Amino Acids And Hydration image

Amino Acids And Hydration

Electrolyte drinks are very common products these days and are increasingly being adopted onsite to promote hydration for those engaged in hard physical labour. Hydration is the key to avoiding heat stress when working in hot conditions, and many sites are adopting this as part of their safety policy. Most people are aware that electrolyte drinks are more beneficial than just water in terms of promoting hydration, but did you know that protein and amino acids can promote hydration as well? This article discusses how amino acids are absorbed in the human gut and how the addition of amino acids to beverages can enhance hydration.


Amino acids are the basis of all life processes and the backbone of complex proteins. These elements help to build and support the cellular functions of transportation, absorption and storage of fluids, electrolytes and nutrients all of which are essential for human survival. Amino acids are obtained from complex proteins from the foods we eat and drink. They are broken down in the gut into peptides and amino acids and then absorbed into the blood. After absorption the body uses amino acids in a multitude of functions and builds them back into proteins to be used when and where needed in the body. Find out more about Amino Acids in our article Amino Acids 101.

amino acids an hydration 1


The gut, in particular the small intestine, is the primary absorption organ for amino acids that come from diet and is the first point of entry to the bloodstream. The gut acts as an interface and a regulating element between the lumen and the rest of the body, controlling the degree and rate of the transportation of the amino acids that are consumed. After absorption, these elements reach the systemic blood circulation through the mesenteric veins, the portal vein system, and the liver. However, not all amino acids enter systemic circulation, some of these are used locally in some metabolic processes that include oxidation, protein synthesis, immunity, etc.


Physiologically speaking, amino acids are transported and absorbed through the gut wall by an active transport process mediated by specialized proteins and by tissue accumulation. As with many other nutritional elements, several studies show that active amino acid transportation depends on sodium-dependent symporters (special transport membranes), the proton motive force and the transport of other amino acids.

Elements like amino acids, which have significant molecular weights and potent electrical charges (amino acids usually have negative electrical charges) can drag other elements that have lighter molecular weights such as water molecules. In this way, the passing of these amino acids through the gut wall is accompanied by water, electrolytes, and other smaller elements.

amino transporter

Several studies have demonstrated the ability of amino acids to stimulate water and sodium absorption in the gut. Hellier et al demonstrated this by administering different concentrations of glycine, alanine, and arginine to a group of subjects, who were young adult male volunteers. Amino acids absorption rates were measured over a 30 cm length of upper jejunum using a modified double-lumen tube incorporating a proximal occlusive balloon. A solution containing water, salt and amino acids was secreted from the balloon into the gut and the absorption (or lack of) was measured. The baseline control case is a saline solution with no amino acid added.

The control case (with no amino acid added) shows no absorption of water from the gut at all. However, when either glycine or alanine were added the absorption of both salt and water increased significantly. Figure 1 shows a plot of the absorption rates of the solution with differing levels of amino acids and the saline solution control case. The significant difference in absorption rate is evident from the plot.

salt absorption 1
Figure 1: Comparitive absorption of amino acid solution and saline. (Data adapted from Hellier, Thirumalai and Holdsworth 1973)
In another study (Seifert, Harmon and DeClercq 2006) , researchers monitored the hydration levels of athletes who imbibed three types of sports drinks; Water, carbohydrate only and a carbohydrate plus protein. The athletes were asked to dehydrate to 2.5% reduction in body weight then rehydrated with one of the beverages. Fluid retention was significantly greater with the protein drink (88%) which was greater than the carbohydrate drink (75%) and lastly the water (53%). Another animal study (Ito, Yamaguchi and Noma 2016) found similar results when they administered whey protein hydrolysates concentrations to anesthetized rats, significantly enhancing water absorption in their perfused small intestine. Indicating that consumption of complex proteins can similarly stimulate water absorption in the gut.


Electrolyte drinks offer a marked improvement to hydration over water alone. They enhance water absorption and retention and replace the vital electrolytes that are lost due to sweating. Research is now showing that the addition of amino acids or complex proteins to a hydration fluid can significantly enhance the absorption and retention of fluid over that of even an electrolyte drink. Further to the that, adding amino acids to a beverage can offer additional benefits by way of being a source of protein or being able to specifically target a needed amino acid that may be lost due to activity. WorkWize contains; Tyrosine, Phenylalanine, Glycine and the BCAA’s all of which the body uses to fight fatigue and produce energy during the day. If you don’t have access to a sports drink the same thing could be achieved by mixing a drink from water, a little salt and flavouring (sugar and squeeze of citrus) and then eating a handful of nuts or seeds on the side to enhance the fluid absorption.


Hellier, M D, C Thirumalai, y C D Holdsworth. 1973. "The effect of amino acids and dipeptides on sodium and water absorption in man." Gut 41-45.

Ito, Kentaro, Makoto Yamaguchi, y Teruyuki Noma. 2016. "Whey protein hydrolysates enhance water absorption in the perfused small intestine of anesthetized rats." Bioscience, Biotechnology and Biochemistry.

Seifert,, John, Joseph Harmon,, y Patty DeClercq. 2006. "Protein Added to a Sports Drink Improves Fluid Retention." International Journal of Sport Nutrition and Exercise Metabolism 16: 420-429.

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