Crank It Up With Creatine

Glycogen is the primary fuel for weight training and other anaerobic exercises. So after exercise it’s critical that you replace glycogen so you can get back into the gym ready to go full force.

A study, hot off the press, was done in part at the University of Copenhagen. Researchers took 33 young healthy men and immobilized their right legs with a cast for two weeks, followed by a six-week heavy resistance-training program for the right knee extensor muscles. Subjects were divided into three groups: one getting a placebo (P) of maltodextrin only, another getting creatine plus the placebo (C), and the third getting creatine and maltodextrin plus proteins (C+P). The calorie count was equal in all three groups’ supplements. The C group took five grams of creatine three times daily (with 36 grams of maltodextrin) during immobilization, decreasing to a single 2.5-gram dose (with 70 grams of maltodextrin) during retraining. The C+P group took 15 grams of creatine, 36 grams of fructose, eight grams of citrate and nine grams of phosphates during the immobilization phase and 2.5 grams of creatine, 20 grams of maltodextrin, 40 grams of mixed proteins, 6.7 grams of mixed amino acids and 25 percent of the RDA for vitamins during the retraining phase.

So what happened? The subjects in the C and C+P groups had much higher muscle glycogen levels than those in the P group. In fact, for those two groups the glycogen levels were about 35 percent higher.

So you’re thinking, Well, I don’t need to take all that protein, since taking creatine (with some added maltodextrin) seems to work just as well, certainly better than carbs alone. But don’t discount the role of protein. It has other functions, such as promoting the recovery of muscle fibers damaged by exercise. If I were a betting man, I’d bet on the protein-carb-and-creatine blend.

Note: According to Jeffrey R. Stout, Ph.D., the creatine (Mega Creatine) and protein powder (Mega MRP) were provided by GNC.

Sex and myostatin. That’s sex as in gender, not sex as in a romp in the sack. Okay, you’re disappointed, but keep reading if you want to learn more about the myostatin gene. Myostatin is a protein that inhibits skeletal-muscle development. That is, the more of it you have, the less muscle you have. In a study done on mice, researchers removed the biceps femoris, gastrocnemius and quad muscles in males and females and looked at how myostatin was regulated. They found roughly 50 percent less myostatin in the male than in the female muscles. Remember, in this case less is more.

The sex difference in myostatin regulation is one of many reasons that male animals carry more muscle. The real question is whether we can do anything to alter (i.e., decrease) myostatin-protein expression. At this point there’s no evidence that we can. Your best bet is to lift weights and eat a lot.

Protein good for bones. You’ve heard the drumbeat from mainstream dietitians: Eating too much protein is bad for your bones, as it makes you lose calcium’or so they say. Well, like so many ideas, that one needs to go into the trash bin. Two recent studies, one published in the Journal of Bone Mineral Research and the other in the American Journal of Epidemiology, indicate quite clearly that eating more protein is actually better for you. Here’s why.

In one of the studies researchers observed 572 women and 388 men, aged 55 to 92, and looked at the association between animal-protein consumption and bone density over a four-year period. They found that the more animal protein the subjects ate, the higher the bone-mineral density in the hip, spine and overall skeleton. In fact (this’ll piss off the vegan crowd), they found that in both men and women, the greater the vegetable protein intake, the lower the bone-mineral density. The other study found the same thing. As the authors put it, ‘Lower protein intake was significantly related to bone loss at femoral and spine sites’ (that’s the thigh bone and backbone).

Next time you hear that eating all that animal protein is bad for your bones, tell ’em to break a leg’cause they probably will if they don’t eat more animal protein.

References
DeRave, W., et al. (2003). Combined creatine and protein supplementation in conjunction with resistance training promotes muscle GLUT4 content and glucose tolerance in humans. J Appl Physiol. In press.
McMahon, C.D., et al. (2003). Sexual dimorphism is associated with decreased expression of processed myostatin in males. Am J Physiol Endo Metab. 284:E377-E381.
Hannan, M.T., et al. (2000). Effect of dietary protein on bone loss in elderly men and women: the Framingham Osteoporosis Study. J Bone Miner Res. 15(12):2504-12.
Promislow, J.H., et al. (2002). Protein consumption and bone-mineral density in the elderly: the Rancho Bernardo study. Am J Epidemiol. 155(7):636-44.

Editor’s note: Jose Antonio, Ph.D., CSCS, earned his doctorate at the University of Texas Southwestern Medical Center. He is a co-editor (with Jeffrey R. Stout, Ph.D.) of and contributor to Sports Supplements (Lippincott Williams & Wilkins), Sports Supplement Encyclopedia (Nutricia), Supplements for Strength-Power Athletes (Human Kinetics) and Supplements for Endurance Athletes (Human Kinetics). For more information visit www.supplementbooks.com. IM