Residence | Weblog posts | Is there a danger from protein over-consumption?
Proteins can at present be present in a variety of product classes. Along with animal proteins, corresponding to meat, fish and eggs, that are the standard supply of protein, complementary sources are a steadily rising sector. What’s extra, any product may be protein enriched as of late. Whereas shoppers have a rising urge for food for proteins, ought to we be nervous about protein over-consumption?
Why is it necessary to eat proteins?
Proteins, like the 2 different macronutrients (lipids and carbohydrates), are a supply of power.
Proteins are composed of a set of amino acids, the order and amount of which decide each their construction and their perform.
There are twenty proteinogenic amino acids, in different phrases amino acids which can be used for the manufacture of proteins.
Of those, 9 are mentioned to be important, because the physique can not synthesize them. They have to subsequently be supplied to the physique in adequate amount by diet with a purpose to meet physiological wants.
The others are known as non-essential because the physique is ready to synthesize them, though they will turn out to be important in sure physiological or pathological conditions (progress, wound therapeutic, an infection, and so forth.).
The physique of the typical grownup male (70 kg) comprises 10 kg to 12 kg of protein, of which 40 % is present in muscle, which is thus thought of to be the primary storage location.
This protein mass is renewed at a median fee of three % of physique weight per day, although the precise determine varies in keeping with the kind of protein. For instance, renewal may be very fast for liver proteins and really sluggish, if not inexistent, for lens proteins.
There isn’t any protein retailer within the physique, as there may be for lipids, for instance. Dietary consumption should subsequently cover these protein renewal wants (on common 10 % à 20 % of the power ration) and the synthesis of nitrogen molecules which can be important to the functioning of the human physique.
Proteins take part within the majority of physiological capabilities: they’ve a structural function (for instance collagen), a useful function (albumin and insulin) and a contractile function (myosine, for instance), in addition to a job within the immune system (for instance immunoglobulins)… Proteins are concerned within the renewal of muscle tissue, bone matrix, and the pores and skin.
In people, the digestion and absorption effectivity of proteins depends on the protein supply. Milk proteins have one of the best bioavailability: 95 % of proteins ingested are correctly absorbed and assimilated by the physique, adopted by meat proteins (94%) and, lastly, plant proteins (90-91%)[1].
Determine 1: Function of proteins within the physique
Proteins subsequently have a basic function within the human physique at each stage of growth, and in adults represent a non-negligible proportion of physique mass. To make sure the right renewal of this protein mass, the food plan should include adequate quantities of protein, particularly important amino acids.
What are the dietary suggestions for proteins?
The suggestions for common wants intention at a impartial nitrogen stability. In France, they’ve been set at 0.83 g/kg/j for wholesome younger adults by ANSES (the French Company for Meals, Environmental and Occupational Well being & Security).
That determine assumes the protein consumption to be of fine high quality. The important amino acids should subsequently be current in adequate amount.
The protein suggestions had been revealed in 2007 by AFSSA (the French Meals Security Company) and in 2016 reiterated by ANSES[2] on the premise of nitrogen stability research and in accordance with North-American (IOM 2005) and worldwide (FAO 2007) suggestions.
The Committee of Consultants established three classes of consumption[3] for non-obese, non-athletic adults below the age of 60, with regular kidney perform and no restrictive food plan (the typical calorie consumption being set at 33 kcal/kg/d):
ANSES recommends that protein consumption be between 10 % and 20 % of the overall power consumed.
What are the dangers related to protein deficiency?
Proteins within the physique endure fixed synthesis and degradation. In regular situations, there may be an inside stability between meals consumption, synthesis by the physique and excretion. The time period “nitrogen balance” is used. This stability is achieved if the amount of nitrogen ingested equals urinary, fecal and pores and skin losses. Sure pathological situations can result in a unfavorable nitrogen stability.
Determine 2: Common metabolic pathways in people
Nitrogen deficiency could cause atrophy resulting from muscle losing, hypoproteinemia with the chance of edema formation, deficiency and malnutrition. It must also be famous that when fasting, the physique breaks down its proteins, particularly within the muscle tissue.
Is there a danger from protein over-consumption?
The potential risks of extreme consumption of proteins are a topic of debate. In 2007, AFSSA declared that there was no danger to well being at as much as 3 times their suggestions.
One danger of consuming an excessive amount of protein is a possible overloading of the kidneys. When the protein synthesis pathway is saturated, extra amino acids are deaminated, producing ammonia. This molecule being poisonous for the physique, it’s transformed into urea, therefore a rise in ureagenesis and subsequently uremia[5]. Simply how a lot the utmost capability for ureagenesis is likely to be is a query that involves the fore when assessing the dangers of over-consumption of proteins.
However research that cope with the results of a high-protein food plan are considerably biased. The info from these research was obtained from topics who had been unsuitable for top intakes, which logically ends in a comparatively low threshold for max ureagenesis capability.
ANSES, in its suggestions, thus set an higher restrict with none conclusion referring to an higher protected restrict that minimizes the chance of weight acquire.
Whereas no research thus far has been capable of show a direct danger from over-consumption of proteins, it’s nonetheless price taking a look at precise protein consumption in contrast with scientific suggestions.
In developed international locations, day by day consumption is estimated to be between 100 g and 120 g of protein per day, 35% of which is of plant origin. That’s equal to a day by day consumption of 1.4 to 1.7 g/kg. For instance, common day by day protein consumption in France is 83.2g, i.e. 16.8% of day by day power consumption[6]. The consumption of proteins in developed international locations is subsequently throughout the consumption really helpful by ANSES.
In creating international locations protein consumption is decrease. Consumption is estimated to be 40-50 g per day, i.e. 0.6 to 0.7g/kg, 85 % of which is of plant origin.
In view of the day by day protein consumption in each developed and creating international locations, it could appear that over-consumption of protein is uncommon.
Physique proteins represent a capital that should be maintained. They should be renewed always with a purpose to maintain that capital and thus high quality dietary consumption is important. There may be at present no documented danger related to over-consumption of proteins. However, the kind of protein within the food plan is of consequence, since over-consumption of crimson meats might symbolize a cardiovascular danger.
Necessities ought to subsequently be met by the consumption of each animal and plant proteins. Nonetheless, the standard of those proteins must be taken under consideration, since sure dietary proteins present the important amino acids. Proteins of animal origin, particularly proteins from milk, provide a bonus in the case of assembly the wants of the physique, particularly at sure key intervals of life, corresponding to throughout being pregnant, progress, ageing and within the context of pathologies.
Sources:
[1] Oberli et al, 2015; Excessive True Ileal Digestibility however Not Postprandial Utilization of Nitrogen from Bovine Meat Protein in People Is Reasonably Decreased by Excessive-Temperature
[2] Opinion of ANSES – Referral No. 2012-SA-0103
[3] AFSSA. 2007. “Rapport de l’Afssa relatif à l’apport en protéines: consommation, qualité, besoins et recommandations“
[4] Decided from the utmost capability for ureagenesis in adults (grownup male weighing 70 kg).
[5] https://www.anses.fr/fr/system/information/NUT-Ra-Proteines.pdf
[6] INCA3 survey (2014-2015), dealt with by ANSES
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