Nutritional Interventions in Osteoporosis

Susan J. Whiting, PhD; Hassanali Vatanparast, MD

Disclosures

Geriatrics and Aging. 2005;8(9):14-20. 

In This Article

Is the Emphasis on Calcium and Vitamin D Justified?

Calcium is the building block of bone. Alone it has a modest but positive effect on bone density in postmenopausal women.[7] The OSC Guidelines indicate that calcium is needed in greater amounts than the typical North American diet provides. Although dairy products and calcium-fortified fruit juice are available in the marketplace, many people do not consume much of these foods. To meet the recommendation for calcium of 1,500mg/d for an individual over 50 years old, one could suggest substitution of calcium-fortified foods for foods not fortified; however, the number of these foods (orange juice, grapefruit juice, and some milks and yogurts) in Canada is limited. Plant-based milk substitutes made from soy, rice, or potato may be fortified with calcium to contain amounts similar to cows' milk. Absorption of calcium is less (in the range of 70-90% of cows milk);[8] however, they are a viable alternative for persons unable or unwilling to consume cow's milk.

Adults over the age of 50 years should consider a supplement containing 500-600mg of elemental calcium. Much has been written on the differences or lack of difference between various calcium supplements. There is greater availability of calcium from calcium citrate compared to calcium carbonate; however, the latter is 80% of the former,[9] a value within the range defined for bioequivalency. Therefore, the choice of supplement may be best made on personal preference which can include cost and formulation (e.g., tablet vs. chewables).[10] Multivitamins do not supply enough calcium as calcium salts providing 500mg elemental calcium take up a lot of room, thus making the tablet impossible to swallow.

Vitamin D has not yet gained as much attention as calcium, but one may expect to see much interest in this nutrient. The OSC recommendations have been confirmed in a recent meta-analysis.[11] Further interest regarding vitamin D relates to its efficacy in reducing falls and, therefore, fractures.[11] In the presence of adequate sunlight, dietary intake of vitamin D is not required. However, when sun exposure is limited in winter or due to deliberate lack of sun exposure, food sources such as oily fishes and fortified foods such as fluid milk or margarine maintain serum levels of 25 hydroxy-vitamin D3, which is the circulating and storage form of vitamin D.[11,12] To ensure sufficient vitamin D intake for persons over 50 years old, a supplement is recommended; diet alone cannot provide the 800 IU/d (20µg/d) vitamin D recommended.[1]

Supplementation with both vitamin D and calcium to forestall postmenopausal and involutional osteoporosis in older frail, institutionalized adults has resulted in fewer hip fractures.[13] In contrast, two recent studies concluded that calcium and vitamin D were ineffective in secondary prevention of fractures.[14,15] They are, therefore, adjuncts to treatment.[1] However, with the promising research on the reduction of falls (and, therefore, fractures due to falls), with vitamin D therapy, this designation as adjunct is not intended to downplay the use of calcium and vitamin D.

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