The science of sports nutrition is an evolving discipline, with new information frequently superseding previously accepted scientific fact. While nutrition topics are discussed at medical conferences around the world, until a few years ago sports nutrition wasn’t a major agenda item. To correct that notable gap, a group of scientists and teachers, all of whom shared an intense interest in the exchange and presentation of the most up-to-date research concerning sports nutrition, formed the International Society of Sports Nutrition.
The ISSN has held three national meetings, the most recent at the soon-to-be-razed Stardust hotel in Las Vegas, June 15–17. I attended the conference with IRON MAN publisher John Balik and his son Justin. Our goal was to obtain information relevant to IM readers.
The conference consisted of a series of brief lectures that lasted an average of 30 to 45 minutes. Unfortunately, that was too little time to cover the information presented by a few of the lecturers. While there were PowerPoint slide presentations aplenty, time constraints meant that slides appeared on the large viewing screen for only a few seconds, challenging even the most expert of shorthand writers. Some lectures were scheduled in direct opposition to others of equal interest, forcing hard choices on attendees.
I also felt that the showmanship of some of the presentations might have been improved, as we were all on technical data overload. One researcher, Paul Cribb, livened things up with a slide of his scenic oceanview backyard in Australia. His injection of humor in the proceedings was a much-appreciated wake-up call for conferees whose attention may have wandered because of the sheer volume of information Cribb was cramming into his limited time slot.
Those criticisms aside, however, much of the data presented at the conference proved useful and practical. What follows is a summary of the info that I obtained, though my notes are admittedly limited.
William J. Kraemer, Ph.D., gave two lectures, the first called “Muscle Growth and Recovery,” which I felt sure would be of value. A professor at the University of Connecticut, Kraemer is an esteemed exercise-physiology and sports-nutrition researcher. Some highlights of his rapid-fire presentation:
•Explosive exercise decreases growth hormone release, while heavy, slower exercise increases it.
•Heavy exercise raises testosterone levels, while light exercise lowers them.
•Exercise increases the density of androgen cell receptors that interact with testosterone, thereby providing an anabolic effect in muscle. Consuming a postworkout protein-and-carbohydrate drink also increases the percentage of androgen receptors.
•Kraemer confirmed that to acquire larger muscles, you need to control the release of corticosteroids, such as cortisol, during and after training.
Paul Cribb, Ph.D., holds a doctorate in exercise biochemistry from Victoria University in Melbourne, Australia. Cribb, who looks like a taller and leaner version of pro bodybuilder Lee Priest—and sounds a bit like him too—lectured on the effects of protein and carbohydrate on anabolic responses to resistance training. Cribb described three study trials that involved nutritional interventions designed to increase the anabolic effects of structured training over a period of 10 to 11 weeks. The subjects were men aged 18 to 36, divided into groups that got whey-protein supplements, creatine monohydrate and carbohydrate supplements either alone or in combination.
The first trial showed that although two groups were on a high-protein diet, supplementing it with whey protein and/or creatine led to greater improvement in strength than supplementing with an equivalent amount of only carbohydrate.
The second study found that a supplement containing creatine, whey and carbs provided a degree of fat loss, increases in lean mass, and strength and muscle gains that were superior to what happened with the same supplement minus the creatine.
The third study examined the issue of supplement timing, involving the intake of a whey-and-creatine compound immediately before and after exercise. That was compared to taking the same supplement at times other than the pre- and postworkout periods. The study confirmed that taking the supplement just before and after a workout led to improved body composition, as well as strength and muscle gains. The supplement contained 40 grams of protein, 43 grams of carbs, 0.5 grams of fat and seven grams of creatine. With that level of nutrition the participants got double the muscle mass gains when they took it just before and just after training.
Robert Wildman, Ph.D., whose books have been reviewed in IRON MAN, gave an interesting but time-limited lecture: “Thermogenic Supplements in Fat Metabolism.” Wildman noted that fat-loss supplements can be broadly divided into three general categories:
ALL1) Thermogenic—represented by caffeine, green tea, bitter orange and capsaicin supplements
2) Lipolytic—conjugated linoleic acid, caffeine, calcium, guarana
Wildman explained that people who tend to be lean show more diet-induced thermogenesis. They burn more calories after a meal than people in whom calories tend to get shunted into fat stores, especially if they take in more calories than they burn as energy.
Green tea’s fat-loss effects extend beyond its caffeine content. It inhibits COMT, an enzyme in the body that degrades catecholamine hormones, such as epinephrine, which is involved in fat oxidation. Green tea also appears to blunt fat-cell differentiation, which leads to the formation of additional fat cells, as well as lipase enzymes needed to digest fat, and studies done with rats show that green tea prevents bodyfat gains even in rats on high-fat diets. Green tea use also blunts weight regain after a diet.
Jeff Stout, Ph.D., in a lecture titled “Protein Intake and Muscle Hypertrophy,” confirmed the importance of getting protein and carbs into the body after training. He noted that adding whey to a carb drink provides 55 percent greater gains in lean mass than carbs alone. The potency of concentrated protein supplements is reflected in the finding that they increase lean mass even in untrained persons. Stout also suggested taking a protein-and-carb drink 30 to 40 minutes prior to training and sipping a carb drink during a workout. That leads to lower cortisol levels during training, which would favor heightened anabolic responses from the workout.
Dr. Kraemer returned to lecture on L-carnitine and exercise. He explained that taking L-carnitine prior to training leads to such benefits as increased fatty acid oxidation, decreased muscle glycogen depletion and less accumulation in muscle of the lactate associated with fatigue. Carnitine increases the density of androgen cell receptors, which leads to greater testosterone uptake into muscle.
The conference also featured a number of interesting poster presentations that briefly summarized new research:
•A hydrolysate, or fraction, of whey protein called MGNF-1 lowered the levels of inflammatory chemicals in muscle while promoting cell growth.
•A study comparing the eating habits of vegetarians and nonvegetarians found that vegetarians not only didn’t lack any required nutrients but also had better-balanced diets than nonvegetarians—likely due to a greater variety of food.
•A study of L-carnitine intake in runners from India found that taking 2.5 grams of carnitine for 21 days led to substantial increase in VO2max, or the ability to take in and use oxygen. That would translate into increased exercise endurance.
•A study compared the effects of two types of creatine supplements—creatine combined with pinitol and plain creatine monohydrate—on exercise performance. While some previous research has found a synergistic effect when pinitol combines with creatine, this study revealed no differences in exercise performance from either form of creatine supplementation.
•The impact of beta-alanine supplements on isometric endurance of the knee extensors, or front-thigh muscles, was measured on subjects who got 6.4 grams of beta-alanine, along with simple sugars, for 28 and 14 days. Previous studies have reported 60 and 80 percent increases in muscle carnosine in those who took beta-alanine for four- and 10-week periods. This time around, 28 days of using beta-alanine led to an 11.1 percent increase in isometric muscle endurance, while using it for 14 days led to a 14.4 percent rise. The effect was ascribed to a higher level of muscle buffering, evidenced by a reduction in the acid levels that lead to muscle fatigue.
•In another beta-alanine study the effect of giving trainees 800 milligrams of beta-alanine four times a day for four weeks was compared to training without beta-alanine. Training alone didn’t increase carnosine levels in muscle after four weeks, but taking a beta-alanine supplement while training did. A 10- and 12-week study of beta-alanine use also showed higher carnosine muscle levels.
•The conference featured the first studies to examine the effects of a controversial arachidonic acid supplement when used with training. Arachidonic acid is a fatty acid that is the cornerstone of a number of prostaglandins, which are hormonelike chemicals produced in the body. At least one prostaglandin is known to promote muscle size and strength gains. The controversy arises because arachidonic acid is not only found abundantly in many protein foods, such as meat, but is also responsible for generating inflammatory prostaglandins that produce pain and illness. Some drugs that treat pain interfere with the conversion of arachidonic acid into those inflammatory chemicals. The purveyor of a commercial arachidonic acid supplement claims that regular intense exercise leads to a depletion of arachidonic acid in the muscle, resulting in a lowered synthesis of anabolic prostaglandins. Supplementing with arachidonic acid restores the body’s allegedly depleted stores.
In the study presented at the ISSN meeting, subjects used a commercial arachidonic acid supplement for 50 days while engaged in a weight-training program. Thirty-one subjects took a gram a day of either a corn oil placebo or an arachidonic acid supplement and ate a high-protein diet, averaging two grams of protein per kilogram of bodyweight daily. There was an increase in peak muscle power in those using the genuine arachidonic acid supplement, but neither group experienced a change in body mass.
Another study looked at the hormonal and intramuscular effects of using the arachidonic acid supplement for 50 days. The study protocols were similar to those of the other arachidonic acid study. Those on the supplement experienced an increase in prostaglandin F2A, the chemical linked to muscle gains, along with a decrease in the inflammatory cytokine, interleukin-6, which has catabolic effects in muscle. Arachidonic acid is most often linked to inflammatory reactions in the body because it is a precursor of various inflammatory prostaglandins, including F2A. In any case, the researchers deemed the increase in F2A found in the arachidonic acid group to be “nonsignificant.”
In a 50-day safety study of arachidonic acid the supplement proved to be well tolerated, without altering whole blood, liver or kidney safety markers.
•A study compared arginine alpha ketoglutarate, a popular ingredient found in nitric oxide–boosting supplements, with two substances: creatine ethyl ester, a newer form of creatine touted as being far more effective than creatine monohydrate, and a proprietary commercial supplement containing creatine gluconate and glycerol.
Four weeks of arginine alpha ketoglutarate use had no effect on adaptations to weight training, such as bodyfat loss, lean mass or muscular performance gains. Creatine ester exerted modest effects on bodyweight and lean mass. The creatine gluconate supplement proved the superior of the three supplements tested in terms of increases in bodyweight, lean mass and repetitions done to failure during training.
•Eurycoma longifolia, also known as longjack or tongat ali, is an herbal preparation that’s supposed to increase testosterone in the body. Researchers examined the effects of EL on testosterone and cortisone levels during intense endurance exercise. The human subjects (most prior EL studies used rats and mice) took either 100 milligrams of EL or a placebo 30 minutes prior to engaging in intensive running.
Cortisol levels were 32.3 percent lower in the EL group than in the placebo group, and testosterone levels were 16.4 percent higher. Those findings led the authors to conclude that taking EL before intense exercise may increase testosterone levels while lowering cortisol levels, a definite anabolic response.
•The effects of using a branched-chain amino acid supplement on cortisol levels during endurance exercise were at the center of a look at a commercial blend of BCAAs consisting of three parts leucine, one part isoleucine and one part valine. The supplement provided a total of 750 to 1,500 milligrams of BCAAs, depending on the dose, and as little as 750 milligrams, or a total dose of three grams over 24 hours, significantly reduced the cortisol levels produced during intense endurance exercise.
The study underscores the importance of taking BCAAs, especially when on a limited-calorie diet that features aerobic exercise. Getting supplemental BCAAs under such conditions may spare vital muscle losses.
There you have it—a portion of the information presented at the ISSN conference. Even given its abbreviated nature, the data should prove useful and practical. IM