In contrast, vegetables, beans, fruits, nuts, and seeds are rich sources of calcium and other important minerals, and do not promote the urinary excretion of calcium. A three cup serving of raw, chopped greens – like kale, bok choy, or collards – provides the same amount of calcium (or more) as one cup of whole milk. Only 32% of the calcium in the cup of cow’s milk can be absorbed by the human body compared to about 50% for many green vegetables.5
It's also important to keep in mind that the effect of nutrition on bone health is more complex than just getting adequate calcium. For example, vitamin K also supports bone health, and vitamin K is abundant in leafy greens.6 Of course, vitamin D also plays a critical role in regulating bone health. Vitamin D promotes the absorption of calcium in the intestine as well as the activity of bone building cells. Medical studies show vitamin D is more effective than calcium for treating osteoporosis.7 The most natural way to obtain vitamin D is through sun exposure, but because of indoor jobs, northern climates, and skin cancer risk it is virtually impossible for most to safely achieve optimal levels of Vitamin D from suns hine alone. Vitamin D supplementation is necessary for most people.
Most Americans take inadequate amounts of Vitamin D and excessive amounts of calcium. Approximately 50% of Americans are deficient in Vitamin D.8 For optimal bone protection, I advise having a blood 25(OH)D test, and then supplementing accordingly to keep Vitamin D levels in the range of 35-50 ng/ml.9,10 If you have not had yet your blood tested, 2000 IU is a reasonable daily dose to start.
Calcium should not be taken in excess, and I recommend limiting supplemental calcium to 400-600 mg. Most of your calcium should be derived from plant foods, not supplements. A recent meta-analysis of many studies has shown that low dose (500 mg) calcium supplementation combined with vitamin D was effective at preventing osteoporosis-related fractures whereas high dose (1000 mg) calcium supplementation was not.11,12,13 Overdosing on calcium actually deactivates the Vitamin D and can weaken bones. My Osteo-Sun formula is an excellent source of Vitamin D that provides the body with just the right dose of calcium and magnesium and all three in the proper ratio for optimal osteoporosis protection.
2Tsukahara N, Ezawa I. [Calcium intake and osteoporosis in many countries]. Clin Calcium. 2001 Feb;11(2):173-7.
3Vondracek SF, Hansen LB, McDermott MT. Osteoporosis risk in premenopausal women. Pharmacotherapy. 2009 Mar;29(3):305-17.
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4Feskanich D, Willett WC, Colditz GA. Calcium, vitamin D, milk consumption and hip fractures: a prospective study among postmenopausal women. Am J Clin Nutr 2003;77(2): 504-11.
5Weaver CM, Plawecki KL. Dietary calcium: adequacy of a vegetarian diet. Am J Clin Nutr 1994;59(suppl):1238S-1241S.
6Shea, MK, Booth SL, Update on the role of vitamin K in skeletal health. Nutrition Reviews, 2008. 66(10): p.549-57.
Iwamoto J, Sato Y,Takeda T, Matsumoto H. High-dose vitamin K supplementation reduces fracture incidence in postmenopausal women: a review of the lit erature. Nutr Res, 2009. 29(4): p. 221-8.
7Tilyard MW, Spears GF, Thomson J, Dovey S. Treatment of postmenopausal osteoporosis with calcitriol or calcium. N Engl J Med. 1992 Feb 6;326(6):357-62.
8University of California - Riverside (2010, July 19). More than half the world's population gets insufficient vitamin D, says biochemist. ScienceDaily. Retrieved February 17, 2011, from http://www.sciencedaily.com¬ /releases/2010/07/100715172042.htm
9Bischoff-Ferrari, H.A., Optimal serum 25-hydroxyvitamin D levels for multiple health outcomes. Adv Exp Med Biol, 2008. 624: p. 55-71.
10Bischoff-Ferrari HA, Giovannucci E, Willett WC, et al., Estimation of optimal serum concentrations of 25-hydroxyvitamin D for multiple health outcomes. Am J Clin Nutr, 2006. 84(1): p. 18-28.
11Bischoff-Ferrari HA, Willett WC. Comment on the IOM Vitamin D and Calcium Recommendations. Harvard School of Public Heal th: The Nutrition Source, 2010.
12Zoler ML. High Vitamin D Intake Linked to Reduced Fractures. Family Practice News, 2010(November 16, 2010).
13Bischoff-Ferrari HA, Orav EJ, Willett, WC, et al., A Higher Dose of Vitamin D is Required for Hip and Non-vertebral Fracture Prevention: A Pooled Participant-based Meta-analysis of 11 Double-blind RCTs, in The American Society for Bone and Mineral Research 2010 Annual Meeting2010: Toronto, Ontario, Canada.
