Seven Reports from the ACSM Meeting

by Edmund R. Burke, Ph.D.

This summer I attended the annual American College of Sports Medicine (ACSM) conference in Seattle to scout out the newest nutrition tips to help athletes perform better, get stronger, lose weight and recover more quickly from exercise. More than 2,000 new studies were presented during the four-day event. The following seven are what I consider to be among the best in sports nutrition and weight management.

Triple Herb Blend Aids Weight Loss
A double-blind, placebo-controlled study by C. Colker, Greenwich Hospital, Conn., assessed the effects of bitter orange (Citrus aurantium) extract, caffeine and St. John's wort (Hypericum perforatum)on body composition, metabolic parameters, plasma lipid levels and mood in overweight but otherwise healthy adults.

Founded in 1954 and based in Indianapolis, ACSM focuses on diagnosing, treating and preventing sports injuries and advancing exercise and nutritional research. Much of the research at the conference represents preliminary data on small numbers of subjects. Oftentimes, information such as the age and sex of subjects, dosages, and complete statistics are unavailable during the short research presentations. In nearly all instances, further studies with larger sample sizes are needed before definitive conclusions can be made.

Twenty-three subjects were assigned to one of three groups: treatment, placebo or control. The treatment group received 975 mg bitter orange extract, 528 mg caffeine and 900 mg St. John's wort each day for six weeks. The other two groups received either a placebo or nothing at all. Subjects were instructed to eat 1,800 calories daily during the study in addition to performing strength-training exercises three times a week.

Body fat decreased, on average, 3.1 kilograms in subjects taking the herbal combination. They also tended to have lowered plasma cholesterol and triglycerides. The treatment group experienced no significant changes in blood pressure, electrocardiogram, heart rate, serum chemistries or urinalysis—indicating that the combination of bitter orange extract, caffeine and St. John's wort safely and effectively promotes weight loss and fat loss when combined with mild caloric restriction and exercise.

There were no significant changes in fatigue or vigor in any of the three groups.

Beta-Carotene Improves Race Times
K. LeBanc and colleagues from Louisiana State University, Baton Rouge, studied the effect of beta-carotene on 5K race performance in 11 well-trained runners. They also evaluated beta-carotene's effects on oxidative stress by meas-uring malondialdehyde (MDA), a marker of muscle damage, in this double-blind, crossover study.

Each runner took 25,000 IU of beta-carotene the day of a race. During the beta-carotene phase, the average race time was 19:18 minutes, compared with 19:55 minutes during the placebo period—the equivalent of a 200-meter lead. Sixty-four percent of the subjects reported feeling better when they took the beta-carotene supplements, but there was no statistically significant effect on MDA levels. These results indicate beta-carotene may improve the race performance of well-trained runners.

Herbal Mix Reduces Lactic Acid
A double-blind, crossover study conducted by J. Lahr from St. Cloud State University, Minn., studied the effect of a formulation of standardized herbal ingredients (sold under both the brand names Metaflex and 2nd Wind) on lactate accumulation during high-intensity exercise. The formulation contains Asian ginseng (Panex ginseng), cordyceps (Cordyceps cinensis), enoki mushroom (Flammulina velutipes), green tangerine peel (Citrus reticulata blanco), reishi mushroom (Ganoderma lucidum) and Siberian ginseng (Eleutherococcus senticosus).

Twelve well-trained college athletes, six men and six women, were paired by their lactate threshold and randomly assigned to receive either 950 mg/day of the herbal formulation or placebo. A single dose of each treatment was ingested daily for five weeks. At the end of five weeks, subjects cycled at their lactate threshold for 20 minutes, rested for 12 minutes and then completed a time trial.

Taking the herbal mix led to significantly less lactic acid accumulation than placebo during the 12-minute recovery period. Although the herbal group finished the time trial 56 seconds faster than the placebo group, the difference was insignificant. The author concluded that compared to placebo, the herbal formulation leads to less lactic acid accumulation following intense cycling and may also improve high-intensity cycling performance.

Androstenedione Has No Worthwhile Benefits
The latest data on androstenedione gleaned from three studies of male college students, each conducted at Iowa State University in Ames, determined that androstenedione did not increase testosterone levels—neither within hours of administration nor after eight weeks of daily supplementation.

Androstenedione supplementation in men did, however, increase concentrations of dihydrotestosterone (DHT, a hormone linked to baldness) and estradiol (a hormone related to female characteristics).

Reduced high-density lipoprotein (HDL, or good cholesterol) levels in one study led researchers to conclude that chronic androstenedione use may increase cardiovascular disease risk. In addition, another study found that after eight weeks of supplementation combined with resistance training three times weekly, androstenedione produced no better gains in strength or muscle mass than placebo.

What Supplements Are College Football Players Taking?
R. Sallis from Pomona College, Claremont, Calif., surveyed supplement use among 263 college football players from five teams in a single NCAA Division III conference. Eighty-seven percent reported trying some type of dietary supplement to enhance their athletic performance. Of the 24 supplements players had previously used, the 10 most common were:

Of the 55 players (21 percent) currently using creatine, 76 percent said it worked for them and 25 percent reported side effects. The most common side effect was muscle cramping, reported by 6 percent of the players. Protein supplements are currently used by 33 players (13 percent), of whom 65 percent felt it worked. Only 8 percent reported side effects such as muscle cramping and dehydration.

Creatine Reduces Injury Risk
The following items are highlights of the more than 25 papers on creatine presented at the conference.

Sports scientists have long argued over optimum creatine dosages. New research finds that elevated creatine levels in muscles and enhanced performance can be maintained for as long as two months on 5 g/day if it follows a five-day loading phase of 25 g/day.

Studies also demonstrate that creatine does not increase the incidence of muscle cramping and may reduce the risk of injury during training. These findings were further supported by evidence that creatine does not cause alterations in fluid or electrolyte balance.

In a study that did not involve athletes, creatine reduced muscle loss and improved anaerobic performance during a weight-loss program combined with weight training.

The Optimum Sports Drink
Measurements of creatine kinase, an enzyme found in muscle cells, are frequently used to indicate muscle damage and stress after exercise. It is thought that the enzyme leaks from cells and into the bloodstream when cell membranes are ruptured.

A double-blind, crossover study by S. Ready of St. Cloud State University in Minn. compared the effects of two sport-drink formulations on post-exercise muscle stress and performance time. Ten college-aged men and women drank either a carbohydrate/protein beverage or a carbohydrate/electrolyte beverage while participating in a simulated duathlon.

Subjects ran for 45 minutes, rested 10 minutes, cycled for 90 minutes and then performed a duathlon time trial. They drank a 360-mL sports drink before they started cycling and again 30 minutes into the ride. Blood samples were collected and analyzed for creatine kinase, lactic acid and glucose.

Seven of the 10 subjects who drank the carbohydrate/protein beverage shaved an average of 27 seconds from their time trials. In addition, their creatine kinase levels decreased 36 percent during the 24 hours after exercise—an indication that extra carbohydrates and protein may reduce post-exercise muscle stress.

Edmund R. Burke, Ph.D., an exercise physiologist at the University of Colorado, Colorado Springs, is the author of Optimal Muscle Recovery (Avery Publishing, 1999).

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