Written by justis berg
16 May 2011

Research Updates

 

 

Leucine-Enriched Essential Amino Acid Drink After Exercise Increases Muscle Growth Genes

If you are looking to pack on some muscle size, you may want to consider adding an essential amino acid drink enriched with leucine after exercise. Researchers examined the anabolic effects of a leucine-enriched essential amino acid drink in young and old men after a bout of resistance exercise. Researchers took muscle biopsies to examine the expression anabolic and catabolic proteins. They found that even though the older and younger men performed the same workout (70 percent of 1 RM, 8 sets of 10 repetitions), young and older men had different genes being turned on after exercise. They found:

 

  1. A protein called REDD2 (catabolic), which is a negative regulator of mTOR (a key anabolic pathway), was reduced in both younger and older men when they drank the leucine-enriched essential acid drink. This means leucine turns off catabolic genes. Good news for everyone!
  2. A protein called Rheb (anabolic), which is a positive regulator of mTOR, was only increased in the young men who consumed the leucine-enriched essential acid drink. This means younger men have greater anabolic genes being turned on after exercise, compared to older men.
  3. They also found IGF-1 levels increased only in the young, while the older men had no changes and also blunted satellite cell activity. Older men have a blunted muscle hypertrophy response to exercise; a decrease in IGF-1 seems to be a key cause.

 

The results of the study suggest that an essential amino acid drink enriched with leucine, which was designed to maximally stimulate protein synthesis, can benefit both older and younger men after resistance exercise, but older men lose key anabolic-signaling pathways compared to younger men.

 

Ø     Drummond MJ, Miyazaki M, Dreyer HC, Pennings B, Dhanani S, Volpi E, Esser KA, Rasmussen BB. Expression of growth-related genes in young and old human skeletal muscle following an acute stimulation of protein synthesis. J Appl Physiol, 2008.

 

 

American’s Jacked Up On Energy Drinks!

The USA has won more gold medals...Americans consume more energy drinks than any other country. Energy drinks vary widely in both caffeine content (ranging from 50 to 505mg per can or bottle). The caffeine content of a 6-ounce cup of brewed coffee varies from 77 to 150mg. The review article explained the FDA approved caffeine and limited the maximum caffeine content of cola-type soft drinks to 71mg/12 fluid oz or 0.02 percent caffeine (Food and Drug Administration, 2003). At least 130 energy drinks now exceed 0.02 percent caffeine recommendations, including one that contains 505mg in a 24-oz can (the equivalent of 14 cans of a typical cola or several cups of coffee). The article also reviews the not-so-bright people who have experienced adverse health problems from energy drink overdose. For example, the “dumb-ass” of the year award goes to a 28-year-old motocross athlete who nearly died when his heart stopped during a competition. He had consumed eight cans of Red Bull over a 5-hour period.

The review article also documented the growing problem of consuming energy drinks and alcohol. As reported in a pervious study, ingestion of a Red Bull with vodka reduced participant’s perception of impairment of motor coordination in comparison to vodka alone. Basically, people think that they were not drunk when consuming Red Bull and alcohol, but they really were. This means people drinking Red Bull with alcohol will leave the bar and get behind the wheel thinking they are fine when they are really drunk! Energy drinks are great preworkout or when mental vigilance is needed, but they should not be consumed with alcohol or taken in excess.

 
Ø     Reissig CJ, Strain EC, Griffiths RR. Caffeinated energy drinks-A growing problem. Drug Alcohol Depend, 2008 Sep 20.

 

 

EPA Reduces Muscle Tissue Breakdown

Fish oil is recommended for a healthy diet because it contains the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), precursors to eicosanoids that reduce inflammation throughout the body. In addition to reducing the risk of cardiovascular disease, recent studies suggest that EPA can have anti-catabolic actions on muscle. To date, EPA has been shown to reduce protein breakdown in cancer patients and during disease conditions, which led to hyper-metabolic disease that led to excess body heat, and during starvation. Researchers from Astron University in the United Kingdom reported EPA blunted protein breakdown, which causes sepsis (a catabolic condition) in rats. They found that EPA completely blocked the actions of a catabolic gene called ubiquitin-protease pathway. Fish oils may be a good supplement to include while dieting because of its potent anti-catabolic actions.

 

Ø     Khal J, Tisdale MJ. Downregulation of muscle protein degradation in sepsis by eicosapentaenoic acid (EPA. Biochem Biophys Res Commun, 2008 Oct 17;375(2):238-40.

 

Spearmint Extract Reduces Testosterone

Spearmint tea is a mint tea type that is advocated for digestive health benefits and relaxation. Spearmint tea was recently found to reduce excess hair growth in women, but scientists really had no idea how. Stay away from spearmint tea; it’s worse than you can imagine! Spearmint is anti-androgenic, meaning it decreases testosterone. Researchers from India reported that long-term use of a spearmint extract caused a decrease in LH, with reductions in testosterone levels in rats. Scientists found that long-term use of spearmint extract caused reduced availability of cholesterol to steroidogenic cells, leading to a downregulation of testosterone synthesis. Skip spearmint tea unless you are looking to look good in a pair of high heels!

 
Ø     Kumar V, Kural MR, Pereira BM, Roy P. Spearmint induced hypothalamic oxidative stress and testicular anti-androgenicity in male rats— altered levels of gene expression, enzymes and hormones. Food Chem Toxicol, 2008.

 

Whey Protein Hydrolysate Enhances Recovery

Whey protein has been shown to be anabolic and increase muscle strength and muscle mass, but what about muscle recovery? Researchers from the Centre for Metabolic Fitness and Nutritional Physiology Research Centre in Australia put whey protein to the ultimate test of muscle damage…eccentric exercise! They had male participants perform 100 maximal eccentric contractions with leg extension and were either given a flavored water, 25g whey protein isolate, or 25g hydrolyzed whey (or whey protein hydrolysate). Hydrolyzed whey is usually a whey protein isolate that have had some of its amino acid peptide bonds broken enzymatically into shorter chains of amino acids. This leads to better absorption in the stomach. Interestingly, peak muscle force decreased approximately 23 percent following eccentric exercise and remained suppressed in the control and whey protein isolate group, but recovered fully in the whey protein hydrolysate group by 6 hours. Muscle soreness increased in all groups, with no difference between any if the groups. The research suggests that whey protein hydrolysates, but not isolate, increases muscle recovery from damaging eccentric exercise. Whey protein hydrolysates seem to be a superior source of whey protein compared to isolates.

 

Ø     Buckley JD, Thomson RL, Coates AM, Howe PR, Denichilo MO, Rowney MK. Supplementation with a whey protein hydrolysate enhances recovery of muscle force-generating capacity following eccentric exercise. J Sci Med Sport, 2008.