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About 1 billion people — particularly children in Central Asia and Africa — suffer from protein deficiency, often due to malnutrition as a result of famine.
While protein deficiency is not common in the U.S. and other developed countries, it can still happen. In many cases, this is because of an imbalanced diet. For example, people who follow vegetarian or vegan diets may be at risk of developing a protein deficiency if they are not careful about including enough protein sources in their meals. 
Keep reading to learn how much protein you need and how to get enough protein in your diet. Plus you’ll learn more about the benefits of protein and why it’s so important in the first place.
What Is Protein Deficiency?
First of all, what does protein do for your body? Proteins are made of amino acids, which are literally the building blocks of life. There are about 20 amino acids that come together in millions of different configurations to create the many different proteins your body requires. Your body needs enough protein to create muscle, skin, hair, hormones, and other important tissues.
A protein deficiency (hypoproteinemia) means someone is not getting enough protein to meet their body’s needs.
We get the protein we need from the food we eat. If our diet doesn’t contain enough protein, we may suffer from protein deficiency. A lack of protein can cause a number of signs and symptoms and even life-threatening health conditions.
There are three basic kinds of protein foods that are important to include in your diet: 
- Complete proteins: These proteins are found primarily in animal sources such as meat, dairy, and eggs. All of the essential amino acids your body needs can be found in these protein sources. However, it’s important to eat healthy versions of these proteins, such as lean meats and low fat cheeses and yogurt, rather than less healthy choices such as processed or fatty meats.
- Incomplete proteins: Plant protein sources are mostly incomplete proteins, which means that they contain at least one essential amino acid, but they do not contain all of the amino acids. Because of this, if you don’t eat animal proteins, you must be sure to eat a wide variety of plant protein sources such as vegetables, beans, legumes, and grains to get the protein you need. You may also need to include a protein supplement in your diet.
- Complementary proteins: These proteins are incomplete on their own, but in combination they work together to provide the essential amino acids you need. A couple of common examples are rice and beans or peanut butter and whole grain bread.
Protein Deficiency Causes
Now that you know what a protein deficiency is, let’s dig a little deeper into protein deficiency causes. Not getting enough protein in your diet is just one cause of low protein. There are also several health conditions and other factors that can cause low protein levels.
Other lack of protein causes may include: 
- Chronic alcoholism resulting in liver disorders such as cirrhosis
- Other liver disorders such as hepatitis
- Problems absorbing nutrients through the intestines (such as celiac disease or inflammatory bowel disease, also known as IBD)
- Kidney disease
- Infections, burns or trauma that cause an abnormal loss of body protein
- Deficiencies in other nutrients or not getting enough calories
- Malnutrition due to eating disorders such as anorexia or bulimia
- Difficulty getting enough protein during pregnancy due to extreme nausea or vomiting
- Not including enough protein sources in a restrictive diet such as vegetarianism or veganism
- Low income and inability to afford a balanced diet
Protein Deficiency Symptoms
What happens in the body when it doesn’t get enough protein? There are several symptoms of protein deficiency to watch out for, some more obvious than others.
Low protein symptoms and protein deficiency signs may include: 
- Swollen or puffy skin (known as edema, resulting from fluid accumulation)
- Losing or thinning hair (alopecia)
- Brittle nails
- Changes in appetite
- Brain fog (not able to think clearly)
- Unexpected weight loss
If you find yourself experiencing any of these signs of protein deficiency, take a closer look at your diet, and also see your health care professional. Your doctor can order a protein deficiency test, known as a plasma protein test, to check your protein levels. This way you can find out if low protein is causing your symptoms. 
Protein Deficiency Complications
What happens if you don’t get enough protein? Over time, chronic protein deficiency could mean you’ll start losing muscle mass, develop an increased risk for health conditions, or experience other side effects.
One of the most severe protein deficiency diseases is known as kwashiorkor. This is a Ghanaian word that refers to firstborn children developing the condition as they are weaned from breast milk and moved to a diet high in carbohydrates but with low total protein. Meanwhile, a new child then begins to receive the mother’s milk. The condition results in significant malnutrition, stunted growth, and emaciation. Fatty liver, or fat accumulation in the liver cells, is also a symptom of kwashiorkor 
Another type of severe low protein complication is called marasmus. This condition happens when you are not getting enough protein or enough calories. Your body then starts to use the protein you eat for energy instead of building muscle and other body tissues.
While kwashiorkor and marasmus are not as common in Western countries, other complications can also result from low protein levels.
Other serious risks of low protein levels include: 
- Fatty liver, which may lead to liver disease if left untreated
- Muscle wasting
- Greater risk of bone fractures
- Stunted growth
- Impaired immune system and more severe infections
- Slow wound healing
- Anemia (low iron)
- Muscle and joint pain
- Low blood pressure and low heart rate
Benefits of Protein
Protein provides many functions and creates tissues in the body. Some of these basic, but important, protein functions include:
- Structural proteins such as keratin, which provides strength to the hair. This is why protein is so important for healthy hair and nails.
- Collagen, a key structural protein that helps support connective tissues
- Hormonal function, such as insulin, which is needed for metabolism.
- Carriers, such as hemoglobin, which carries oxygen in the blood
- Enzymes, which help cause important chemical reactions, such as the exchange of oxygen and carbon dioxide during respiration (breathing)
Protein and Weight Loss
Ever notice how a protein-rich meal (a fish or chicken dinner, for example) helps you feel more full? A higher protein intake helps to boost metabolism and reduce appetite. By eating more protein than carbs and fats, you can help to increase the hormones that help you feel full and reduce the hormones that make you feel hungry. This combination then helps you to lower the amount of calories you eat. In fact, eating more protein can also help you burn more calories.  Eating more protein can also help cut down on cravings and snacking because you feel more satisfied.
A diet that’s higher in protein than fats and carbs also helps to fight muscle loss as we age (or build mass if trying to add size). Weight loss usually impacts both fat and muscles, causing a reduction in both. Combining strength training with high protein diet can help to both keep your metabolism up and maintain muscle mass. 
Spread your protein intake out throughout your day so that you eat some at each meal. Experts also recommend aiming to get about 25 percent to 30 percent of your calories from protein if your goal is to lose weight. It’s still important to make sure you are burning more calories than you are eating.
A diet higher in protein also seems to help maintain weight loss. 
Eating a diet that’s higher in protein and lower in carbohydrates causes the body to go into ketosis. Ketosis is a process where the body burns its own fat to create energy rather than burning carbohydrates. In the short term, eating a diet much higher in protein can be an effective strategy to help lose fat. But this type of diet seems to lose its effectiveness after about six months. The reason why isn’t entirely clear at this point. [11, 12] However, in general it’s still important to eat a balanced diet that includes an appropriate amount of proteins, healthy carbs (like vegetables and fruits), and healthy fats.
Best Protein Sources
You may be wondering how to get enough protein in your diet. The most basic way to get enough protein-rich foods is to eat a balanced diet. Remember, animal sources provide complete proteins. Plant sources don’t provide complete proteins on their own, but they are also an important source of fiber.
Eating lean meats and other healthy animal sources of protein, along with lots of plant sources like leafy green vegetables, beans, and nuts, will provide a balanced diet with plenty of protein.
If you follow a vegan or vegetarian diet, in order to get enough protein from plant sources, be sure you eat a variety of vegetables, legumes, beans, and possibly include a protein supplement in your diet as well.
If you are eating a healthy, balanced diet but find that you have signs of protein deficiency, be sure to see your doctor to find out what’s causing your symptoms.
- Fish: Salmon is a good source that also has healthy omega-3s. Tuna and sardines are other options to consider.
- White-meat poultry: The dark meat is higher in fat. Remove the skin to remove most of the saturated fat.
- Skim and low-fat milk, cheese, and yogurt: These dairy products are also a good source of calcium and vitamin D.
- Eggs: One egg a day is a healthy and affordable source of protein (omit the yolk to reduce fat content).
- Lean beef: You can also get iron, zinc, and vitamin B12 from lean beef.
- High-quality protein shakes or smoothies: Protein powders may come from animal sources or they may be vegetarian or vegan. Be sure to make sure the product is high-quality and doesn’t contain too much sugar.
- Lentils and other legumes: 1 cup of cooked lentils = 18 grams of protein (plus 37 percent of your daily RDA of iron!)
- Edamame: 1 cup = 17 grams of protein
- Hemp seeds: 3 tablespoons = 10 grams of protein
- Quinoa: 1 cup = 8 grams of protein (plus many other important vitamins and minerals)
- Peanut butter: 2 tablespoons = 8 grams of protein
- Peas: 1 cup = 8 grams of protein
- Potatoes: 1 large potato = 7 grams of protein
- Sun-dried tomatoes: 1 cup of dried tomatoes = 6 grams of protein
- Chia seeds: 2 tablespoons = 5 grams of protein
- Spinach: 1 cup of cooked spinach = 5 grams of protein
A couple of other important vegetable sources are powerhouses of protein:
- Beans: Beans have the most protein out of any vegetable source and the fiber will help you feel full.
- Nuts: Just 1 ounce of almonds contains 6 grams of protein—almost as much as a broiled ribeye steak! Nuts are also a healthy source of omega-3 fatty acids.
In general, the FDA recommends that an adult should consume about 50 grams of protein each day, based on a 2,000 calorie diet. But how much protein you need depends on how old you are and whether you’re male or female, plus how much you exercise. Your age also impacts how much protein you need. Research suggests that the average protein requirements for most people is as follows: 
- Infants: 10 grams a day.
- Children: 19-34 grams a day.
- Teenage boys: 52 grams a day.
- Teenage girls: 46 grams a day.
- Adult males: 56 grams a day.
- Adult females: 46 grams a day (pregnant or breastfeeding women need 71 grams)
If you have a job that is physically demanding, or you are very athletic, you may need more protein than the average person. You also need to get more protein if you are building muscle mass or trying to maintain muscle mass (such as bodybuilders). Older adults also need more protein to help compensate for loss of muscle mass and to help prevent osteoporosis. 
- A protein deficiency (hypoproteinemia) means someone is not getting enough protein to meet their body’s needs.
- The effects of protein deficiency can cause serious health risks.
- How much protein you need depends on how old you are and whether you’re male or female.
- If you have a job that is physically demanding or you are very athletic, you may need a higher protein intake.
- Adequate protein intake in combination with a balanced diet may support healthy blood sugar levels.