Fruits and vegetables serve as rich sources of alkaline potassium salts, however, modern diets now consist of greater levels of acid precursors from disproportionately higher protein and cereal grain intake and disproportionately lower fruit and vegetable intake.¹ For example, approximately 99% of Australian children, 97% of men and 95% of women do not consume the recommended daily serves of vegetables, and only around 30% of adults and 46% of children consume sufficient serves of fruit each day.² US National Surveys now highlight potassium as a nutrient of public health concern because fewer than 3% of US adults have potassium intakes greater than the daily adequate intake level of 4,700 mg.³

It has been proposed that suboptimal potassium intake contributes to a chronic, systemic state of low-grade metabolic acidosis. To maintain systemic pH homeostasis and mitigate the degree of acidosis, alkaline salts of calcium are liberated from the skeleton and calcium and phosphorus are lost permanently in the urine; actions which contribute to declines in bone density over time.^1,4

A randomized, double-blind, placebo-controlled trial of 83 women with postmenopausal osteopenia was carried out to investigate the effects of potassium citrate (K-Citrate) supplementation (40 mEq; equiv. 1564 mg daily) on bone resorption and formation.⁵ Levels of bone turnover markers, specifically urinary N-telopeptide of collagen type I (u-NTX), amino-terminal propeptide of type I procollagen (P1NP) bone specific alkaline phosphatase (BSAP) and osteocalcin (OC) were compared. Changes in bone mineral density (BMD) were also examined. At the end of the 12 month trial period, K-Citrate decreased both u-NTX (p=0.005) and serum P1NP (p<0.001) starting at month 1 and continuing through month 12. No significant change was seen in BSAP or OC. No significant change was seen in lumbar or hip BMD between the two groups. The authors concluded that for women with postmenopausal osteopenia, K-Citrate may serve as a potential treatment for bone loss that is well tolerated without any significant known long term consequences.

A randomised, double-blind, placebo-controlled trial evaluated K-Citrate supplementation (60 mEq; equiv. 2400 mg/day) on fracture risk in healthy elderly persons without osteoporosis (n=201; > 65 years). At the end of the 24 month trial period, treatment with K-Citrate resulted in a significant increase in areal BMD at lumbar spine (p<0.001) and volumetric BMD at several sites tested (p<0.05), improved bone microarchitecture, and significantly diminished fracture prediction score in both sexes.⁶ 

A meta-analysis of the effect of alkaline potassium salts on calcium and bone metabolism provides compelling evidence for a calcium- and bone-sparing effect of these salts. The results strongly favour evidence for a reduction in bone resorption following supplementation with potassium bicarbonate or potassium citrate, as well as a reduction in calcium and net acid excretion; a finding that has the potential to translate into preventative measures for osteoporosis.⁷

These findings highlight the need for practitioners to consider the beneficial role of potassium in supporting bone health, particularly in those patients with suboptimal dietary intake. Practitioners should consider the following treatment approaches:

• Recommend that patients supplement with potassium. The minimum level of potassium intake to prevent potassium deficiency in adults has been estimated to be 2.35 g/day (from a combination of diet and supplementation).⁸
• Educate patients in the importance of consuming potassium-rich foods such as fruit and vegetables (e.g. bananas, oranges, grapefruit, pineapples, apples, tomatoes, apricots, avocadoes, potatoes, spinach, and sweet potato), beans, wholegrains, nuts, parsley, and blackstrap molasses.
• Also consider other factors such as Vitamin K2, Calcium, Vitamin D3, and key cofactors including Magnesium, Manganese, Zinc and Boron to promote bone health where diet may be lacking.

 

References

1. Moseley, K.F., et al., Potassium citrate supplementation results in sustained improvement in calcium balance in older men and women. J Bone Miner Res, 2013. 28(3): p. 497-504.
2. AIHW, Australia's Health 2018. AIHW: Canberra.
3. Bailey, R.L., et al., Estimating Sodium and Potassium Intakes and Their Ratio in the American Diet: Data from the 2011-2012 NHANES. J Nutr, 2016.
4. Lemann, J., Jr., D.A. Bushinsky, and L.L. Hamm, Bone buffering of acid and base in humans. Am J Physiol Renal Physiol, 2003. 285(5): p. F811-32.
5. Gregory, N.S., et al., Potassium citrate decreases bone resorption in postmenopausal women with osteopenia: A randomized double blind clinical trial. Endocr Pract, 2015. 21(12): p. 1380-6.
6. Jehle, S., H.N. Hulter, and R. Krapf, Effect of potassium citrate on bone density, microarchitecture, and fracture risk in healthy older adults without osteoporosis: a randomized controlled trial. J Clin Endocrinol Metab, 2013. 98(1): p. 207-17.
7. Lambert, H., et al., The effect of supplementation with alkaline potassium salts on bone metabolism: a meta-analysis. Osteoporos Int, 2015. 26(4): p. 1311-8.
8. Gaby, A., Nutritional Medicine. 2nd ed. 2017, Concord, NH: Fritz Perlberg Publishing.