Potassium and Acid/Base Balance for Bone Health

Potassium is the third most abundant mineral in the body. It is a critical nutrient in the body, playing a main role in cell to cell communication. Potassium is also critical for plant growth, being one of the key nutrients used in even the most basic of fertilization programs. Potassium accumulates in plant cells, making fruits and vegetables a good dietary source.

Several studies suggest that potassium citrate combined with calcium and vitamin D may support healthy bone. In a randomized, double-blind placebo controlled trial involving 201 elderly healthy men and women, 60 mEq (2,345 mg) of potassium citrate daily increased bone mineral density at the lumbar spine by 1.7 after 24 months.  These effects are believed to be due to the alkalinizing effect of potassium citrate (potassium chloride does not have the same effect).  Potassium citrate reduces dietary acidity, helping to facilitate calcium absorption and decrease urinary calcium loss.

Bone is a dynamic tissue that is constantly being reshaped by osteoblasts, bone-building cells that are responsible for laying down protein and minerals that make up the bone matrix, and osteoclasts, which break down older tissue critical for maintenance and repair.  An acidic environment inhibits osteoblast function and increases osteoclast activity skewing the bone remodeling process towards breakdown, while an alkaline environment stimulates bone-building and lessens bone breakdown.  

Fruits and vegetables provide potassium and promote an alkaline environment to support healthy bone, while animal protein and grains generate metabolic acids. The breakdown of amino acids and phosphate generates hydrogen ions (increasing acidity), while the breakdown of citrate produces bicarbonate (increasing alkalinity). Research suggests that a normal Western diet generates approximately 1 mEq of acid per day. This metabolic acid load requires neutralization by bicarbonate ions and mineral ions from bone. Metabolic acidosis has been associated with increased calcium excretion believed to be from the bone tissue.

Choosing a diet rich in potassium-rich fruits and vegetables and supplementing with 200-1,200 (5 mEq-30 mEq) potassium citrate can promote an alkaline environment to support healthy bone. However, it is not advised to supplement with larger amounts of potassium citrate. Large doses of potassium can cause diarrhea, and high levels of potassium in the blood can cause potentially fatal cardiac arrhythmia.

Other nutrients that are important for bone health include calcium, vitamin D, magnesium, vitamin K and trace minerals. 

References

1. Jehle S, Hulter HN, Krapf R. 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 Jan;98(1):207-17.
2. Bushinsky DA. Acid-base imbalance and the skeleton. Eur J Nutr. 2001; 40:238–244.
3. Kurtz I, Maher T, Hulter HN, Schambelan M, Sebastian A. Effect of diet on plasma acid-base composition in normal humans. Kidney Int. 1983 Nov;24(5):670-80.
4. Sebastian A, Harris ST, Ottaway JH, Todd KM, Morris RC Jr. Improved mineral balance and skeletal metabolism in postmenopausal women treated with potassium bicarbonate. N Engl J Med. 1994 Jun 23;330(25):1776-81.
5. Jehle S, Zanetti A, Muser J, Hulter HN, Krapf R. Partial neutralization of the acidogenic Western diet with potassium citrate increases bone mass in postmenopausal women with osteopenia . J Am Soc Nephrol. 2006 Nov;17(11):3213-22.
6. 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 Jun;90(6):3528-33.