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From The March 2001 Issue of Nutrition Science News
Ribose Recovery
by Edmund R. Burke, Ph.D
There are times when athletes train so hard that they actively deplete the amount of energy stored in their muscle cells to the point where it cannot be restored efficiently before their next workout. When this happens, a long-term reduction occurs in a vital energy compound known as adenosine triphosphate, or ATP. A deficiency of ATP can negatively affect athletic performance and overall energy levels.
A new dietary supplement is now available that appears to help stimulate natural ATP production. D-ribose, also called ribose, is the sugar that begins the metabolic process for ATP production. ATP is a nucleotide made of adenosine coupled to three phosphate molecules. Adenosine is made up of adenine and ribose.
In the body, ribose is produced through a series of metabolic reactions that begin with glucose, another simple sugar. Once created, ribose goes through another series of reactions to produce nucleotides, compounds used to manufacture molecules necessary in ATP generation. When ATP is broken down, chemical energy is produced and ATP becomes adenosine diphosphate (ADP). The energy-generating processes of the cell then take glucose and recreate ATP from ADP and the process begins again.
As a simple sugar, ribose forms the carbohydrate portion of DNA and RNA, the building blocks of life. This unique 5-carbon sugar occurs naturally in all living cells, including all cells in the human body.
Despite ribose's ubiquitous nature, the heart and muscle cells are not efficient at making ribose. In fact, during times of metabolic stress, such as during strenuous exercise or diminished blood flow, cells are not able to form enough ribose to rapidly replace nucleotides as they are used.1,2 Furthermore, there is no known food source that supplies a sufficient amount of ribose to be metabolically significant. Until recently, drug companies used ribose almost exclusively to make other products such as antiviral drugs and riboflavin. However, thanks to new production techniques, the cost of manufacturing ribose has decreased, allowing athletes to use it to increase energy.
Muscle Performance
In theory, supplemental ribose acts as an ergogenic aid to improve performance in high-power exercises by improving recovery time of ATP. Because ribose is a precursor to adenosine, ribose supplementation could theoretically increase the de novo synthesis, or resynthesis, and regeneration of ATP from other nucleotides such as ADP, which when broken down produces phosphate to build more ATP. Recently, several human studies have investigated ribose as a potential sports supplement.
In one trial, conducted by John Berardi and Tim Ziegunfuss, Ph.D., at Eastern Michigan University, Royal Oak, eight young men participated in a double-blind, placebo-controlled, randomized, crossover pilot study to evaluate the effects of ribose supplementation on repeated sprint performance.3 Tests involved six 10-second sprints on a bicycle ergometer with 60 seconds of passive rest between sprints. Subjects ingested four 8 g doses of ribose or a placebo during a 36-hour period. The final dose was taken two hours prior to the sprint tests.
After the sprints, subjects observed a five-day wash-out period and then repeated the experiment ingesting the alternate supplement. Results revealed that changes in peak power (2.2 to 7 percent) and mean power (2 to 10 percent) were good but not significantly higher in the majority of sprints (four of the six) when taking the ribose. At face value these findings do not support the potential ergogenic value of ribose supplementation. However, the authors also reported that results were not significant because the study had too few subjects. These findings suggest additional research using larger sample sizes may be able to detect a significant effect in healthy subjects.
An additional study, conducted by Janson Witter and Scott Trappe, Ph.D., at Ball State University, Muncie, Ind., investigated the effect of ribose supplementation on performance and energy recovery during and following high-intensity exercise.4 In this pilot study, two subjects were given 30 g/day ribose and two were given placebo for three days prior to three days of sprint ergometer exercise, two sessions per day, for a total of six sessions. Exercise sessions consisted of 15 10-second sprints with resistance set at 7 percent of body mass and with 50 seconds of rest between sprints. Muscle biopsies were taken before the first exercise session, immediately following the final exercise session, and after 48 hours of rest.
The results show that power per kilogram body weight, peak power per kilogram, and total power per kilogram were all consistently higher in the ribose subjects than the placebo subjects. On average, increased power output was 9 to 9.9 percent higher with ribose administration. Thigh-muscle biopsies analyzed adenine nucleotides of each subject and showed ribose subjects were able to more effectively utilize their energy stores and recover more quickly following exercise. Following supplementation, ribose subjects began exercise with higher nucleotide pools and finished the exercise sessions with lower nucleotide pools as the result of greater energy utilization, but recovered to a higher level than placebo subjects after 48 hours of rest.
A possible explanation of the enhanced recovery may be that the ribose supplementation increased de novo synthesis of adenine nucleotides. While the sample size was small, a key point to this study was the consistently higher power outputs and better recovery. Although the 9 to 9.9 percent increase in power output was not considered statistically significant, it probably would have reached significance if there were more subjects.
Lastly, Jose Antonio, Ph.D., and colleagues at the University of Delaware in Newark recently conducted a study to determine the effect of ribose supplementation on body composition and exercise performance in 16 male bodybuilders.5 Subjects were randomly assigned to 10 g/day ribose or placebo during the four-week test. Each subject participated in a daily heavy resistance training program designed for muscle building. On day one, repetition maximum-strength bench press and the total number of repetitions performed during 10 consecutive sets to muscular failure at a submaximal load for the bench press were ascertained. There were no baseline differences between groups for any of the measured parameters. By the end of four weeks, the ribose group experienced a significant increase (+29.8 percent ribose vs. +7.4 percent placebo) in the number of total repetitions performed for the 10 sets to muscular failure. Exact time between sets was not given, but it had to be several minutes between sets to allow adequate recovery in a study of this nature.
Recommended Dosing
These and other studies lead researchers to think ribose may be helpful, but more studies are needed. There are two caveats before you decide to advise customers on a ribose regime: First, ribose needs to be present when the body's muscles, and cells will use it to salvage ATP. In other words, ribose must be used during and immediately after exercise. Ingesting it more than one-half to one hour from the time of exercise is expected to have little effect. Manufacturers and scientific consensus indicate using 35 g at the start of exercise and 35 g right after exercise. During long-term, high-intensity exercise, such as competitive sports and those activities indicated in the previous studies, 35 g can be taken every hour with a sports drink.
The second thing to keep in mind is that the exercise needs to be intense and long—as befitting multiple reps—and have anaerobic bouts in order to expect ribose to have a significant effect. If a person is doing exercise that is at a training rather than intense level, one would not expect them to see a benefit. It is when an athlete is training intensely in order to move to a higher level of fitness, or when he or she is performing in competition and thus surpassing normal energy output, that energy stores are run down enough to benefit from ribose. In these situations, ribose will enable the cells to salvage and recycle the adenine nucleotide precursors to ATP.
The available data suggest that ribose supplementation may have utility in athletic performance, including strength, power and high-intensity activities. The metabolic pathways necessary to synthesize ribose in the intact muscle are limited, and multiple lines of investigation indicate that supplemental ribose may have benefit by increasing the speed of ATP repletion and enhancing functional recovery. Further clinical studies in humans are likely to be forthcoming in this area, which may provide further insight into this compound's role in improving muscle energy metabolism in athletes and active individuals.
Sidebars:
ATP: The Energy Currency
Edmund R. Burke, Ph.D., an exercise physiologist at the University of Colorado, Colorado Springs, is author of D-Ribose: What You Need to Know (Avery, 1999) and Optimal Muscle Recovery (Avery, 1999).
References
1. Hellsten-Westing Y, et. al. Decreased resting levels of adenine nucleotrides in human skeletal muscle after high-intensity training. J Appl Physiol 1993;74:2523-8.
2. Stathis CG, et al. Influence of sprint training on human muscle purine nucleotide metabolism. J Appl Physiol 1994;76:1802-9.
3. Berardi JM, et al. Effects of ribose supplementation on repeated sprint performance: a pilot study. Med Sci Sports Exer 2000;32:S60.
4. Witter JP, et al. Effects of ribose supplementation on performance during repeated high-intensity cycle sprints. Abstracts accepted and presented at the Midwest Regional Chapter of the American College of Sports Medicine. 2000 Oct 5-7. Grand Rapids, Mich.
5. Antonio J, et al. The effects of ribose supplementation on body composition and exercise performance in recreational male bodybuilders. Final report submitted to Bioenergy and abstract submitted to national meeting of the American College of Sports Medicine. Baltimore, Md. May 2001.
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