Alka-Plex Use for Sports Nutrition

 

 alkalplex

Introduction

 I would like to comment on a product known as Alka-Plex® manufactured by pH Sciences®. The goals of this document are two-fold:

 

  1. To provide a basic understanding of the importance of acid-alkaline biochemical balance for professionals concerned with optimizing the performance of college athletes; and
  2. To provide technical details of the Alka-Plex® product and its potential application for college athletes.

Before beginning, let me introduce myself.

My name is Susan E. Brown, PhD, CNS. I direct both The Center for Better Bones and The Better Bones Foundation in East Syracuse, New York. I hold a doctorate in anthropology, specializing in medical anthropology, and am a New York State certified nutritionist. My authored and co-authored books include Better Bones, Better Body: Beyond Estrogen and Calcium—a comprehensive rethinking of the true nature, causes and best prevention and treatment of osteoporosis; The Acid-Alkaline Food Guide—a best-selling guide to the acid- or alkaline-forming nature of foods; and The Mend Clinic Guide to Menopause and Beyond. I have more than 25 years of experience in clinical nutrition, bone health research, and lay and health professional nutrition education. I consult on socioeconomic, cultural, educational, and health issues, and have taught in universities in North and South America. My name is on numerous academic and popular articles about health and nutrition. More information on my current work can be found on my website at www.betterbones.com.

Many years ago I began what has become a two-decade long analysis of the role that chronic low-grade metabolic acidosis plays in the maintenance, or loss, of both bone and muscle mass. I, along with noted scholar, Russell Jaffe, MD, PhD, wrote a groundbreaking, peer-reviewed article on acid-alkaline balance and bone health, which was published in the Nov/Dec 2000 International Journal of Integrative Medicine. (See attached reprint.). Since those early days my research has expanded to the analysis of the impact of chronic low-grade metabolic acidosis on a variety of health and fitness concerns. The first four chapters of my bestselling book, The Acid-Alkaline Food Guide, provide an introduction to the new science on pH balance and health.

 Finally, I would mention that I am very familiar with the history and mission of pH Sciences®. Several years ago, pH Sciences® asked me to review a human safety study on Alka-Plex® early in the product development cycle. All in all, I am very familiar with the nutrition and biochemical principles surrounding the product.

 Brief Description of Alka-Plex®

 Alka-Plex® is registered with the U.S. Food and Drug Administration (FDA) as a New Dietary Ingredient (NDI). In order to receive an NDI designation, the product developer has to submit safety and uniformity studies to the FDA. Fewer than 600 supplements (out of the more than 50,000 being sold in the U.S.) have been able to secure NDI status with the FDA. (See attached communications to and from the FDA.)

 Alka-Plex® is a combination of dietary minerals, all of which are listed as GRAS (generally recognized as safe) by the FDA.[1] The GRAS ingredients are mixed and held in their unaltered composition in a precisely formed granule using a patented process.[2]

Alka-Plex® granules are made by using microscopic calcium carbonate carrier particles to hold magnesium hydroxide, potassium chloride, and potassium hydroxide (i.e., magnesium and potassium salts). Calcium carbonate is chosen as the carrier because it does not react with the magnesium and potassium salts and is a stable carrier for those components. The microscopic carrier particles are coated with micro-crystalline cellulose and croscarmellose sodium. Then they are assembled (agglomerated) into granules in order to protect and maintain the integrity of the magnesium and potassium salts. The result is an alkalizing composition that survives the stomach and does not neutralize beneficial stomach acid HCL (hydrochloric acid). Alka-Plex® dissolves slowly in the intestinal tract where it does the most good. It is worth repeating that the unique patented Alka-Plex® formulation alkalizes while avoiding the neutralization of necessary stomach acid. This is in clear contrast to the widely used alkalizing mineral bicarbonates.

 The Alka-Plex® granule is designed to help the user maintain a healthy pH level by providing a mild alkalizing effect. A one-gram tablet of Alka-Plex® has about 12 mEq of alkalizing capacity. Since safety studies have used one gram for every 50 lbs of body weight, this is the safety dosage adopted by the FDA in their dietary ingredient letter for Alka-Plex®. Thus, a 150-lb athlete might use three one-gram tablets providing 36 mEq of alkalizing capacity.

 

Chronic Low-Grade Metabolic Acidosis

 And why, you might ask, would one need an alkalizing aid to achieve optimum pH balance? The answer to this question is found in our contemporary dietary patterns. To better understand this we start with some biochemical basics. For on-going survival our body must maintain its pH within a very tight range. For example, the viable human arterial blood pH range is just 7.4 ± 0.5 pH units. Even minor variations from these values are biologically costly and even life threatening. Our immune defense and repair mechanisms, and a host of cell and system enzyme catalysts all do their best in an exquisitely narrow pH range. The lungs, kidneys, and blood proteins play major roles in maintaining the required pH balance, which, as a whole, prevents a threatening level of excess acid (free hydrogen ions) from accumulating in the body.[3]

 Diet, however, also plays an important role in this process, and metabolic acids can, and do, accumulate as a result of modern eating patterns. Specifically, in contrast to our ancestral eating patterns, the contemporary diet is acid-forming as documented by several researchers.[4],[5],[6] To detail, European specialists calculate that the daily net-acid load of current Western diets averages 50–100 mEq/day.[7],[8] Less specific, and probably less accurate, calculations from the US Third National Health and Nutrition Examination (NHANES III) report the average American diet to be highly acid-producing, with a positive net acid load of 48 mEq/day.[9],[10] The contemporary diet-induced metabolic acid load stands in stark contrast to the medical anthropology calculations that our ancestral pre-agricultural diets were highly base-forming with a negative acid load of some 88 mEq/day.[11],[12]

 The excessive acid load of contemporary diets is not difficult to understand when one considers the abundance of low-mineral processed foods; the significant intake of highly acidic beverages such as coffee, alcohol, and soft drinks; the often excessive intake of refined grains and flesh foods; and the low intake of alkaline-forming vegetables, fruits, nuts, seeds, and spices. This dietary metabolic acid load results in the prevalence of a non-life threatening, but suboptimal, physiological state properly defined as “chronic, low-grade metabolic acidosis.”[13]

A growing body of scientific research documents the relationship between chronic low-grade metabolic acid load and a variety of health concerns including bone loss and osteoporosis, dental health, kidney health and kidney stone formation, muscle mass retention, and exercise performance and endurance. However, few, except scholars in the field, understand the nature and subtleties of pH balance and its influence on health, wellness, and performance.[14] As suggested above, when free protons (i.e., acid) are released or generated faster than the body can buffer them, a condition of “metabolic acidosis” can arise. Overt metabolic acidemia is incompatible with life. Low-grade, chronic metabolic acidosis, as can be induced by an imbalanced diet, while not life threatening, takes its toll on cellular functioning and performance.

 Alka-Plex® granules are being introduced to provide the user with a mild alkalizing effect to neutralize the excess acid load generated on a daily basis. In this capacity as a nutritional alkalizing compound, Alka-Plex® granules have an influence on muscle, athletic endurance, and recovery. A one-gram tablet of Alka-Plex® has about 12 mEq of alkalizing capacity.

 Intense Exercise and Metabolic Acid Load

Diet, however, is not the only source of increased metabolic load. It has long been documented that intense exercise induces a state of metabolic acidosis. The consequent buffering required results in disturbed mineral homeostasis and increased urinary calcium loss. For example, a bout of resistance exercise was shown to increase urinary calcium independently of osteoclastic activation in men.[15]

 More specific to this white paper, pH balance and the pre-exercise state of alkaline reserve compounds appears to significantly influence recovery kinetics and endurance capacity.[16],[17] In these studies alkalizing mineral citrates, bicarbonates, lactates, and chlorides were successfully used to buffer metabolic acids produced through intense exercise with a resultant delay in exhaustion, and enhanced athletic performance. Sodium bicarbonate is perhaps the most widely studied alkalizing agent used to enhance athletic performance. In a dose dependent manner short-term intake of sodium bicarbonate has been shown to reduce the exercise-related drop in pH, improve anaerobic performance,[18] improve intermittent sprint performance,[19] and offer erogenic benefits in the performance of short-term high-intensity work.[20],[21]

 

Benefits of Alkalization for Athletes

 It has long been known that intense exercise increases free proton concentration (i.e., acid) in contracting skeletal muscles.[22],[23] Traditionally, most physiology courses have recognized the phenomenon as “lactic acidosis.”[24] Recent studies, however, indicate that acid generation from “lactic acidosis” may be a small, if any, part of the total acid load generated during intense exercise.[25],[26] One line of current research suggests that intracellular acidity causes exercise fatigue, and not the accumulation of lactate ions.[27] Another suggestion is that the interstitial potassium accumulation which results from intense muscle functioning leads to the development of fatigue. These latter researchers used sodium citrate to reduce plasma hydrogen concentration (acid concentration) and increase plasma bicarbonate concentration, linking interstitial H+ (acid) and K+ accumulation during intense exercise.[28]

 While the long-held theory of lactic acidosis as the cause of exercise muscle fatigue is undergoing revision, lactic acidosis and exercise-induced acidosis still continue to fascinate sports medicine physiologists because the onset of acidosis, whatever its origin, is a well-recognized cause of fatigue.[29],[30]

 Numerous studies have tested the hypothesis that greater skeletal muscle alkalinity leads to greater muscle endurance. Decreases in muscle tension and inhibition of phosphofructokinase synthesis (an enzyme that is key to energy production) are directly tied to acid accumulation in the muscle tissue.[31],[32] Furthermore, as mentioned above, several clinical trials have shown that increases in alkali reserves pre-exercise enhance endurance and performance.

Systemic acid-base balance in the body is maintained by complex chemical, respiratory, and renal processes.[33] The most powerful and best understood extra-cellular buffer for acute acid-base changes in the body is bicarbonate.[34] Sodium bicarbonate was recognized as an aid to intense exercise in the late 1920s. In the 1980s a great deal of interest focused on using sodium bicarbonate—an “acidosis mitigation theory”—to enhance exercise performance.[35] A series of more recent trials also used sodium citrate as the alkalizing agent with beneficial effects on athletic performance.[36],[37],[38],[39] When used in high doses, sodium citrate has been shown to work in a similar way to sodium bicarbonate on plasma alkalinization and exercise performance.[40]

Ingesting high-dose sodium bicarbonate, however, frequently causes gastrointestinal distress and dehydration. Additionally high-dose bicarbonate has the potential to neutralize essential stomach acid. High-dose sodium citrate, used at times in these trials, is also often associated with gastrointestinal distress, diarrhea, increased flatulence, and bloating.[41] The distress experienced with both sodium bicarbonate and sodium citrate loading is likely due to the large sodium load, dehydration caused by increased osmotic load to the gut, and significant carbon dioxide gas production.[42] Nonetheless, both alkalizing therapies remain interesting, relatively safe methods of testing the acidosis mitigation theory of enhancing athletic performance.[43] Of note is the fact that the United States Olympic Committee and the International Olympic Committee do not include bicarbonates or citrates on their banned substance list.[44]

  Benefits of Alka-Plex® for Athletes

 Two independent studies of athletic performance with compositions using Alka-Plex® were initiated pH Sciences®.

 

Seattle Performance Medicine Clinic. Dr. Emily Cooper, MD, monitored and charted 25 different physiological responses for two elite male cyclists using different levels of supplementation of a pH Sciences® composition. One intervention level used was low dose using just one of the 1,000 mg Alka-Plex® granules. The second intervention used 2,000 mg of Alka-Plex® granules. Note that both of the doses of Alka-Plex® granules used in this study were well below the safety dose adopted by the FDA.

 

The conclusions from Dr. Cooper’s pilot study are as follows:

 

  1. With the 2,000 mg dose of Alka-Plex® granules, there was an increased time to fatigue for both subjects relative to baseline testing. The improvement was 258% for subject A and 28% for subject B.

 

  1. Lactate levels at exhaustion, relative to baseline testing, were substantially lower when athletes took 2,000 mg of the pH Sciences® composition (17% for subject A and 50% for subject B). This lowered lactate level was in spite of the increased work performed.

 

  1. Muscle recovery improved significantly for both athletes whether they took 1,000 or 2,000 mg of Alka-Plex® granules.

 Montana State University Clinical Trial. Daniel Heil, PhD, Chair of the Human Performance Lab, conducted research to confirm or refute Dr. Cooper’s findings in a double-blind, placebo-controlled study.

 Dr. Heil used 24 well-trained, competitive Nordic skiers for his study. Subjects in a blinded fashion were divided into a placebo control group and an active intervention group. Baseline testing was done for both groups. Dependent measurements of interest included several measures of upper body strength, as well as cardiovascular and blood lactate responses to the upper body tests. These variables were then re-measured after a 7-day supplement loading phase. The loading phase consisted of daily use of 1,000 mg Alka-Plex® granules for every 50 lbs of body weight.

 

This double-blind, placebo controlled clinical trial confirmed Dr. Cooper’s pilot study findings. The conclusions from Dr. Heil’s study, as published in the Journal of the International Society of Sports Nutrition, are as follows:

 

  1. Athletes taking the pH Sciences® Alka-Plex® composition increased significantly their upper body power output (i.e., strength) by 4% to 6% in short 10 second and 60 second tests.
  2. Lactate levels were reduced by almost 10% with athletes taking the pH Sciences® composition in spite of their greater power output.

 

  1. Overall stress (as measured by heart and respiratory rates) was significantly lower as was the overall energy expenditure (as measured by reduced sub-maximal VO2) for athletes taking the pH Sciences® composition in spite of their greater power output.[46]

 

NCAA/WADA/USADA Banned Substance

 

The National Collegiate Athletic Association (NCAA), the World Anti-Doping Agency (WADA) and the United States Anti-Doping Agency (USADA) publish lists of banned substances for athletes.

 

The NCAA prohibits:

  • Stimulants
  • Anabolic agents
  • Alcohol and beta blockers (banned for rifle only)
  • Diuretics and other masking agents
  • Street drugs
  • Peptide hormones and analogues
  • Anti-estrogens
  • Beta-2 agonists

 Alka-Plex® contains:

  • Calcium (as calcium carbonate)                     225 mg    or    22% DV
  • Magnesium (as magnesium hydroxide)             1 mg    or    <1% DV
  • Potassium (as potassium hydroxide and

potassium chloride)                                         35 mg    or      1% DV

 

Inert ingredients are identified as water, micro-crystalline cellulose, and croscarmellose sodium.

 

 There are no prohibited ingredients in Alka-Plex® and there is no need for prohibited ingredients in order for the athlete to experience improved health and performance. pH Sciences® has submitted the composition to WADA and independent testing laboratories to confirm that the composition contains no prohibited substances.

 

Advantages of Alka-Plex®

 

  • The Alka-Plex® formulation appears to significantly improve the performance of intense athletics in parallel fashion to that achieved by the well tested alkalizing agents, high-dose sodium bicarbonate or sodium citrate.
  • The Alka-Plex® formulation, however, does not cause gastrointestinal distress as does high-dose sodium bicarbonate or sodium citrate.
  • The Alka-Plex® formulation does not deliver excessive levels of unwanted sodium as does supplementation with sodium bicarbonate or sodium citrate.
  • The Alka-Plex® formulation appears further to enhance post-exercise muscle recovery and overall reduces the stress impact of intense exercise.

 

Safety and Possible Contra-Indications for Alka-Plex®

 

As described elsewhere, Alka-Plex® is made from ingredients that are listed by the FDA as “generally recognized as safe” or GRAS. Stanford Research Institute conducted an acute oral toxicity study of the composition and I participated in follow-up interviews with ten (10) subjects who had used Alka-Plex® granules for a two-year period. Our findings were submitted to the FDA as part of their review prior to issuing the NDI for Alka-Plex®.

 

A few general cautions should be noted for the use of Alka-Plex®. First, 1,000 mg of Alka-Plex® contains about 225 mg of calcium. A 150-lb athlete using three of the 1,000 mg tablets a day would be obtaining 675 mg calcium from the Alka-Plex®. Athletes taking calcium supplements should consider reducing or eliminating their supplemental calcium intake and use Alka-Plex® as their primary source in order to avoid overconsumption of calcium. While the daily RDA of calcium to prevent deficiency diseases in adults ages 19–50 is 1,000 mg, the Tolerable Upper Limit is 2,500 mg.[47]

 

Further, tetracycline-related antibiotics should not be taken at the same time as any foods containing significant amounts of calcium. The calcium binds with the antibiotic and reduces its absorption. This problem is eliminated if two hours separate the ingestion of the antibiotic and the calcium-rich food. Further, it is appropriate to check with one’s physician before supplementing with calcium if one has any of the following unusual conditions:tumor that dissolves bone, incomplete or infrequent bowel movements, kidney stones, kidney disease, sarcoidosis, hyperparathyroidism, high amounts of calcium in the blood, or extreme loss of body water.

 


[1] See US Code of Federal Regulations: 21CFR 184.1191; 21 CFR 184.1428; 21CFR 184.1631; 21CFR 184.1622; 21CFR 175.105; and REGNUM - 977005-28-9.

[2] United States Patent 6,270,708. Gurol, August 7, 2001. Agglomerating and drying apparatus; and United States Patent 6,143,221. Gurol, November 7, 2000. Agglomerating and drying apparatus.

[3] Brown, S. E. and Jaffe, R. Acid-alkaline balance and its effect on bone health. International Journal of Integrative Medicine 2(6), Nov/Dec 2000.

[4] Sebastian, A., Frassetto, L. A., Sellmeyer, D. E., Merriam, R. L., and Morris, R. C., Jr. Estimation of the net acid load of the diet of ancestral pre-agricultural Homo sapiens and their hominid ancestors. American Journal of Clinical Nutrition 76(6):13081316, 2002.

[5] Maurer, M., Riesen, W., Muser, J., Hulter, H. N., and Krapf, R. Neutralization of Western diet inhibits bone resorption independently of K intake and reduces cortisol secretion in humans. American Journal of Physiology Renal Physiology 284(1):F32-F40, 2003.

[6] Frassetto, L., Morris, R. C., Jr., Sellmeyer, D. E., Todd, K., and Sebastian, A. Diet, evolution and aging—the pathophysiologic effects of the post-agricultural inversion of the potassium-to-sodium and base-to-chloride ratios in the human diet. European Journal of Nutrition 40(5):200-213, 2001.

[7] Remer, T. and Manz, F. Estimation of the renal net acid excretion by adults consuming diets containing variable amounts of protein. American Journal of Clinical Nutrition59:1356–1361, 1994.

[8] Remer, T., Berkemeyer, S., Rylander, R., and Vormann, J. Muscularity and adiposity in addition to net acid excretion as predictors of 24-h urinary pH in young adults and elderly. European Journal of Clinical Nutrition61:605–609, 2007.

[9] Sebastian, A., Frassetto, L. A., Sellmeyer, D. E., Merriam, R. L., and Morris, R. C., Jr. Estimation of the net acid load of the diet of ancestral pre-agricultural Homo sapiens and their hominid ancestors. American Journal of Clinical Nutrition 76(6):1308–1316, 2002.

[10] Pizzorno, J., Frassetto, L. A., and Katzinger, J. Diet-induced acidosis: is it real and clinically relevant? British Journal of Nutrition 103(8):1185–1194, 2010.

[11] Sebastian, A., Frassetto, L. A., Sellmeyer, D. E., Merriam, R. L., and Morris, R. C., Jr. Estimation of the net acid load of the diet of ancestral pre-agricultural Homo sapiens and their hominid ancestors. American Journal of Clinical Nutrition 76(6):1308–1316, 2002.

[12] Remer, T., and Manz, F. Paleolithic diet, sweet potato eaters, and potential renal acid load. American Journal of Clinical Nutrition 78(4):802–803, 2003.

[13] Pizzorno, J., Frassetto, L. A., and Katzinger, J. Diet-induced acidosis: is it real and clinically relevant? British Journal of Nutrition 103(8):1185–1194, 2010.

[14] Frassetto, L., and Sebastian, A. Age and systemic acid-base equilibrium: analysis of published data. Journals of Gerontology A 51(1):B91–B99, 1996.

[15] Ashizawa, N., Fujimura, R., Tokuyama, K., and Suzuki, M. A bout of resistance exercise increases urinary calcium independently of osteoclastic activation in men. Journal of Applied Physiology 83(4):1159–1163, 1997.

[16] Oöpik, V., Saaremets, I., Medijainen, L., Karelson, K., Janson, T., and Timpmann, S. Effects of sodium citrate ingestion before exercise on endurance performance in well-trained college runners. British Journal of Sports Medicine 37:485489, 2003.

[17] Robergs, R., Hutchinson, K., Hendee, S., Madden, S., and Siegler, J. Influence of pre-exercise acidosis and alkalosis on the kinetics of acid-base recovery following intense exercise. International Journal of Sport Nutrition and Exercise Metabolism 15(1):59–74, 2005.

[18] Douroudos, II, Fatouros, I. G., Gourgoulis, V., Jamurtas, A. Z., Tsitsios, T., Hatzinikolaou, A., Margonis, K., Mavromatidis, K., and Taxildaris, K. Dose-related effects of prolonged NaHCO3 ingestion during high-intensity exercise. Medicine and Science in Sports and Exercise 38(10):17461753, 2006.

[19] Bishop, D. and Claudius, B. Effects of induced metabolic alkalosis on prolonged intermittent-sprint performance. Medicine and Science in Sports and Exercise 37(5):759767, 2005.

[20] McNaughton, L., Backx, K., Palmer, G., and Strange, N. Effects of chronic bicarbonate ingestion on the performance of high-intensity work. European Journal of Applied Physiology and Occupational Physiology 80(4):333336, 1999.

[21] Pizzorno, J., Frassetto, L. A., and Katzinger, J. Diet-induced acidosis: is it real and clinically relevant? British Journal of Nutrition 103(8):1185–1194, 2010.

[22] Gevers, W. Generation of protons by metabolic processes in heart cells. Journal of Molecular and Cellular Cardiology 9(11):867–874, 1977.

[23] Gevers, W. Generation of protons by metabolic processes other than glycolysis in muscle cells: a critical view. [letter to editor] Journal of Molecular and Cell Cardiology 11, 328, 1979.

[24] Katz, A., and Sahlin, K. Regulation of lactic acid production during exercise. Journal of Applied Physiology 65:509–518, 1988.

[25] Robergs, R., Exercise-induced metabolic acidosis: where do the protons come from? Sportscience 5(2), 2001. Available online: sportsci.org/jour/0102/rar.htm.

[26] Street, D., Nielsen,J. J., Bangsbo,J., and Juel, C. Metabolic alkalosis reduces exercise-induced acidosis and potassium accumulation in human skeletal muscle interstitium. Journal of Physiology 566(Pt 2):481489, 2005.

[27] Van Montfoort, M. C., Van Dieren, L., Hopkins, W. G., and Shearman, J. P. Effects of ingestion of bicarbonate, citrate, lactate, and chloride on sprint running. Medicine and Science in Sports and Exercise 36(7):12391243, 2004.

[28] Street, D., Nielsen,J. J., Bangsbo,J., and Juel, C. Metabolic alkalosis reduces exercise-induced acidosis and potassium accumulation in human skeletal muscle interstitium. Journal of Physiology 566(Pt 2):481489, 2005.

[29] Mainwood, G. W., and Renaud, J. M. The effect of acid-base balance on fatigue of skeletal muscle. Canadian Journal of Physiology and Pharmacology 63(5):403–416, 1985.

[30] Mainwood, G. W., Renaud, J. M., and Mason, M. J. The pH dependence of the contractile response of fatigued skeletal muscle. Canadian Journal of Physiology and Pharmacology 65(4):648–658, 1987.

[31] Ibid.

[32] Ui, M. A role of phosphofructokinase in pH-dependent regulation of glycolysis. Biochem Biophys Acta 124(2):310–322, 1966.

[33] Guyton, A. C., and Hall, J. E. Textbook of Medical Physiology, 9th ed. Philadelphia: Sounders, 1996.

[34] Ibid.

[35] Webster, M. J., Sodium bicarbonate. Pages 197–207 in Performance-Enhancing Substances in Sport and Exercise, ed. M. S. Bahrke and C. E. Yesalis. Human Kinetics, Champaign, IL, 2002.

[36] Linossier, M. T., Dormois, D., Brégère, P., Geyssant, A., and Denis, C. Effect of sodium citrate on performance and metabolism of human skeletal muscle during supramaximal cycling exercise. European Journal of Applied Physiology and Occupational Physiology 76(1):4854, 1997.

[37] Potteiger, J. A., Nickel, G. L., Webster, M. J., Haub, M. D., and Palmer, R. J. Sodium citrate ingestion enhances 30 km cycling performance. International Journal of Sports Medicine 17(1):711, 1996.

[38] Shave, R., Whyte, G., Siemann, A., and Doggart, L. The effects of sodium citrate ingestion on 3,000-meter time-trial performance. Journal of Strength and Conditioning Research 15(2):230–234, 2001.

[39] Street, D., Nielsen,J. J., Bangsbo,J., and Juel, C. Metabolic alkalosis reduces exercise-induced acidosis and potassium accumulation in human skeletal muscle interstitium. Journal of Physiology 566(Pt 2):481489, 2005.

[40] Linossier, M. T., Dormois, D., Brégère, P., Geyssant, A., and Denis, C. Effect of sodium citrate on performance and metabolism of human skeletal muscle during supramaximal cycling exercise. European Journal of Applied Physiology and Occupational Physiology 76(1):4854, 1997.

[41] Shave, R., Whyte, G., Siemann, A., and Doggart, L. The effects of sodium citrate ingestion on 3,000-meter time-trial performance. Journal of Strength and Conditioning Research 15(2):230–234, 2001.

[42] Webster, M. J., Webster, M. N., Crawford, R. E., and Gladden, L. B. Effect of sodium bicarbonate ingestion on exhaustive resistance exercise performance. Medicine and Science in Sports and Exercise 25(8):960–965, 1993.

[43] McNaughton, L. R. Bicarbonate ingestion: effects of dosage on 60 s cycle ergometry. Journal of Sports Sciences 10(5):415–423, 1992.

[44] The World Anti-Doping Agency (WADA) Prohibited List. Available online: http://www.usada.org/prohibited-list/?gclid=CI_Q49Pp37ICFVTNOgodsWMAmQ.

[45] Cooper, E. Elite bicyclist endurance and muscle recovery pilot study at two dose levels. Unpublished study is available from pH Science Holdings, Inc. (206) 683-5080.

[46] Heil, D. P., Jacobson, E. A., and Howe, S. M. Influence of an alkalizing supplement on markers of endurance performance using a double-blind placebo-controlled design. Journal of the International Society of Sports Nutrition 9:8, 2012. DOI: 10.1186/1550-2783-9-8.

[47] Office of Dietary Supplements, National Institutes of Health. Available online: http://ods.od.nih.gov/factsheets/Calcium-QuickFacts/. (accessed 9-25-12).