Putting the D in Density
With so much research, in 1993, FDA allowed for a health claim that calcium, plus a healthy diet and physical activity, may reduce osteoporosis. In January 2010, FDA allowed for a similar claim to be made of the combination of calcium and vitamin D, and many experts say calciums benefits cannot be separated from vitamin D. Calcium needs vitamin D to be absorbed into the body and incorporated into bone.
In 2010, The IOM increased the reference intakes (DRIs) of vitamin D saying most Americans under the age of 70 need 600 IU/d of vitamin D, while those older than 70 may need as much as 800 IU/d. The CRN called the report, a modest step in the right direction that fell short of truly capturing the extensive and positive research that has consistently supported the need for people to significantly raise their vitamin D levels. CRN said the committees modest increase of vitamin D DRI in the form of estimated average requirements (EARs) for adults and its doubling the tolerable upper intake level (UL) from 2,000 to 4,000 IU/d for adults still, lags behind the mountain of research demonstrating a need for vitamin D intake at levels possibly as high as 2,000 IU/d for adults, according to Andrew Shao, former senior vice president, scientific and regulatory affairs at CRN.
As Shao said, a 2010 study from University of Wisconsin, Madison, found daily intakes of at least 1,000 IU or more of vitamin D are required to achieve optimal vitamin D status.1 Researchers there also noted the risk of toxicity with high amounts of vitamin D intake is low.
The benefits of the vitamin D/calcium combo are much-proven for bone health. A 2010 study from Athens found dietary intervention with vitamin D and calcium via supplementation with fortified dairy products can have a favorable effect on arm, total spine and total body BMD compared to a control group.2 A review of 167 studies in 2007 determined more than 700 IU/d of vitamin D3 with calcium supplementation compared to placebo had a small beneficial effect on BMD, and reduced the risk of fractures and falls in individuals with osteoporosis.3 A Denmark study found a one-year intervention with calcium and vitamin D reduced bone turnover, significantly increased BMD in patients younger than 70 years, and decreased bone loss in older patients.4 Together, the nutrients reduced hip fractures and total fractures, and probably vertebral fractures, in both men and women of all ages whether they had previous fractures or not.5 However, researchers found vitamin D alone was not effective in preventing fractures.
Vitamin K also aids calcium in its bone-building task, as osteoblasts produce a vitamin K-dependent protein called osteocalcin, which helps remove calcium from the blood and bind it in the bone matrix. A 2008 Japanese study found vitamin K was strongly associated with a reduction in hip fracture in men and women; this association was stronger than magnesium, vitamin D and calcium alone.6 Vitamin K comes in two formsphylloquinone (K1), which comes from foods, such as green, leafy vegetables and green tea; and menaquinone (K2), which comes from bacteria in the gut. In postmenopausal women, high doses of both forms improved indices of bone strength in the femoral neck and reduced the incidence of clinical fractures, according to researchers who reviewed seven studies that lasted at least two years each.7 Vitamin K2 helped maintain bone strength in the neck and hip in postmenopausal women, whereas the women taking a placebo experienced a weakening of their bones,8 and 5 mg of vitamin K1 supplementation for two to four years may protect against fractures and cancers in postmenopausal women with osteopenia.9 However, evidence has shown vitamin K2 is more effective than K1 in preventing bone loss.10
Manufacturers may also want to combine vitamins K and D, as studies have shown they can prevent bone loss and increase bone fracture healing,11 and may be effective for sustaining BMD in early postmenopausal women.12
Dont discount B and C vitamins, as both vitamin C and B6 are needed to make collagen, which holds bone together. A 2008 USDA study found total vitamin C intake was positively associated with femoral neck BMD among male nonsmokers.13 And, in a 17-year follow up to Framingham Osteoporosis Study, subjects in the highest tertile of total vitamin C intake had significantly fewer hip fractures and non-vertebral fractures compared to subjects in the lowest tertile of intake.14 However, the researchers found dietary vitamin C intake was not associated with fracture risk, so supplements may be the solution. Previously, the Framingham Study found subjects with higher total or supplemental vitamin C intake had fewer hip fractures and non-vertebral fractures as compared to subjects with lower intakes.
Vitamins B12 and B6 were inversely associated with hip fracture risk in a 2008 study, which also found mean bone loss was inversely associated with vitamin B6.15
Mining for Bone Health
Magnesium is the fourth most abundant mineral in the body, and almost 50 percent of total body magnesium is found in bone. Magnesium helps calcium regulation, and magnesium deficiency has been shown to alter calcium metabolism and the hormones that regulate calcium, which can lead to a reduced BMD.16 Further, researchers at Tufts University in Boston found magnesium contributes to maintenance of BMD in elderly subjects.17 In postmenopausal women, oral magnesium supplementation suppressed bone turnover,18 and increased bone mass better than estrogen alone when combined with calcium and a multivitamin supplement.19 Iron combined with calcium also increases bone strength. Iron was associated with greater BMD at five sites (lumbar spine L2-L4, trochanter, femur neck, Ward's triangle and total body), and increasing levels of iron intake (greater than20 mg) were associated with greater BMD at several bone sites among women with a mean calcium intake of 800 to 1,200 mg/d in a University of Arizona study.20
Phosphorus and fluoride are also thought to play a role in bone mass development.21
References are on the next page...
References for "Bones: Vitamins and Minerals"
1. Binkley N, Ramamurthy R, Krueger D. Low vitamin D status: definition, prevalence, consequences, and correction. Endocrinol Metab Clin North Am. 2010 Jun;39(2):287-301
2. Moschonis G, et al. The effects of a 30-month dietary intervention on bone mineral density: the Postmenopausal Health Study. Br J Nutr. 2010 Jul;104(1):100-7. Epub 2010 Apr 7.
3. Cranney A, et al. Effectiveness and safety of vitamin D in relation to bone health. Evid Rep Technol Assess (Full Rep). 2007 Aug;(158):1-235.
4. Hitz MF, Jensen JE, Eskildsen PC. Bone mineral density and bone markers in patients with a recent low-energy fracture: effect of 1 y of treatment with calcium and vitamin D. Am J Clin Nutr. 2007 Jul;86(1):251-9.
5. Abrahamsen B, et al. Patient level pooled analysis of 68 500 patients from seven major vitamin D fracture trials in US and Europe. BMJ. 2010 Jan 12;340:b5463. doi: 10.1136/bmj.b5463.
6. Yaegashi Y, et al. Association of hip fracture incidence and intake of calcium, magnesium, vitamin D, and vitamin K. Eur J Epidemiol. 2008;23(3):219-25.
7. Iwamoto J, et al. High-dose vitamin K supplementation reduces fracture incidence in postmenopausal women: a review of the literature. Nutr Res. 2009 Apr;29(4):221-8.
8. Knapen MH, Schurgers LJ, Vermeer C. Vitamin K2 supplementation improves hip bone geometry and bone strength indices in postmenopausal women. Osteoporos Int. 2007 Jul;18(7):963-72.
9. Cheung AM, et al. Vitamin K supplementation in postmenopausal women with osteopenia (ECKO trial): a randomized controlled trial. PLoS Med. 2008 Oct 14;5(10):e196.
10. Yamaguchi M, et al. Effect of vitamin K2 (menaquinone-7) in fermented soybean (natto) on bone loss in ovariectomized rats. J Bone Miner Metab. 1999;17(1):23-9.
11. Gigante A, et al. Vitamin K and D association stimulates in vitro osteoblast differentiation of fracture site derived human mesenchymal stem cells. J Biol Regul Homeost Agents. 2008 Jan-Mar;22(1):35-44.
12. Yasui T, et al. Effect of vitamin K2 treatment on carboxylation of osteocalcin in early postmenopausal women. Gynecol Endocrinol. 2006 Aug;22(8):455-9.
13. Sahni S, et al. High vitamin C intake is associated with lower 4-year bone loss in elderly men. J Nutr. 2008 Oct;138(10):1931-8.
14. Sahni S, et al. Protective effect of total and supplemental vitamin C intake on the risk of hip fracture--a 17-year follow-up from the Framingham Osteoporosis Study. Osteoporos Int. 2009 Nov;20(11):1853-61.
15. McLean RR, et al. Plasma B vitamins, homocysteine, and their relation with bone loss and hip fracture in elderly men and women. J Clin Endocrinol Metab. 2008 Jun;93(6):2206-12.
16. Elisaf M, Milionis H, Siamopoulos KC. Hypomagnesemic hypokalemia and hypocalcemia: clinical and laboratory characteristics. Miner Electrolyte Metab. 1997;23(2):105-12.
17. Tucker KL, et al. Potassium, magnesium, and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women. Am J Clin Nutr. 1999 Apr;69(4):727-36.
18. Aydin H, et al. Short-term oral magnesium supplementation suppresses bone turnover in postmenopausal osteoporotic women. Biol Trace Elem Res. 2010 Feb;133(2):136-43.
19. Tranquilli AL et al. Calcium, phosphorus and magnesium intakes correlate with bone mineral content in postmenopausal women. Gynecol Endocrinol. 1994;8:55-8.
20. Harris MM, et al Dietary iron is associated with bone mineral density in healthy postmenopausal women. J Nutr. 2003 Nov;133(11):3598-602.
21. Vicente-Rodríguez G, et al. Independent and combined effect of nutrition and exercise on bone mass development. J Bone Miner Metab. 2008;26(5):416-24.