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Rev . Medicina Desportiva informa , 2018 ; 9 ( 4 ): 19-21 .
Protein supplementation
André Filipe Oliveira Cabrita 1 , Prof . Doctor José Luís Themudo Barata 2
1
Medical student at the University Beira Interior ; 2 Professor of University of Beira Interior ; Director of the Nutrition Physical Activity department of Hospitalar da Cova da Beira . Covilhã . Portugal
ABSTRACT
Protein supplementation is a widespread practice in the general population , especially among the athletes . The risk of its consumption for the health is low , especially if the consumed products have a quality assurance certification . The protein supplementation with whey , casein and branched-chain amino acids has been shown to be an excellent option to complement the diet and to obtain the maximum yield of the physical exercise , providing numerous health benefits without association to relevant adverse side effects .
KEYWORDS
Whey , casein , BCAA
Introduction
The consumption of nutritional supplements is a growing practice in today ’ s society , especially among professional and recreational athletes , especially because the risk for health is low . 1 On 2013 , Sousa et al 2 found that two thirds of the Portuguese elite athletes consumed several types of nutritional supplements , and the vast majority of them were unnecessary . 3 The main reason for taking nutritional supplements by the athletes is the belief that they provide benefits that cannot other advantages . 1 , 4 For others , supplementation is seen as a method of recourse to ensure protein intake with high quantity and quality and restricting caloric intake at the same time .
The International Society of Sports Nutrition ( ISSN ) recommends that physically active individuals try to meet their daily nutritional requirements through food 5 , since food can easily and economically provide all essential amino acids needed for muscular protein synthesis .
The use of protein supplements constitutes a possible health risk due to the poor regulation and quality control to which they are subjected prior to their marketing . This risk is considered low if only the supplements of recognized companies are consumed , whose products are properly tested and certified with regard to safety and food efficiency . 1 Still , most users consume excessive doses , the that in addition to unnecessary , it may prove to be dangerous to health due to the risk of ingestion of doping substances , among others . 4
Milk serum protein ( whey )
Cow ’ s milk contains two primary protein sources : casein and whey . This represents about 20 % of the milk proteins and casein the remaining 80 %. 6-8 Whey protein complex obtained from milk serum , a residue resulting from clotting of milk for industrial cheese production . For many years , milk serum was considered a waste product in the dairy industry . 6
The protein complex whey contains a high concentration of essential and branched chain ( BCAA ) amino acids compared to other protein sources , estimated to be approximately 26 % of BCAA ( leucine , isoleucine and valine ). 6 , 8 These amino acids are efficiently absorbed and used by the body , and whey is considered a fast absorption protein ( 8-10g / h ) 7 , 9 , unlike casein , which is considered a slow absorption protein ( 6g / h ). 10 , 11 The BCAA , in particular the leucine , are important factors in the growth , construction and repair of the tissues . 6 , 8
Recent evidence suggests that whey intake ensures greater availability of essential amino acids and insulin , being the most influential source of protein known to be able to increase muscle anabolism . 12
Its contents in sulphur-rich amino acids , such as cysteine and methionine , increases the immune and antioxidant function by the intracellular conversion of glutathione , a potent intracellular antioxidant . 6
The percentage of whey in the commercial formulas varies :
• Isolated – 90 to 95 %
• Hydrolyzed – variable
• Concentrated – 25 to 89 %.
a ) Functions
The main mechanism through which the whey exerts its effects is the intracellular conversion of cysteine into glutathione , which is a potent antioxidant . 6 Due to its wide range of constituents , whey acts on several functions of the human body :
• Antimicrobial and antiviral activity 5 , 6 , 13
• Immunologic modulation 6 , 13
• Slimming , with loss of fat mass and preservation of lean
7 , 8 , 13 , 14
mass
• Protein synthesis and muscle recovery 6 , 8 , 14
• Anti-hypertension , antioxidant 6 , 8 and anti-inflammatory 8 , 13
• Decrease of triglycerides , LDL and total cholesterol , and insulin resistance in the obese patients 7 , 8
• Anti-atherosclerosis and anti-arterioesclerorisis 7
• Provides satiety 7 , 8 , 12 , 14 by increasing the levels of leptin , CCK , LPG-1 and prolonged suppression of ghrelin 8 , 9 , 12
• Decrease of blood glucose levels 8 .
b ) Clinical applications
Due to its diversity of biologically active components , supplementation with whey has been investigated for prevention and treatment of various clinical situations , being indicated in the following cases :
• Gain muscle mass
• Cancer 6
• Hepatitis B 6
• Cardiovascular diseases 7 , 8 , 14
• Osteoporosis 6
• Anti-microbial agent
• Wound healing 6
• Metabolic syndrome , obesity and dabetes Mellitus Type 2 7 , 8 , 13 , 14 .
c ) Side effects
No side effects are known caused by supplementation with whey 6 , 8 , 12 ,
Revista de Medicina Desportiva informa july 2018 · 19