Protein is one of your body’s essential building blocks—so it’s only natural to wonder if protein deficiency symptoms may develop if you don’t get enough in your daily diet. 

You may already know that protein helps you build muscle and plays a key role in helping you feel full and satisfied throughout the day—but it does so much more than it’s typically given credit for. Protein lives in every cell in your body, according to the U.S. National Library of Medicine. From your bones to your skin, it keeps you running on all levels. 

Why is protein important?

Protein is a complex macronutrient with a bevy of responsibilities. It provides the amino acids (molecules that join forces to create proteins) your body needs to function, which is essential for everyone, not just those who frequently hit the weight racks at the gym. “When most people think about getting enough protein in their diet, they start to think about building muscle,” Adam M. Gonzalez, Ph.D., C.S.C.S., associate professor of allied health and kinesiology at Hofstra University in New York, tells SELF. “But what many people don’t realize is that lots of things in our bodies are made up of protein.”

Protein contains 20 amino acids, including nine essential amino acids. Essential amino acids can’t be made by your body on its own, so they have to come from food, according to the U.S. National Library of Medicine. Nonessential amino acids can either be produced by our bodies naturally or taken in from our food.

“All of these amino acids are involved in everything in our body: our blood, our tissue, our muscles, our immune system,” Andy Brill, M.D., emergency medicine physician at the Cleveland Clinic in New York City, tells SELF. When your daily protein intake is too low, your body has a really hard time doing what it’s supposed to do to keep you alive.

What happens when your body is low in protein?

Protein deficiency is a condition in which an individual doesn’t get enough protein to satisfy their body’s requirements. Frank J. Lacqua, M.D., FACS, a colon and rectal surgeon at Richmond University Medical Center, tells SELF that people with this health issue typically “display symptoms like weakness, fatigue, recurrent infections due to a diminished immune system, and thin, brittle hair and nails.” (We’ll dive into the full list of protein deficiency symptoms below.)

Worth noting: “Protein deficiency, just like a lot of things in the field of medicine, is a spectrum,” says Dr. Brill. “You can have a mild protein deficiency and conversely, you can have a severe protein deficiency.” However, it’s important to note that severe, life-threatening forms of protein deficiency are rare, particularly in the United States. “In our society, it would be uncommon to see very severe deficiencies, unless the individual has an underlying intestinal disorder, liver or kidney disease, or a psychiatric eating disorder,” explains Dr. Lacqua.

That’s because most people in the U.S.—even those who don’t eat meat—tend to get enough protein in their diets. According to a 2013 study funded by the National Institutes of Health and published in the Journal of the Academy of Nutrition and Dietetics, the median protein intake of vegetarians and vegans is still above the recommended dietary allowance (RDA). 

And how can you tell if you have low protein levels? Per Dr. Lacqua, clinicians will order a “simple blood test” to check your albumin and globulin levels (two types of proteins found in your blood) to determine if they are, in fact, too low. The state of decreased protein levels in the blood is medically known as hypoproteinemia. 

How much protein do you need?

So, how much protein do you need? The answer isn’t so simple, because it varies from person to person. Protein needs are based on your age, sex assigned at birth and gender identity, health history, and how much exercise you typically get in a day, according to the U.S. National Library of Medicine. But for a general idea, the RDA for a healthy adult with minimal physical activity is 0.8 grams of protein per kilogram of bodyweight every day, per guidance published in the Annals of Nutrition and Metabolism. That equates to 0.36 grams of protein per pound of bodyweight. For example: The recommended daily protein intake for a 200-pound person is 72 grams. 

That said, people who frequently exercise may require more protein. In a 2016 position statement from the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine, experts advised active adults and athletes to aim for 1.2 to 2 grams per kilogram of bodyweight (or 0.5 to 0.9 grams of protein per pound).  

If you’re looking for more personalized protein recommendations based on your lifestyle, consider chatting with a registered dietitian or your health care provider to ensure you’re meeting your needs. They can help assess your diet to see if your protein intake is falling short.

What is the main cause of protein deficiency?

The main cause of protein deficiency is, of course, not eating enough protein-rich food sources. However, Dr. Gonzalez explains that certain groups of people need to pay closer attention to their protein intakes, like vegans, vegetarians, and the elderly. Severe deficiencies can also occur in individuals with gastrointestinal health problems like celiac disease, ulcerative colitis, or Crohn’s disease, says Dr. Brill, as these disorders can make it difficult to properly absorb proteins in the gut. Again, clinical protein deficiency, even among vegans, is pretty rare, since hitting 0.8 grams of protein per pound of bodyweight isn’t super challenging for most Americans who have access to plentiful food (even if that food is all plant-based).

What are the signs of protein deficiency?

Protein deficiency symptoms vary based on how severe the condition is. However, there are some red flags worth considering for a true deficiency, even though it is rare:

1. Protein cravings

If you’re not eating enough protein, in the short term, your body may tell you by literally craving it, Dana Hunnes, Ph.D., R.D., senior dietician at UCLA Medical Center and adjunct assistant professor at the Fielding School of Public Health, tells SELF. You should give in to these cravings. If you’re really jonesing for a chicken sandwich or a bowl of lentil soup, listen to your body and eat up.

2. Sugar cravings

“Protein (along with fat) digests slower than carbohydrates. If you eat a meal that is mostly carbohydrates with not enough protein, it will digest more quickly and will cause your blood sugar to rise,” Alissa Rumsey, M.S., R.D., a New York City-based dietitian and the author of Unapologetic Eating. This rise is followed by a drop—and when blood sugar is constantly spiking and dropping, we crave more sugar. The key is to eat protein with carbs so that everything digests more slowly, and the blood sugar changes are more gradual over time.

3. Hunger

You’ve probably noticed that you tend to be hungrier throughout the day when you have a lack of protein in your meals. That’s because protein decreases your level of the “hunger” hormone ghrelin and stimulates the production of other hormones that make you feel satiated.⁵ As a result, not getting enough protein can increase your appetite and actually cause you to eat more.

4. Weakness and fatigue

“For most people, eating too little protein over the course of one day will not make you feel less energy or strength, particularly if you are getting a sufficient number of calories in that day,” Hunnes says. But long term, your body may break down your muscles to try and supply your body with sufficient protein, leading to loss of energy and strength, she explains. 

Dr. Brill deems weakness and fatigue as two of the earliest signs of protein deficiency. While inadequate protein can lead to these symptoms even in younger people, it can be especially worrisome for older adults. A 2018 systematic review and meta-analysis published in the journal Nutrients found that not getting enough protein was associated with frailty in those age 60 or older, which is an age-related syndrome characterized by symptoms such as weakness, slowness, low energy and activity, and unintentional weight loss.⁷

5. Loss of muscle mass

“If we don’t get enough protein, our bodies actually won’t be able to rebuild properly and we’ll start to lose muscle mass,” Colleen Tewksbury, Ph.D., R.D., previously told SELF. This is especially true for people who are older. With a protein deficiency, amino acids still need to be harnessed for necessary bodily functions like tissue repair and the creation of essential enzymes. To do this, muscle proteins are used as the source, which may lead to the loss of muscle mass. 

6. Skin, hair, and nail problems

A 2019 study published in the Indian Dermatology Online Journal looked at people consuming less than half of the recommended daily allowance of protein (meaning they were severely deficient) and noted that they faced skin and hair problems including hair loss, acne, melasma, and premature aging. The study authors note that one reason for this is because protein acts as a building block for healthy hair, skin, and nails. 

7. Impaired immune function or slow-healing injuries

“Protein is needed to build the components of our immune system,” Rumsey explains. “If you are under-eating protein, over time your immune system may weaken.” That’s why protein deficiency may affect wound healing in the long run, ultimately slowing down the road to repairing cells that help keep your body healthy.

8. Risk of bone fractures

It’s important to remember that protein helps make up the structure of all cells, including the ones that make up your bones. So, it’s not surprising that protein deficiency has been linked to bone fractures. This is more prominent in older adults, who already have a higher risk of this complication. A 2018 study reported that “calorie and protein intake are significantly lower in geriatric patients with hip fracture compared to patients without fracture.”

9. Fatty liver

Fatty liver occurs when fat droplets deposit inside of liver cells, and it’s a symptom of kwashiorkor, a severe form of protein malnutrition that typically only impacts infants and children in poverty-stricken regions of the world. Left untreated without the help of a medical professional, it can lead to non-alcoholic fatty liver disease.

10. Edema (swelling)

A sign of a serious protein deficiency is swelling, medically known as edema by doctors, and it’s one of the telltale signs of kwashiorkor. According to Dr. Brill, people with a severe protein deficiency can develop edema—or fluid buildup—in their legs, feet, and abdomen, which is caused by profoundly low levels of albumin (a protein found in the blood). Again, this is unlikely to happen unless you’re very malnourished.

How to get more protein

Luckily, since the cause for low protein is simple, so is the solution: Mild protein deficiency—meaning you may have low levels but are not malnourished—can be reversed by eating a sufficient amount of protein-rich foods, says Dr. Lacqua. You’ll still want to aim for a balanced diet that includes energy-boosting carbs and satiating, unsaturated fats, too.

Severe protein deficiency, however, may require medical attention. In the rare case of malnutrition for the average person in the U.S., these severely low levels can cause someone to become “frail and debilitated” to the point that they are unable to eat on their own, explains Dr. Brill. The careful process of “refeeding” can take weeks and even up to a month, as doctors will typically do this in a hospital setting to gradually provide essential nutrients and calories.

What are some protein-rich foods to add to your diet?

Because most people won’t have a true protein deficiency, boosting the amount you eat through food will likely be the route to choose when trying to build a balanced plate—and there is a wide variety of protein-rich foods to choose from.

What’s really crucial is that you’re incorporating all nine essential amino acids into your diet on a daily basis. “Complete” protein sources contain all of these amino acids. “Those are typically animal-based proteins: dairy, meats, eggs, whey protein, and casein protein,” says Dr. Gonzalez.

Of course, not everyone eats meat, and there are tons of vegan protein sources that can help you meet your needs. Just one important thing to keep in mind: “One of the pitfalls of the plant-based protein sources is that they do not contain all of the essential acids,” explains Gonzalez. Luckily, by combining multiple plant-based protein sources throughout the day—say, rice at lunch and lentils at dinner—you can collect all nine amino acids and be set with your daily protein intake. Need some mealtime inspo? Here are some high-protein foods to stock your pantry with for quick and easy dishes.

The post 10 Protein Deficiency Symptoms to Be Aware Of appeared first on SELF.