A lack of protein in the diet can result in loss of muscle mass, skin issues, edema, and other symptoms of protein deficiency. In this article, we will discuss the most common protein deficiency symptoms and how you can make sure you meet your daily protein needs.
What Is Protein?
Protein is the primary building block of all the tissues in our body. According to MedlinePlus:
“Proteins are large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body’s tissues and organs.
Proteins are made up of hundreds or thousands of smaller units called amino acids, which are attached to one another in long chains. There are 20 different types of amino acids that can be combined to make a protein.” (1)
Different Types of Protein
As mentioned above, there are 20 different types of amino acids that can be combined to make a protein. Of these 20 amino acids, 9 are considered “essential,” and the other 11 are considered to be “non-essential.” Essential amino acids are called essential because our bodies cannot produce them on their own, and they must be obtained through diet. Non-essential amino acids, however, can be produced by the body. They are still essential for our health, but because the body can synthesize them, they are not labeled as “essential amino acids.” Non-essential amino acids are mainly synthesized from glucose (carbohydrates). (2)
How Much Protein Do I Need Daily?
According to the MayoClinic:
“The recommended dietary allowance to prevent deficiency for an average sedentary adult is 0.8 grams per kilogram of body weight. For example, a person who weighs 165 pounds, or 75 kilograms, should consume 60 grams of protein per day.” (3)
Keep in mind this is “to prevent deficiency.” Your specific protein needs may vary depending on your lifestyle. For example, bodybuilders and athletes need significantly more protein to support muscle repair and growth.
While it is extremely important to meet your daily protein needs, consuming too much protein can also be harmful. Protein is not stored in the body. Once protein needs are met, the remaining protein is used for energy or is stored as fat.
Extra protein intake can result in elevated blood lipids and can even cause heart disease because of increased fat consumption, particularly saturated fat. Saturated fat has benefits but in moderation. Extra protein intake can also tax the kidneys and can be a risk factor for people with kidney disease. (3)
High-protein diets, particularly those containing high amounts of animal protein, may also lead to the buildup of uric acid in the blood. This is because these foods are high in purines, chemical compounds that form uric acid. Elevated levels of uric acid in the blood can cause gout, permanent bone, joint, and tissue damage, kidney disease, and heart disease. (4)
So, how much protein is too much? The MayoClinic states that:
“Excessive protein intake would be more than 2 grams per kilogram of body weight each day.”
Using the same example from above, if a person weighs 165 pounds, or 75 kilograms, then consuming more than 150 grams of protein in a day would be considered excessive and may have potential negative health effects.
So, for a person weighing 165 pounds (75 kilograms), the ideal range of protein consumption is between 60 and 150 grams daily, with 60 being the low end of the spectrum and 150 being the high end. This means the ideal average range of daily protein intake for someone with this weight would be about 80-120 grams of protein per day—with 60 being the minimum to prevent protein deficiency symptoms.
Of course, you will have to consider your own weight in this equation, as well as your level of activity. If you work out often, you may want to lean more toward the higher end of the average range—especially on days you are working out.
What Are the Signs and Symptoms of Protein Deficiency?
If you fail to meet your daily protein requirements, you could develop signs and symptoms of protein deficiency. Some of the most common protein deficiency symptoms in adults include:
1. Muscle Loss
One of the primary signs of protein deficiency is the loss of muscle mass. The muscles of the body contain the greatest amounts of protein, and so they are also one of the first places we can look to assess the protein levels in the body.
When your diet is lacking in dietary protein, the body takes the protein from the skeletal muscles in order to provide it to more important tissues and functions in the body. This can lead to the loss of muscle mass over time if daily needs are consistently unmet.
The loss of muscle mass is one of the first major signs of protein deficiency, and it can occur even in cases of only moderate insufficiency. This is why it is essential to meet the minimum daily requirements for protein. This is also one of the most common symptoms of protein deficiency in elderly people.
Edema is another symptom of protein deficiency, particularly in cases of severe protein deficiency. Edema is the medical term for water retention or swelling of the tissues, which is characterized by puffy or swollen skin. It can occur systemically throughout the body or can be localized to certain areas of the body.
Edema occurs when capillaries, the tiny blood vessels in your body, leak fluid. This is believed by scientists to be caused by low amounts of human serum albumin, which is the most abundant protein in blood plasma. (5) When the levels of this protein are reduced, it can lead to lower oncotic pressure, causing fluid accumulation and swelling in the tissues (edema).
3. Skin, Hair, and Nail Issues
Protein deficiency can also have a negative effect on your skin, hair, and nail health. Hair is primarily composed of protein, and a lack of protein in the diet can cause your hair to become brittle and may even lead to hair loss over time.
In children, protein deficiency is commonly distinguished by red, flaky skin or by patches of skin that have changed pigmentation. Brittle nails are also a common symptom of protein deficiency.
4. Increased Appetite
Not surprisingly, a lack of protein in the diet can also result in an increased appetite and food cravings. Protein is a macronutrient, and if your protein needs are not met, your body may increase your appetite in an attempt to restore protein levels to normal. Protein deficiency may cause you to crave savory foods particularly, as these are often higher in protein than sweet foods.
5. Fatty Liver
Fatty liver, or the accumulation of fat cells in the liver, can also be caused by protein deficiency symptoms. If not treated, this can develop into fatty liver disease, which can damage your liver and inhibit proper liver function. This is a major health risk, as the liver performs over 500 individual tasks for the body—including the synthesis of non-essential amino acids.
Researchers are not entirely clear why protein deficiency can lead to fatty liver, but they believe it is because a protein deficiency can lead to the impaired synthesis of fat-transporting proteins in the liver. (6)
6. Weakened Immunity
Another concerning symptom of protein deficiency is a weakened immune system, which can lead to an increased risk of colds and other infections, greater severity of infection, and decreased wound healing.
The immune system does not work entirely by itself but relies significantly on the nutrients that we provide it with on a daily basis. Protein is one of the major nutrients needed by the immune system for proper functioning—among others. Reduced immune function can occur even in mild cases of protein deficiency, so it is important to make sure you meet your protein needs each day.
How Can I Meet My Daily Protein Needs?
It can be difficult for some people to meet their daily protein needs, particularly when on a vegan or vegetarian diet. Animal foods (particularly animal meat) have far more protein than plant foods, so protein deficiency is less common in people that include animal foods in their diet.
Most plant-based eaters get the majority of their protein from grains, nuts, seeds, and legumes. Below, we’ll share some data on the amount of protein found in some of these foods. This info is based on the amount found in a ½ cup serving size (uncooked). For example, ½ cup of uncooked quinoa contains about 12 grams of protein. Keep in mind that these foods are not served uncooked, but since they expand when cooked, their nutrient content is often measured based on their dry or uncooked form.
Some of the top plant-based sources of protein include:
- ½ cup quinoa; provides 12 grams of protein
- ½ cup of brown rice; provides 7 grams of protein
- ½ cup of buckwheat; provides 8 grams of protein
- ½ cup of black beans; provides 20 grams of protein
- ½ cup of pinto beans; provides 15 grams of protein
- ½ cup of lentils; provides 23 grams of protein
- ½ cup of almonds; provides 20 grams of protein
- ½ cup of peanuts; provides 17 grams of protein
- ½ cup of hemp seeds; provides 20 grams of protein
- ½ cup of sunflower seeds; provides 12 grams of protein
We can see that the amount of protein in plant foods is significantly lower than in animal foods:
- ½ pound of hamburger; provides 42 grams of protein
- ½ pound of chicken breast; provides 70 grams of protein
- ½ pound of salmon; provides 45 grams of protein
- ½ pound of turkey breast; provides 58 grams of protein
So, we can see that even if someone were to eat ½ cup of black beans, for example, with each meal, they would still only be getting 60 grams of protein. Black beans are a fairly high protein source when it comes to plant foods, and ½ cup is a decent serving, especially if you are eating other foods with it. It is totally possible to meet your protein needs by eating plant-based foods alone, but it requires more consideration as it is easier to fall short of the daily requirements while on a plant-based diet.
Hopefully, this points out the importance of tracking your protein intake, especially if you are vegan or vegetarian. Often, people on a vegan diet will also include protein powders and supplement with amino acids to ensure proper protein intake.
Some people on a vegan diet also will eat products made of concentrated soy or soy protein isolate. While these may have high amounts of protein, they are also high in estrogen compounds that can have negative health effects. Not to mention, the majority of the soy (and corn) on the market today is genetically modified (7). So, if you are going to eat soy-based foods, make sure they are organic, and ideally, do not rely on them as staples in your diet.
The best way to meet your protein needs is by doing a bit of research into the foods you commonly eat and seeing how much protein each food contains. Once you have a good idea, you’ll be able to know how much protein you are getting with each of your meals. You can then see how much protein you need specifically by calculating your body weight in kilograms, multiplied by .8. This will be the minimum amount of protein that you should eat in a day.
You can also multiply your body weight in kilograms by 2, which will provide the maximum amount of protein (in grams) that you should consume in a day. Ideally, you will aim to get somewhere in between your minimum and maximum protein needs—depending on your level of activity and the type of exercise you perform.