The majority of those involved sooner or later have a question about taking sports supplements. Today we will talk about the benefits and harms of protein which is the most popular product among fitness enthusiasts.
Protein is a powder that is high in protein (typically 60-90%) and low in fat and carbohydrates. Most importantly, it is an easily digestible protein, which is why it is so popular with people involved in sports. Protein is the perfect helper for your muscles, because they need food and building material during stress.
But like any product, protein powder has its pros and cons. Let's take a closer look at the arguments about the benefits and harms of protein.
Top 15 Benefits of Protein
It is unlikely that protein would have gained such popularity if it were not for a number of convincing arguments about its benefits:
1. Protein contributes to muscle growth, which means achieving maximum sports results.
2. This is an exceptional product because it carries protein without large amounts of carbohydrates and fats.
3. Promotes suppressing appetite by lowering blood sugar levels and increasing the level of free amino acids.
4. It is an excellent snack option at work or at home.
5. You can easily gain your daily protein intake, which is especially important for vegetarians and not special lovers of meat and fish.
6. Protein powder easy to use... It is enough to dilute it with milk or water, and the protein meal is ready.
7. Quickly and easily absorbed by almost 100%, does not create heaviness in the abdomen.
8. Gives the body full amino acid complex.
9. Normalizes insulin levels, both in healthy people and in patients with type 2 diabetes.
10. Helps athletes to increase their endurance, strength and energy.
11. You will finally close the question of what to eat after training. Highly digestible protein is a great post-exercise solution.
12. Powder convenient to store and you can always take it with you. Unlike milk and cottage cheese, it is not a rapidly perishable product.
13. Proteins are usually sold with additives, so you can choose the flavor you prefer: chocolate, strawberry, vanilla, etc.
14. Protein in sports supplements is naturally occurring and completely physiological in relation to the human body.
15. Protein is safe for health if you do not exceed the dosage and exercise.
5 main disadvantages of protein
But protein, like any other product, also has disadvantages:
1. Protein can cause eating disorders... People suffering from lactose intolerance are especially at risk. But even this can be avoided if you buy supplements that do not contain this component. For example, whey protein isolate or hydrolyzate.
2. Excessive protein dosage can negatively affect work liver and kidney... If you suffer from diseases of these organs, then it is better to limit the intake of sports nutrition.
3. Protein powder practically "empty" a product that does not contain vitamins and microelements. True, there are exceptions when manufacturers specifically enrich it with useful substances.
4. Because of high cost not every practitioner can afford the regular purchase of sports supplements.
5. Pure protein is not the most delicious product. To improve the taste, manufacturers add to it sweeteners, flavorings and colorants.
As in any other, even the most natural products, you need to know when to stop. Here are some simple tips on how not to wrap a very worthwhile protein product to the detriment of your health.
Sooner or later, many people involved in strength sports think about the need to take additional food supplements. On television, in magazines, newspapers, disputes about the dangers and benefits of sports nutrition do not stop. That anabolic steroids negatively affect the human body, probably everyone already knows. Is protein harmful or not? Is it really necessary for athletes and will its use lead to health problems in the future? Let's try to figure it out.
What is protein
The English word protein is translated into Russian as "protein". And protein is a necessary component of a healthy human diet, since it is involved in all life processes: 
- is responsible for building bone and muscle tissues of the body;
- protects against bacteria and viruses;
- is a source of energy;
- regulates the metabolism in the body;
- carries oxygen in the circulatory system;
- keeps skin, nails and hair in good condition.
In sports nutrition, protein is a powder that is high in protein. It is easily absorbed by the body and contains all the essential amino acids.
Protein powder is made from natural extracts of foods containing animal or plant protein:
- dairy products;
- meat;
- peas.
The raw materials go through several stages of cleaning and drying, as a result of which a completely natural protein concentrate is obtained, which is used in sports nutrition as an additional source of energy and material for building and regenerating muscles.
How protein affects health
According to doctors, the use of a protein powder of good quality and in a reasonable dose does not have a negative impact on health. On the contrary, in many scientific works the beneficial effect of protein on the human body has been proven.
Protein is good for both men looking to gain muscle mass and women looking to lose weight, get rid of skin problems and have strong healthy hair and nails.
All parents know what an important role protein plays for a growing child's body, so the question may arise: is it possible for children to have protein? Experts agree that protein powder in an age-specific dosage affects the child's body (from 3 years old) only in a positive way. Therefore, if it is difficult to feed a child with meat or cottage cheese, but he will be happy to drink a protein shake at an age dose, there will be no harm in this.
Lack of protein in the human body leads to:
- sleep disturbance;
- depression and irritability;
- decreased immunity;
- frequent stool disorders;
- weight gain;
- slow wound healing;
- dry skin;
- brittle hair and nails;
- the development of various diseases.
Poor nutrition and diseases of the gastrointestinal tract lead to symptoms of insufficient protein in the body, and for people with increased physical activity and athletes, it is simply unrealistic to achieve a daily protein intake from food. This is why eating protein powder is a must.
It is important to understand that protein is an extract from products, and any product has properties, contraindications and daily intake. In accordance with this, the benefits of the protein or the harm that can be done to the body are determined.
Daily protein intake
The daily protein requirement is individual and depends on the age, gender and physical activity of a person. As recommended by the World Health Organization the normal protein intake is considered to be 0.8 - 1 g / kg of body weight... This is the average for an adult with moderate physical activity. For children under 18 and pregnant women, the protein norm is 2 g / kg per day.
People engaged in hard physical labor and athletes should take 2.5 g of pure protein, for girls and women whose task is to lose weight and maintain good physical shape - 1.5 g / kg of body weight.
Exceeding the daily intake of protein up to 3 g / kg leads to side effects: indigestion and kidney disease.
While it is almost impossible to exceed the protein norm with regular food, it is easy when using protein powder. This is why it is very important to follow the correct dosage when preparing your protein shake and not exceed the recommended dosages indicated on the protein powder can.
Protein Powder Types
Before you buy protein from a sports nutrition store, it's important to figure out which powder is right for you. For this you need to know the individual characteristics of the body(intolerances, allergies, chronic diseases) and take into account the purpose of use:
- gaining muscle mass;
- weight loss;
- recovery after power loads;
- maintaining general health;
- replenishment of the missing amount of protein from food (vegetarians, people with diseases of the abdominal cavity).
To prevent protein powder from harming the body, it is recommended when choosing it to be guided by the advice of a trainer and attending physician, who will prescribe the type of protein that meets your needs in the necessary and sufficient dosage.
Animal Powders
Protein powder based on animal products is most popular among athletes: 
- Egg protein is an excellent source of protein, the benchmark among protein powders, containing all the essential amino acids. Has the highest amino acid absorption rate - 1.00... It is the egg white of choice for bodybuilders seeking to gain muscle mass. It builds muscle fibers faster than any other protein. Recent Scientific research have shown that the use of egg protein strengthens the heart and blood vessels, increases the level of good cholesterol... There is only one contraindication to taking egg white - an allergic reaction to chicken eggs.
- Milk Protein is another highly absorbable protein powder with a full complement of amino acids. Milk proteins can help you lose weight, lower blood pressure and rebuild muscle fibers after exhausting workouts. The main disadvantage is the lactose content, so milk protein is harmful for people who have lactose sugar intolerance, which is reflected in the disruption of the gastrointestinal tract. Milk protein consists of two types of proteins: casein ("slow") and whey ("fast") proteins, which can be purchased separately.
- Casein protein is a protein found in cottage cheese. It is absorbed very slowly (up to 7 hours), due to which the muscles are fed with amino acids for a long time. Suppresses hunger for a long time, so casein is useful for losing weight.
- Whey protein is preferred over dairy protein when building muscle. Absorbed by the body completely and in a short time (within 30-50 minutes).
- Protein from beef meat is a rarity in sports nutrition stores and has a high price, therefore it is significantly inferior in popularity to egg and dairy proteins, but its advantage is the creatine content, good tolerance (an option for athletes with allergies to lactose or chicken egg protein) and fast digestibility ...
Powdered proteins based on animal origin are completely natural, contain all essential amino acids, and are easily digestible. They are completely safe for women, men and even children. They can harm only people with individual intolerance to animal proteins and with an increase in the recommended dose.
Plant Based Protein Powders
Plant-based protein powders are vegetarian options for proteins, but they are completely complete and are beneficial to overall health. In addition to amino acids, they also contain fiber and polyunsaturated fatty acids.
There are proteins based on hemp, flaxseed, brown rice, peas. These types of protein powders are rarely found on the market, most often they are included in a mixture with other proteins.
The most common plant-based protein powder is soy protein.... In terms of protein content, quality and digestibility, it is the closest to animal protein powder (digestibility coefficient 0.95). It is able to quickly restore muscles after physical training and contributes to their rapid growth.
But there is an opinion that soy protein is dangerous for men, because it contains phytoestrogens that are similar in action to female sex hormones. Is protein harmful to men's health? Let's consider further.
Effects of soy protein on the body
Some side effects can indeed occur with long-term use of soy protein in men. Most often it is an allergic reaction to soy, less often - digestive disorders due to gluten intolerance.
Numerous studies have shown that phytoestrogens do not have harmful effects on men's health and do not reduce potency, if the recommended dose is not exceeded. If consumed in excess, the production of the hormone lipase, which is responsible for the breakdown of fat, may decrease, which will lead to a set of fat mass, rather than muscle mass.
For women (especially during menopause), soy protein is most preferable, since its use normalizes hormones and prevents the development of breast cancers.
When choosing a soy protein product, you need to pay attention to the manufacturer and the price, since you can buy low-quality protein from genetically modified soy, which will do more harm to health than good.
The negative effects of using protein blends
It has been proven that protein powder has a positive effect on the body. The harmfulness of protein to human health occurs only when:
- individual protein intolerance;
- improper sports diet(replacing main meals with protein shakes);
- non-compliance with the dosage.
The following symptoms indicate obvious protein intolerance:
- protein rash, itchy skin;
- redness of the sclera of the eyes, lacrimation;
- discomfort in the gastrointestinal tract;
- intoxication of the body (nausea, vomiting, fever).
What else can protein be harmful? It is quite rare to find good quality pure protein powder in sports nutrition stores. Mostly, protein blends are marketed, enriched with various additives in order to increase the nutritional value and improve the taste of the protein.
The side effects of their use largely depend on the content of these additional substances in the composition. When buying a protein blend, it is important to carefully study the qualitative and quantitative composition.
What are the ingredients in protein mixes that should alert you?
- Taurine is an amino acid added to all energy drinks... In small doses, it has a positive effect on health, but an excess of taurine makes the body work for wear and tear, increases the risk of diseases of the nervous and cardiovascular systems.
- Synthetic sweeteners (Sweeteners). They are not absorbed by the body and cause irreparable harm to health in some diseases: in case of renal failure (cyclamate), phenylketonuria (aspartame), diseases of the heart and blood vessels (aspartic acid). The use of sugar substitutes in large doses has an extremely negative effect on health, especially for children and adolescents.
- Thickeners (Gum Blend): xanthan gum, carrageenan. Provides optimal consistency when preparing a protein shake, but regular use of these additives, according to the latest scientific data, can lead to stomach ulcers and the occurrence of gastrointestinal cancer.
- Synthetic sugars: Dextrose and Maltodextrin are important components of sports nutrition that affect the speed of recovery after exercise, but excessive consumption of sugars increases the likelihood of developing diabetes, obesity, and heart disease. High doses of dextrose often cause digestive problems.
By adding various components to the composition of protein mixtures, manufacturers are not always guided only by the benefits they bring to the body and improve the taste. This is more often done in order to reduce the cost of the product, because a protein concentrate (60-85% protein) or a hydrolyzed isolate (consists of 90% protein) will cost much more than a cocktail mix with nutritional supplements.
Protein Bars
Protein bars are another source of protein besides high protein blends. Their protein content should be higher than fat and carbohydrates. Unfortunately, many manufacturers, disguised as protein bars, produce products containing a wide variety of ingredients.
Therefore, if the purpose of consuming a bar is to additionally obtain a high dose of protein, then you must very carefully read the label about the composition and calorie content of the product. A high-quality protein bar, like a protein powder, will only benefit, and a cheap fake will harm health and excess weight.
What to look for when buying and consuming protein
It has been proven that taking quality protein in the correct dosage does not harm human health. But it is worth paying attention to the following points: 
- High-protein foods should only be prescribed by a doctor or sports coach.
- You need to purchase protein powder or mixture only from well-known and trusted manufacturers.
- You can not replace the main meals with proteins and get some of the protein from meat and fish products, legumes and cereals, nuts.
- With the constant intake of high-protein mixtures throughout the year, an imbalance of hormones and electrolyte imbalance can occur in the body.
- With the continuous use of protein mixtures for 5 years, irreversible degenerative processes begin in the liver tissues, various diseases of internal organs develop.
That is why it is necessary to take protein courses under the strict supervision of a physician. Uncontrolled long-term use is fraught with serious complications and health problems.
Protein is a useful, completely natural biological food supplement, the correct use of which in sports and dietary nutrition does not harm the body, but helps to achieve goals and improve health. Side effects occur only with the use of low-quality protein mixtures, in a high dose or with individual intolerance.
Most nutritionists have long agreed that chicken eggs are one of the most valuable foods. The fact that almost no diet is complete without eggs convinces us that eggs are useful and necessary for our body.
However, supporters of proper nutrition still have questions. Is cholesterol in eggs harmful? What is healthier than yolk or protein? In what form is it better to use the egg - boiled or half-cooked?
Nutritional value of egg yolk
Let's start with perhaps the most valuable part - the yolk, which contains 100% of all fat-soluble vitamins A, D, E and K contained in the egg, as well as carotenoids - lutein and zeaxanthin.
The yolk contains 90% of the calcium, iron, zinc, thiamine, folic acid, vitamins B6 and B12 found in the egg. And only 10% of these microelements are found in egg white.
Yes, it contains more proteins than the yolk (3.5 g versus 2.7 g), but only because the protein itself is larger in volume. More importantly, in the yolk, proteins are combined with healthy fats, and in protein - by themselves. By consuming proteins without their binding to fats, we deplete our own vitamin A reserves, and also contribute to the development of cellulite.
What about cholesterol?
As for the "terribly bad" cholesterol in the yolks, there is no reason to be afraid. Studies have shown that those people who ate up to 4 eggs a day had lower blood cholesterol levels than those who ate only one egg.
The case of two brothers is widely known. One of them ate over a hundred eggs a month, and his blood cholesterol dropped from 150 to 130 mg / dL. In the diet of the second brother, red meat, butter and eggs were completely absent. His cholesterol was kept at an extremely high level of 300, and only statins (drugs to artificially lower blood cholesterol) managed to reduce it to a safe 200 mg / dL.
More than 80% of all cholesterol is synthesized by the liver, and less than 20% of the body gets from food. Moreover, if more cholesterol is supplied than necessary, then its absorption is sharply reduced.
There is only one conclusion from this - do not worry about the cholesterol contained in eggs. And even more so, because of the mythical fear of overdoing it with cholesterol, you should not deprive yourself of such a valuable component as egg yolk.
Yolk lutein and zeaxanthin dramatically reduce the risk of eye diseases such as macular degeneration and cataracts, while choline stimulates mental activity and regulates blood insulin levels.
Egg white - benefits and harms
Now let's move on to the egg white. Here, not everything is as rosy as with the yolk. Mother Nature provided for the squirrel as a protection and food source for the chick for the first time of its existence. And she endowed this "protective casing" with a very interesting properties... Thirteen of the 14 proteins in protein have antimicrobial properties. Usually there are enough of them to keep the egg from bacteria and viruses, but in large quantities they can affect the bacteria in our body, especially if there are problems with the intestines.
For example, the protein lysozyme, which is usually not dangerous, can dramatically impair digestion and absorption. nutrients... Moreover, some components of egg white can penetrate the weakened intestinal wall and provoke autoimmune diseases.
The protein avidin blocks the absorption of biotin, a substance that is responsible for the synthesis of fatty acids and blood sugar levels. Some people do not tolerate egg white at all, although they eat yolks without problems.
Nutritionists may argue and say that during cooking, most of the negative properties of protein disappear, but practice shows the opposite. Up to 30% avidin retains its activity even after long boiling. In any case, protein should only be eaten well-boiled or well-done. Yolks can be safely consumed raw. This is not only tastier, but also healthier.
As you know, most nutrients loses its properties when heated over 100 degrees. Therefore, it is more useful to eat the yolk raw (for example, eggnog) or with minimal culinary processing (poached eggs).
How many eggs can you eat? It is reliably known that eating up to three eggs a day is absolutely safe for health. Although doctors are aware of cases when people ate more than 25 eggs a day and lived to old age, while maintaining a normal level of cholesterol in the blood and excellent health.
I see only one weighty reason why it is worth giving up such a valuable product - moral convictions, ideological vegetarianism, which does not allow eating "killer" food. For these people, there is only one alternative to eggs - dairy products and / or vegan vitamin B12 and omega-3 fatty acid supplements.
There is a widespread belief among builders of their own muscles - "the more protein, the better" and often such people, without making calculations, consume the maximum possible amount of protein foods and supplements. What do scientists say about excessive amounts of protein in the body - can it harm?
Protein intake
To begin with, you should recall the official guidelines for protein intake. For example, the NSCA sports nutrition guidelines for gaining lean muscle mass recommend, in addition to a moderate excess of calories (10-15% above normal), to consume 1.3-2 g / kg body weight per day.
And with the active phase of reducing the percentage of fat, scientists recommend even increasing the protein intake rate - up to 1.8-2 grams / kg of body weight per day. Moreover, the lower the percentage of fat (for example, in preparation for a competition), the higher the requirements for protein intake. If the goal is to reduce the percentage of fat to very low values, it is recommended to increase the protein intake to 2.3-3.1 g of protein per 1 kg of body weight per day..
Let's now find out what happens to our body when we consume high amounts of protein.
Excess protein and kidney
Don't ask yourself this question if you have healthy kidneys, and control your protein intake if they are sick. The smartest approach is to gradually increase your protein intake to a higher level in your diet, rather than "jumping with both legs at the same time."
Usually, with increased protein intake, it is recommended to drink more water... One reason is to reduce the risk of kidney stones. However, there is still no clear scientific justification why this should be done, but perhaps this is a reasonable approach.
Observations of active male athletes and measuring the level of urea, creatinine and albumin in the urine showed that in the range of protein intake from 1.28 to 2.8 g / kg body weight (that is, at the level of the recommendations described above) no no significant changes were observed (1). However, this experiment lasted only 7 days.
Another study (2) also showed no associations between protein intake and kidney health (in postmenopausal women).
A study with nurses (3) confirms the findings. However, this suggests that the data on the safety of the protein does not apply to cases of kidney failure and other kidney diseases, and also that non-dairy proteins of animal origin may be more dangerous to the body than other proteins.
It has been suggested that protein intake leads to functional changes in the kidneys (4). Protein can affect kidney function (5,6), therefore, when using it, there is a possibility of damage... The most pronounced results were obtained during experiments on mice (protein ranged from 10-15% to 35-45% of the daily diet at a time) (7,8).
Also, in the course of one study (9) with the participation of healthy people, it was found that a doubling of the amount of protein consumed (from 1.2 to 2.4 g / kg of body weight) leads to an excess of the norm for indicators of protein metabolism in the blood. There was a tendency towards adaptation of the organism - an increase in the glomerular filtration rate, but this was not enough to bring the uric acid and blood urea levels back to normal within 7 days (9).
All these studies, first of all, suggest that too much protein leads to too rapid changes, and the process of gradual increase in volume does not impair renal function (10). This means that it is more advisable to gradually change the amount of protein intake over a relatively long time.
Protein-restricted diets are recommended for people with kidney disease, as this will slow down the seemingly inevitable deterioration (11,12). Lack of control over protein intake in patients with kidney disease speeds up (or at least does not slow down) the decline in their performance (3).
Excess protein and liver
There is no reason to believe that normal amounts of protein, which is part of the normal diet, could be harmful to the liver of healthy rats and humans. However, there is evidence from preliminary studies that very large amounts of protein after a long enough fast (more than 48 hours) can lead to acute liver injury.
When treating liver disease (cirrhosis) recommend reducing protein intake, since it is the cause of the accumulation of ammonia in the blood (13, 14), which makes its negative contribution to the development of hepatic encephalopathy (15).
In at least one animal model, it has been shown that liver damage develops with a cyclic alternation of 5-day periods of sufficient protein intake and periods of protein deficiency (16). A similar effect was observed with the consumption of food containing 40-50% casein after a 48-hour fast.(17). In animal studies (18,19), there was preliminary evidence that increased protein intake (35-50%) at the time of resumption of feeding after a 48-hour fast can harm the liver. Shorter periods of fasting were not considered.
Amino acids are acids, aren't they?
We remind you that proteins are complex organic compounds composed of smaller “building blocks” - amino acids. In fact, proteins consumed in food are broken down into amino acids.
Theoretically, it is possible to prove the harm of amino acids due to their excess acidity. But this is not a clinical problem: their acidity is too low to cause any trouble.
Read how our body regulates the acidity / alkali balance in the text ““.
Excess protein and bone mineral density
The analysis of a large observational study does not show any association between protein intake and the risk of bone fractures (a measure of their health). An exception is the situation when, against the background of an increased dose of protein in the diet, the total calcium intake falls below the level of 400 mg / 1000 kcal daily (although the hazard ratio was rather weak and amounted to 1.51 when compared with the highest quartile) (26). In other studies, a similar correlation was not found, although logically this would be expected (27,28).
Soy protein itself appears to have an additional protective effect on bone in postmenopausal women, which may be related to the isoflavone content in soy (30).
The Role of Strength Training
Ironically, there is a study on this topic in rats. Rodents were exposed to high doses of protein in their diet, resulting in impaired kidney function.
But "resistance training" (apparently, one of the groups of rats was "loaded" physically) reduced the negative effect in some of them and had a protective effect (8).
Mentioned studies:
1. Poortmans JR, Dellalieux O Do regular high protein diets have potential health risks on kidney function in athletes. Int J Sport Nutr Exerc Metab. (2000)
2. Beasley JM, et al Higher biomarker-calibrated protein intake is not associated with impaired renal function in postmenopausal women. J Nutr. (2011)
3. Knight EL, et al The impact of protein intake on renal function decline in women with normal renal function or mild renal insufficiency. Ann Intern Med. (2003)
4. Brändle E, Sieberth HG, Hautmann RE Effect of chronic dietary protein intake on the renal function in healthy subjects. Eur J Clin Nutr. (1996)
5. King AJ, Levey AS Dietary protein and renal function. J Am Soc Nephrol. (1993)
6. Dietary protein intake and renal function
7. Wakefield AP, et al A diet with 35% of energy from protein leads to kidney damage in female Sprague-Dawley rats. Br J Nutr. (2011)
8. Aparicio VA, et al Effects of high-whey-protein intake and resistance training on renal, bone and metabolic parameters in rats. Br J Nutr. (2011)
9. Frank H, et al Effect of short-term high-protein compared with normal-protein diets on renal hemodynamics and associated variables in healthy young men. Am J Clin Nutr. (2009)
10. Wiegmann TB, et al Controlled changes in chronic dietary protein intake do not change glomerular filtration rate. Am J Kidney Dis. (1990)
11. Levey AS, et al Effects of dietary protein restriction on the progression of advanced renal disease in the Modification of Diet in Renal Disease Study. Am J Kidney Dis. (1996)
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