Osteoporosis is a Western lifestyle disease that is characterised by brittle bones caused by pores within the bone matrix. This is thought to result from bone resorption and increased calcium excretion. Postmenopausal women are particularly at risk of developing osteoporosis. The development of osteoporosis increases the risk of fractures considerably, particularly of the lower arms and femur. The aetiology of osteoporosis is complex, but the observation that the risk of developing osteoporosis is considerably higher for those living in developed nations, as well as the observation that it takes decades to manifest has lead to speculation that it is caused by long term adherence to the typical Western diet. The traditional viewpoint is that low calcium intakes cause osteoporosis because calcium is required for correct bone health. However, administration of supplements to those with osteoporosis does not consistently prevent deterioration of the condition suggests that other factors are involved.
One factor that has been recently considered important in the development of osteoporosis is a shift in the acid-base balance of the blood. Diets high in protein and phosphorus containing foods such as meat and soft drinks result in the production of sulphuric and phosphoric acid, respectively. These acids can then dissociate in blood, a phenomenon that results in an increased hydrogen ion concentration, with a resultant acidification of the blood. Plant foods are high in potassium salts, and when these salts are metabolised they have an alkalinising effect, caused by an increased bicarbonate concentration in the blood. Therefore poor quality protein rich diets that are devoid of high intakes of plant foods do not adequately neutralise the acidity caused by normal metabolic processes. The low grade chronic acidification of blood may cause the resorption of bone and a loss of calcium in the urine, leading to osteoporosis.
If potassium salts from fruits and vegetables are beneficial at alkalinising blood, and acidified blood is a cause of calcium excretion, then it might be expected that supplements of potassium salts may be beneficial at alkalinizing the blood and preventing calcium excretion. Observations from studies investigating the effects or potassium salts suggest that this is the case. For example in one study1, researchers investigated the administration of potassium citrate supplements to women for 3 months and observed significant reductions in the acidity of urine. The reduction in urinary acid was accompanied by a reduction in markers for bone resorption such as deoxypyridinoline and hydroxyproline. These results suggest that potassium salts are effective at reducing bone resorption and the acidity of the blood. Based on these results it might be considered that the benefits of calcium in the diet may relate more to the alkalinizing effects of calcium salts rather than the presence of calcium per se.