Protein is essential for various functions of the body, including building and repairing muscles, suppressing hunger, stabilizing blood sugar and maintaining healthy hair and nails.
Most foods contain some protein, but there are still many people who do not consume enough protein. When protein is lacking in your diet, especially for long periods of time, it can cause deficiencies and potentially lead to adverse effects.
Your body will show signs and symptoms when experiencing protein deficiency. Beware of these red flags and make sure to replenish your protein intake to avoid further deterioration of health.
What Are The Causes Of Protein Deficiency
Some factors can affect the absorption and utilization of protein. For example, people with the following health problems are at a higher risk of protein deficiency.
1. Chronic enteritis
Many essential nutrients are decomposed and absorbed in the small intestine. Inflammatory bowel disease can cause small bowel disorders, which affect the absorption of nutrients, including protein.
2. Liver disease
The liver plays a vital role in processing and synthesizing proteins. If the liver has a problem (such as hepatitis or cirrhosis) and cannot function normally, the body will not get enough protein.
3. Kidney problems
The kidney functions like a sieve. When it works normally, it filters waste out of your blood and into your urine. It then excretes the urine out of the body, while retaining useful nutrients, including protein.[*]
If the kidney function is impaired, the protein in the blood will leak into the urine, causing hypoproteinemia and proteinuria. This condition is common in people with high blood pressure, diabetes and kidney disease.
4. Malnutrition
Diet-related malnutrition can also lead to insufficient protein intake.
This is more likely to happen in the following situations:
- Long-term dieting for weight loss.
- Sufficient food cannot be guaranteed with low food intake.
- Severe nausea and vomiting during pregnancy.
- People who suffer from eating disorders such as anorexia or bulimia can’t get enough protein from their diet.
- Allergies or intolerances to certain foods (such as egg allergies, gluten and lactose intolerance) may lead to many nutrient deficiencies (including protein).

What Are The Symptoms Of Protein Deficiency
1. Problems with hair, nails and skin
Protein is the main component of hair, nails and skin. If you don’t get enough protein, you will find that your hair becomes dry, fragile and thin, your skin appears patchy and cracked, or your nails may become brittle.
These symptoms are more common in people with severe protein deficiency.
2. Muscle loss
When you find that your muscles become looser and lose their elasticity, it may be caused by the insufficient protein.
Muscles are mainly composed of 75% water, 19% protein, 3.5% soluble non-protein and 2.5% fat. It can be said that your muscles are the body’s largest protein storage warehouse.
A lack of protein can lead to reduced muscle mass, especially in the elderly.
In addition, people who are dieting to lose weight are prone to muscle loss because they do not get enough nutrients, especially protein.
3. Frequent hunger
Eating more protein can increase satiety, which can help to reduce your appetite and calorie intake. This is very good for weight control.
If you do not get enough protein and are accustomed to eating a high-carbohydrate diet, you will find that you are hungry again soon after eating. This is because carbohydrates take less time to digest than protein and fat. Therefore, food stays in the stomach for a shorter time, making you feel hungry more often. This leads to overeating, to satisfy your constant feeling of being hungry.
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4. The chance of infection increases
When the human body lacks protein, there may not be any changes in the beginning. However, in the long run, your body may lose important protective capabilities, making your immune system more vulnerable and less capable to work properly.
A compromised immune system can increase the risk and severity of infection, which is also a common symptom of severe protein deficiency.[*]
Even a mild lack of protein intake may compromise your immune system, making you ill.
5. Easy to fracture
Your bones not only need calcium, but they also need enough protein to build and maintain bone density and bone strength. Studies have shown that insufficient protein intake increases the risk of fractures.[*]
If you don’t get enough protein to fuel your brain, muscles and other organs, your body will borrow protein from other places, including storage in bone tissue. This can cause your bones to become fragile and break more easily.
6. Wounds are not easy to heal
Protein can help the body repair damaged tissues. Low protein levels directly lead to a decrease in collagen, thereby slowing the healing process of the wound.
Moreover, the loss of protein will be further aggravated during the wound healing process. Due to the leakage of fluid from the affected area, your body may lose up to 100 mg of protein per day.[*]
Therefore, a high-protein diet is essential in the process of wound recovery.
7. Edema
When you eat enough protein, the protein circulating in your blood—especially albumin—helps prevent fluid from accumulating in your tissues.
If the body is severely lacking in protein, there will be signs of edema, especially in the abdomen, legs, feet and hands. This is due to the decrease in serum albumin levels.
8. Anxious or depressed
Your brain needs to use a chemical substance called a neurotransmitter to transmit information between cells. Many of these neurotransmitters are composed of amino acids, which are the basic building blocks of protein.
Therefore, if you don’t eat enough protein, it can be difficult for your body to produce enough neurotransmitters. This can affect the normal function of your brain. For example, if your dopamine and serotonin levels decrease, you may feel restless or depressed.
In addition, insufficient neurotransmitters can cause brain fog and an inability to concentrate, as well as sleep disturbances.
How to eat enough protein
Generally speaking, healthy adults should consume at least 0.8 grams of protein per kilogram of body weight (1 kg = 2.2 pounds) per day. For example, a 180-pound person should eat at least 65 grams of high-quality protein every day.[*]
However, the “correct” amount of protein depends on many factors, including activity level, age, muscle mass and current health status.
Eating a diverse diet can help to avoid protein deficiency.
In your daily diet, it is also helpful to reduce carbohydrates and increase the intake of high-quality protein, such as lean meat, chicken, fish, dairy products, eggs, etc.
For vegetarians, some of the best sources of protein are whole grains, lentils, soybeans and other legumes, soy products, nuts, seeds and vegetables.
Drinking a whey protein shake before and after fitness and exercise can repair damaged muscles and help increase muscle mass and burn fat.
In short (as long as you are not too picky or dieting) no matter what type of diet you follow, you should always make sure that you get enough protein to avoid health problems caused by protein deficiency.