Dr. Joel Fuhrman: Vegan Diet May Help Reduce Risk of Osteoporosis
This article was contributed by Dr. Joel Fuhrman. Dr. Fuhrman is a best-selling author, nutritional researcher and board certified family physician specializing in nutritional medicine. Learn more by visiting his informative website at DrFuhrman.com and his blog at Diseaseproof.com, and following Dr. Fuhrman on Facebook and Twitter.
About 10 million Americans already have osteoporosis, and 34 million are at risk.[i] Contrary to popular belief however, low intake of calcium is not the primary cause of osteoporosis. While Americans have the highest calcium intake in the world, we also have one of the highest hip fracture rates in the world.[ii] The standard American diet causes much of the consumed calcium to be lost in the urine. Salt, caffeine, sugar, and animal products (including dairy products) leach calcium out of bones and promote urinary calcium loss.[iii] The Nurses’ Health Study followed 72,337 women for over 18 years and found that dairy intake did not reduce the risk of osteoporosis-related hip fractures.[iv]
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.[v]
Calcium isn’t the only important nutrient for bone health
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, but not in dairy products.[vi] 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.[vii] The most natural way to obtain vitamin D is through sun exposure, but because of indoor jobs, our climate, and skin cancer risk it is virtually impossible to achieve optimal levels of Vitamin D from sunshine alone. Vitamin D supplementation is necessary.
How much calcium and Vitamin D are necessary to protect against osteoporosis?
Most Americans take inadequate amounts of Vitamin D and excessive amounts of calcium. Approximately 50% of Americans are deficient in Vitamin D. [viii] Reviews of studies indicate Vitamin D blood levels should be range between 36-48 ng/ml in order to achieve maximal benefits.[ix],[x] 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. If you have not had yet your blood tested, 2000 IU is a reasonable dose to supply your body with adequate Vitamin D.
Too much calcium may interfere with Vitamin D’s effects on bone health.
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[i]NOF. “Bone Health Basics.” National Osteoporosis Foundation. 2010. http://www.nof.org/aboutosteoporosis/bonebasics/whybonehealth (accessed February 2011).
[ii]Tsukahara N, Ezawa I. [Calcium intake and osteoporosis in many countries]. Clin Calcium. 2001 Feb;11(2):173-7.
[iii]Vondracek SF, Hansen LB, McDermott MT. Osteoporosis risk in premenopausal women. Pharmacotherapy. 2009 Mar;29(3):305-17.
Massey LK, Whiting SJ. Caffeine, urinary calcium, calcium metabolism and bone. J. Nutr. 1992 3 Sep;123 (9): 1611-14
Sellmeyer DE, Stone KL, Sebastian A, Cummings SR. A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women. Study of Osteoporotic Fractures Research Group. Am J Clin Nutr. 2001 Jan;73(1):118-22.
Teucher B, Fairweather-Tait S. Dietary sodium as a risk factor for osteoporosis: where is the evidence? Proc Nutr Soc. 2003;62(4):859-866.
Wynn E, Krieg MA, Lanham-New SA, et al. Postgraduate Symposium: Positive influence of nutritional alkalinity on bone health. Proc Nutr Soc. 2010 Feb;69(1):166-73.
[iv]Feskanich 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.
[v]Weaver CM, Plawecki KL. Dietary calcium: adequacy of a vegetarian diet. Am J Clin Nutr 1994;59(suppl):1238S-1241S.
[vi] Shea, 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 literature. Nutr Res, 2009. 29(4): p. 221-8.
[vii]Tilyard 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.
[viii]University 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
[ix]Bischoff-Ferrari, H.A., Optimal serum 25-hydroxyvitamin D levels for multiple health outcomes. Adv Exp Med Biol, 2008. 624: p. 55-71.
[x] Bischoff-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.