Whey Protein Enhances GLUT-4 and Glucose Uptake
The benefits of a high-quality whey protein supplement has an ever-growing list of health benefits such as: weight loss, increases in muscle mass and strength, increase in glutathione levels (your body’s main water-based antioxidant), increase in immune system function, decreased recovery time, and symptoms of overtraining. One of the lesser-known properties of whey protein is its ability to increase muscle glycogen stores and cellular glucose transporters (i.e., GLUT4) in the muscle. In sum, whey protein has anti-diabetic properties.
Glucose transporter type 4, also known as GLUT4, is an “insulin-regulated glucose transporter”. It is found primarily in both muscle and fat tissue and is responsible for insulin-regulated glucose transport into the cell. In response to insulin or muscle contractions, GLUT-4 translocates to the cell membrane, where it is inserted to increase glucose transport. When activated Glut4, moves to the surface membrane of muscle cells and allows for nutrients to be absorbed and stored inside.
Intense muscular contractions activates GLUT4. This is why its so important to get BCAA and glucose into your system after exercise because calories more likely to be shuttled towards muscles to help facilitate recovery leaving fewer calories available for fat storage. GLUT4 activation appears to last for several hours after a workout (depending upon the amount of muscle contractions performed).
In essence, GLUT4 acts like a cellular sponge so that muscle can soak up glucose after exercise. Initially, there is a rapid, insulin-independent increase in the muscle glycogen stores, which is caused by activation of GLUT4. So you may be asking, what are the advantages of having increased GLUT4 activity? Your muscles will feel full when they’re full of glycogen, plus GLUT4 can maximize the anabolic effects of insulin while minimizing body fat storage. Researchers wanted to examine how whey protein impacted GLUT4 activity both at rest and after exercise. They divided rats into six groups, treating and feeding them with experimental diets for nine days as follows:
- Casein Control (control casein);
- Whey Protein (whey protein);
- Whey Protein Hydrolysate (whey protein hydrolysate);
- Casein plus exercise;
- Whey Protein plus exercise; and
- Whey Protein Hydrolysate plus exercise.
After the experimental period, muscle GLUT4 were analyzed. The results showed clearly that the consumption of whey protein and whey protein hydrolysate increased the translocation of GLUT-4 when compared to the casein-fed animals. This increase in GLUT-4 was consistent with increases in glycogen because with more glucose transporters in the cell, the availability of glucose and synthesis of glycogen could both increase. The researchers found that consumption of whey protein hydrolysate significantly increased the concentrations of GLUT4 and glycogen.
These results should encourage new studies dealing with the potential of both whey protein and whey protein hydrolysate for the treatment or prevention of type-2 diabetes, a disease in which there is reduced translocation of GLUT4 to the plasma membrane. The important finding for bodybuilders is that the consumption of whey protein has anti-diabetic properties even without exercise. Also, taking whey after exercise seems to encourage muscle glucose uptake and enhanced muscle recovery.
Morato PN, Lollo PC, Moura CS, Batista TM, Camargo RL, Carneiro EM,
Amaya-Farfan J. Whey protein hydrolysate increases translocation of GLUT-4 to the
plasma membrane independent of insulin in wistar rats. PLoS One. 2013 Aug