that causes porous, weak bones that break easily. One meta-analysis of 13 studies found that adults over the age of 65 with a higher protein intake had a lower risk of bone fractures.

6. Muscle Loss

Skeletal muscle, the muscle attached to bones, is the type of muscle that helps your body move. Consuming higher amounts of protein can help build and maintain skeletal muscle mass and strength.

Your body breaks down skeletal muscle tissue for energy when there’s not enough protein for use. This leads to muscle atrophy (decrease in muscle mass). Even minor muscle loss can affect your movement and strength.

7. Anemia

Anemia is a common symptom of marasmus. Anemia is a condition where your body has a reduced number of red blood cells or hemoglobin, the protein that helps your red blood cells transport oxygen from your lungs to the rest of your body. Your body needs iron to make oxygen-rich red blood cells.

Anemia is often treated with iron supplements or by eating more iron-rich foods.

8. Weight Loss or Gain

Many factors can contribute to weight loss as a result of protein deficiency. People who have marasmus may experience reduced heart function, which can lead to weight loss. Reduced heart function can also increase a child’s risk of developing an arrhythmia, or irregular heartbeat.

Eating a lower protein diet can also lead to weight gain. For example, protein is often more satiating than carbohydrates, meaning you feel full for longer periods of time after eating protein. Therefore, eating more protein might lead to lower caloric intake overall.

More research is needed to determine how protein affects weight, but shorter-term research studies demonstrate that a high-protein diet can contribute to weight loss and prevent weight regain.

Common Risk Factors

About one billion people in the world do not get enough protein in their diets. It’s commonly seen in areas with a limited food supply and lower levels of education about healthy eating. For example, about 30% of children in Central Africa and South Asia have a protein deficiency.

Protein deficiency is not very common in the United States. However, some people are at a higher risk, including:

• People with cancer
• Older adults, specifically those who receive home-delivered meals or are in a long-term care facility
• Children who are abused or severely neglected
  

How To Get More Protein in Your Diet

Talk to your healthcare provider if you’re concerned you may not be eating enough protein. They might refer to a registered dietician (RD), a healthcare professional who specializes in nutrition. 

You can also try incorporating more protein into your diet. High-protein foods include:

• Dairy products like milk, yogurt, and cheese
• Soy products like edamame, soymilk, tofu, and tempeh
• Beans like black beans and chickpeas
• Legumes like lentils and peas
• Meat and poultry
• Fish and shellfish
• Nuts and seeds 
• Eggs
• Quinoa
• Seaweed

When To See a Healthcare Provider

Reach out to your healthcare provider if you or someone in your care has symptoms of kwashiorkor or marasmus. Getting medical care early on can help prevent possible complications.

A Quick Review

Protein is essential to health. It helps with growth and development, and it helps repair cells and make new ones. Protein deficiency can cause symptoms such as swelling, stunted growth, a weakened immune system, skin and hair changes, and bone and muscle loss.

You can get more protein in your diet by adding foods like beans and legumes, meat, seafood, eggs, and nuts. Reach out to your healthcare if you’re concerned that you or someone in your care is not eating enough protein.