What is blood for protein? Total protein in the blood is low: what does this mean and what to do? Reasons for increased total protein in the blood

Among builders of their own muscles, there is a widespread opinion - “the more protein, the better” and often such people, without making calculations, consume the maximum possible amount of protein products and supplements. What do scientists say about excessive amounts of protein in the body – can it be harmful?

Protein intake rate

To begin with, we should recall the official recommendations for protein consumption. For example, in the manual for sports nutrition NSCA for gaining lean muscle mass is recommended to consume in addition to a moderate excess of calories (10-15% above normal). 1.3-2 g/kg body weight per day.

And during the active phase of reducing the percentage of fat, scientists even recommend increasing the rate of protein consumption - up to 1.8-2 grams / kg of body weight per day. Moreover, the lower the percentage of fat (for example, when preparing for competitions), the higher the requirements for protein consumption. If the goal is to reduce the percentage of fat to very low values, it is recommended to increase 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 large amounts of protein.

Excess protein and kidneys

Don't ask this question if you have healthy kidneys, and control your protein intake if they are diseased.

The smartest approach is to gradually increase protein intake to a higher level in the diet, rather than jumping in with both feet at the same time. Usually, With increased protein intake, it is recommended to drink more water

. One of the reasons is to reduce the risk of kidney stones. However, there is no clear scientific basis yet for why this should be done, but it may be a reasonable approach.

Observations of active male athletes and measurements of the levels of urea, creatinine and albumin in 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.

A study involving nurses (3) confirms these findings. But it does suggest that the protein safety data does not apply to cases of kidney failure and other kidney diseases, and that non-dairy animal proteins may be more harmful to the body than other proteins.

It has been suggested that protein intake leads to functional changes in the kidneys (4). Protein may affect kidney function (5,6), therefore, when using it, there is a possibility of damage to them. The most pronounced results were obtained in experiments on mice (protein ranged from 10-15% to 35-45% of the daily diet at a time) (7,8).

Also, one study (9) of healthy people found that doubling the amount of protein consumed (from 1.2 to 2.4 g/kg body weight) led to higher than normal levels of protein metabolism in the blood. There was a tendency for the body to adapt - an increase in the glomerular filtration rate, but this was not enough to bring uric acid and blood urea levels to normal within 7 days (9).

All these studies primarily suggest that too much protein leads to too rapid changes, and the process of gradually increasing volumes does not worsen renal function (10). This means that it makes more sense to gradually change your protein intake over a relatively long period of time.

People with kidney disease are advised to use protein-restricted diets, as this will slow down the seemingly inevitable deterioration of the condition (11,12). Failure to control protein intake in patients with kidney disease accelerates (or at least does not slow down) the decline in kidney function (3).

Excess protein and liver

There is no reason to believe that normal levels of protein intake as part of a normal diet would be harmful to the liver of healthy rats or humans. However, there is preliminary research suggesting that very large amounts of protein after a sufficiently long fast (more than 48 hours) can lead to acute liver injury.

During treatment liver diseases (cirrhosis) it is recommended to reduce protein intake, since it causes the accumulation of ammonia in the blood (13,14), which makes a negative contribution to the development of hepatic encephalopathy (15).

It has been shown in at least one animal model that liver injury occurs during cycling between 5-day periods of sufficient protein intake and periods of protein deficiency (16). A similar effect was observed when consuming a meal containing 40-50% casein after a 48-hour fast.(17). Animal studies (18,19) have provided preliminary evidence that increased protein intake (35–50%) at the time of refeeding after a 48-hour fast may cause liver harm. Shorter periods of fasting were not considered.

Amino acids are acids, right?

We remind you that proteins are complex organic compounds consisting of smaller “building blocks” - amino acids. Actually, 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 balance of acidity / alkaline content in the text “ “.

Excess Protein and Bone Mineral Density

Analysis of a large observational study shows no link between protein intake and the risk of bone fractures (an indicator of bone health). The exception is when, with increased dietary protein, total calcium intake falls below 400 mg/1000 kcal daily (although the hazard ratio was quite weak at 1.51 when compared with the highest quartile) (26). Other studies have failed to find a similar correlation, although this would logically be expected (27,28).

Soy protein itself appears to have an additional protective effect on bone tissue in postmenopausal women, which may be related to the isoflavone content of soy (30).

The Role of Strength Training

As funny as it may seem, there is a study on this topic in rats. The rodents were acutely exposed to large amounts of protein in their diet, causing their kidney function to deteriorate.

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).

Research mentioned:

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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