While calcium and vitamin D have garnered most of the attention when it comes to bone health, we should note the importance of fruits and vegetables in building strong bones. The typical American diet that is low in fruits and vegetables and higher in sodium, animal protein, and refined grains can lead to an acid-base imbalance by increasing the acid load of the body. More bone loss occurs in this acidic state. A plant based diet increases the alkalinity of the body and leads to less calcium excretion. Alkalinizing foods include vegetables, especially leafy greens, fruits, nuts and seeds. Even though citrus fruits such as lemons, limes, oranges and grapefruits are acidic, they are alkalinizing after they are consumed and metabolized.
A 2009 study published in the Journal of Clinical Endocrinology found that adding an alkaline salt (potassium bicarbonate) promoted calcium absorption, even when consuming a high protein diet. Potassium rich foods provide a natural source of bicarbonates which can help buffer acidic pH levels. The potassium-rich DASH diet is high in fruits, vegetables, low fat dairy and has a low acid load. It is typically encouraged to lower high blood pressure, but it has also been shown to significantly reduce bone turnover which over time may increase bone mineral density and reduce the risk of osteoporosis. ( J. Nutr. October 1, 2003 vol. 133 no. 10 3130-3136)
A 2003 study in the November issue of The Journal of Nutrition found fennel, celery root, prunes, oranges, French beans, mushrooms and red wine residue to significantly protect against the breakdown of bone tissue when compared to other items such as soy, corn, potatoes, tomatoes and spinach. The compound hesperidin, a flavonoid found in citrus, has also been shown to reduce the number of cells that break down bone.