Glutamine

Dr. Dwayne Jackson

Glutamine is one of the most abundant amino acids found in skeletal muscle and the circulation. It is naturally occurring in the human body but is also found in foods such as, beef, chicken, milk products, eggs, spinach, cabbage, and beets. Glutamine is considered a conditionally essential amino acid, as the body’s supply may not meet the demand under conditions of heavy metabolic stress— like that experienced with bodybuilding style training and dieting.

In the world of glutamine supplementation there seems to be two camps— the naysayers and the supporters. It is absurd that there are naysayers, as there are many science-backed reasons to use this amino acid to your advantage.  Research published in the International Journal of Sport Nutrition and Exercise Metabolism provides the latest “case-in-point” supporting glutamine as an erogogenic aid for those who weight train.

Using a double blinded and placebo controlled crossover design, researchers from Dalhousie University (Halifax, Nova Scotia, Canada) investigated the impact of L-glutamine supplementation on quadriceps muscle strength recovery and soreness ratings following eccentric exercise. Subjects (males and females) took glutamine or a placebo once per day for 3-days and completed a bout of eccentric leg extension exercise at 125% of their predetermined max. They reported that short-term glutamine supplementation increased leg strength recovery by about 5% (measured as peak torque) in all participants immediately after and 72 hours post eccentric leg training. Also, they found that the relative increases in leg strength recovery were greatest in men who took glutamine. For all subjects, glutamine supplementation resulted in a decrease in muscle soreness over the course of 3 days by 18-40% in all subjects.

ACTION POINT: This study shows that the benefits of glutamine supplementation on muscle recovery can be seen within a few days after adding it to your supplement regimen. As always, we recommend taking 5-10 grams of glutamine 3 to 4 times daily. Always remember to include taking a dose 30-60 minutes pre- and post-workout.

Reference:

Legault Z1, Bagnall N, Kimmerly DS. The Influence of Oral L-Glutamine Supplementation on Muscle Strength Recovery and Soreness Following Unilateral Knee Extension Eccentric Exercise. Int J Sport Nutr Exerc Metab. 2015 Mar 26. [Epub ahead of print].

Glutathione

Glutathione is a powerful antioxidant and free radical scavenger, which keeps oxidative stress in check under severe metabolic stress (like during intense exercise). Keeping free radicals under control during exercise has been shown to delay fatigue and increase training volume.

A recent study published in the Journal of the International Society of Sports Nutrition provides mechanistic and supporting evidence for the use of glutathione boosting supplements to decrease fatigue during exercise. In this study, researchers from Japan found that glutathione supplementation delays muscle fatigue by suppressing blood lactate levels as well as fatigue related psychological factors in healthy men.

ACTION POINT: There are a few ways you can boost your body’s glutathione levels. The most reliable and affordable way to support endogenous glutathione production is to take 600-1200 mg N-Acetyl Cysteine (NAC) 30 minutes prior to training or with a meal. Otherwise, like the current study, you can take 1 gram of reduced glutathione 30 minutes prior to training.

Reference:

Aoi W, Ogaya Y, Takami M, Konishi T, Sauchi Y, Park EY, Wada S, Sato K, Higashi A.

Glutathione supplementation suppresses muscle fatigue induced by prolonged exercise via improved aerobic metabolism. J Int Soc Sports Nutr. 2015 Feb 6;12:7.

Another reason to take vitamin D

Fundamentally, vitamin D is needed for calcium metabolism and calcium absorption in the body. It also regulates numerous genes and plays significant roles in regulating inflammation and immunity. In skeletal muscle, it has been shown that vitamin D is important for calcium regulation, protein synthesis and muscle growth. We can get an abundance of vitamin D from the conversion of 7-dehydrocholesterol in the skin during sun exposure and this topped off through dietary sources. According to current studies athletes are generally vitamin D deficient, which may impair muscle function and performance.

Still not convinced to take vitamin D? Well, a recent study presented at Experimental Biology 2015 in Boston MA suggests that one’s vitamin D status can predict their testosterone level. The team of scientists from East Carolina University and Womack Army Medical center (North Carolina) provided evidence suggesting that deficient blood vitamin D concentrations inhibit testosterone production and potentially limit human performance in extremely fit high-performance army personnel.

ACTION POINT: The best way to see if you are vitamin D deficient is to have your physician test your blood vitamin D (i.e., 25[OH]D) levels. Alternatively, there are a number of “finger prick” tests available online.  Current research suggests that athletes should strive to achieve blood 25[OH]D levels greater than 75 nmol/L. As far as a dose is concerned, it has been shown that 2000–5000 IU of vitamin D3 per day for 8 weeks increases serum 25 [OH]D to optimal levels (greater than 75 nmol/L).

Reference:

Laurel Wentz, Cristóbal Berry-Cabán, Jerad Eldred and Qiang Wu. Vitamin D Correlation with Testosterone Concentration in US Army Special Operations Personnel. April 2015 The FASEB Journal, vol. 29 no. 1 Supplement 733.5