Protein is a crucial component of a well-balanced diet. It comprises diverse chemical compounds known as amino acids, the fundamental ‘building blocks.’ Amino acids play a significant role in constructing and maintaining tissues and synthesizing enzymes and hormones. Additionally, they are essential for developing bones, blood, skin, cartilage, and muscles. Protein is integral for energy metabolism and cellular processes, and it supports the body’s immune system in warding off illnesses. Furthermore, protein can also serve as a source of energy. Overall, protein stands as the cornerstone of maintaining optimal health.
What is protein deficiency, and who is most at risk?
Protein deficiency, or hypoalbuminemia, is characterized by insufficient proteins or one or more essential amino acids in the body. On the other hand, protein turnover is a term used to describe the equilibrium between the breakdown and synthesis of proteins within the body’s cells. This process is essential for maintaining overall protein balance and ensuring proper bodily function (Bernát, 2012) (Hawkins, 1985).
Individuals who consume sufficient protein often need help maintaining a well-balanced diet. This is especially true for elderly individuals (Baum et al., 2016) and those battling cancer who may encounter difficulties meeting their required protein intake (Pearlstone et al., 1995) (Horstman & Sheffield-Moore, 2015). In cases of severe protein deficiency, a condition known as kwashiorkor can develop, leading to significant malnutrition. Research indicates that the adverse functional impact of such protein insufficiency includes a weakened immune response, consequently heightening the susceptibility and seriousness of illnesses within a particularly vulnerable population: women and children (Keller, 1988).
Ten Signs and Symptoms of Protein Deficiency
1. Edema
Nutritional edema, or protein-energy malnutrition, is edema caused by low plasma protein levels (Liu et al., 1931). Plasma proteins usually act as “water magnets,” drawing water into the blood vessels. When the level of protein in the blood is low, water can leak out of the blood vessels and accumulate in the tissues, leading to the condition known as edema. This accumulation of water in the tissues causes swelling, a characteristic of edema (Britannica, T. Editors of Encyclopaedia, n.d.).
2. Skin, hair, and nail problems
Protein deficiencies can lead to various issues with hair, nails, and skin. Your body requires proteins like elastin and collagen to maintain healthy hair, skin, and nails. When your body cannot produce these proteins, you may experience symptoms such as brittle or thinning hair, dry and flaky skin, and deep fingernail ridges. While nutritional deficiencies are not the sole cause of these problems, it’s essential to consider the role of diet in maintaining the health of your hair, skin, and nails (McLaren, 1987).
3. Loss of muscle mass
Over time, insufficient intake of dietary protein can lead to a condition known as muscle wasting or muscle atrophy. This condition can reduce muscle strength, making it more challenging to maintain balance and slowing down the body’s metabolism, which may contribute to fat mass gains (Krieger et al., 2006) (Leidy et al., 2007).
4. Fatty liver
Kwashiorkor is a severe form of acute malnutrition that can increase fat in liver cells, a condition known as fatty liver. This condition is commonly observed in cases where there is a lack of protein in the diet. When the body does not receive an adequate amount of protein, it can lead to fatty liver disease, which may result in liver inflammation, scarring, and potentially liver failure (Ampong et al., 2019).
5. Mood Changes
The human brain relies on neurotransmitters, chemical messengers responsible for transmitting information between cells. These neurotransmitters are primarily composed of amino acids, essential protein components. When your body does not receive enough protein from your diet, it becomes difficult for your body to produce a sufficient quantity of neurotransmitters. This deficiency can, in turn, affect your brain’s functioning, leading to mood changes and difficulties with cognition (Li et al., 2020).
6. Appetite/Hunger
Dietary protein is known to be more filling than carbohydrates and fats, as supported by findings from short-term and immediate feeding studies (Booth et al., 1970) (Johnson & Vickers, 1993). Individuals often feel less energetic and more hungry when their diet lacks protein, as protein provides energy and helps them feel satisfied.
7. Weakness and Fatigue
Studies indicate that even a week of insufficient protein intake can notably impact the muscles supporting posture and movement, particularly for individuals aged 55 and above (Lindle et al., 1997) (Putra et al., 2021). A prolonged protein deficiency can lead to muscle mass loss, decreased overall strength, and slow metabolism. Additionally, insufficient protein intake can lead to anemia, as inadequate oxygen supply to the body’s cells can result in fatigue (Azzolino et al., 2020).
8. Slower Healing Process
Protein deficiency is shown to slow the healing process, reduce collagen formation, and cause wound splitting. The wound healing method includes blood clotting, inflammation, cell movement and growth, and tissue restructuring. When the body responds to an injury, the metabolic needs of the wound area increase, leading to a continuous loss of protein through wound exudates. If not addressed, this protein loss can hurt the immune process, potentially causing delays in transitioning from the inflammatory to the proliferative phases (Barchitta et al., 2019).
9. Getting and Staying Sick
Kwashiorkor is a disease recognized by healthcare providers worldwide as one of the main types of severe protein-energy undernutrition. It is predominantly a protein deficiency and is most commonly found in developing countries with diets high in starch and low in proteins (Heikens & Manary, 2009).
10. Bone Health
A sufficient amount of protein is essential for maintaining strong and healthy bones. When insufficient protein is insufficient, bones can become more susceptible to fractures due to decreased bone mineral density and weakened muscles. For individuals with osteoporosis, low protein intake may lead to an increase in the risk of falls and subsequent fractures (Cauley, 2013). In older adults, inadequate protein intake and age-related changes in metabolism, immunity, hormone levels, and sensitivity can lead to malnutrition and further compromise bone health (Boirie, 2009). On the other hand, a higher protein intake may have a protective effect against trabecular bone loss compared to a standard diet (Groenendijk et al., 2019).
The Recommended Dietary Allowance for Protein for Different Demographic Groups
In 1941, the US National Research Council set the first Recommended Dietary Allowances (RDAs) for protein, energy, and eight essential vitamins and minerals at the behest of the National Defence Advisory Commission (Murphy et al., 2016). The RDAs represent the average daily intake of nutrients necessary to meet the needs of most healthy individuals in a specific group (97 to 98 percent). These guidelines ensure that people obtain adequate nutrition for good health and well-being (Institute of Medicine (US) Food and Nutrition Board, 1998).
Public Protein RDA
The Recommended Dietary Allowance (RDA) for protein is set at a modest level of 0.8 grams per kilogram of body weight, equivalent to about 0.36 grams per pound of body weight. This recommendation is a guideline for the average healthy adult to ensure an adequate protein intake for overall well-being and health (Lonnie et al., 2018a).
Athletes/Active People Protein RDA
Research indicates that physically active individuals should consume approximately 1.2 to 2.0 grams of protein per kilogram of body weight (0.5 to 0.9 grams per pound). This recommendation applies to both strength and endurance athletes, highlighting the importance of adequate protein intake for athletes, weekend warriors, and fitness enthusiasts engaged in various forms of physical activity (Egan, 2016).
Elderly Protein RDA
Protein is essential for elderly adults, as experts recommend a protein intake between 1.2 and 2.0 grams per kilogram of body weight per day or even higher. The recommended dietary allowance (RDA) for protein is set at 0.8 grams per kilogram of body weight per day, considerably lower than the recommended intake levels (Wolfe, 2012) (Wolfe et al., 2008). The RDA reflects a value at the lowest end of the acceptable macronutrient distribution range. Studies show that a significant portion of adult men (about 38%) and adult women (about 41%) have dietary protein intakes below the RDA. This highlights the importance of ensuring that elderly adults receive adequate protein to support their health and well-being (Fulgoni, 2008) (Pasiakos et al., 2015).
Foods that are Highest in Protein
Dietary proteins are essential nutrients in various sources, including animal-based foods like meat, poultry, and eggs, as well as plant-based foods like legumes, nuts, and seeds. In addition to these traditional sources, proteins can also be consumed from alternative sources such as algae, bacteria, and fungi (mycoproteins). Plant-based foods are the primary global source of protein, constituting approximately 57% of daily protein intake. This is followed by animal-based sources such as meat, dairy, fish, and shellfish, which collectively contribute to the remaining 43% of daily protein intake, with beef accounting for 18%, dairy for 10%, and fish and shellfish for 6%. Other animal products comprise 9% (Lonnie et al., 2018a).
Interventions: What should I eat if I have a protein deficiency?
Suppose you have been advised by your healthcare provider, dietitian, or health coach to address a protein deficiency. In that case, you should consider increasing your consumption of a variety of protein-rich foods, such as:
1. Nuts and seeds, including almonds, pistachios, cashews, and flax seeds, are rich in protein and provide healthy fats, fiber, and essential vitamins and minerals.
2. Legumes, such as lentils and beans, offer a great source of plant-based protein, fiber, and various nutrients.
3. Eggs, which are a complete source of protein and also contain essential vitamins and minerals.
4. Seafoods, like fish or shrimp, are high in protein and supply omega-3 fatty acids and other beneficial nutrients.
5. Whole grains like quinoa provide protein, fiber, vitamins, and minerals.
6. Poultry, like chicken or turkey, is a lean protein source and contains essential nutrients such as iron and B vitamins.
7. Dairy products, like Greek yogurt or cottage cheese, offer a convenient source of high-quality protein, calcium, and other essential nutrients.
* (Heger, 2021).
Different Types of Protein Powders
Protein powder is a popular nutritional supplement for muscle growth, recovery, and overall health. Several types of protein powder are available, each with unique characteristics and benefits. Whether you’re vegan, lactose intolerant, or simply looking for the best option for your fitness goals, a protein powder is right for you. Here are eight common types of protein powder:
1. Pea Protein, Hemp Protein, Brown Rice Protein, and Soy Protein
Plant-based foods such as soy, brown rice, peas, and hemp seeds have less protein than meat and fish. However, food processors can extract most fat and carbohydrates from these foods and isolate the protein, creating protein-rich powders. While some people claim that most plant proteins are incomplete, meaning they do not contain optimal levels of all the essential amino acids needed to support protein synthesis in the body, this is not a significant concern as long as a variety of plant proteins are consumed regularly (Overduin et al., 2015) (Melina et al., 2016).
2. Egg and Egg White Protein
Eggs are widely regarded as an excellent source of high-quality protein, surpassing cow’s milk and beef. While egg whites are particularly famous for their protein content, it’s worth noting that the yolk contains more protein per gram. Specifically, egg whites contain 10.8g of protein per 100g, while egg yolks contain 16.4g per 100g (Stevens, 1991).
Each type of protein powder varies in terms of its amino acid profile, digestibility, and potential allergens, so choosing the right one based on your individual needs and preferences is essential.
3. Whey Protein Isolate, Whey Protein Concentrate and Casein Protein
Whey proteins (from animals) are commonly available in two forms: whey protein concentrates, which contain about 80% protein, and whey protein isolates, which contain about 90% protein. These proteins are derived as by-products during the processing of other dairy products, particularly cheese, and casein, which is the slowest absorbable form of whey. Whey protein isolates undergo further processing to remove fat and lactose, producing higher protein content. Whey protein is known for its high quality and faster absorption, making it a popular choice for athletes and fitness enthusiasts (Boland, 2011).
Conclusion
Protein is a crucial body component, serving as a fundamental building block. It is critical in supporting the structure and proper function of muscles, skin, enzymes, and hormones. Understanding the role of protein in the body is crucial. When protein intake falls short of the body’s requirements, it leads to protein deficiency.
While protein deficiency is rare in the Western world, inadequate protein intake, known as Kwashiorkor – the most severe form of protein deficiency, is predominantly found in children in developing countries where malnutrition and imbalanced diets are prevalent. Protein deficiency leads to various health issues and affects the body’s functioning in demographic groups such as the elderly, children, females, and athletes.
Even when protein deficiency is marginal, symptoms can start to appear. It is crucial to recognize the signs of low protein intake or deficiency. This article outlines ten key symptoms that suggest low protein intake or deficiency. Additionally, it provides information on supplements and food choices that can help you ensure adequate protein intake in your daily diet.
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