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The Effect of Alkaline Potassium Salts on Calcium and Bone Metabolism

  • Deborah E. SellmeyerEmail author
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Abstract

Diets in industrialized nations are no longer based predominately on potassium rich fruit and vegetables, resulting in substantially lower potassium intakes as well as the alkaline anions such as bicarbonate and citrate that accompany potassium in fruit and vegetables. The reduction in potassium and alkali intake while maintaining adequate dietary protein intake leads to an imbalance between the acid producing and the base producing components of the diet. This dietary net acid load is theorized to require mobilization of skeletal base to aid in acid neutralization, leading to ongoing skeletal resorption to maintain systemic acid base homeostasis. Short-term calcium balance studies suggest that supplementing the diet with alkaline potassium salts lowers urine calcium losses with no increase in stool calcium, resulting in a net improvement in calcium balance. The majority of studies examining potassium supplements also suggest bone resorption is reduced by potassium citrate or bicarbonate. However, not all studies show a reduction in bone turnover and the two existing bone density trials provide conflicting results. In particular, controversy remains over whether the benefits to calcium metabolism demonstrated in the short-term calcium balance studies persist. To address this controversy, we conducted a randomized, placebo controlled trial in 52 men and women (mean age 65.2 + 6.2 years) who were randomly assigned to potassium ­citrate 60, 90 mmol, or placebo daily with measurements of bone turnover markers, net acid excretion, and calcium metabolism including intestinal fractional calcium absorption and calcium balance at baseline and 6 months. At 6 months, 24-h urine calcium was significantly reduced in both potassium treatment groups and fractional calcium absorption was not changed by potassium citrate supplementation. In subjects randomized to potassium citrate 90 mmol/day, net calcium balance was significantly improved compared to placebo. Serum C-telopeptide, a marker of bone resorption, decreased significantly in both potassium citrate groups compared to placebo, while bone specific alkaline phosphatase did not change. Our study supports the hypothesis that supplementation with alkaline potassium salts such as potassium citrate has the potential to improve skeletal health. Studies with definitive outcomes such as bone density and fracture are needed.

Keywords

Potassium Acid base Osteoporosis Calcium balance Protein Citrate Bicarbonate Bone Diet 

Notes

Acknowledgements

This work was funded by a contract from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (N01-AR-5-2275) and supported by the National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Health, through UCSF-CTSI Grant Number UL1 RR024131. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.

Potassium citrate and placebo were provided by Mission Pharmacal Company, San Antonio, TX. Mission Pharmacal had no role in the study design, conduct of the study, data analysis, or the manuscript.

References

  1. 1.
    Cooper C. The problem – health impact of osteoporosis. Scand J Rheumatol. 1996;25 Suppl 103:3–5.CrossRefGoogle Scholar
  2. 2.
    Campion JM, Maricic MJ. Osteoporosis in men. Am Fam Physician. 2003;67(7):1521–6.PubMedGoogle Scholar
  3. 3.
    Bischoff-Ferrari HA, Dawson-Hughes B, Willett WC, et al. Effect of Vitamin D on falls: a meta-analysis. JAMA. 2004;291(16):1999–2006.PubMedCrossRefGoogle Scholar
  4. 4.
    Adler S, Lindeman RD, Yiengst MJ, et al. Effect of acute acid loading on urinary acid excretion by the aging human kidney. J Lab Clin Med. 1969;72:278–89.Google Scholar
  5. 5.
    Agarwal BN, Cabebe FG. Renal acidification in elderly subjects. Nephron. 1980;26:291–5.PubMedCrossRefGoogle Scholar
  6. 6.
    Frassetto L, Morris Jr RC, Sebastian A. Effect of age on blood acid–base composition in adult humans: role of age-related renal functional decline. Am J Physiol. 1996;271:1114–22.Google Scholar
  7. 7.
    Hilton Jr JG, Goodbody M, Kruesi OR. The effect of prolonged administration of ammonium chloride on the blood acid–base equilibrium of geriatric subjects. J Am Geriatr Soc. 1955;3:697–703.PubMedGoogle Scholar
  8. 8.
    Lemann Jr J, Gray RW, Pleuss JA. Potassium bicarbonate, but not sodium bicarbonate, reduces urinary calcium excretion and improves calcium balance in healthy men. Kidney Int. 1989;35:688–95.PubMedCrossRefGoogle Scholar
  9. 9.
    Sebastian A, Harris ST, Ottaway JH, et al. Improved mineral balance and skeletal metabolism in postmenopausal women treated with potassium bicarbonate. N Engl J Med. 1994;330:1776–81 [see comments].PubMedCrossRefGoogle Scholar
  10. 10.
    Sakhaee K, Maalouf NM, Abrams SA, Pak CY. Effects of potassium alkali and calcium supplementation on bone turnover in postmenopausal women. J Clin Endocrinol Metab. 2005;90(6):3528–33.PubMedCrossRefGoogle Scholar
  11. 11.
    Ceglia L, Harris SS, Abrams SA, et al. Potassium bicarbonate attenuates the urinary nitrogen excretion that accompanies an increase in dietary protein and may promote calcium absorption. J Clin Endocrinol Metab. 2009;94(2):645–53.PubMedCrossRefGoogle Scholar
  12. 12.
    Frassetto L, Morris Jr RC, Sebastian A. Long-term persistence of the urine calcium-lowering effect of potassium bicarbonate in postmenopausal women. J Clin Endocrinol Metab. 2005;90(2):831–4.PubMedCrossRefGoogle Scholar
  13. 13.
    Rafferty K, Davies KM, Heaney RP. Potassium intake and the calcium economy. J Am Coll Nutr. 2005;24(2):99–106.PubMedGoogle Scholar
  14. 14.
    Marangella M, Di SM, Casalis S, et al. Effects of potassium citrate supplementation on bone metabolism. Calcif Tissue Int. 2004;74(4):330–5.PubMedCrossRefGoogle Scholar
  15. 15.
    Dawson-Hughes B, Harris SS, Palermo NJ, et al. Treatment with potassium bicarbonate lowers calcium excretion and bone resorption in older men and women. J Clin Endocrinol Metab. 2009;94(1):96–102.PubMedCrossRefGoogle Scholar
  16. 16.
    Jehle S, Zanetti A, Muser J, et al. Partial neutralization of the acidogenic Western diet with potassium citrate increases bone mass in postmenopausal women with osteopenia. J Am Soc Nephrol. 2006;17(11):3213–22.PubMedCrossRefGoogle Scholar
  17. 17.
    MacDonald HM, Black AJ, Aucott L, et al. Effect of potassium citrate supplementation or increased fruit and vegetable intake on bone metabolism in healthy postmenopausal women: a randomized controlled trial. Am J Clin Nutr. 2008;88(2):465–74.PubMedGoogle Scholar
  18. 18.
    Sellmeyer DE, Schloetter M, Sebastian A. Potassium citrate prevents increased urine calcium excretion and bone resorption induced by a high sodium chloride diet. J Clin Endocrinol Metab. 2002;87:2008–12.PubMedCrossRefGoogle Scholar
  19. 19.
    Karp HJ, Ketola ME, Lamberg-Allardt CJ. Acute effects of calcium carbonate, calcium citrate and potassium citrate on markers of calcium and bone metabolism in young women. Br J Nutr. 2009;102(9):1341–7.PubMedCrossRefGoogle Scholar
  20. 20.
    Yergey AL, Abrams SA, Vieira NE, et al. Determination of fractional absorption of dietary calcium in humans. J Nutr. 1994;124:674–82.PubMedGoogle Scholar
  21. 21.
    Lee W, McCabe GP, Martin BR, Weaver CM. Validation of a simple isotope method for estimating true calcium fractional absorption in adolescents. Osteoporos Int. 2011;22(1):159–66.PubMedCrossRefGoogle Scholar
  22. 22.
    Tang BM, Eslick GD, Nowson C, et al. Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis. Lancet. 2007;370(9588):657–66.PubMedCrossRefGoogle Scholar
  23. 23.
    Feskanich D, Willett WC, Stampfer MJ, Colditz GA. Protein consumption and bone fractures in women. Am J Epidemiol. 1996;143:472–9.PubMedCrossRefGoogle Scholar
  24. 24.
    Abelow BJ, Holford TR, Insogna KL. Cross-cultural association between dietary animal protein and hip fracture: a hypothesis. Calcif Tissue Int. 1992;50:14–8.PubMedCrossRefGoogle Scholar
  25. 25.
    Sebastian A, Frassetto LA, Sellmeyer DE, et al. Estimation of the net acid load of the diet of ancestral preagricultural Homo sapiens and their hominid ancestors. Am J Clin Nutr. 2002;76(6):1308–16.PubMedGoogle Scholar
  26. 26.
    Sellmeyer DE, Stone KL, Sebastian A, Cummings SR. A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women. Study of Osteoporotic Fractures Research Group. Am J Clin Nutr. 2001;73(1):118–22.PubMedGoogle Scholar
  27. 27.
    Dawson-Hughes B. Interaction of dietary calcium and protein in bone health in humans. J Nutr. 2003;133(3):852S–4S.PubMedGoogle Scholar
  28. 28.
    Bonjour JP. Protein intake and bone health. Int J Vitam Nutr Res. 2011;81(2–3):134–42.PubMedCrossRefGoogle Scholar
  29. 29.
    Lin PH, Ginty F, Appel LJ, et al. The DASH diet and sodium reduction improve markers of bone turnover and calcium metabolism in adults. J Nutr. 2003;133(10):3130–6.PubMedGoogle Scholar

Copyright information

© Springer-Verlag London 2013

Authors and Affiliations

  1. 1.Department of EndocrinologyJohn Hopkins University, School of MedicineBaltimoreUSA

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