<body><h1>Ribose</h1><p><br></p><p> syn. D-ribose </p><p> syn. 5-(hydroxymethyl)oxolane-2,3,4-triol</p><p> </p><p><div id=’imgblock’><img data-pointer=’9121’/></div></p><h2> Description: </h2><p> Ribose is a naturally occurring monosaccharide. It is specifically classified as a pentose sugar. Ribose is directly involved in the synthesis and function of several important biological components. These include ribonucleic acids, nucleotides, and riboflavin. Ribose is also integral to muscle energy metabolism. It is used in the synthesis of adenosine triphosphate (ATP), the main form of stored energy for living cells.484 It also appears to positively modulate the production of free radicals during intense exercise. Ribose is widely available as a sport supplement product, where it is typically applied to help replenish ATP after exercise.</p><p> </p><p><div id=’imgblock’><img data-pointer=’7852’/></div></p><p> Under normal conditions, the body maintains sufficient levels of ATP. As the muscles reach exhaustion during exercise, however, they may no longer be able to replenish ATP levels fast enough to keep up with its utilization.485 One study examining a number of different exercise methods found that some reduced ATP levels by nearly 50%.486 This depletion was associated with impaired recovery of phosphocreatine, reduced pH, and reduced inorganic phosphates. ATP levels can take many days following intense exercise to fully return to normal, resulting in a prolonged metabolic state that can interfere with optimal performance. Studies examining the effect of ribose on ATP metabolism suggest that it has an especially strong influence on post-exercise ATP replenishment, helping to restore pre-exercise levels more quickly.487 The main mode of action for ribose is to play a supportive role in the pentose phosphate pathway. More specifically, it serves as a substrate for the production of phosphoribosyl pyrophosphate (PRPP), an intermediary in the synthesis of ATP. The availability of PRPP is regarded as a rate-limiting step in the ATP energy cycle. This means that its levels are directly tied to those of ATP. Ribose is also found in limited concentrations in skeletal muscle, so an increase in this nutrient can lead to an increase in PRPP, and thus a downstream increase in the availability of ATP. The exact ergogenic value of manipulating ATP concentrations in this manner is still the subject of much research. Under some conditions, however, ribose supplementation may improve exercise capacity and athletic performance.</p><p> </p><h2> Promoted Benefits:</h2><p> Ribose is promoted to increase ATP levels, improve exercise endurance, and enhance athletic performance. </p><p> </p><h2> Clinical Studies: </h2><p> Ribose has been shown to improve performance in placebo-controlled studies with trained adults. It has a Clinical Support Rating of 5 (5/5).</p><p> </p><p> One placebo-controlled study examined the effects of four weeks of ribose supplementation in a group of recreationally active bodybuilders.488 The subjects took 10 g of ribose per day, and followed a controlled heavy resistance training program. Muscle strength and endurance were evaluated by assessing bench press 1-rep maximum weight and total repetitions to failure over 10 sets. Subjects taking ribose noticed a statistically significant improvement in bench press 1-rep max (+3.6 kg versus +2.2 kg) and total work (+19.6% versus +12%) compared to placebo. There were no changes in body composition. This study had methodological problems, however, as only five subjects used the supplement (small group size), and the placebo group appeared to be better trained at the beginning (inhomogeneous groups).</p><p> </p><p> A second placebo-controlled study examined the effects of ribose supplementation with high intensity exercise in a group of healthy trained men.489 The subjects consumed 10 g of ribose per day (5 g twice daily) for five days. Exercise performance was evaluated at baseline and after supplementation by performing two 30-s ergometer cycle sprints under resistance (Wingate anaerobic sprint test). Blood was also sampled for several metabolic markers. While the supplementation of ribose failed to increase peak power, average power, or muscle torque during the Wingate test, or favorably influence ammonia or lactate levels, it did support muscle endurance during the second post-supplementation sprint. Subjects taking placebo noticed a slight decline (-18 J) by this point in the experiment, while performance was maintained with ribose.</p><p> </p><p> Another placebo-controlled study examined the effects of acute ribose supplementation on anaerobic exercise performance in a group of healthy subjects.490 Participants took 32 g of ribose over a 32-hour window (4 doses of 8 g each). Exercise performance was evaluated before and after supplementation with a series of six 10-second cycle sprints under resistance. The supplementation of ribose produced a statistically significant increase in peak power (+10.9 %) and average power (+6.6%) during sprint number two. Although not statistically significant, there were also strong trends of improvement in peak and average power during sprints number one, number three, and number four in subjects taking ribose. </p><p> </p><p> While the results with ribose are not always positive, studies like these do suggest that its supplementation may improve exercise performance under some conditions, especially with regard to recovery after repeat high intensity activities. Further research is needed to better understand the ergogenic value of ribose.</p><h2> Empirical Evidence: </h2><p> Ribose is widely available as a stand-alone nutritional supplement. The feedback on its use as a sport supplement tends to be poor. Some users do appear to notice ergogenic benefit to its use. This is typically centered on a faster rate of recovery following treatment, and a better ability to perform at high level for longer durations (recovery and endurance). The benefits appear to be most noticeable with athletes and bodybuilders who are very in tune with their bodies and personal performance limits, and thus better able to notice minor changes. A stronger strong percentage of users, however, fails to attribute any significant benefit to the use of ribose. It is unknown if this is due to unrealistic expectations, the influence of training or dietary factors, or individual insensitivity to this supplement. Ribose has an Empirical Evidence Rating of 2 (2/5).</p><h2> Effective Dosage: </h2><p> Based on clinical studies, a dosage of 10-32 g per day is recommended. Ribose is typically taken with carbohydrates to avoid hypoglycemia. </p><h2> Side Effects / Safety: </h2><p> Ribose was well tolerated during clinical studies, with only minor reports of side effects.491 A small percentage of users do appear to notice gastrointestinal distress (loose stool, nausea, diarrhea) with its use. This appears to be more pronounced with higher doses. Ribose can also produce a hypoglycemic (blood sugar lowering) effect. It is most often consumed with carbohydrates to avoid a significant reduction in blood glucose.</p><p> </p><p> </p><p> </p></body>
