Protein supplements, widely consumed by athletes, young adults, and teenagers, offer a convenient way to increase protein intake, build muscle mass, and enhance recovery. Available in various forms, including powders, gummies, protein bars, and ready-to-drink shakes, these supplements impact nearly every system in the body. While protein supplements were initially designed to provide athletes and bodybuilders with an extra source of protein, they are now being used in the dietary management of patients with various medical conditions, such that researchers have been studying the effects of protein supplementation on health.
Benefits of Protein Powder Drinks
Weight Management
Consuming more protein can help you feel full longer, build lean muscle, and support your metabolism. Protein is an important nutrient for weight loss. Getting enough protein may support a healthy metabolism and reduce your appetite. It may also help you lose body fat without losing muscle. Protein shakes are a convenient way to add more protein to your diet and have even been shown to aid weight loss. Protein has been shown to help decrease hunger and appetite, partly due to the release of fullness hormones GLP-1 and PYY. Studies also show that higher protein intake may result in less hunger throughout the day. Protein supplement consumption is known to cause decreased weight gain and fat deposition and improve insulin sensitivity in the human body.
One small 2015 study found that a high-protein breakfast helped older women consume up to 135 fewer calories later in the day, compared with a low-protein breakfast or skipping breakfast. A 2016 meta-analysis of five studies also connected high protein intake and increased fullness. However, review authors caution that factors like body weight, eating behavior, and other health issues all play a role in the sensations of fullness. Furthermore, another review published in 2020 reports that ingesting more than 35 grams (g) of protein at once appears most effective for effects like less hunger, a reduced desire to eat, and greater feelings of fullness. Only a few studies have looked at protein shakes and appetite specifically. One 2019 study with nine young women with obesity found that a whey protein drink actively reduced appetite. In a 2021 study, participants given a high protein shake before their workout reported feeling less hungry after exercising than when given a lower protein shake with an equal number of calories.
Muscle Growth and Recovery
Protein is essential for muscle growth. Many athletes and gym enthusiasts consume protein shakes because they believe they will help them bulk up after strength training. An increase in the muscle protein synthesis and an improvement in the net protein balance are observed in patients who exercise regularly and consume protein supplements. In addition to muscle growth, a meta-analysis also determined that the supplements have a small to moderate effect on muscle recovery. Several studies reported that protein consumption after a workout provides greater benefits in increasing protein synthesis and muscle hypertrophy. Therefore, it is a common practice among bodybuilders to consume fast-digesting protein supplements such as whey protein immediately after exercise.
A high protein diet, especially when combined with strength training, can help build muscle. Because muscle aids metabolism and energy production, building muscle is a great way to keep your metabolism healthy. This is especially true if you follow a calorie-restricted diet to lose weight. That’s because extreme calorie restriction may result in muscle loss and fat loss. This loss of lean muscle may slow your metabolism, making it easier to regain weight once you stop the restrictive diet. Conversely, eating sufficient amounts of protein, combined with strength training, may help prevent this muscle loss and resulting metabolic slowdown.
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A 13-week study in older adults with obesity found that those who consumed an extra 20 g of protein weekly (in the form of a shake) gained 2.8 pounds (lb), or 1.3 kilograms (kg), more muscle mass than those who ate less protein. Plus, in a 6-week study, participants followed either a low or high protein diet, which included shakes. Each diet was calorie-restricted. Notably, participants following the higher protein plan gained 2.4 lb (1.1 kg) more muscle and lost 2.9 lb (1.3 kg) more fat. As well as contributing to muscle growth, protein can help repair damaged muscles and tissues. As a result, athletes may use protein powder to speed up recovery from muscle soreness after exercise. Many studies report that taking protein supplements after exercise can aid recovery by reducing muscle damage and improving muscle performance and muscle protein synthesis.
Improved Insulin Sensitivity and Blood Pressure
Protein supplement consumption is known to cause decreased weight gain and fat deposition and improve insulin sensitivity in the human body. WPs are a tremendous source of BCAA, like leucine, isoleucine, valine, lysine, and threonine, which can induce insulin secretion. Subjects consuming whey protein-based supplements regularly show significantly lower systolic blood pressure, while subjects who consume soy-based protein supplements have been reported to show a significant decrease in their systolic and diastolic blood pressures. Lower postprandial glucose levels have been observed in diabetic subjects as well, which can be attributed to the lower glycemic index of these supplements. This can lead to an indirect decrease in diabetes-related complications. Various mechanisms come into play after consuming high-protein meals that stimulate the central nervous system directly through the bloodstream at the level of the hypothalamus or indirectly through the vagus nerve, resulting in reduced weight gain and fat buildup and improved insulin sensitivity in the body.
Cardiovascular and Liver Health
Favorable effects of soy protein consumption have been observed on the serum lipid profile, with significant decreases in serum low-density lipoprotein and triglyceride levels. Whey-derived peptides have antihypertensive properties that primarily work by inhibiting the angiotensin-converting enzyme (ACE) found on the surface of vascular endothelial cells. By inhibiting ACE, WP increases the concentration of bradykinin, a potent vasodilator, leading to a more significant vasodilatory effect. Some whey-derived peptides may also enhance nitric oxide production, improving vascular function. WP contain high levels of cysteine, providing potential antioxidant properties. Cystine, produced from the oxidation of cysteine, is also essential for producing the antioxidant glutathione. This contribution to glutathione synthesis can alleviate liver damage and ameliorate oxidative stress. Patients with nonalcoholic steatohepatitis who took oral WP isolate supplements experienced improved liver biochemistries, increased plasma glutathione, and reduced hepatic macrovesicular steatosis. Recent studies have also suggested that WP components can positively affect patients suffering from hepatitis C and B, so that it may be used as supplemental therapy. In patients suffering from hepatitis B, lactoferrin is thought to exert its effect on the modification of hepatitis B virus and hepatitis C virus infections by interacting with host cell molecules, preventing the virus from adhering to and entering the cells.
Immune System Modulation and Cancer Treatment Support
WP is a promising treatment for patients with immunity-related diseases because it can help regulate the immune system by significantly increasing lymphocyte proliferation and human neutrophil responses. WP can modulate the immune system and has antibacterial, antiviral, and antifungal properties. Several studies have shown the potential benefits of protein supplementation in treating cancer-related cachexia, which causes progressive muscle and adipose tissue atrophy; thus, protein supplementation is often recommended for these patients. WP, in particular, contains high levels of leucine and other essential amino acids, crucial for muscle protein synthesis and preservation of lean body mass.
Other potential benefits
Whey is a source of bioactive compounds like immunoglobulins, lactoferrin, α-lactalbumin, and glutamine, which have been proven to boost the levels of incretin hormones and restrict the activity of dipeptidyl peptidase-4, ultimately resulting in increased sensitivity of β-cells to glucose, promoting β-cell growth, and safeguarding against apoptosis. In addition, GLP-1 also slows down the emptying of the stomach by relaxing the upper part of the stomach, decreasing movement of the antrum, and increasing the tone of the pylorus. This helps regulate energy intake and prevent glucagon secretion, improving glycemia after a meal. Whey consumption has been shown to upregulate gut peptide hormones such as cholecystokinin, polypeptide YY, GLP-1, and glycosylphosphatidylinositol, decreasing appetite and significantly impacting satiety. WP components like α-lactalbumin and β-lactoglobulin have a preeminent ability to reduce markers of the inflammatory response, such as monocyte chemotactic protein-1 and chemokine ligand-5, and suppress the production of the inflammatory cytokine interleukin-6, thus inhibiting the significant monocyte migration across the endothelial lumen, a crucial early step in atherosclerotic plaque formation.
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Types of Protein Powders
Protein shakes are made by mixing protein powder with water or another liquid, plus optional other ingredients. Although most people don’t need protein shakes to meet daily protein requirements, protein shakes can be convenient if you have limited access to high protein foods or experience trouble meeting your needs through food alone. You can buy protein powder and mix it yourself or purchase premade liquid shakes.
Different types of protein powders contain different nutrients. Protein shakes use different types of protein in varying amounts. They may include:
- Whey protein: quickly absorbed, dairy-based, and contains all nine essential amino acids
- Casein protein: slowly absorbed, dairy-based, and provides all essential amino acids
- Soy protein: plant-based and offers all essential amino acids, plus soy isoflavones that may provide some health benefits
- Hemp protein: plant-based, contains all essential amino acids, rich in omega-3 and omega-6 fatty acids, and has a high arginine content
- Rice protein: plant-based but lower in the essential amino acid lysine
- Pea protein: plant-based and less allergenic alternative to soy and whey protein, but lower in the essential amino acids cysteine and methionine
- Egg: Egg white protein offers a useful alternative for people who are lactose intolerant or have a dairy allergy.
- Beef: This type of protein is rich in leucine, glutamine, and other amino acids.
Certain protein powders and drinks contain a mix of protein types. For example, many plant-based brands combine types to diversify the amino acid profile. Some dairy-based protein powders combine whey and casein to provide immediate and longer lasting effects on muscle synthesis.
Which Type of Protein Is Best?
Different types of protein may affect your body in distinct ways. For instance, whey is typically absorbed more quickly than casein. This makes it optimal for promoting muscle protein synthesis after exercise. It may also help you feel less hungry in the short term. While some small studies have shown whey protein to be more effective for weight loss than soy and other plant-based proteins, others show no real difference. As such, individual lifestyle factors may be more important than the type of protein regarding weight loss or other desired outcomes.
One key factor to consider is the quality of protein you purchase. Whey, casein, and soy are considered complete proteins. This means they contain sufficient amounts of all the essential amino acids your body needs. All the same, these three may induce an allergic reaction in some people. Rice and pea protein are often considered less allergenic. However, rice protein is low in the essential amino acid lysine. Pea protein is low in the essential amino acids cysteine and methionine. Hemp protein is also considered less allergenic. Furthermore, it contains sufficient levels of all essential amino acids. As such, it can be considered a complete source of protein. As long as you regularly consume a variety of protein sources, opting for incomplete proteins in your protein shake is unlikely to be a problem. That said, it’s always best to talk with a doctor or registered dietitian before adding new supplements to your diet.
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Whole Food Alternatives for Protein Shakes
Protein powders aren’t the only way to add additional protein to your shakes. Here are a few whole foods you can use in place of protein powder:
- Greek or plant-based yogurt: Greek yogurt is naturally rich in protein, as are plant-based alternatives made from soy. Each provides around 6-10 g of complete protein per 3.5 ounces (oz), or 100 g.
- Nuts and seeds: Most nuts and seeds pack around 5-7 g of protein per 1 oz (28 g). Combine with soy or hemp milk for a complete source of plant-based protein.
- Spirulina: This blue-green algae offers around 8 g of complete protein per 2 tablespoons (14 g). This serving also covers 95% of the Daily Value (DV) for copper and 22% of the DV for iron.
- Tofu: This popular soy food contains around 5-13 g of complete protein per 3.5 oz (100 g), depending on the variety. It has a naturally mild flavor, so you can blend it with frozen fruit and liquid to yield a protein-rich shake.
- Puffed quinoa: This pseudocereal provides around 10 g of complete protein per 2.5 oz (70 g). Expect it to thicken and add a slightly nutty flavor to your shake.
- Oats: This grain offers around 5 g of protein per 1.5 oz (40 g). Combine with cow’s milk or hemp milk to get a complete source of protein.
These protein-rich ingredients are an easy addition to homemade shakes. Simply combine them with your choice of dairy or plant-based milk, fruit, and leafy greens for a nutrient-rich, whole-food alternative to protein powder-based shakes.
Potential Risks and Considerations
While protein supplements offer numerous benefits, it's crucial to exercise caution and consider potential risks associated with their consumption.
Kidney Health
Dietary protein intake plays a significant role in determining the workload of the kidneys, affecting glomerular filtration. Intake of high amounts of protein brings about a sudden increase in glomerular filtration rate (GFR) and renal blood flow, up to 100% from the baseline. Long-term high-protein intake may accelerate renal function decline in those with preexisting chronic kidney disease (CKD) who consume at least 90 g/day of protein. Low urinary pH, hypocitraturia, and hypercalcemia increase the risk of nephrolithiasis. Therefore, for those suffering from CKD, reducing protein intake can help reduce hyperfiltration and slow the progression of chronic nephropathies. According to the nutritional guidelines in CKD (K-DOQI 2020), to reduce the risk of end-stage kidney disease in adults with CKD 3-5 (who are not on dialysis) and are metabolically stable, it is recommended to follow a low-protein diet that provides 0.55 to 0.60 g of dietary protein per kilogram of body weight per day. Alternatively, a very low-protein diet can be followed, providing 0.28 to 0.43 g of dietary protein per kilogram of body weight per day with additional keto acid/amino acid.
It is also important to consider that a container of protein supplement contains not only protein but also various amounts of sugars, additives, and preservatives, which are added to enhance flavor and increase shelf life. For example, a supplement of WP concentrate may contain more than 25% (up to 80%) of protein by weight.
Mental Health and Skin Issues
Research has shown that chronic protein supplementation may increase the expression of anger and acne in athletes. Studies have shown that BCAAs in WP compete with tryptophan and reduce serotonin synthesis, a neurotransmitter linked to impulsivity and depression, potentially causing anger-related symptoms. WP containing insulin-like growth factor-1, associated with promoting cell growth and division, sebum production, and increased estrogen factors, could explain the association between the high consumption of WP products and acne.
Allergies and Gut Microbiota
While WP is generally considered easily digestible and beneficial, it contains components like beta-lactoglobulin that can cause allergies, particularly in children who are intolerant to cow’s milk. Symptoms of WP allergy may include atopic dermatitis, respiratory problems such as asthma and coughing, gastrointestinal discomfort, and even life-threatening anaphylactic reactions in infants. High-protein diets can significantly influence the composition and function of the microbiota by causing amino acid fermentation in the colon. This fermentation process leads to the production of potentially harmful metabolites, including ammonia, amines, phenols, and sulfides.
Supplement Quality and Regulation
The Food and Drug Administration (FDA) doesn’t typically review supplements for safety and effectiveness before they hit the shelves. Thus, it’s important to research the ingredients in your protein powder and the brand’s trustworthiness. When possible, choose a protein that has undergone third-party testing. The Food and Drug Administration (FDA) does not regulate protein powders. According to a 2020 analysis, many of the best-selling protein powders contain heavy metals, such as lead, cadmium, and arsenic. Therefore, people should always be cautious when buying protein powders and choose a product from a reputable supplier.
Potential Side Effects
When you drink them as part of a balanced diet, protein shakes can support good health. But some people may have the following side effects:
- Gas, bloating, diarrhea or cramps: If you’re lactose intolerant, some whey protein shakes may irritate your stomach. Large servings can also cause constipation and nausea. Look for nondairy shakes instead.
- Allergic reactions: An allergy to dairy-based protein can also trigger a rash, swelling, or a runny nose.
- Possible toxins: A report released by the Clean Label Project found some protein powders have heavy metals, pesticides, and other toxins, including mercury, lead, and arsenic. It’s unlikely that they have enough heavy metals to cause any serious health effects, but it’s still a good idea to drink them in moderation.
Dosage and Timing
According to international consensus, the daily reference intake of protein for the healthy adult population is 0.8 g/kg body weight. However, individuals who engage in physical activity may require more protein, ranging from 1.2 to 2 grams per kilogram of body weight. It is best to avoid consuming too much protein. Some powders contain up to 80 g per serving, which is too much for most people. Excessive protein can strain kidneys, leading to damage and kidney disease. Excessively high protein levels in the diet can also result in a reduced intake of other beneficial foods, such as fiber-rich fruits, vegetables, and legumes that the body uses to feed and sustain gut bacteria.
The optimal timing of protein supplementation is unclear. The amount and timing of consumption of protein supplements are considered to play a role in muscle hypertrophy and recovery. Several studies reported that protein consumption after a workout provides greater benefits in increasing protein synthesis and muscle hypertrophy. Therefore, it is a common practice among bodybuilders to consume fast-digesting protein supplements such as whey protein immediately after exercise.
Who Can Benefit from Protein Powder Drinks?
Protein powders can benefit many people, especially athletes, older adults, vegetarians, and vegans. They are a convenient source of complete protein and sometimes contain other nutrients. Protein shakes can be useful in very specific circumstances:
- When you’re growing: Teens need more protein, especially to fuel their workouts, since their bodies are still growing. Teenage athletes need more - 0.5 to 0.8 grams per pound per day. The Academy cautions, though, against teens using protein supplements. Too much protein can be hard on your kidneys and can cause dehydration. It's best for teens to get most of their protein from foods.
- When you’re starting a workout program: If working out is new to you and you’re trying to build muscle, you’ll need more protein than normal. The same is true when you're starting a workout program that's more intense than your usual one.
- When you’re recovering from an injury: When you're injured, you need extra protein to help your body heal.
- If you’re vegetarian or vegan: A well-balanced plant-based diet can provide all the protein you need, but protein shakes can be a convenient addition.
- I'm trying to lose weight: Makers of protein shakes may say that their products help lower body fat or promote weight loss. Some studies find that consuming a higher than usual amount of protein in your diet may offer benefits. For example, eating or drinking products that are high in protein may help you lower body fat, keep lean muscle, feel full and lose weight.